500 Hp @ 5000 RPM vs 7000 RPM - Which is Faster?

[@boostaddict_]

Well put. 500hp is 500hp. All that matters is effectively getting it to the ground. 500hp at 12000 rpm is useless if you can't get it through a transmission.

[@AlexLTDLX]

Or, I'll add another caveat - getting the power to the pavement without wheelspin.

[@WarriorOfEden3033]

@@AlexLTDLX stop mocking me 😂

[@mr.bitsbyte4664]

Thank you for explaining this so clearly. Lots of people seem to think that a motor with lots of torque can beat a motor with higher horsepower, and completely fail to understand that torque is worthless without RPMs. You can make a 15000rpm motorcycle engine pull a tank by changing your gearing.

[@WallaceMorrison]

I've been drinking and seriously have no idea what I'm doing over here laying on the couch thinking about these cookies

[@tunedbyeazy3538]

I thought this was a comparison on 5000 rpm vs. 7000 rpm with the same hp? All of a sudden, there is a lighter rotating assembly in the 7000 rpm motor 🤦🏻‍♂️

[@AlexLTDLX]

I talk about EXACTLY that starting at 2:16 in the video.

[@KingJT80]

an engine that spins a higher RPM but makes the same power is going to have a lighter assembly physically you almost cant get around that now the 500 HP @5000 RPM is doing it with nitrous vs 500 @7000RPM N/A and now ive thrown in a can of worms 400 HP 347+100 shot vs 500HP N/A 302

[@tunedbyeazy3538]

@@KingJT80 so what's wrong with having a just as light rotating assembly on the lower rpm as the higher rpm motor?

[@KingJT80]

@@tunedbyeazy3538 what would be the need for it is what you should be asking

[@tunedbyeazy3538]

@KingJT80 has nothing to do with needing. It all has to do with a very straight-up comparison. Once you change one engines rotating assembly weight, it's no longer a fair comparison. That is all I was saying.

[@Mgmcontrollers1]

Great video! As always! Thank you Alex!

[@rimka11]

Yes, that is what i am saying every time. It's wheel torque that count not crank. But some of them dumbasses don't really understand what "at the wheels" mean. They see a power and torque number saying at the wheels and this is where their information processing stops.

[@802Garage]

My initial guess was that they would be the same, provided yes gearing equalized torque to the ground, since horsepower is just torque per time essentially. I also thought the 7,000 RPM car might have an advantage due to some kind of efficiency, but I couldn't really think of why. Thanks for the fun video.

[@Texas_Road_Warrior]

You can do some fun math with this… if 5000rpm and 7000rpm are happening at the same wheel speed, wheel torque is identical 🤣 both cars will accelerate identically as long as they average the same power… with a CVT (just because it’s easier to explain) the RPM is constant and the gear ratio is irrelevant, as long as the HP output is the same with different engines the wheel torque will remain CONSTANT even know 2 engines might output WILDLY different torque… it’s all math, horsepower how much work the torque is able to complete. And torque is how hard it’s twisting

[@Kirmo13]

The second half became a manual vs automatic comparison

[@AlexLTDLX]

Because it's relevant to the topic.

[@monstercameron]

I haven't even watched yet and it's a trick question. The transmission is more important here

[@AlexLTDLX]

More than one trick...

[@bingoberra18]

This was a game of "let me set the rules and then explain why I will break them"

[@AlexLTDLX]

I can see why you'd see it that way. But if I just put up a video like this and went on camera and said, "it depends," I'd get crucified. 99.9% of the time, the higher rpm car will win. It's a very specific set of circumstances that are somewhat unlikely where it wouldn't. The intent of the video (which perhaps I could've mentioned) is more as a guide of how to build a quicker car - go for more rpm (unless, of course, there are other constraints). But as another commenter pointed out (and I made a point of saying), these are hypothetical cars. This video came about because I'm thinking of adding about 500 rpm to my own car, specifically for the converter reasons I'd mentioned. I'm currently seeing about 11-12% slip at the stripe - I'd like to see about half of that ideally.

