Big Boost!! Full Results!! 1 Mistake!! Compound Turbo 4.8L!!

Two turbos, three waste gates and two waste gate controllers-just 1 mistake! Here in part 4 (the finale), I supply complete dyno results of the compound turbo 4.8L LS. It's making boost! I finally got the compound turbo system up and running on the little motor. I combined a little CXRacing 76-mm turbo with a (big) LJMS Borg (Billet Wheel) S480-cuz I had both at the shop! Find out what happened when I left the waste gate controller line off the Turbo Smart waste gate controlling the big turbo! Did it go ballistic?

[@heytonyman]

Love the longer video with the in depth analysis. Something about a compound setup just sounds mesmerizing, almost demonic 👍🏻

[@BLKMGK4]

I want to see one with a supercharger - best of both worlds!

[@donnalance4942]

P I like the idea of all the brains u put in it pretty much cool

[@wakjob961]

I can tell you're passionate about your work...you're a lucky dude to be doing what you love. ...and it shows. Cheers man!

[@cerberes]

Your like Engine Masters on steroids. good job Richard. I'm enjoying your content.

[@Brock_Landers]

Dick-Terd...sorry man, I have a friend named Richard, and that's what I've always called him. I'll go sit in the corner now...🤣 🤣 🤣

[@Brock_Landers]

You're absolutely right though. I have Motor Trend on Demand and You're absolutely right about Richard's channel. Engine Masters pales in comparison to Richard's...

[@kylemilligan752]

Mr Holdener, I am glad you have come so far and are now able to do the research you love and share it with everyone. I've been reading, following your work in magazines, and buying a pile of your books for about 30 years now. A million thanks to you sir, for a mountain of REAL and unbiased data.

[@richardholdener1727]

Kyle Milligan happy there are Guys Out there who like dyno results as much as I do

[@kylemilligan752]

I lived out my dreams as a kid, reading about your tests and research. Had a dynojet 248 in house, built and tuned all kinds of V8's, turbo 4's and everything inbetween. It was a great time. Glad to see you making a good living at it😁 Good job Mr Holdener😁 One of my Heroes

[@jessemurray1757]

love the longer detailed format man. Glad you got to play and we were entertained

[@richardholdener1727]

Thnx-should be like this going forward!

[@plumbs7199]

Thanks , very interesting vid . I’m glad you fixed the 4.8 lt and got it all working ! Looking forward to the next vid !

[@SuprSi]

2nd time I'm watching this series, appreciate the knowledge you've given us!

[@dennishill9873]

I pressed “ like” times🤣🤣🤣. Thank you for doing experiments we would never dare do.

[@boostaddict_]

In this configuration, that cooler is actually an aftercooler. It's after all the compressor stages. If it were mounted between the turbos, then it would be an intercooler.

[@woog74]

You post so much great/useful content that is right to the point. This video is one of the most interesting for learning. I doubt I will ever be messing with compounds, my brain barely comprehends singles, but this was very interesting.

[@keithstella2278]

Yet another very informative video. Glad to see you love your work (play). Keep up the great videos.

[@tptrsn]

Ridiculously good tech here Richard, thank you!!

[@richardholdener1727]

Thank you for watching

[@vortecturbo]

I think what you did was pretty awesome Richard. it's something I've wanted to do for a while. Personal funds haven't been there even though I have just about everything gathered up to do such. I thought of this process about 4-5 years ago. The issue that I see with what you did was you built a very inefficient exhaust feed for the primary turbo and then downsized it going to the larger Turbo.(also two wastegates are not needed for a single system.like unless if it's a big boost Set up. A larger wastegate ex.60 mm for the primary side would give you a lot better control what the primary Turbo. Also would allow the volume necessitated to drive the secondary Turbo it would bring down the drive pressure a good bit. Because now the primary turbo going along for the ride since the secondary Turbo is really doing the work. Also with the secondary turbo since you have so much energy coming out from the primary turbo plus the wastegate bypass you need to run a larger gate example 66 mm the secondary side which would give you a lot better control with the secondary Turbo. And would allow the volume necessity to do drive secondary turbo it would bring down the drive pressure a good bit. Because now the primary turbos going along for the ride since the secondary turbo is really doing the work. also with the secondary turbo since you have so much energy coming out from the primary turbo plus the wastegate bypass you need to run a larger gate example 66 mm to the secondary turbocharger. You can stage the wastegate Springs differently between the primary and secondary Turbo no problem and if you can figure it properly you can control it all on one boost controller. Plus sizing a turbo properly for the application is also very critical. You can stage the wastegate Springs differently between the primary and secondary turbo no problem and if you can figure it properly you can control it all on one boost controller. Plus sizing the turbos properly for the application is also very critical. I would definitely have a smaller turbo than a 76 for the primary something long the lines like a board Warner S366 with a lager than usual exhaust hosing for such a small motor if you're really wanting it to come on violent like a PDS blower car.

