ENGINE vs CHASSIS DYNO

[@CharmleysChopShop]

Thank you for saying what all of us with no voice are thinking.

[@eddamoo]

Amazing video and myth-busted 99% of dyno operators that dont understand basic physics. Thank you! So your WHP results are 82.7% and 82.3% respectively, meaning that 95BHP uplift (and higher RPM) only resulted in a 0.4% increase in losses. That is probably entirely caused by the higher RPM peak.

[@ttank1994]

Sorry Richard, but I got a bone to pick with you on your math and driveline loss explanation... Original LS2 = 394 RWHP and 476 HP at the crank. Drive line loss is calculated as follows: 476-394 = 82 hp loss now divide that with what you started with because you are calculating loss: 82/476 = 17.22% drive line loss. After Mods LS2: 461 RWHP and 560 HP at the crank. 560-461 = 99 99/560 = 17.68 % drive line loss. In summary: Stock LS2: 476-394 = 82 82/476 = 17.22% mod LS2: 560-461 = 99 99/560 = 17.68% The small increase in percentage between the two scenarios can probably be attributed to increased friction from the differential and transmission. and increased inertial losses because you are literally accelerating everything in the drivetrain quicker with more power. your loss of 82 hp when stock and 99 HP when modded proves a set driveline loss in a certain amount of HP is wrong. That honda engine could easily spin the drivetrain on the monster truck you spoke of. And give me a gear reduction on the input shaft and I could spin that drivetrain with a 5 HP Briggs.

[@jasongass1829]

I agree with your math. I think manuals fit the fixed percentage but not automatics. Overdrive automatics seem so soak up about 100hp on a 250hp engine or a 450hp engine. Huge difference in percentage.

[@ttank1994]

@@jasongass1829 autos get a bit more fuzzy especially if you got a loose converter and your not locked up. Then a chassis Dyno is a heart breaker until you hit the track

[@MrPureAnger]

Yea, if anything this video showed more evidence that it actually is percentage driveline loss, in the case of this setup around 17.5% but it is interesting that the loss percentage grew with power, of course that only gives more support to it not being a fix number loss. Would definitely be interesting to boost the motor and see the percentage loss at 800hp or higher, at this rate it seems like it would grow to over 20% if that was consistent.

[@patlandymore7035]

Awesome test Richard, you’re the man!! I’ll include myself with the others who have asked about other dyno tests you may have done showing how to reduce frictional drivetrain losses. Thinking Lubes, different tires, auto trans vs manual etc. The other category I’d like to see explored is inertial drivetrain losses. Heavy vs light wheels/tires, TH-400 vs Powerglide, aluminum driveshaft etc etc. You get the idea. To show folks how it’s not just about building engines to win races, it’s the complete vehicle.

[@richardholdener1727]

tire size and weight, drive shaft weight (alum or carbon fiber), light flywheels (I have a test on that), etc...

[@bernie232]

@@richardholdener1727 will these topics come up in future videos?

[@patlandymore7035]

Will be really cool to see those results sometime!

[@MPbdy]

My car definitely runs harder after putting a carbon BC2 clutch vs a monster LT1-S twin. Took 20 pounds off the crank.

[@lucysmith4242]

I would also like to see auto non locked vs auto locked vs manual

[@lloydholt6511]

Great video. Keep making them. You make a lot of people think. That’s a good thing! Kind of takes the bs out of a lot of generalized statements people are want to make. That’s what I love about your videos. They are informative, educational and thought provoking.

[@patrickmontgomery6353]

I can't get over how many times you've had to just explain at the start of a video about your hp numbers vs factory hp numbers and why they're different. This is excellent information. All people have to do is listen. Thanks Richard, and don't ever stop being you. I saw you on fastest car also...

[@richardholdener1727]

that was fun with Chad

[@the496elcamino]

I love these explanations, you clear up the misconceptions. I Never get tired of learning something.

[@cannonroberts5129]

Nice explanation. Only about half of my mustang chassis dyno customers would understand 25% of what you said. It’s all about repeatability of the dyno!

[@dmc5681]

With the LS2 the drivetrain losses "stock" were 82/475 = 17.2%, modified 99/560 = 17.7% which is fairly close to a constant %. similary with the torque 56/465 = 12.0%, modified 66/494 = 13.4% a bit more variation. But it seems more % based than fixed...

[@evillancer4580]

it's varying with rpm, the torque figure is at a lower rpm.

[@lucysmith4242]

Evil lancer to build off this dude. Rotational and friction losses increase with RPM. So if he made peak numbers at 1 RPM and peak numbers at a different RPM the rotational losses would be different. And we're also ignoring friction. Would be nice to see him compare two points at the same RPM

[@evillancer4580]

@@lucysmith4242 i took a few points from the graphs, 4k, 5k and 6k. the power loss percentage rose with rpm but 'torque' losses were pretty constant.

[@ChurchAutoTest]

Good piece. I generally agree with much of what has been said (losses from engine dyno to chassis dyno are actually a multivariate equation that is not a simple percentage). However, I would like to point out that any chassis dyno that uses inertia as its primary loading tool and does not control sweep time will introduce one additional variable in the loss equation - namely the inertial losses of the drivetrain mass. On a dynojet, for example, a 300 whp car will accelerate through its rpm range in time X. Increase that power to 400 whp and it's probably going to take somewhere on the order of 10% less time to complete that sweep. That means you area accelerating the driveline, from the flywheel back, 10% faster which increases the amount of energy you're losing before it reaches the rollers. So in addition to the frictional loss changes with increasing power, you have to consider inertial loss changes too. Unless you're running fixed sweep time on a load controlled dyno, then you're good - even if that may not be the best way to tune the engine ;)

[@richardholdener1727]

agreed-we control the rate on the engine dyno, don't on an inertia dyno but can on the Superflow chassis dyno, lots of stuff here

[@MPbdy]

I’m missing something here. 461/560 = 17.7% loss. 476/395 = 17% loss. If anything driveline losses increased marginally?

[@69JANKS]

dankmac Yes lol 🤦🏻‍♂️

[@aussiejonno]

He said that dopey

[@MPbdy]

I guess I need to rewatch everything I heard he was saying a driveline took predominantly a fixed amount of power to turn and while each car is different it is not a fixed percentage of loss.

[@ho6b9s]

I'm with you... this test and data suggests that drivetrain loss is indeed a scaled percentage, counter to most of the video. The conclusion we were set up for was that we expected the 82hp loss observed before modification would show up again after modification. The final chassis dyno instead showed a 100hp loss, right inline with the percentage loss (again, counter to the video's claims). It is worth noting that it's possible we're missing some data -- was the final chassis dyno at similar conditions to the dyno before? Maybe it was a hotter day? Maybe there was some other difference that could account for that 20hp disparity.

