LOW BUCK LS TURBO TEST-BIG SINGLE VS SMALL TWINS

SINGLE VS RACING 7875 vs TWIN GT3582s-WHAT WORKS BEST? DO SMALL TIME TURBOS OFFER BETTER BOOST RESPONSE THAN A BIG SINGLE TURBO? WHICH TURBO SET UP MAKES MORE POWER? CHECK OUT THIS TEST WHERE I COMPARED A SINGLE 7875 GEN 2 FROM VS RACING TO A PAIR OF GT3582s FROM CXRACING. I RAN THEN AT 4 DIFFERENT BOOST LEVELS AND MONITORED BOOST AND BACK PRESSURE.

[@bestusernameevahhh5802]

By a show of hands, how many people now have a Disassembled LS in their shop right now because of this guy? We love you Richard. Thanks for kweping hotrodding alive.

[@One_LuvZ]

L59 currently to install on Z32

[@kobygrimes1234]

✋️

[@lucasmullins5100]

Richard Holdener proving that not all heroes wear capes’s and also making me want to spend more money

[@toob247]

@james avery more money not all the money's

[@georgeschnakenberg7808]

All the money's

[@davelowets]

One has to pay, to play..

[@Cultofpersonality09129]

Hero? Get help.

[@allenl9031]

I just read from Freiburger, that Sonny Leonard has passed away. RIP to a race engine legend.

[@niknasstie]

It took intill 2021 for some bad ass enough to do this test.

[@Its_Jimmy132]

Matt Happel made 1K+ WHP in a SBE gen III 6.0 Colorado in 2017

[@8bert9]

I would have never thought that the bigger turbo would bring bigger power in at the same lower RPM. Nice test!

[@davelowets]

@@stevenp3176 What "stock turbos"? A 4.8 LS never came with ANY turbos... 🤔

[@BlindBatG34]

I've got to imagine turbo lag is the only thing keeping the driveline from doing an emergency eject from 700+hp in a 4500lb truck.

[@natemartinez4595]

6000lb truck in my case lol

[@brooks3racing1]

It not the HP it’s the torque. Most guys will pull timing at peak torque to help.

[@davelowets]

I CAN tell you that a 4L60 lasts about 3 weeks behind a setup like this... 😞

[@cooperechols7322]

rip🤧

[@anthonybillings6554]

This is a great test!!! Specially the extra information you dropped at the end!

[@GregoryBirulkin]

This is one of your best comparative KZbin videos. Thank you!

[@Drekoushranada]

I'm looking forward to setting up my system. Your videos been beyond educational!

[@dee9117]

Dude you are freaking awesome keep up the great work and I’ll absolutely keep watching likeing and sharing

[@smp3745]

Sir I Thank you. Dude is spilling out real racecar knowledge more than any collage you will ever goto

[@sanfordrhudy774]

I almost pulled the trigger and order a couple GT35's. Richard Holdener, thank you for all of the knowledge that you freely feed us!! YOU DA MAAAAN!

[@JimOrr_OK]

As a long time truck driver I’ve known about putting some heat into the turbo before a hard pull but I never had the reason explained like this. Thank you

[@TurbineResearch]

Thanks Richard ! You're the man

[@maclogan6872]

One if the more informative tests. Thanks R H

[@michaelblacktree]

Interesting results. Thanks for sharing! 👍

[@tomlenza2768]

Awesome vid. ! Love your channel ! I went to a trade school for automotive technology back around 2005 and learned a lot. it was great but god dam I wish u had been my teacher! Keep up the great work. I look up to u!

[@jplperformance9073]

Love the tests and the channel

[@basscube5]

Great video as usual! I have a set of GT35s (Vs racing style) in a Fox. When the build started I had a garden variety 4.8 with a BTR stg 2 turbo cam and I'd describe the boost response exactly like you found. The power band was ~5000-7500. I currently have a 10:1 5.3 with ported 799s, all else identical and there's wayyy more midrange power now. Pump gas with meth, predominantly street car with a 4l80E for reference.