[@bingoberra18]

@@AlexLTDLX If youre talking real world actual improvements there is no general rule. It usually comes down to what is most cost effective vs. performance gains. What if you have valve float and a "dying" power curve already? Then you need to fix that before upping the RPM. Someone else might anyway need a bottom end rebuild, maybe it makes more sense to go for a 383 build over a 350 in that case. Though for a future video I would like to know more about converter tuning as I have no experience of that and would ideally want to build myself a nice street/strip Powerglide car (the one in mind would be really light) and it would be interesting to understand where the sweetspot would be for a 1/8 mile strip and street car.

[@AlexLTDLX]

Those are all valid points; which again is why this is a hypothetical. For a glide, you want anywhere from around 700-1,200 rpm fallback on the shift, with enough stall and torque multiplication (also known as "k factor") to get it out of the hole as hard as possible without tire spin. In an optimized 1/8 mile car, you'd want to see less than about 14% slip - in a quarter mile car, you'd want to see less than 10% - ideally around 6% or so. If you have a really high winding engine, it's possible to be in the mid single digits for slip in the eighth. I'd do a video on converter tuning, but I don't think it'll get a whole lot of views based on the demographics of my audience here, unfortunately. Keep in mind that raising the shift point generally doesn't change the rpm that the engine will fall back to on the shift (assuming you haven't added power). Hope this helps. BTW - I did do one converter video: kzbin.info/www/bejne/n5S5qGCHdpiEgtE

[@mccanlessdesign]

Always a fun analysis.

[@FixItStupid]

The MAN With Tech. & The Math !!! AlexLTDLX

[@LainesNitro]

From a physics standpoint, both of them would finish simultaneously. This is easily derived from the energy conservation law, since all the speed comes from kinetic energy and all the energy comes from power, which is incidentally a measure of energy over time. The RPM or torque itself play no part in a calculation. Of course, it should be mentioned, the cars here are "ideal" in a sense that they experience no losses and apply full power throughout the race.

[@MrPizzaman09]

What about the added rotational energy to spin up the engine's rotating assembly and flywheel to a higher RPM?

[@AlexLTDLX]

You only do that once - and typically before the race starts. Once you're racing, it's no longer in play. Good thought though.

[@MrPizzaman09]

@@PistonAvatarGuy Energy is squared with rotating speed.

[@MrPizzaman09]

@@PistonAvatarGuy It gets more challenging to figure out when you consider only a single shift too in this drag racing situation. More flywheel might actually help and you might get to recycle the energy on the 1-2 shift

[@zqzj]

Great synopsis. Thanks

[@2camsam]

The gear ratio's are also worse in the manual transmissions. Due the sound decibel laws they can't gear them as well as the auto.

[@AlexLTDLX]

I actually didn't know there was legislation affecting gear ratios aside from the EPA's mpg requirements.

[@markg7030]

Gear ratios are for leverage. There are no noise pollution laws at the track unless mufflers are specified.

[@machwind3266]

If we are dealing with reality, the motor with more area under the curve(in relation to power and rpm) will produce more average torque over its power band. Also, drivetrain parasitic action has to be taken into account. The car with the least dynamic drivetrain drag will be easier to propel. Aerodynamic drag is also a big factor in the ultimate top speed of the car.

[@doncarlson8391]

Excellent point about area of power under the curve!

[@GoldenCroc]

I like to add "between shifts", since not all people get it and think its the total power curve that matters otherwise.

[@robbioe]

Helped me understand more about why higher RPM's don't equate to faster

[@bingoberra18]

it equates to faster under the right circumstances, just like it doesnt under the wrong circumstances.

[@nathaneel4059]

Usually it is because if you just spin the motor faster the AFR in the cylinder get's worse and worse because the mix is to slow through the drag it gets from intake, air filter and so on and thorugh that you loose more power than you gain. But if you tune it with a bigger intake and exaust and everything then it still can "breath" at high rpm and produce the same torque at higher rpm.

[@VcArena]

So lets say they both have a 308 rear gear, and a auto then who wins?