[@aussiejonno]

@@MPbdy exactly but your wondering why you have further percentage of loss, you've answered your own question

[@opieg7333]

But, But! 15%.... lol.... you are not making this easy Richard... personally I love that. Glad someone long ago sat me down and explained that the dyno is a comparative analysis tool and the "number" isn't something to worry about or chase. That advise has saved me a lot of money. This video should be mandatory watching before viewing any "dyno run - we made XXXXXhp" videos on KZbin.

[@cajunroadwarrior]

Explains why manufacturers love front wheel drive so much. You get less power loss since the transaxle has everything so compact vs RWD has transmission, driveshaft, and axle. This is a really cool video.

[@hoonaticbloggs5402]

They love fwd because the consumer likes fwd. more cabin space.

[@beartodrift5345]

Awesome explanation, I thought I was conservative with chassis vs engine but you brought up some great points. I love the fixed loss for drivetrain vs %

[@canadianmarauder1923]

Excellent video Richard.

[@CraigWeaverAuto]

This is one I’ve been waiting for. Nice work!

[@brendan1675]

Great Video, would be interested in seeing more drivetrain mod videos and their effects on the dyno.

[@loki91t]

I calculated based on your peak numbers on the 240 for in chassis and on engine dyno to be 14.2% loss plus 14.37 fixed hp loss. Calculating whp from 476 engine hp - 14.2% and then - 14.37 gives 394whp. Conversely adding 14.37 to 394 and then dividing that result by (1-.142) gives 475.9hp. [edit] Applying the same logic to your van after watching the video where you made those modifications (155whp stock vs 225hp engine stock and 252whp “modified” in chassis vs. 354 engine hp at the same state of modification on dyno) I calculated your variable loss in the van was 24.8% and 14.186 hp fixed loss. Calculating whp from engine hp or vice versa in that case gives 0% error both stock and modified.

[@loki91t]

On the 240 with modification using the 14.2% variable and 14.37 fixed hp loss: using the whp input of 461 the calculated engine hp is 554. 1.07% error vs. your 560 measured. Using the 560 engine dyno number to calculate whp comes up with 466whp - 1.1% error versus your measured values. I would like to note, however, that your rpm points for peak power on the modified engine changed more significantly between engine dyno and chassis dyno than they did before modifications, so that may account for the greater error.

[@DJDinaggio]

The stock LS2 made 394/409 on the chassis dyno and 476/465 on the engine dyno. That's a 17.2% drivetrain loss at peak HP and a 12.0% loss at peak TQ. The modified LS2 made 461/428 on the chassis dyno and 560/494 on the engine dyno. That's a 17.7% drivetrain loss at peak HP and a 13.4% loss at peak TQ. This shows that even if you add more power to any given vehicle, the percentage drivetrain loss essentially remains the same at any given engine rpm. However the drivetrain loss percentage isn't fixed across the rpm range so you can't use the same loss percentage to guesstimate crank HP/TQ from RWHP/RWTQ.

[@richardholdener1727]

yes I think i proved that I am wrong

[@johnterpack3940]

@@richardholdener1727 As another commenter pointed out, the problem lies in the type of chassis dyno used. There's no way to distinguish between drivetrain losses and the losses from accelerating the dyno. A more powerful engine will accelerate the dyno faster, which uses more power. You were absolutely right, bolting 100 HP of nitrous to an engine will not magically raise the drivetrain resistance. It can't, that's just not how machinery works. It will always take X power to spin a given gearbox at a give speed, regardless how much power is actually available. But the power required to accelerate a flywheel, like the roller of a chassis dyno, absolutely depends on the rate of acceleration... which can increase with available power.

[@woods-garage]

Nice video, thanks. It makes sense that a given drivetrain has a fixed loss through it, so percentage loss changes with horsepower output. Never thought of it this way. 👍

[@lucysmith4242]

Hey Richard, I'm a bit late to the comment party, but I busted out some equations and you're correct. Certain components have parasitic loss that are only dependent on rotational inertia and angular acceleration. So a drive shaft at 5,000 rpm saps the same power despite the torque output the engine is making at that given rpm. Frictional losses usually scale with heat, and RPM. So this too would be solely dependent on engine RPM. The science and math behind a torque converter is a different ball game though 😳 P = ((Engine Torque - Drivetrain)(RPM))/(Power Constant) Drivetrain Losses (rotational only) = inertia * angular acceleration Example: Given 100KW engine @ 5000 RPM with power constant of 9565 100 = ((net torque)(5,000))/(9565) Bet torque = 190.845 N bet torque by components: This is a fictional car with fictional drivetrain so numbers are used for an example. These numbers will indicate engine torque and rotational inertia and angular acceleration of drivetrain components. Engine Torque = 220 N m Drivetrain Losses = 29.155 N m Drivetrain Losses = inertia * alpha ^ we can see drivetrain Losses due to rotational inertia times angular acceleration are independent of engine torque. They do scale with rpm Putting it together: 100Kw = ((220 - 29.155)(5,000)/9565 Without drivetrain loss: 115Kw ~ 15% drivetrain loss Now 1000Kw motor: 1000Kw = ((1942.155 - 29.155)(5,000)/9565 Without drivetrain loss: 1015.24Kw ~ 1.524% drivetrain loss Power loss due to rotating components increases with the inertia of the components and the RPM. These equations ignore friction and are for a locked converter or clutch.

[@richardholdener1727]

thnx -hope you didn't do too much math

[@AlexLTDLX]

As several have mentioned, torque converters make a HUGE difference in chassis dyno numbers. Particularly with transmissions like a powerglide. That loss can be looked at as a percentage, because slip increases as power increases. Also, chassis dyno converter slip is almost always different than slip at the track - I've seen both more slip and less slip vs slip on a dragstrip depending on the dyno. 550 rwhp through a glide is comparable to 650-700 rwhp through a manual. In fact, 550 rwhp through a glide is enough to run high 9's at 140+ mph at 3,500 lbs. 550 rwhp through a manual at 3,500 lbs might get you in the high 10's if you're a great driver.

[@Raymonkey77]

Last questions on this one, a simple mod of removing the cats and something like a cold air intake, how much can a stock ECU adjust to the modification? Say on a 99 Ford v6 duratec 3.0 for example. Im a little intimidated to add ring gap and a single turbo for boost. Can the stock ECU with mustang GT injectors adjust to the mods over time? Same with either adding compression by removing head or deck? Factory rated at 200. Know that power mods tend to kill the stock transmission. Would add extra trans coolant and oil catch can. Would also replace the stock water pump and go with deans waterless coolant.

[@richardholdener1727]

it does not self adjust well at WOT-it needs to be tuned

[@Val_Killmore]

I've been telling this to old guys in the auto world for years and its finally nice to be vindicated. Great work Richard!