[@finnroen2334]

Excellent test. Thanks.

[@jasonrodgers9954]

Richard, thank you for taking the time to make the video! On the gt35 turbos, what kind of increase down low would you have with an all ball bearing better quality gt35?

[@button-puncher]

Another great video. Thanks! Lag makes sense. Turbine maps only start at 1.25PR, really get going at 1.5PR, and are fully spooled at 2.0PR. One of your setups is at 1.0 and the other is 1.5. GT3582's are good for 1,000HP at 7psi. Like you said, too big for the 4.8L but perfect for a 6.0L. Better match would be Twin GT3082R turbos. They'd be good for 800HP at 7psi and 1,110 at 15psi. Borderline too small would be twin GT3076R turbos. Good for 600HP at 7psi and 875 at 15psi. Those would be great on the street.

[@patlandymore7035]

An absolutely super test! Really liked the lower rpm comparison showing the twins 150 lb/ft down compared to the singles. I wasn’t expecting that. Thanks for doing what you do Richard!!

[@dbjunior1238]

Now lets see a compound turbo setup compared to the dual turbo setup

[@drs2000rr]

Awesome video !!! Richard, Running twin gt3582rs, with turbo blankets and header wrap helps the spooling consistency. Being that the twins are less responsive on the 4.8. It Would be great to compare responsiveness in a twin gt35 setup in the 5.3 and 6.0 vs the gt45. These are the things that keep me up at night, Thanks again for all of the shared Knowledge.

[@delagto_5340]

Exactly what I was thinking. As long as the early lag could be minimized it should be fine. The gt45 I would assume will always have the upper hand despite displacement. Although the displacement could aid the spool for the gt35s they are pretty big for a no lag twin set up.

[@drs2000rr]

@@delagto_5340 I’m running them due to space constrictions, they love to be Brake boosted prior to a launch and they love to rev to 7600 rpm. I think more boost and a high revving Ls would show the benefit of twin gt35s.

[@delagto_5340]

@@drs2000rr I’m trying to figure out something for my car and I think that might be the way I’m going to go. The twins can be mounted right next to the bell housing. I’m a cam only car and personally rather have something that can me tamed and wild when wanted to be. Plus I can just turn it up haha 😆

[@drs2000rr]

@@delagto_5340 awesome, make sure you address heat control with heat wrap and aluminum tape over every wire and hose running through the area, and you should be ok, get a good scavenge pump to pull all the oil out of the turbos, and run a low psi warning light incase the pump fails. Happy Boosting

[@delagto_5340]

@@drs2000rr thank you for the tips ! I’ve been searching the forums and reading up everything I need to do. Most of it is exactly what you said. If I take it on i will document it for sure. Thank you!

[@KreatorOfDeath1985]

I'm thinking more about a single turbo now after watching this. Hmmm

[@BronkStang]

Same dude. Plus cheaper n easier

[@nowayjose596]

It depends a lot on packaging in your individual application i.e. the room to run 1 big downpipe or 2 smaller downpipes, etc.

[@BronkStang]

@@nowayjose596 I’ve got plenty of room but after watching this it’s like dude look at how much more torque he was making under 3500 RPM with one single big turbo

[@KreatorOfDeath1985]

@@nowayjose596 68' chevelles have a LOT of room under the hood. I could put 4 turbos in there hahaha

[@nowayjose596]

@@BronkStang I think if he kept going up in boost you'd see the lower RPM responsiveness of the single and twins start to mirror each other more closely and the twins then starting to make more power at the top end thanks in part to their lower backpressure. That's why he emphasizes the sizing of your turbo(s) for your displacement/boost level/preferred RPM range is more important than if you go single or twin.

[@heytonyman]

Great lesson in boost threshold. I suppose what a loaded dyno can’t show is the lag difference between single and twins. I suspect the lighter mass twins will come to life faster when stabbed from a 5000rpm roll, and also recover faster after a gear change in a stick car.