[@AlexLTDLX]

Most likely the lower rpm engine would win in that case.

[@oscarzt1652]

3:45 not forgetting that the automatic mustang has 10 speeds!

[@AlexLTDLX]

Yeah, that's one heck of a transmission.

[@Kirmo13]

I feel like the power curve would be higher for the 5000 rpm car at lower rpms therefore giving it a faster acceleration

[@AlexLTDLX]

It isn't, and it doesn't. Check out the new LT6. Peak power at over 8,000 rpm.

[@Kirmo13]

@@AlexLTDLX well then I'm even more lost. Are we talking about real engines or hypothetical engines? And how is the comparison fair if one engine makes more power if you rev it higher? The way I understand it is that we have two engines who produce peak power at different rpm. However, since the power is identical, their top speed will be identical (assuming everything else is equal). So the question becomes which one accelerates faster. And I think the 5000rpm accelerates faster because it has to have more torque to reach that hp at lower rpm than the other engine.

[@Kirmo13]

and btw, I have 0 on-hand experience with powerful engines and sprots cars. I'm just trying to understand how that stuff works based on my previous knowledge. I might be totally off

[@AlexLTDLX]

Torque at the flywheel is irrelevant. In fact, a common point of confusion is that torque by itself does no work - it isn't power. I go into detail on this in this video: kzbin.info/www/bejne/nIXCnWVtmJKVkMk Keep in mind nobody races at idle; or low rpm for that matter. Converters are specifically designed to flash into the engine's powerband - and the more a converter flashes (i.e. higher rpm), the easier it is to make one with a higher K factor (torque multiplication) that also still comes closer to locking up at higher rpm (as mentioned in the video - the further up the rpm band you go, the less slip you have - the 5,000 rpm engine is likely to see as much as 20% slip at peak power; I'd expect the 7,000 rpm engine to be around 5-6% - a huge difference). You are correct about the top speeds being equal.

[@Kirmo13]

@@AlexLTDLX I understand the difference between torque and power, but saying that torque does no work is like saying "guns don't kill, it's the bullet that kills". Power is torque x rpm, so if the torque of the 5000 rpm car is always higher than the 7000 rpm car in the 0-5000 range, then it will have more power across the range. Now that I'm thinking about it, it's not fair to compare power of both cars at the same rpm since the 7000 car can go higher so it will have a different gear ratio. About the torque converter, that flew completely over my head. I understand what you're saying, but have no idea if that's actually how they operate. I'll concede that you might be right for automatic transmissions (which now also makes sense why you were talking about transmissions in the video), but what if the cars are single speed manual? Would the 5000rpm car reach top speed before the 7000rpm car? (with gear ratios that make them reach the same top speed)

[@UPsideDOWNworld321]

what would be faster if both cars had same gearing and manual just using one gear like 3rd gear from 30 to 100 mph

[@AlexLTDLX]

The one with the lighter engine and transmission rotating parts would win. If they're the same, then the cars should be even; but with manuals, you lose a lot of time shifting - no matter how good you are.

[@Jamxknife]

This is why v8s are faster in the 1/8th mile than 4 bangers. But 4 bangers can actually some what compete in the 1/4 and other high mph racing.

[@davidperry4013]

My favorite is 500+ hp @ 8000 rpm, flat-plane crank DOHC V8, dual-clutch Tiptronic transmission, 2 seats, and a curb weight of 3500 lbs or lighter. Ferrari FTW.

[@RotaryJunkie]

Fox is always the answer though. In this case, a Fox with a Voodoo and BMW DCT. Suddenly we've hit every one of your targets for like... 50-60k making someone else do the dirty work.

[@freshkryp69]

Whoever makes the most explosions down the track wins!~

[@jamielombardo5292]

My guess would be the 5,000 RPM would get there first because it reaches torque Peak first

[@mxguy2438]

Would be interesting to have the two torque or power curves and plot out their acceleration side by side over a run.

[@AlexLTDLX]

It might be possible to do that with a Dragy. But getting two identical cars with different HP peaks would be much harder.