[@jimkillen1065]

Not sure but i heard they added a lock up to the power glide i some of the high hp . There is now convertor that can be unbolted to chage stator. Seems like Neil Chance and Georend brothers

[@jimmy_olds]

How does gearing affect the chassis dyno numbers? For instance running a the car with 3.00 gears and swapping them for 4.56’s? Or maybe even easier, if the trans is a TH350, 2nd gear vs 3rd gear

[@gcelectricalandairconditio4999]

from my experience there the power figure usually doesn't move much as the dyno calculates it, however the torque number usually is higher or lower depending on the gearing

[@richardholdener1727]

running in different gears changes the power you see at the wheels, so do rear end gears

[@jimmy_olds]

Richard Holdener it’d be interesting to see the differences gearing would make. Good stuff

[@AB-80X]

Such a great video Richard. Thank you.

[@notme8121]

Great video but what I would like to know is since even a drivetrain with an overdrive transmission is still under driven at the rear-end what happens if I for example run a test with 342 gears then change to 456 gears. Isn't my power going to increase dramatically on the chassis Dyno?

[@francfurian8215]

So good Richard, makes sense. It will stop a lot arguments around hp numbers. Cheers😊

[@slopoke22]

When I was at SAMTech. We had a 915 hp n/a 400 inch Windsor with Glidden heads for a hot street nmra car. We put in car and on dyno and it made 660 hp. Through auto. Ran 8.50s. It was a high winder, 9800 rpm. We also had a record holder camaro, 433" and 1033hp that didn't lose quite as much, it was a Jericho. It went 8.0x -8.2

[@bcbloc02]

Also I bet those losses for the big drivetrain are much greater on an inertia style chassis dyno than they are on a load style chassis dyno. Another thing about factory hp numbers is as far as I know they are all measured at steady state versus swept. I believe swept numbers like you generate tend to also trend higher than factory because you can avoid a lot of heat soak that robs power when doing sustained loads.

[@lukemorgan3368]

He’s at it again!! Good stuff!! 👍🏻😬

[@peterchown1552]

Awesome video with easy to understand calculations, now Richard where is the truth on the factory muscle car big blocks, something similar to the greatly interesting small blocks from back in the day.

[@UnityMotorSportsGarage]

Don't forget the effects of high stall Converters and the effects of power loss.... They eat up a ton! My 600hp 393w makes 420rwhp!

[@SealofPerfection]

Yeah, that's just what I was thinking, that's just the difference between the auto and a stick. Not to mention the bigger rear end in that old van as well, heavier rotating stuff sucks up more power.

[@slopoke22]

When I was at SAMTech. We had a 915 hp n/a 400 inch Windsor with Glidden heads for a hot street nmra car. We put in car and on dyno and it made 660 hp. Through auto. Ran 8.50s

[@williamsands647]

If you do the settings on speed versus HP though you'll have a huge area under the curve because you get into the powerband so quick.

[@KingJT80]

And even that changes with a lockup stall converter

[@SweatyFatGuy]

Something you are missing about torque converters is torque multiplication. A converter can more than double the torque at the crank, it does this with the stator design, but it only happens near stall speed. Once it becomes 'locked' meaning the impeller and turbine are both going the same speed (stall speed) the effect of the stator diminishes rapidly. But you can have 500ftlbs at the crank and with the right converter design have more than 1000ftlbs going into the input shaft. This is the reason automatics are faster than manual cars, it is not the speed at which you can shift, Ronnie Sox made a manual sound like an auto, but an auto with the right stall is always faster than a manual once you get above a certain power threshold. If you drive around in low powered low torque vehicles, the manual will be faster. Once you are far enough over the drive line loss of the auto, and the torque multiplication comes into the mix, the manual version is going to feel faster because it can be more violent, but will be slower than the auto. e.g a Honda is faster with a manual because its not making enough torque anywhere to make up the difference in driveline losses, whereas a 455 BOP or 454 is going to be making enough power that the auto will be faster. Even the auto LS1 4th gen F bodys were faster than the manuals, all because of the torque multiplication, but the manual felt 'faster' because it can be shifted violently. With small Fords that are low on torque, its a tossup. One might do better than the other. When it comes to chassis dyno, you can see the converter flash multiplication if you start the test below stall speed. The torque will spike then gradually fall off then make the same curve you see on a engine dyno after a certain rpm. It varies greatly by what the combination is. You also get slippage with more stall, unless its a lock up converter with a clutch in it. The manual has a lot less slippage, but no torque multiplication, and the parts are usually lighter, but you are still spinning the counter shaft and all the other gears when in the 1:1 gear. As for weight, a 9" converter and internal parts of an auto is a lot lighter than your average flywheel, clutch, pressure plate, and everything that has to spin inside a manual. A stock 13" converter is kinda heavy, but only us crazy 455 Pontiac guys race with them. Not only how much power you have, but where it makes it matters. Over 300hp/350tq the auto is probably going to be faster with less final drive gear, due to how a converter works.

[@Bige4u]

From the past 20 yrs or so, hot rodders and machine shops i used to hang with would have the average 80hp loss through the driveline.... fast forward to today, seems spot on.

[@wesgates5632]

My dynocom chassis dyno has a drive loss function that calculates the number based on the decel of the roller. I assume the one at Westech has a similar thing?

[@deanstevenson6527]

Wes Gates : Coastdown drag function. Yes, but its not often used. Its how the US Federal Motor Vehicle Emission cycle road loads are added. See See “Fordsix.com/search.php?keywords=DRIVETRAIN+LOSSES&terms=all&author=xctasy&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search” fordsix.com/viewtopic.php?f=5&t=6711&p=46683&hilit=drive+train+losses#p46683

[@timtaylor6147]

Just a note about ring gap. Even NA combos at high power need extra too. Power is heat and heat is the factor that you need to gap for

[@baby-sharkgto4902]

Awesome facts, Richard

[@nitrusmr2]

Hey Richard I love your videos. I have a Chassis dyno (older Dynojet 248) but not engine dyno, so your experience here is very helpful. You said the drivetrain loss was not a percentage, but more of a fixed number. Your example of the upgraded LS 240 speaks to the opposite. 394/476 = 82.7% and 461/560 = 82.3% Those numbers are damn close to a fixed percentage. My guess/theory is that the drivetrain loss as a fixed amount stays they same, but because the more powerful dyno pull takes less time the required horsepower is more. After all isn’t horsepower work divided by time? We’re doing the same work (drivetrain loss) in less time so that’s more power lost. Let me know in the comments. (Hah)

[@hotrodray6802]

IME The pulls are usually made at a 300 rpm per second increase and the dyno automatically increases the load to maintain that rate. JME 😁

[@duramax78]

Best channel on KZbin.