[@mikefpe]

Great work, This is a very informative video. Compound turbo set ups are no easy feet and there is a lot of conflicting information and opinions on the internet (as always). I’m building a compound turbo 4 pot zetec on my channel and was led to believe you can run the main boost controlling wastegates in the manifold to atmosphere with the other bypassing the little turbo. Effectively controlling the overall boost pressure from both units and relieving the back pressure. I can’t wait to get mine up and running to start seeing first hand what works and what needs tweaking to get the most out of the set up.

[@ThePeopleVerse]

Lots of info to digest. Looks like you put alot of work into this one. 👍

[@richardholdener1727]

It was a lot of building, fixing the motor, testing and editing, but that's how we learn and have fun.

[@mikewestgrove4248]

Great setup! Interesting data. Nice work !

[@michaelperry355]

Love that braille welding!

[@ShakeyJake1984]

And love your videos! Keep em coming! I'm learning a lot!

[@briangammey2189]

Love the videos now! What was the back pressure before the small turbo at 21psi? Maybe you could do a video on crossover pipe size next. Since the internet engineers claim two inch pipe is all you need or you will kill velocity and spool time. Keep up the good work, you need your own show on motor trend.

[@nelsonperez9385]

Good stuff brother keep up the awesome work

[@jesserasso1042]

Bro you do everything rite even if it is wrong your the one testing and doing this for all of us I dont see anyone else doing what you do

[@BoostForBreakfast]

The 76mm turbo was too big on the small turbo if you run an 80mm for a big turbo. You need to look at the pre/post compressor pressure ratios on each turbo and get them into their efficiency range in their compressor maps Should size sorta like this: - a larger turbine t4 67mm with 60mm gates and a t6 80mm big turbo. Drop intake duration & lift on the cam to get the turbos into their realistic efficeny PR's for this setup: Take for instance an T04r-derived 67mm and a s480 based 80mm: 67mm: 1.4-2.4 PR 80mm: 2.0-3.2 (Yes, they can be taken higher, but lets be realistic on total boost). which means on the low end: (if atmospheric is 14.5psaiA ish) Psi interstage (between turbos): ~14-15psiG (2.0pr) Manifold(after small turbo): 21psiG (1.5) - 33psiG (2.4). You need to monitor pressure between each stage and adjust the gates to hit the best PR for the desired overall boost. On compounds, boost is your friend, so you need to size the cam differently than on a single stage setup. Almost like a PD blower cam. Much smaller lift and shorter duration on the intake side

[@richardholdener1727]

did you miss the part about these being the turbos I had laying around?

[@BoostForBreakfast]

@@richardholdener1727 No, I didnt. I was just making suggestions to help with the educational process of your videos. If you watch my vids, a lot of what we do is just from stuff laying around so I get and appreciate your work. I was simply making suggestions that can be applied in the future to help.

[@richardholdener1727]

@@BoostForBreakfast thnx for the advice

[@monsterram6617]

@@richardholdener1727 I didn't miss the part about you doing this with parts lying around. But that doesn't change facts. These turbos are improperly sized and the piping is a disaster. So if you were doing a "here's what not to do on a compound setup", you knocked it out of the park. But a lot of us want to see it done right. You should take BoostForBreakfast 's comment to heart, as there was more useful information concerning properly sizing compounds in his comment, than in your compound video series. But I get it, you had this stuff lying around. 🤦‍♂️

[@BoostForBreakfast]

@@dj4monie yea, not much discussion on my channel about stuff yet. I was referring to the 'budget' stuff that is on there. I need to put together more content - just been very busy with work. Gale is one of the kings in the diesel world - i follow a lot of his stuff.