[@MrLightning54]

To me it sounds like whichever kit packages better in your vehicle is the one you should choose if the right size turbo / turbos are available for your power goals. Great video!

[@bradspeed]

100% agree, if there is no space to run the twins a go single.

[@MrLightning54]

@@bradspeed I have a single on my car (2011 5.0 Mustang) and love it.

[@blixxy1320]

@@MrLightning54 I bet she rips

[@bcbloc02]

So now we need this test rerun with tighter ar housings to see what happens. 🤠

[@austindoud273]

It's probably just gonna give you a couple hundred rpm and choke the top

[@LaimisBMW]

@bcbloc02 Or just up the boost and see how the single will perform with that excesive back pressure.

[@littleherms3285]

.63ar is as small as they get in a T3.

[@wayneallen2047]

Awesome. I'm getting ready to do the same now

[@outlawstang]

Hey Richard love the videos very informative do you think you could do this for a 4.6 2v with a on3 turbo kit thanks keep it up 🤩🤩🤩

[@besearchingforwisdom6267]

You've gained 100k subs since I started to follow, Congrats dude.

[@richardholdener1727]

thnx-it has been amazing

[@sinistersilverado965]

@@richardholdener1727 you are a hard working guy, you deserve it

[@russtynuts]

In the diesel game we change timing down low to help with EGT heat to spool a big single

[@iancole85]

Epic video 🎉

[@dennisrobinson8008]

That heat in the exhaust test is similar to the rear mount result. The initial response is better but output over most of the curve is the same.

[@motorosso3349]

Very informative; any ideas, other than cut and try, to determine which turbo is going to have the best response and good power? Are you familiar with "Maximum Boost" by Corky Bell?

[@aaronkeller8269]

VS actually had me purchase smaller hot sides as response time was not ideal with a T56 behind a 5.3. Only $100 per turbo so it wasnt that bad of a hit. But once I put the 6.0 in the car, the larger hot sides were needed as they light off ALOT faster. About a 1500rpm difference in peak boost range.

[@Brock_Landers]

Thanks Rich. I'm really depressed tonight, so thanks for posting such an uplifting video buddy. I really appreciate it.

[@KreatorOfDeath1985]

YYYEESSS can't wait!

[@joetovar46]

Would like to have seen a comparison of the back pressure vs boost for both configurations. Also running each combination to its maximum boost/power would also be a good comparison.

[@nowayjose596]

Agreed. I suspect that as boost continued to increase the lower RPM responsiveness of the single would start to mirror that of the twins and the twins would make a bit more power up top thanks in part to their lower backpressure.

[@littleherms3285]

Ya, I was pretty disappointed he only went to 13psi. Should have at least gone to 18. All of those turbos don't get to their happy place until 16psi. Response is over rated. A good converter can fix A LOT. I had a 2.6L motor with a 70mm on it. Just gotta drive it like a man, it did rev to 8k which helped.

[@robertbenson1966]

Love your videos, i try to make sure that I like them to make your analitics good. Lmk if there is something we fans can do to help. So i road race, sebring, Watkins glen and other tracks, so how long do you think a motor can run at 1000Hp My laps are 1-2 minutes and we run 30 minute sprints. Full throttle is not long because tracks have lots of turns. I just bought a VS turbo and intercooler. I have a 10.5:1 small block chevy, dry sump circle track motor, bowtie block, brodix spch heads, im planning to have 5 pounds boost with a solenoid for 10 pounds on straight away. FYI i bought a VS racing turbo for my car based on your videos. You see guys are spending 50,000$ for 900Hp nascar engines, and i said thats silly, ive seen Richard make power with boost. So my plan is my 475 Hp NA engine will be 600Hp with 5 pounds and 875 at 10pounds. I only run race gas and will keep timing locked at 25 degrees. Your the best and i share your videos on Facebook all the time

[@azreeal1]

I love to see this with a 1500hp goal. I'd bet the twin setup spools faster than a huge single, but there's only one way to know for sure :)

[@richardholdener1727]

if they are both sized for 1500 hp-then it's a toss up

[@ruebenb83]

Yo, Rich! New to building domestic motors. Love the info you put out, wondering if you have any content on which transmissions to use with these high HP motors? Which engine management?