[@B0RN2RACE100]

Richard “Rick Sanchez” Holdener to everyone guesstimating crank HP by chasis Dynos: “you’re all wrong and I can prove it mathematically”

[@deanstevenson6527]

Alejandro Gomez :"And He Is Right". See www.hotrod.com/articles/1003phr-1975-chevrolet-laguna-torque-converter/ for variable hp loss on the chassis dyno verses a proper 560 hp gross on the engine dyno. WPC have done an Imperial Ton of back to back dyno comparisons. RH has just sumarised a generality. Response or reaction dyno testing has higher levels of inaccruacy compared to Direct Measurement. A chassis dynomometer keeps mom about the figures. A Superflow engine dyno in a direct reading dyno cell is as good a reading device as the trap speed at a drag strip, but it does hp and torque at every rpm fron start to finish. On a chassis dyno, everything is an attenuated reading.

[@Dayandcounting]

@@deanstevenson6527 He's not correct. The 240 test showed that power train loss stayed around 17% with a slight increase from more friction, it was not a fix number it was a fixed percentage. 394C/476E is 82.7% Drive train loss is 17.3% or 82hp. 461C/560E 82.3% or 96hp drive train loss is 17.7%. If it stayed close to the same it you should have seen the power train loss percentage drop to around 14.7% or 82hp with the more powerful build. If he boosted the engine to 700hp the whp in that car would be around 575 with power train soaking up about 125hp. The power losses are variable because they are result of acceleration of inertial mass and friction. It takes more work to spin a given mass up faster and the dyno is measuring that rate of change. Now the part about the chassis and engine for measuring change is relative and correct

[@deanstevenson6527]

@@Dayandcounting I agree with you on tour summary. Its what I have found from my study as a 9 year old to my 51 years now. This was discussed at length by Roger Huntington and Hale and specifically by Vizard in the Third revision of the A series Mini book. The loss factors are indeed percentage and fixed, but counterweight, tire losses and heat consumption from axle and gearbox have a variety of sub factors. Some times the semantics of the words get in the way of a valid, terse and true eveywhere description. I cut Mr RH some slack since he supplies the information that proves he made a descriptive "mistake".

[@badazz28]

I agree with your premise that drivetrain loss could be relatively static, but the example at the end seemed to contradict it. Having an 80ish hp drop before mods, I was expecting 85ish after, but it went down 100, keeping that 17% figure in tact.

[@Raymonkey77]

To delete the factory cat, have you heard of moving the O2 sensor towards the rear of the car to move the sensor out of the flame front that can help correct the reading without having to add a chip to correct the data to the factory ECU?

[@richardholdener1727]

THE FLAME FRONT?

[@Raymonkey77]

@@richardholdener1727the burning fuel in the exhaust that enters the cat. Wouldn't an o2 sensor be exposed to a flame instead of just hot exhaust gas without the cat?

[@averyalexander2303]

Great information, thanks! One thing you overlooked about drivetrain losses being fixed though is that if the vehicle has an automatic transmission the torque converter slippage will increase when pushing more power through it, effectively increasing the losses through it. If the torque converter is locked this doesn't apply though.

[@minigpracing3068]

What if you took the power unit from a transmission dyno and installed it in a chassis on a chassis dyno. Then you should be able to measure the actual losses for the drive line.

[@cc23001]

Love it! This test actually proves there's an increase in drivetrain loss as power increases. More data analysis would reveal a % loss/hp increase. I'd love to see these drivetrains exposed to bigger increases in power then compare the RATE of loss! %/100 hp if you have "blank" drivetrain is the truth as far as I can see

[@indianracers3644]

I noticed the same thing meaning increase in the loss going to the chassis Dino however I am guessing since it’s nearly impossible to duplicate the intake exhaust and assessory configuration on the chassis Dino compared to the engine Dyno there’s some additional losses intake +exhaust +accessory on the chassis Dyno. Great test/video!!

[@kevmay21]

I agree I would expect the drivetrain losses to be relatively fixed but doesn't the LS comparison at the end of the video support the percentage theory. As you said the relative increases in HP from Engine to chassis remained roughly the same as you upgraded the engine. Wouldn't we expect the percentage gain to be greater on the chassis dyno because power increased but frictional losses in the drivetrain remain relatively fixed? If I take 394/475 I end up with 17.23% drivetrain loss. If I take 461/560 I get 17.68% drivetrain loss. It shows power loss increased from 82hp to 99HP

[@Calvin-Nelson]

While I agree that some components in the drivetrain will have fixed losses with power, the test you just showed us proves otherwise. The A test for the LS engine had 18% drivetrain loss (82hp). The B test had 18% drivetrain loss (99hp). If what you are claiming is true, we should see the same 82 hp drivetrain loss on both tests, but we don't. What am I missing? I would think a torque converter would very much not be a fixed loss. More power you apply to a torque converter, the more loss it has. I've seen that first hand.

[@NBSV1]

The percentages generally stay the same. So, yes. If you put more power through it it looses more power in the drivetrain.

[@Calvin-Nelson]

@@NBSV1 That is not what Richard claimed in the video.

[@richardholdener1727]

I think I proved i was wrong

[@Calvin-Nelson]

@@richardholdener1727 Oh... Not the answer I was expecting. Lol...

[@erwinnijs1]

There are other things you have to factor in too. The type of dyno has an impact. With inertia dynos you have to factor in the moment of inertia of the drivetrain since they don't have a constant sweep rate. Faster acceleration means more power loss. Then there is tire slip. The more power you have, the more slip you have or the more the tire distorts, the lower the numbers are compared to an engine dyno. A nice comparison would be between an engine dyno, a axle-hub dyno and a chassis dyno. All with the same sweep rate.

[@jimkillen1065]

I been to the dyno shoot outs for diesel trucks normally they go to lock up on converter. .. Be a interest shoot out for see the effects of differant convers in fluid coupling CRAPPY fluid coupling i seen that especially when you add more boost

[@brotherskrillrc6042]

Question , on what you where talking about on the example trophy truck big motor made 800hp dyno stand , installed it made 640 to wheels so if you really put the small 130 hp engine in truck it would be negative hp and would it even be able to move or would what torque it had left in it be able to move it to 25mph or faster maybe? Or even beable to turn the wheels on the dyno

[@grahamnovak1629]

he has admitted that he was wrong in this video

[@robertheymann5906]

Why are dyno tests done with lower than normal coolant temps?

[@richardholdener1727]

safety

[@stephanM5]

I am curious Richard about how a engine dynamometer works either at the flywheel or chassis. How much resistance is generated against an engine, how does the dyno know how much resistance to apply to a given engine, how is the resistance created, and how does it quantify the horsepower and torque of a particular engine?

[@richardholdener1727]

it a water brake-it is controlled to maintain a desired acceleration rated based on the output

[@Low97ss]

Excellent video Richard!