[@colonelk3000]

For illustration purposes it would be great to see a comparison between this and the S480 big turbo as just a single on the 4.8 (ie what happens when you run the big turbo only in a normal non-compound setup) :)

[@richardholdener1727]

I have it vs an S475 I ran on this motor

[@colonelk3000]

@@richardholdener1727 new to the channel so may have missed it :)

[@richardholdener1727]

colonelk3000 no worries my friend -the results of the s475 aren’t up-you are the only one that knows I ran it-so shssssh-don’t tell any one

[@benjaminofuasia9236]

@@richardholdener1727 I seen the comment. The secret is out hahaha

[@kylemilford8758]

Results the same, just power comes on later in the powerband

[@B0RN2RACE100]

You should do that quick spool valve with an open header into a twin scroll turbo, show us the back pressure and all that good info. And if it worth it for a big motor

[@kansai9685]

great video and information as always

[@TurboJohn74]

Love the grassroots breakdown, beats the big corp shows

[@brandonpanozzo86]

So much info you the man richard

[@socleanmx6]

We appreciate all you do.

[@mlchristopher]

Very interesting setup - thank you. Better audio would make a huge difference in the overall video quality.

[@MrLandslide84]

This guy is me, with money. LOL. "Bro, what if we....." I'd be skipping thru aisles of my own racking, with a shopping cart, "this, and this, ooooooo you too, yup need this".

[@kdsboosted4954]

I should be receiving my compound setup short block from the machine shop next week. 🤙

[@chruisallen7932]

Hey Dick, its one thing to survive a dyno pull, but keep an eye on the smaller turbo rpm, might only be blowing through it but rotation speed will chernobyl that wind pump of yours. Much love on your vids, we should link up.

[@SreidMX]

I know a couple dudes asked about lower end torque but I think we’d love to see the results of a built 4.8 and see how far you can push it down in the rpm range like 2200 to 4500 which is where most street and towing get done

[@hydrocarbon8272]

Generally when sized right it spools faster than the small turbo and makes the power of the big turbo. Plus the big turbo can use a much oversized turbine equivalent to what you'd size for an engine with the displacement the engine w/small turbo spits out. THAT is where sizing comes into play. If the large turbo is too small, it chokes the engine. Too large and it relies on the small turbo too long.

[@lapieces]

That's the purpose of compound turbo, to spool faster. Besides 8 cylinders will spool a single turbo pretty well

[@SreidMX]

lapieces I think that makes sense in theory but demonstrating it is another deal. For a lot of guys sizing a turbo properly is still black magic, and going off anecdotal evidence is lucky at best. A lot of these motors are going into trucks, Richard and I have chatted about this a bit already. This is good conversation to have because there is a lot of doubt out there regarding towing with a turbo ls.. which from my research has been done with great success.

[@SreidMX]

Hydrocarbon82 fully agree, and my comment below touches on that a bit.

[@beaugouin4383]

feed the masses!!! love it!!!!

[@btiracingmotorsports7492]

Good video and commentary 👍🏼

[@richardholdener1727]

thnx

[@johnny2fast661]

Double the pressure, double the fun. Don't forget lower egt with Compound turbos.

[@201mBrasil]

thank's from Brazil !

[@richardholdener1727]

thnx for checking us out

[@GregoryBrettin]

Very cool info!

[@curvs4me]

That's the sweetness of it. Sized properly with plenty of wastegate on the primary with a 30-35% larger secondary you can eliminate lag and get boost off launch without cooking the valves and turbine two stepping. Two step sucks for the turbo and the motor.