[@ruebenb83]

roller rockers?

[@nsmturbo5902]

I originally planned on twins but the plumbing takes up a lot of room. I'm gonna go back with a bigger single for ease of installation. I really wanted the cool factor of 2 but the S10 don't got the space.

[@oliverscorsim]

This was awesome man but hey I really wanted to see just this test butt can you post the back pressure too I wanna see the curves

[@tylerphelps4868]

This test got me thinking of another that would be interesting, and I apologize if you’ve done it already and I just haven’t seen it. In the coyote community, twins are generally the preferred method of turbocharging because it’s said that large singles end up having too much backpressure and that it causes issues with the valvetrain. That’s according to several tuners. I’d be curious just how different the total backpressure readings would be between similarly rated combinations like you have here and just how much that may or may not affect valvetrain. One can probably inference from the response rates of the two in this test that the single would have a fair amount more?

[@collinvickers1402]

Richard have you considered doing a video on single 7875 vs twin 7875? The 7875 can come in .96 backhousing helping with spool, but very curious on power differences between single or twin of the same turbo if there would be a big difference in power due to less heat, back pressure etc. Also curious if stock(ish) trim 4.8/5.3 could spoil two and see how it comes in on dyno

[@cboy132]

Single with more response. I love it. Where's the remote? Building a 2011Caprice 6.0 with a S480 in the spare tire bucket. Thanks!

[@ToprankImporters]

The heat statements with response outputs got me thinking about header wraps and turbo heat shields. Have you tested them?

[@jensgustavsson2871]

nice test richard! what size is the twin turbos ? compressor inlet and turbin in and out?

[@jsmcortina]

Good testing. Could you provide links to exact turbos used ? (Web shops or manufacturers pages please!)

[@tonymorris3798]

Twins will make similar power to a big single. The real advantage of twins is "Transient Response" usually called "lag". The ultimate test would be - make sure the exhaust housings are equivalent (same back pressure and similar spool rpm), set the dyno rpm to hold peak-torque-rpm, run the engine at that speed with light throttle, nail the throttle and record the boost response vs time at constant engine speed.

[@richardholdener1727]

that's not how an engine dyno works-that is a chassis dyno

[@time8533]

I would like to see you run twin 7875 on a gen one 406 and see what kind of power it pumps out. 👍

[@The3chordwonder]

I think I remember before you saying that headers help across the board with turbo, just like NA. Since in this test, the low RPM spool was where most of the difference was, I'm curious if the headers affect how fast it spools up, or if it is kind of a linear boost across all RPMs? I'd be curious to see a headers vs stock manifold test with a turbo (Or pair for that matter).

[@CanadianOnlooker]

The heat issue & turbo response reminds me of learning turbo spool is effected by energy as heat & pressure not just pressure from exhaust flow. EGT & air fuel ratio had a big effect, & because of those the variable cam timing had spool effects. I then looked into WRC anti lag using a gas turbine pre turbo, & a pressure tank to create not only air pressure to the turbo, but burning fuel to create heat/ energy to spool.. Subaru called it the rocket anti lag & its cool af if you Google it

[@richardholdener1727]

I''m familiar

[@FastFoxx82]

Two 7675 🤪 test would be cool too

[@MrZX1206]

Silly question here, what if you plumbed your exhaust like a compound? All 8 cylinders' exhaust goes into one of the turbos, then into the other turbo making for quick spooling. Next plumb your cold side like a normal twin setup, where each one breathes out into the intercooler, then the engine's intake manifold (not stacked boost). I imagine your back-pressure would be super high, but could you bleed it down with strategically placed waste-gates? You could use your single turbo Y pipe setup, then add the 2nd turbo onto the output of the 1st.