[@jimstover6747]

how about a 6.2LT1 or a l86 then stroke it for a 416lt.ththe en toss on a msd intake port the heads . No body is doing this in the magazines. These engines offer so much more power than LS platform. love the channel. Great work Richard

[@duradim1]

I learned a lot from this video. Now I can act even more like a know it all. Watch out world.

[@zfreak2808]

I use a OBD II sensor, measure time and speed, use my previously measured drag and rolling resistance, and a spreadsheet to calculate my horsepower and torque. It's notchy due to the time steps, but pretty accurate. The trick is separating out drag from rolling resistance. Gotta find a very flat surface. Gotta know air density. Gotta do a very long rolling resistance test because it can be slightly non-linear. Gotta do multiple test.

[@04silverado6.0]

Sounds accurate but for the time put in i would pay 100-150 for 3 pulls at a dyno lol

[@woodgrain18]

Let me start by saying I am a very blessed person and very thankful for everything I have and proud of what I have done for a 29yo with a G.E.D married with a son and daughter recovering opiate addict I used from 19yo to 25yo and been clean and sober now for almost 5 years basically since December 6th 2015 two days after my son was born but so I basically racing stopped when I was 21 but I did do something alot addicts cant do do I kept my job at SCI started in 2012 as a PM tech (preventive maintenance guy) I still work there and worked my way up to 3rd shift maintenance foreman and took care of my family I wasn't a bum but my priorities were definitely not in order like passin out in the bathroom with a needle in my arm lol I'm also really thankful my daughter my daughter ain't gonna remember (Well I hope she dont) me walkin around the house like a zombie and nodding out burning holes in all my shirts with cigarettes and just basically being a junky and me and my wife have been together since we where 15yo and got married in 2013 I have put that angel of woman through hell and she stayed with me through it all I would honestly be dead if it wasn't for her if it wasn't for my kids wife and grandparents I would probably still be a junky or dead. With that out of the way I can finish this really long post leading up to engine dynos lol, my grandparent's are who raised me my pawpaw is basically my dad and nanny is my moma and my hot roding drag racing church of god preacher pawpaw basically raised me in a little shop and the race track if it wasnt for him I wouldn't have any thing he has thought me almost everything I know about cars in general, drag racing, engine building and basically getting shit done on a shoe string budget put me in his 81 Camaro when i was 13 running 7.50 index lol we where not dirt poor but definitely not even close to being on easy street lol he is a hard working man and he made me understand at an early age if you dont work your butt off you wont have anything especially race cars lol so that made me understand to have anything you have to work he is 77yo now but like a year being sober and doin right and being a man and finishing version 1 of my turbo 1999 z28 basic wuhan warrior turbo and 5.3 th400 setup me and him where at the dyno this was before knew anything about tuning really but after I took him for a ride and after doin a 100mph burnout he started crying telling me how proud he was of me for finally getting my life together and finally being able to finish and see things through besides the days when my kids where born that's the third best day of my life that man has always been my hero and the best human being on this planet I honestly cried more or the same as my kids birth that day. Since then everything thing I do I give 110% effort and since I got my life together and worked my ass off to give my kids and wife the best I can provide for them and still do some racing if the old lady says I can LoL bit like I said I'm not rich and rely alot on making what I got work and other people's junk work lol I sold my 99 Z28 6 months ago that car went through 4 versions three where turbo sbe 5.3's and 4.8s but the last one was my attempt to go fast and for my little oddball engine combo it went 5.30's @ 130+mph it was a grudge and N/T car that I put together with junk it had a filled 2003 ls6/LS1 block with used diamond pistons tsp rods and crank and PRC CNC'ed 799's borg t6 s480 88mm billet wheel 1.32 exhaust housing Huron speed single t6 kit on methanol with a set of 325pound billet atomizer injectors that cost about as much as my short block lol with a bad ass PTC converter Holley hp ECU a th400 that I h have no clue how it kept taking everything I threw at and didn't complain and a strange 12 bolt rear 4.10 gear I couldn't afford more motor or to put it on a diet and it needed way more cage than it had but with anything you throw the beans at something breaks all the time I loved that car but it got to the point where it wasn't a street car and not fast enough or to fast and a buddy offered to buy it and I put it on him as a roller then I was sad but excited because I could finally finish my dream black 03 gmc single cab Sierra with roll up windowa grey cloth I got from a old man with 75,xxx miles on it that iv been slowly putting together for 3 years it's a street/strip deal that came out better than I thought it would I didn't skimp on nothing it has nicer parts than the race car did I got it running like 3 or 4 months ago the only things that where kinda threw together was the motor and turbo because I ran out of money and I was have boost withdrawals lol I had a half filled ls2 block and some forged D.S.S pistons that where for the truck but that was it so I brought it to my engine builder with some gen4 4.8 rods and crank and the top end off the bullet from the Camaro I have a pretty tall black 102mm summit brand aluminum intake and TB LJMS cam ls7 lifters basically every thing including the lifter trays so I had to cut the hood a little so since I had to cut it for the front of the intake and charge pipe I decided on a 5" hood exit exhaust so my buddy threw my little 329 or 330 ls2 together for me I already had the Huron speed single kit for it but no turbo so another local buddy who ran x275 a few years ago basically gave me a 4yo garret 85mm x275 class legal turbo for little of nothing the truck is th400 swapped so I reused my trans and converter and the Holley efi its lowered 2" up front and 4" out back and calvert everything back there and used strange double adjustables and strange parts in the rear end axles 4.30 gear spool but it's still 6 lug in the rear up front it's got calvert 90/10's and a 5 lug conversion with 17" Weld black Alumastars and weld RTS single beadlock 15x11 s77's with Hoosier 28x10.5w's the first time at the track with the little motor it went 6.83 @ 103 mph on its 5th pass already 8 tenths from my e.t goal! Well for fathers day morning the wife said she needed the shop vac so I go to the garage and there's Forged Texas speed crank and some stock length ls2 forged Summit rods and summit 4" pistons total seal rings arp headstuds no more wuhan head studs and a fluidampner balancer and a bad ass LJMS turbo cam my baby went all out her and my buddy kept it a good secret because I was so damn surprised it's been together for about a week and turnt all the way down and on waste gate with 7 pound springs in the gates and its TUFFF I cant wait to sprinkle all the timings and fuels and boosts!! All these years of 3rd shift and dealing with dummies that cant push three buttons and not doin drugs is paying off!!!! LoL. Sorry for the life story but I was feeling good about myself today

[@DMR67442]

The more horsepower you made on the engine the more you lost at the wheels. The 360 lost 70 horse the first LS two test lost 86 hp and the second one lost 99 hp. So it shows the more power you generate the more the chassis dyno absorbs. A chassis Dino operator once told me that a big difference is Hon how hard you anchor the car down with the tie straps, will affect how much loss because of the increased friction at the wheels to the diner. It was a great test and it’s nice to see the differences

[@utahcountypicazospage5412]

Depends on your transmission and differential and accessories and always smoothing five mustang dyno or dynojet also if you have gears or stall can rob power on a dyno but give a mechanical advantage

[@eformance]

So it sounds like improving the parasitic losses in the drivetrain could be a bigger bang for the buck than engine upgrades. Going to an electric water pump, putting expensive lubricants, and perhaps choosing different gear ratios might help with power. I'd be really curious to see back to back tests on different synthetic lubricants, vs parts store house brands. I'm also curious how different gear ratios factor into frictional losses. Do the smaller pinion high numeric ratios take more or less power than larger pinion lower numeric ratios? I would assume that higher side loading of the gears would result in more frictional losses. I'm also curious how the tires affect those frictional losses -- IIRC up to a given speed, tire frictional drag is the primary drag you are fighting on a car.