[@genepatrick]

i would love to see an update with this. maybe get more of that low end that you were talking about and see how early and flat you could get the horse power. as always great video. its also funny to watch your older stuff compared to what you put out now. you've gotten a lot better at editing. you should consider "remastering" some of your older content :)

[@LandonRoy-cv9rt]

Dear Richard... You may have the best "job" of any man....if you can call what you do work and not just having the timenof your life lol. Good work as usual👍

[@russbrensing8982]

Very good video. I'm very interested in how much torque could be produced from a 4.8 or 5.3 if the lower end was built. I'm always wishing I had more torque with the smaller LS.

[@wild12valve]

Hey love your videos. Ideally you'd have one big wastegate before the small turbo that controls both banks, and vent it to atmosphere, that way you control both turbos at the same time, if you slow down the small turbo compared to the larger one you're losing the whole point of the compund setup, the slower the small turbo moves the less air it multiplies and the less exhaust that passes through the turbine because it's spinning slower.

[@ygtcbee23]

The compound turbo made a believer out of me. Thought it was too complicated till I saw the low end boost numbers with the adjustment. Next time run it with 12psi down low. Want to see those numbers

[@Chris-bn1bn]

I'm sure that most everyone would really like to see how tunable/possible output. I've been thinking alot about this set-up myself. Thanks

[@Chris-bn1bn]

It would be nice if there were forged internals. What good is a motor that wouldn't last 500 miles, not to mention to see how much power a compound set-up can make with a high reving short stoke engine. Thanks for the info that you bring us.

[@salvadorebertolone]

an interstage bypass bleed may be a good idea. turbine engines with multiple compressor stages usually have them to control surge for different sections of compressor stages as the compressors come up on their maps differently and surge often requires a partial tear down or at a minimum a borescope inspection

[@georgem.6136]

Really cool video

[@richardholdener1727]

thnx

[@Incognitodemons]

I have been toying with this idea for a rotary engine for circuit use to gain torque down low but still have high boost levels at the rotary crazy rpm range but I can not figure out how to size the turbos properly. I do want to do a trick intake set up to play with those compounds as well.

[@jakestern95]

I'd love to see an optimized compound setup, with intercoolers after each stage, on proper built motor.

[@kjewer1]

I'm not sure mine is properly built or optimized, but 1200 hp on a 2 liter 4 cylinder with ice water intercooling for each stage works very well.

[@srage9188]

😼Hey Richard, when you get done with compound turbos. Do a boosted engine with 12.5:1 compression. With whatever fuel it takes.

[@richardholdener1727]

S rage that works

[@joshuafarwell9761]

Ill be around 12.5:1 compression in my audi a4 1.8t on e85 With compound turbos. Should make about 500awhp. I think high compression is the way to go if you have access to corn juice

[@jeromieysommers2032]

Ever think about trying a turbo from a Duramax with a variable vane tubo. Should create so big response. It be super fun to try and make that combo work. Gives u one more thing u can control to make controllable boost and response.

[@vgnfab]

I have a compound turbo Subaru outback. two holset diesel turbos. Been driving well over a year. I haven't added a wastegate between the two turbos yet. Getting some emaps setup soon.

[@Sruikyl]

Interesting results! Thank you for testing this stuff. I was wondering if you've ever messed around with the steam ports? A lot of guys say they just block them off but some say if you do you can cause hot spots in the cylinder heads? has any testing been done on this with multiple temp sensors and/or egt sensors?

[@richardholdener1727]

we usually don't run them on the dyno but have not tested them with sensors are you described

[@Dunehoon]

Awesome!

[@bradpittman5075]

I believe the compound turbo systems and combo boost centrifugal plus turbo are probably designed around high altitude performance. Like airplanes. Where at sea level a single supercharger may make enough boogie but at 20,000 it doesn’t. I like the idea but I think the turbos are good enough now that big single or twins is probably going to yield the best results. Cool test though.

[@AndyFromm]

That's some interesting piping

[@Hitman-ds1ei]

That was real interesting, some things I predicted to myself but some things surprised me a little, would like to see you do a compound positive blower/ turbo deal, I know LSA blowers are not as plentiful as 4.8 & 5.3 motors but how about it, LSA blower stock cam with big turbo then LS9 cam same combo then perf NA cam then blower cam then turbo cam, like to see pressure ratios and boost curves compared to compound turbo deal

[@shainiac]

My right ear thanks you.