[@JPANDLIFE05]

I think the response of the single turbo is much better than the twins because all the 8 cylinders of exhaust gas is being feed into one turbine housing, while the twin turbo set-up splits the exhaust flow into 4 cylinders of exhaust gas flow per turbine housing. This tells me the exhaust pressure and volume from all 8 cylinders into 1 exhaust turbine housing is much higher than the 4 cylinders per turbine housing. This might be the reason for the greater responsiveness on the single turbo setup. This is only my opinion. I've never tested this theory, but this just makes the most sense to me. Now, if you do a compounded twin turbo setup, i think the outcome will surpass the single turbo setup in every aspect!

[@richardholdener1727]

it's turbo sizing

[@bstgarage7803]

When you run these gen 3 4.8's with the gen 4 rods and forged pistons, are you balancing the bottom end or just going full send?

[@martyhildebrand6392]

Would like too see more on a 408 Ford stroker twin turbos

[@bartpang]

I wonder if you changed rpm climb rate on the dyno if it would show a bigger response (Turbo lag) difference.

[@kellyheath8547]

I would like to know the weight of the turbos. Light is right! if a s480, or 78/75 can save 10 or 15 pounds over twin 62's then that could be a deciding factor. The other challenge is usually packaging.

[@tomcelica1030]

Richard I am about to make a video on polishing piston tops or “crowns”. Have you done this type of testing on the dyno? If so, what were your conclusions? Thx buddy!

[@fryloc359]

In one of the facebook groups I'm in, a guy built a quad turbo vette kart. I'd like to see the dyno chart for that.

[@The3chordwonder]

I don't know the flow rates, but is there something smaller than the GT35 that would pair it up against the single GT45? This was a great test and goes against everything I had thought. I don't think anyone is going to argue that a single turbo setup is way cheaper! Were those on 91 octane pump gas, or race gas?

[@kst8engineer]

@Richard Holdener, now you've got my curiosity up as to how a big/small sequential twin turbo combination would compare in terms of power potential and responsiveness. I'm thinking the flow limitation on the hot side of the small turbo would still limit the power potential.

[@richardholdener1727]

NOT IF YOU SWITCH EXHAUST FLOW OVER TO BIG TURBO

[@richardmorrison6134]

Did you know you can get the GT45s with a .68 exhaust A/R? Would make an interesting test for twins.

[@theidahomegarage8090]

I'd really like to run a super reliable 408 w/706, stage 2 btr truck cam, cheap twin system ata intercooler. Could I do that on 91 and 10-12lb spring in a waste gate reliably? I'd like to not have to do all the extra for a boost controller hopefully just spring pressure.

[@jaceyrondeau8133]

I'm building a twin set up with 2 of the VS Racing Gen2 78/75 turbos. They will be fed by a Dart SHP 427 sbf. Uncharted territory for me so will have to see how it goes)

[@shaneshane1379]

13 pounds.of.back pressure on each head compared to 18 pounds total for both heads raises thought. Pressure is pressure, but in reference to the turbo efficiency, I would have to say the single is more efficient. At 18 pound the single made the same near power level than 2 turbos that took 13 pounds of back pressure each. As far as the engine, lower back pressure is less effort on the engine to feed the boost. Therefore, maybe it won't blow up the first day you get it running.

[@corvetteZ3r]

Ready for your 4.2 atlas test my man!

[@hydrocarbon8272]

I'm curious if smaller GT30's with large hotsides would do better. The gt35's have much larger compressors combined (40% more flow) but obviously more hotside restriction, so they could be acting like the tc76 in the previous test.

[@hongmihnhahn7081]

wondering, in diesel just small change of boost is needed to fuel up. in gasoline, there is no necessary any adjustment with boost up?