[@PrettyOkayAtBoats]

So like 70 horsepower for average drivetrain loss? That seems low. Not alot of accessories on the chassis dino?

[@tomwhite9034]

I would think weight effects gear ratio and then power. So heavier the vehicle lower the gear ratio and more power lost from engine to the wheels and opposite if weight is less. I could be wrong

[@SouthernCrossMotors]

That is so good. So many arguments about this 😂🤣 Makes sense. The more power, the less loss as a percentage but the effort used to turn the drivetrain is the same. Also tyres make a difference. Good street radials vs mud and snow rally tyres. Rally tyres use more power than a “tight” radial tyre. I lost 20 hp at the wheels due to running rally mud and snow tyres over the standard street tyre.

[@datasailor8132]

Not to mention low air pressure in the tires.

[@richardholdener1727]

we picked up 15 hp on a Kit Cobra with more air pressure in the tires-easiest 15 hp ever

[@deanstevenson6527]

Mike Cantwell : Thanks for postive imput MC. You said Tyre. Hail King. I Say Colo(u)r, but I am tired.....

[@deanstevenson6527]

Steve Partain : Its a King from Bib Le Cool Thymes. The King of Tyre. I think its where the first Firestone was made. However, I have been wrong before, and its just my opinion.

[@MrPureAnger]

If you look at the data from the video, it actually shows a higher percentage loss from more power.

[@cuzz63]

Interesting comparisons. Anyone spend much time trying to decrease drivetrain losses?

[@n8_b123]

Straight cut dog engagement gearboxes seem to have less loss than helical synchro boxes. Usually it is easier to increase power than decrease drivetrain loss. But of course, if you increase power enough, you need to beef up the drivetrain, and then hey presto you habe higher drivetrain losses again

[@Torquemonster440]

Check out Uncle Tony's Garage. He has a project that's powered by a Mopar slant 6 that is primarily focused on utilizing parts and pieces that reduce drivetrain losses to compensate for the low power engine. He is focused heavily on on weight reduction with that project also. Cool stuff.

[@FirstLast-bi8xi]

Circle track magazine did a bit on this, pinion angle makes a measurable difference iirc. May have been a NASCAR thing aswel.

[@richardholdener1727]

Uncle Tony does good stuff over there

[@brillyanse]

Thanks for the valuable and concise info. Everyone was telling me different stuff when it came to dynamometers and transmissions lol.👍

[@Levibetz]

Thanks for doing this one! The drivetrain loss thing has always driven me a bit nuts. I think the crux of the issue is that engineers use drivetrain loss percentage to evaluate how efficient a powertrain is. On that same note, I think drivetrain loss should always be calculated by hp loss/engine hp, as it's a representation of how much of the power from the engine is lost to drivetrain. The bummer is, if we do the math, the numbers don't back the idea that it's a straight HP loss, drivetrain loss as a percentage actually goes up. Granted, there's a ton of variables to control for here, but still.

[@RandomLifeTimothy]

What is wrong with 2 people?

[@richardholdener1727]

dislikers be disliking

[@mattiasjansson4102]

So why did the peak number come 200rpm lower on the chassis dyno ?

[@richardholdener1727]

I didn't do the tuning on the chassis dyno-I suspect timing

[@mattiasjansson4102]

@@richardholdener1727 i have a LY6 wit BTR stage 3 cam and a 4l80e on the Chassis dyno peak was at 6150rpm which is a little lowrpm compared to your dyno sessions so im thinking is torque reflects different on a chassis dyno than a engine dyno.

[@1stamendmentsupporter]

Most car enthusiasts never have their machines on a dyno; however, many have been at the drag strip. I'm curious to find a similar analysis of weight / trap speed HP calculators (i.e. Wallace Racing), versus chassis dyno results.

[@richardholdener1727]

the problem with weight and trap speed is sometimes traction and driving talent can alter results

[@davidreed6070]

Always great, what do you think about ambient air temperatures

[@richardholdener1727]

I like them to be cool

[@The_R-n-I_Guy]

I would rather know exactly what power I have to the ground. Engine dynos are good for building engines, but I want to know what I'm driving with

[@CP110]

ok, it doesn't really matter

[@timtaylor6147]

Richard , have you run a setup with all the accesories on the 5,3 ?

[@richardholdener1727]

that video is up

[@dentellreed7088]

Sorry to go off topic but I'm still waiting for my stage 2 ls cam! Please! I need a R.H. stage 2 cam!

[@richardholdener1727]

go get a BTR-mine will be a while

[@henryrobinson9837]

could you do one of rear end ratios? i know a little physics behind it ,so should be the same . but just curios

[@AdamOpheim]

Consider doing a windage test for LS setups? Maybe using truck and LS1 pan? Super common for us to uncover the pickup in an LS1 pan when launching so many run up to 2.5qts "overfull" Lots of rumors about big losses due to windage. Maybe mace back to back pulls adding a qt of oil at a time? See if power drops? I've run 7.5qts in my LS1 pan. With no sign's of trouble. And my oil pressure doesn't drop at the drag strip anymore.

[@richardholdener1727]

windage is real-we usually run less oil in the pan on the dyno-harder to do in the car

[@AdamOpheim]

@@richardholdener1727 I don't doubt it's real, but how real? I did back to back testing t the track and saw no drop in MPH up to 7.5 qts. I'm just curious what a dyno shows.

[@vigilantseeker7779]

Absolutely outstanding knowledge richard thank you for all you do its refreshing to see real info without some over bloated mouth spitting fables. Just true facts! 👍

[@evillancer4580]

the percentages look pretty constant before and after the mods... interesting that the percentage changes across the rpm range, approx 17%, 13% and 9% at 6k, 5k and 4k rpm respectively.

[@evillancer4580]

Thinking out loud, if you take RPM out then we are basically looking at torque, and looking at the torque loss that looks 'more constant' across the curve.