[@bingoberra18]

All things equal as stated in the beginning of the video they should be parallell all the way. Of course in reality you need to talk area under the curve and other details which does not make it that easy. Still, horsepowers wins races, unless the way of utilizing that engine is less efficient than utilizing a different less powerful one.

[@mxguy2438]

@@bingoberra18 I agree. But to add nuance and make the conversation more complete, acceleration closer to the starting line is more important than the same acceleration later. Acceleration is from force/mass. Force is torque. Put more torque to the pavement earlier and the car with more torque but the same power gets a head start and can beat a car with more power. I.e, look at ev's and how good their ETs are vs their trap speeds, and 4 cyl turbo cars which are the opposite. This is why I'd like to see /do a side by side comparison. Imagine something like a 3rd gen Camaro TPI 400 vs one with a Victor jr on a 302. Tune both to make 300 wheel and otherwise identical except for the rear gear. Given the torque curve for each motor, it would be simple to make a graph of a 1/4 mile on the x axis and put acceleration on the y axis.

[@bingoberra18]

@@mxguy2438 Sure, but in the example the lower torque engine was geared to equal the torque to the ground of the higher torque engine, this can be done also in real life. However at the launch having a lot of rotating mass might be of benefit since it might help setting big slicks in motion. I just dont really like this video as it goes out saying they are equal in every way, and then starts changing that. If they are truly equal besides rpm and geared for the rpm then there is no actual theoretical difference in the acceleration or torque to the ground. Where the example falls is that in reality there are so many variables and there is no point in discussing it theoretically. Better to just analyse what is actually winning on drag strips around the world and why theyre winning.

[@KingJT80]

@@bingoberra18 and what USUALLY wins around the world? high RPM engines that get into the power band quickly and make power up higher. not a lot of low grunt engines wins races...unless the entire class/rules are built around specific parameters for that to happen

[@Kirmo13]

Assuming that each of those figures is their max hp ofc

[@slopoke22]

The horses at rpm wins. So many factors involved in goin fast at the track, though

[@AlexLTDLX]

That's true. There are so many variables at play - this is just a hypothetical which eliminates most of those variables.

[@Kirmo13]

How do you know the gear ratio to keep it in the powerband? As far as I understand, we don't care about the gear ratio

[@AlexLTDLX]

I give that info in my previous video on shift points.

[@Kirmo13]

@@AlexLTDLX I'll check it out

[@falkor3865]

FORD doesn't do 4 bolt mains..lol What kind of block are you running?

[@AlexLTDLX]

That's an 8.2" deck Dart Iron Eagle Sportsman (yes, they made one - it's between the SHP and Iron Eagle). Good eye!

[@bdtodd50todd38]

In the late '70s I had a '70 Cuda with a mild 440 auto and 4.11 gears. I tried a set of 4.56 gears and ran the same ET. The only difference was RPMs through the lights. Can you explain?

[@AlexLTDLX]

Without more data, I'd have to give it my best guess. The converter was effectively tighter with the 4.56 gear ratio because it was loaded less - but this would be a slight difference because going from 4.10s to 4.56 isn't that big of a difference in a mild combination. Weather is the more likely culprit - it wouldn't take much to lose a couple mph. When I used to run the Whipple on my car, the difference between so-so air and great air was as much as 6 mph - 131.xx vs 137.xx.

[@bdtodd50todd38]

@@AlexLTDLX Thanks. This was back in the day when no one was even aware of making adjustments for air or temp.

[@ovalwingnut]

That was definetely the Einstein answer - impressive. Put another way, the higher RPM engine can take more advantage of "gearing".. Imagine a 700 HP @1000 rpm. Yes? No? Let me have it :O) Cheers.

[@cj-wm3fi]

I'm guessing Roger has more PHP(paw hp) than the Catahoula mix. MoRFTW!

[@AlexLTDLX]

lol

[@frankenstein01]

thinking about a coyote swap, alex? lol

[@AlexLTDLX]

No - but you're on the right path. I do want to pick up another 500 or rpm in my car's powerband just for the converter issue.