[@eb972]

The hand gestures kill me. Lol

[@richardholdener1727]

why can't he just stand still

[@n8rivera74]

Because...*waves arms* EMPHASIS! It’s like yelling, but without caps.

[@markmmm1737]

Isnt the point of compound turbo for high pressure boost. Wouldnt a sequential turbo setup give you the same result in a better way? Still a very interesting subject, nice job.

[@richardholdener1727]

Sequential might be a better choice for an LS-just harder to plumb

[@RonnieT123]

Cool fun!

[@trevohlson9733]

Awesome video only one thing wouldn't it be better to have the small compressor feeding the larger turbo inducer and then going through the cooler to the motor so it helps to minimize lag for the large turbo but i have seen it done both ways

[@andyharman3022]

Tractor pullers have been doing compound turbos on diesels since the 1970's, at up to 3 stages and 240 psi boost. Then they started doing 2 stage compound turbo at up to 80 psi boost on diesels converted to run on methanol with spark ignition in the 1980's. Go to a tractor pull and look at these guys' engines and talk to them. They're pulling 4500 HP from International 466's, they must know something.

[@ShakeyJake1984]

The third wastegate and big turbo are the only things creating boost. The first turbo is being bypassed by the way you have it routed.. try eliminating the third wastegates and let the first 2 vent to atmosphere. That way the little turbo can work with the large turbo like it needs to..

[@richardholdener1727]

THAT DIDN'T WORK

[@NTRGFX]

Hey Richard! Could you make a video about how to control boost and tune effectively. I feel like most people know how turbos work but don't know about wastegates, blow off valves, etc.

[@n8rivera74]

+1

[@dilsher12]

I think the atmospheric turbo needs to be larger both the turbine and compressor side to move more air at a lower pressure ratio.

[@wbmjr46]

What about doing something on the Vortec 454/496 2001-2009. Would be interesting to see what kind of power you can get out of the stock bottom end, even though they are all iron motors.

[@richardholdener1727]

William Moody I would love to but not much support for them

[@hondatech5000]

I know I saw the compound test I must have missed this one 👍

[@Dirtfloorfab]

Glad you got this thing working. Probably not viable for the weight and complexity but sure is cool to see

[@richardholdener1727]

sometimes I just need to have fun! That usually just means spending a lot of extra time and money!

[@Dirtfloorfab]

@@richardholdener1727 I know that struggle

[@Danielvarady]

Im thinking of a twin gt45 turbo build on a 6.0 liter! Can you do a video about backpressure i need more info please. Thanks. I like all your videos your my go to for all l s info Richards!😊👍

[@soundslikealot]

Awesome test, learned a ton! Thank you! As for the future videos (or maybe I’ve missed it?) I would like to know about choosing a cam for different applications. I guess the most popular engine is still 5.3 but how do I choose the cam for my vehicle? Racing VS street VS towing. It’s not always about maximum power ;) There’re some popular cams like 220/224, 228/230 etc. but you have probably the biggest data and results on all of those.

[@dennistate9951]

If you are running a street driven car or truck and you want a little more power then an LS TRUCK cam will do the job. If your looking for a little more power/ torque than that a COMP CAM or BTR cathedral port cam in the low 230 duration on the intake side will do the job. Now if your looking a little more high end HP than I would shoot for a RECTANGULAR PORT CAM in the mid to high 230-239 duration on the intake side cuz it will have a lot more exhaust duration that the cathedral port style cam.. just my opinion.. just wanted to give you a little a point in the right direction so you can dig into some more research on the info I gave you.. take care bud

[@soundslikealot]

Dennis Tate thank you! 🙌 Question was answered 👍

[@exvils]

well, in this case where one turbo is smaller than other, i would run with spool valve (or other type of TB in exhaust), so i get boost in low rpm, but still carry it to higher rpm with bigger turbo.. in your case to get smaller backpressure, i would put one more wastegate before 1st turbo and also use at least air-air intercooler as heatsink after 2nd turbo

[@debbiehipsher3855]

Dude u r awesome

[@johnparrish9215]

Mr. Holdener, nice test although I'm surprised at the high back pressure, I thought the two wastegates would have lowered that. I was looking around on KZbin and found DeBoss Garage did something similar but completely different. Lookup: Four diesel turbos on an LS and you will find theirs. You made a lot more peak power but their torque curve is glorious, in the LAST (when everything worked) run A lot to learn in both experiments.