[@vitoaugello1677]

Rich how many cups of coffee do you drink a day? you might want to cut back. Your videos are the most informative on the web. Thanks

[@richardholdener1727]

no coffee-i do like coffee ice cream though-but only 1 brand

[@bradyelich2745]

Do comparison between Ford, Chevy, Mopar drive train losses. Ford C4 vs C6, etc. C4 vs. Chevy 2 speed.

[@SweatyFatGuy]

that would be a few months of work and require either adapter plates for all the transmissions so you can run the same engine, or figuring out how to make the exact same torque curve with various engine designs. The adapter is going to be far easier and more cost effective, but then how much power it makes plays a HUGE part in how much it loses. I could test the transmissions and different rear ends if I had a chassis/hub dyno available, since I have engines that make a metric shit tone of torque from idle to 5000, that is going to show you what effect the parts will have on power, but its going to be a much larger loss across the board for smaller engines like an sbc making 350ftlbs at its peak. The ratios and where the engine makes the most of its torque matters a lot more than which trans is behind it. The Th400 is heavier and uses more power to turn it than a Th350 or 2004R, the 700R4 has a deeper first gear, but the first three of the others are very close to each other. The PG has a first gear very close to 2nd in the Th350 and Th400, so its like starting off in 2nd with either of those, but a chassis dyno is only testing it in whatever gear is 1:1. I ran a Th350, Th400, 2004R, and 700R4 behind a 455 in my 70 GTO with a 2.93 rear gear. It ran essentially the same with every transmission, mid 12s despite weighing 4000lbs going down the track. Slight differences due to the deep first in the 700R4 up to the 330ft, but after that they all ran essentially the same, because the ratios are very close to each other. The PG works good in light cars that have lots of rpm, usually with small engines, that have a deep final drive. Put it in something like my heavy RPM limited GTO and its going to be slower, no matter how little power it uses, its like starting in 2nd after all. The 455 has enough grunt to pull it, but it will negatively effect the ET running a PG behind it with that tall gear. The 455 in my car doesn't have enough RPM to make up for the 4.10 to 5.13 gear you need with the PG, it will be done around the 1/8th and will be slower with the deep gear than with a Th400 and 3.08-3.55 gear. Its all about where it is making its power, and 550ftlbs from 2000-4500rpm means you don't need nor want lots of gear, it will simply move through the range too fast and do less work. If you have a weak little engine with barely enough power to turn the trans, then it makes a big difference. Just like the 800hp or so it takes to spin the blower on a top fuel hemi, which is nothing to the nitro fueled hemi, but more than most small blocks ever will make.

[@ryanaxberg9263]

don't be so bossy

[@jonvenden4284]

The last set of numbers for the c6 that I saw years ago was 25 hp. I think C4 was down below 20 Hp. Turbo 400 and torqueflite 727 took less power than a c6. Turbo 350 and a powerglide would be down around 20 hp. Basically there is so many variables it is really hard to calculate. Another test done to see if gear ratios in the axle would change power and it did like 5 hp at best. With these transmissions would changing gear ratio's affect the power consumption probably. What torque converter are going to run also will effect this. I always figure between 50 hp to 100 hp loss once it is in a vehicle excluding things like one ton with dual wheels or large tires. Richard proved that point that this is a reasonable assumption.

[@LC-qp7pr]

No you.

[@deanstevenson6527]

Brad Yelich : This has been done in Australia and the USA on a raft of publications. Its SAE info. I can say the best real world source is via the Moroso/ Hale 1/ 4 mile horsepower conversion and all the of HP book and Popular Hot Rodding articles which featured APT in Arizona wirh David Vizard. Ak Miller, Car Craft Hot Rod and Australian Wheels magazine also did a huge amount of chassis dyno verses SAE Net and SAE Gross hp comparisons. The summary info was done by the late Richard Lander (IIRC) Ive publicised these before on FordSix.com and Four Eyed Pride and they use the summary details from David Vizard and Hondata's NZ 1600 cc/ 97 cubic inch LandSpeed record holder Doug McMillan. To sumarise....The tire looses and automatic torque converter losses impact massively against counterweight or eddy current or hub wheel current generators, with the old reaction based Mustang dyno showing the greatest spread. The 626 hp gross engine dyno 1975 Monte Carlo Laguna test on a NASCAR style 355 with a range of torque converters showed a 63 to 45% total gross hp loss with a 12 bolt, 275 mm rear tire, THM 400 in Car Craft and Hot Rods later summary article. On other tests, it drops to 1.26 with a T5 trans in a 7.5 axle and 225 section tire car on a Mustang dyno, always showing a net 5 to 10 precent more rear wheel hp loss than most other dynos. Those 63, 45 and 26 % losses are Indicated Chassis Dyno to Gross Engine dyno losses. On a 660 or 1320 foot drag strip, trap speeds prove that real Net SAE to rwhp losses drop to jusy 15 to even 10%, because the two lane surface is the best counterweight and power asbsorpsion device known to mankind. Only Total Automatics and LenTech have the info you require. Ive posted it from a priveleged info source in FordSix back in 2015. It came from the 1/8 and 1/4 mile runs Hale and Landers used. As stated by other engineers, the real problem with chassis is reaction loads on the power absorbsion devices. A torque converter on a chassis dyno will be massively variable...the dyno is attempting measure a five order reactive load with a spring balance. 1.Part dyno absorbsion, 2. part torque converter, 3. part counterweight, part rpm acceleration rate ( 4. 300 or 5. 600 rpm increase per second). David Vizard, Doug McMillan, Richard Lander, Mr Hale, Richard Holdener ...they have all given the best info.

[@guyconnell2250]

I would ask if you were serious about potential flaming from guys who correct you in the comments for saying "460 hp" instead of "459.9", but, sadly I know you are serious. I just don't get people most of the time. In my 40s I thought I had things figured out. Now in my 60s, the petty shit people do constantly baffles me. Like the two who "disliked" the video here. What is to dislike? Seriously.

[@richardholdener1727]

might be someone that dislikes me for some reason-it's always part of being a human

[@goodmanboattransport3441]

My Dad had an AMC Jeep, wagoneer with the 360, late 70s era, and I kid you not, the book spec on HP was 95, if I remember correctly, then it totally made sense why it only got 5 to 8 MPG!

[@richardholdener1727]

seems pretty low

[@goodmanboattransport3441]

@@richardholdener1727 I took a look, I was recalling KW, 95 KW, still it's an anaemic engine

[@gentilejoshsaved1646]

What do you do to stay in good shape sir? You sure are excited about your job, it makes it fun to watch you.

[@androiduberalles]

Would be interesting to see how boost changes between the engine and chassis dyno

[@robertb3409]

Great video, Richard have you ever calculated the drivetrain losses on a fox body Mustang with a t5 transmission.

[@richardholdener1727]

I think I did this on a Mustang way back as well

[@robertb3409]

Thanks for getting back to me so quickly.