[@MB-ib5ji]

I would so love to see a 1 liter Chevy Sprint turbo big Bang. heck you already have the turbo just take one of those who you got there... and has anyone else wondered if you could rub Richards head if some of that turbo knowledge would rub off?

[@ToddFordingLSX]

Will probably never happen but would be so cool

[@billybadass-ru8st]

you read that wrong...at same boost..11lbs., single is much better! Thanks for all you do. You have best channel out there for engine development.

[@richardholdener1727]

1 is not better than the other-chose for packaging or looks (turbo sizing can make twins and single otherwise identical)

[@Dodgevair]

If I go the twin route..gonna try a pair of G25-660 .72s I think the twin 3582s might have been a bit of overkill and hence not quite as responsive?

[@BruceLee-xn3nn]

GMT gearheads has put LS heads and intake on a 351w block.With twin turbos.

[@MrZX1206]

what is gmt gearheads?

[@strong_voice_of_truth]

I would have used twin 3076r on a 4.8 at those boost levels. Should spool quicker and be capable of nearly 1000hp.

[@tangstanggt5006]

I would like to have seen both at higher boost levels. Id bet the twin turbo setup would maintain the same boost rate and make more power at the same boost when reaching peak power potential. Lets see some 25+ psi runs.

[@d4rkmods738]

I would like to see a true t6 twin scroll setup vs open t4 setup on same turbo 😀

[@teal_2v338]

Soo if i do twin turbo my 4.6 , for a good overall power gain like the gt45 single did, should i pick even smaller turbos the the gt35? What size twin would be the best? For exemple a max of 6-700hp?

[@dennisroberts2857]

I like single gt-45 setup looks like more of street have setup twins or summit would make good drag race for top end.

[@shorty808100]

I know what it is on a big V8 a single is gonna spook up faster, but on a four cylinder or 2jz race engine I think a twin turbo or compound setup would be far better than a single turbo setup because they rev far higher and have a larger power band, I would like to see this done with a purpose built drag four cylinder or 2jz and see which is better I think for that the twin would be better but for V8’s you wanna make some boost get you a single 108mm turbo

[@DoctorMotorcycle]

That's very surprising to me that you had a 1:1 Pressure Ratio on the T3 Flanged GT3582's on 13psi of boost. I suspect you could go even smaller on the turbo's and still keep the PR under well under 2:1. I've always thought it would be cool to do a twin GTX3076 setup (or hell, even GTX2867's) with a small a/r to have a more "factory sized" setup that spools really fast and has the OEM turbo sized punch on a 4.8/5.3 LS.

[@richardholdener1727]

we could use gt3076s at this power level

[@AdamOpheim]

Thanks again for the test! Might try the .63 housing GT35's, esp. on a 4.8. (you can buy just the housings pretty cheap) The .82 AR exh housings are on the large side. I run the .63 AR T3 GT3582's with the billet 64mm upgrade ($250 ebay turbos) and the response is like a light switch on a mild gen4 5.3 (gm "hot cam") ... Although like most turbo autos I run a stall that's around 3400 anyway, so maybe I'm not seeing the early RPM issues. Crank that boost up for us and see if the twins shine!

[@tonymorris3798]

Agree. The twins were effectively running a bigger exhaust housing than the single - later spool and lower back-pressure.

[@jackstoepfer1494]

Would do recommend the same .63 on a cam 6.0?

[@AdamOpheim]

@@jackstoepfer1494 depends how you want them to act. Do you want more response down low, or more power and rpm up high?

[@jackstoepfer1494]

@@AdamOpheim I would say low to mid range. It’s for an off road truck. I want to hear the turbines when cruising around.

[@AdamOpheim]

@@jackstoepfer1494 Hearing them is usually a matter of exhaust. Housing size won't change that. Some turbines are just louder than others in general too. Mine weren't that loud and I just had 14" of 3" pipe on them. If you don't plan to push it much past 600-700 range , and want quickest spool possible, the .63's are fine IMO.