[@doncarlson8391]

IMHO, not enough variables defined in the opening statement. If only the engines and gearing are different, I'd bet the parasitic losses in the 7000 rpm setup, would be higher and the 5000 rpm combo would win. Windage and sheering the oil losses would be enough to give the win to the 5000 rpm combo. But optomizing each combo and being on a track would be a good race. Interesting bench racing subject.

[@beaches2mountains230]

ANDREW PIKE PLEASE RESPOND..THE PEOPLE DESERVE TO KNOW !

[@cartermackenzie1135]

Richard holdeners comments on his destroked LS3 vids say otherwise lol but i wanna build one anyways

[@AlexLTDLX]

Richard is a good guy, but he races dynos, not cars. In this case, we're talking mostly driveline and acceleration effects which isn't Richard's forte. Again, his info is valuable, but it's not a complete picture.

[@cartermackenzie1135]

@AlexLTDLX I 100% agree. Torque is great except when you can't keep your tires planted. I have a 23 silverado with the 10 speed and I can spin the tires without launching it from a stop because of the gearing in 1st. Spinning tires doesn't get you anywhere, power is only useful if you can put it down, so making power at higher rpm gives the same advantage as boost by gear in a way.

[@nathaneel4059]

But if both cars are exactly the same exept the time they produce top power and you would make a pull from low rpms wouldn't the 5k car be faster because it delivers the 500 hp erlier. Well 500 is a lot but if you would like take 100 so the weels don't spinn and you don't do a standing start like say in 2nd gear at 1500rpm?

[@AlexLTDLX]

The numerically higher gears in the higher rpm engine makes up for the difference; along with the other factors I mentioned.

[@nathaneel4059]

@@AlexLTDLX so you can make a car instantly fastesr if you put the power band higher and adjust the gear ratio for it. If so that is very fascinating

[@AlexLTDLX]

Yes, but it depends. If it's a manual transmission car, then no, there won't be much difference. An automatic will absolutely be faster for the reasons I explained in the video.

[@jeffsnyder2051]

ROGER that!!😂

[@darinr9424]

Bs... it's not the tq at a given rpm. It's overall power and tq through the entire rpm that matters a ton also... example. All things are equal both are 350 hp same gears same converter and theoretical same traction. One makes 350 on nitrous the other is all motor.. both end up makin the same power.... the nitrous car will smoke the other... it makes far more overall power than the other... period and no way around it

[@AlexLTDLX]

Power takes torque into account - your second sentence is redundant. If the nitrous car and the N/A are both geared appropriately and have converters that match the engine's power bands, and both make the same peak power, the results will be as stated in the video. Also, the nitrous car's converter will either be super tight N/A or super loose on spray (like 20% + slip at the big end) - don't get me wrong, the nitrous car would be more fun to drive (until the bottle runs out), but the physics don't lie.

[@theodavies8754]

The 500 hp motorcycle wins. Build in lightness.

[@captainboose8788]

The correct answer is 5000 rpm

[@AlexLTDLX]

I love racing people like you.

[@captainboose8788]

​@@AlexLTDLXIrreverent statement to the question at hand. In 2 identical cars the one that makes the 500 at a lower RPM wins. Unlike the video where you dance around different gearing and tq converters

[@AlexLTDLX]

Ok, if you insist. But in the vast majority of cases, you're wrong for all the reasons I've explained. On the other hand, just for grins, give me one reason why the 5,000 rpm car would win. I've spent 30 years making custom positive displacement power adder setups. I know torque. And I know it's fun on the street & great for breaking stuff but useless for winning races.

[@captainboose8788]

@@AlexLTDLX Again; if both cars are identical, with the same gearing, the one that males 500@5k will always make more tq and therefore more usable power under the curve, without the need for a gearing Handicap

[@AlexLTDLX]

No, the 5,000 rpm car won't make more torque at the wheels (the only place it matters). It'll make the same torque at the wheels. Watch the video - it's explained with visual aids. Torque isn't power. In fact, torque does no work by itself. I go into detail with this here: kzbin.info/www/bejne/nIXCnWVtmJKVkMk