[@TexasCamSultants]

I'm confused, if it is a fixed amount of power to turn the drivetrain, why is the power difference of the non modified engine 82 horse power between chassis and engine dynos, and the difference in power on the modified motor 99 horsepower between chassis and engine dynos? That is a significant difference if it takes x amount of horsepower to turn the drivetrain. Shouldn't the loss be uniform?

[@TexasCamSultants]

Ok, so I figured it out, and have to say, the way it is explained in the video is somewhat confusing. As I understand it to be explained is there is a fixed amount of drivetrain loss, when it "should" be said that each car has a fixed percentage of drivetrain loss. In the case of the 240sx with the LS2, each time that car basically had a 17% drive train loss. Based upon this, essentially, someone could take a factory output for their engine, strap their car to a chassis dyno in stock trim, and whatever that loss percentage is, could be applied to that vehicle from then on. That is of course assuming that the manufacturer did not under inflate the number as we've seen them do from time to time.

[@stephanM5]

This is such a great show. Richard does videos on engines that are actually interesting and you end up learning something.

[@richardholdener1727]

don't tell anyone about the learning part

[@hoonaticbloggs5402]

All dyno’s are different. They are a measuring tool. Only use for setting up engines and comparing modifications

[@xgears_rb_x]

Never been so early great work as usual.

[@warpigolet]

Since you can load a chassis dyno at lower rmp, I would like to see wide lsa vs tight lsa. Long duration and then short duration. Closer to real street. You still have to leave the line before you get to cruising rpm.

[@SuperSilvi1990]

Can you do a video on hub dynos? I feel like hub dynos are great for tuning but do not actually give you the power your car can ACTUALLY put to the ground. They don't take into account the rotational mass of the wheel and tire along with the tire grip that you car can put down.

[@garagecedric]

For me i wouldn't even bother with anything other than a load controlled hub dyno. Having tyres in between is only a pain imo, creating uncertainties that are hard to quantify and that easily vary alot. The less variables the better.

[@SuperSilvi1990]

@@garagecedric I completely agree its great for tuning because all you have to worry about with hub dynos is vibration and burning up clutches lol. but I feel like you should also test it on a rolling road dyno afterwards to see if it can actually put that number to the road once the weight of the tire and wheel are taken into affect. Seeing how much of a difference between the two would be cool. Edit: also if you cant put that number to the ground then it really doesn't help you at all imo.

[@garagecedric]

@@SuperSilvi1990 no I don't see the point of going to a rolling road dyno after the hub dyno. A good hub dyno can be runt static and transient in whatever ramp speed you want if you want to calibrate it dynamically. Any fine tuning in driveability is then best done on the road after that. The dyno is not a good place to evaluate tyre grip, that is best done on the correct surface=track or road.

[@SuperSilvi1990]

@@garagecedric I dont think your understanding what I said. I never said it's better in any shape or form. I said I would like to see the difference between the two due to the weight difference with and without the tire and wheel factor after it's been tuned. The benefits of hub dynos far outweigh the rolling road dynos. I've been in the situation where I had too hard of a tire on my car and it wouldn't hook up. so I went and bought better tires and dynoed the car again. Again the difference between the two dynos numbers not the use case in which hub dynos are superior.

[@stackymcgee761]

Any update on your cams???

[@richardholdener1727]

be a while

[@davidreed6070]

Do you think as much as 30 hp could be gained or lost by air temperatures going from 72 to 92

[@ericsperformanceparts1647]

Great info Rich.

[@hotrodray6802]

🔔👍😁 I apologize if I missed it in the past, but, is there a plausible explanation for the dip in the torque curves on the engine dyno around 3300 + - rpm in nearly EVERY engine? Thank you.👍 😎😎🇺🇸

[@eddieweaver3609]

I always thought that drivetrain loss should be a fixed number. It did not make sense to me to use a percentage. Drivetrain loss should not be more on a higher hp engine. Thanks for confirming my theory.

[@MrPureAnger]

If you look at the data, it shows a relatively constant % loss, it actually increased as the power went up.

[@deanstevenson6527]

225 HP SAE gross with out fan, but with exhaust verses 155 rear wheel hp on his 360 Tradesman van on tires with fan in the engine bay and 727 Torqueflite is indeed a 45 % power loss on that test condition. I cut Mr RH some slack since he supplies the information that proves he made a descriptive "mistake". Power loss is more or less uniform, what varies is chassis dyno counterweight rate to torque converter and tire rolling resistance losses. It's pretty much uniform, aside from those. If he added an A833 4 speed, the loss factor would have been 1.27, not 1.45, a gain of 22 rear wheel hp, 177 instead of 155 rwhp. Based on my 38 years of dyno test info from five sources.

[@richardholdener1727]

45% POWER LOSS?

[@deanstevenson6527]

@@richardholdener1727 From the 225 HP at 4500 rpm you had on the dyno in the engine dyno to the 155 rear wheel hp you logged on the chassis dyno at Westech. I'm guessing the last 155 RW hp was measured in Second gear , where the two 235R 15 tires at 30 psi doing about 68 mph consume about 12 HP. The flywheel effect between the power absorbing device and the torque converter consume the lions share of the rest, with the planters gears and hypoid drive only taking off about 17%. I have from Wheels Australia, 1977 to 1981, about 35 automatic transmission Mustang chassis dyno figures, with conversions from factory rated to rear or front wheel figures, and with torque converters, an SAE Gross to RWHP factor of 1.45 ( 45 % ) is on the low side. Highest loss was 80% on a GM-Holden 202 THM 180C in line six, lowest was 54% on a Ford Falcon 250 with C4 automatic. The rolling resistance, converter, axle and inertial interplay vary with braking acceleration rate. The manual transmission losses were lower, smallest loss was about 17% on a front drive Alfa Sud, but this all depends on another unknown, having a healthy specimen to test in the engine bay...

[@henryrobinson9837]

so its y=ax+b, instead of y=ax, would be a closer approximation but would be depend on individual car chassis,cool video

[@ChipsAndSparksGarage]

Interesting stuff, Richard. Have you ever tested the effects of the Dyno Operator, on the results? In particular, RPM sweep speed. I would imagine the inertia of the drivetrain would eat a lot of power during a fast RPM sweep. Thanks for all the cool tests that you do! 👍 Tony B

[@richardholdener1727]

we alter the speed sometimes on the engine dyno

[@NBSV1]

Depending on the chassis dyno you can set how fast it lets it gain speed. Slowing it down helps get rid of driveline weight losses. But, if you slow it down to much everything gets to hot during the run.

[@joerogers1364]

Dyno Mythbusters starring Richard Holdener. Busting the 15% loss manual trans rule of thumb to pieces. And presented in a way that I'll be able to explain it to my dumb friends too.

[@TheRoyal769sr]

I hit the like Before the video begins!

[@richardholdener1727]

that's what I like to hear

[@josephvincent7912]

Me too ever time!!