[@k.j.hopkins7111]

The difference between the twins and the single down low, how much difference would there be with a 5.3 of a 5.7 liter? Would the responsiveness with the twins down low not be as drastic?

[@troyclaerhout2412]

Twins and a trans brake is my pick.

[@dbjxxl4822]

Hey man, thanks for all the hard work you do putting out tons of good content! Quick question...for you, how come Dyno pulls don't really ever go below 3,000 RPMs? For example, when you want to build a daily driver, streetable combo especially in a heavier vehicle like a truck, it'd be nice to see what it would do from like 1,500 RPMs up. Is that an issue with how the dyno works, that it can't or they that gutless down low that it doesn't pay to? LOL Just wondering, thanks again for all your hard work.

[@richardholdener1727]

the dyno can load down that low-but how often are you at WOT at 1500 rpm?

[@dbjxxl4822]

@@richardholdener1727 I get what you're saying, I guess that's why they make different RPM stall converters and rear gear ratios lol. Thanks for the reply! Always looking forward to your next test!

[@kencohagen4967]

Ok, what about one small turbo, and one large turbo. One adding all its boost at low rpm, then one that takes over all the way to top rpm? The idea would be to make more low end torque at low rpm to get the car off the line and out of the corner, then at a given rpm power gets extended to red line. Would a valve be needed to shut down exhaust to the small turbo once there’s enough flow to get boost out of the larger turbo, and the opposite on the low end?

[@3800TURBO]

Be interesting to see what genuine gt3582r make. Id have thought those twins would way out do the single up top.

[@smp3745]

You need to do a run with a balance pipe in-between each turbo in the front of the engine and do another dyno pass

[@speedbuggy16v]

you sir are a bad influence, but you are correct, "twin turbo" does roll off the tongue nicely, I know in my head that a single will make way more power than I need... But twins oh boy, who does not love a set of twins.

[@bdog3869]

Richard while you have shown that single vs twins are pretty close. My question is if your looking for a quicker spool, and I know you’ll loose some top end power does it still go that a single vs twins would have the similar results for spooling necessarily while also attempting to keep a somewhat higher HP outcome? Greatly appreciate your input on this.

[@richardholdener1727]

single vs twin is a non issue-turbo sizing vs na power curve dictates spool response

[@twinturbohq]

What about truck manifolds vs equal length headers?

[@MrBlackbutang]

Yes it does! Back pressure is the key. Why did you run different turbos? True test would have been same turbo’s single vs twin. They would be air flow capabilities

[@richardholdener1727]

your choice is not a single or twin of the same turbo, you would never pick two turbos that size unless your goal was to make twice as much power. Sized properly for the desired goal, single and twin can do the same thing

[@parkerwayne4323]

Will you please do an 8.1 vortec build

[@SMOKEY-JAYS-DIESEL]

Hey Richard, please do this same test using the same big turbo and one of the little twin turbos Do a compound build that way it gets rid of exhaust back drive pressure I bet the numbers will be a lot better

[@richardholdener1727]

I have compound turbo vids up

[@SMOKEY-JAYS-DIESEL]

@@richardholdener1727 awesome brother. I will check them out

[@tunerdadtunerdad7927]

Thank you.

[@derekconard8234]

Richard you need to do some twin turbo bbc testing and stuff I know you love ls but give us bbc guys some nice info and testing would love to see some 496-540 with vs racing turbos or borgs

[@richardholdener1727]

I have several twin BBC videos up

[@seanlutzi2911]

Richard, im all in on the single turbo but my question is how do you tap into the lower RPM if your not looking for top end speed. Im looking for towing so what A/R should suffice(.68-.83?) on a 5.3 Silverado Heck i only need 5-7 psi tops.... but want it to hook up earlier in the power band.. say 2800-3400 rpms

[@richardholdener1727]

size the turbo for the desired combination of power and response-a single Gt3582 will be responsive