[@richardholdener1727]

as explained, there was a reason we didn't add more torque down low but it is certainly possible

[@johnparrish9215]

@@richardholdener1727 When I said the torque curve was glorious I'm referring to how long and flat it was, not the amount.

[@richardholdener1727]

@@johnparrish9215 no worries, you can shape the curve nicely with dual controllers on a compound

[@rickyvwt]

Richard I thought the hole compound turbo was made for getting a "flat line" HP and torque wise, so you dont loose power in the rev range?

[@gsxr1100lw]

Can you try a compound turbo setup on a GM series 2 3800 v6 or GM 4200 inline 6 since there are plenty of them in the junkyard.

[@tuloko16]

BW s280 and s400 make a killer combination on a 6.0.

[@Sawmods]

The hands bro the hands.

[@richardholdener1727]

Corey Cripps articulate and gesticulate

[@albertdeleon6272]

Everybody was kung fu fighting

[@curvs4me]

Questions? Did you size the turbos for peak efficiency across them in the maps? IE smaller turbo peak efficiency is maybe 8 pounds? And the larger one likes 15? The boost reference for both turbos needs to be tied together. Smaller from start to end of peak efficiency and same with the larger, whatever it may be. To get desired boost level, differential across both will move in sync. Once the ranges are set u never control separately. You'll get more power that way at the same boost level across the board. I learned that jazz from Shane at Mazworx. He does an interview with High Performance Academy. Vid is called 3000hp, 150 psi of boost

[@mikemaccracken3112]

Pretty cool. Those stock rods and pistons do not liked to be clubbed over the head at low rpm. Richard what was the timing at low rpm?

[@richardholdener1727]

in the teens-13-14

[@kennethporst4359]

With a a setup like this im looking for : Higher low end power/ longer high end torque/ and continuous shift boost.

[@funfun8095]

Richard "HANDS" Holdener! LOL ;)

[@capsoval]

Got a test for you to do. How about a 4.8 compound turbo setup with twin ebay gt45’s as the “big” turbos”. Have no idea what size primary turbo to use so that’s up to you.

[@ZaneCronk]

Great content, how about doing a twin charged setup with a roots blower? I’m more interested in How to produce low down torque than massive hp numbers. Great video though

[@Mtnbike121]

Cubic inches solves that.

[@abec666]

If wg line of both turbos are on the same reference spot on the intake what will happen is this: Small turbo spools -> makes 7 psi and that psi opens all the wastegates including the big turbo wastegate. This way you as a result make 7psi on the small turbos and then you take them out of the equation aka you bypass them, and have that 7psi from the big turbo. Small turbo has its wategates wide open, air follows the less ressistance pass and all gases go through the wategates to the big turbo for it to make 7 psi. The thing that you can do this mean you have enough wastegate flow on the small turbo and thats perfect. The thing that you couldnt raise pressure on the big turbo is not because of back pressure its the opposite. Its because the combination of 2 things 1) pressure multiplies on compound turbos 2) wastegate reference point. If big turbo pressurises to 2 p.r (1bar) and that air goes to small turbo to be pressurised again to 2p.r. (1 bar) Final result wont be 1 bar + 1 bar = 2 bar. It will be 2pr x 2pr aka 4 times the atmospheric ressure AKA 4 bars of boost. What this means is that IF the small turbo receives pressurised air the final boost will be multiple times your small turbo wastegate and will open too quick. For your desired pressurisation. The trick is to put the big turbo wastegate line to the intermediate charge piping and then you have the staged compression result and boost controll. This way youll see how fast the boost raises because of the multipling effect. if you hook a boost gauge on the intermediate piping youll see that when the big turbo is sleeping you have vaccum or 0 bar reading. When the small turbo wastegate opens and you have enought exuast gases for the big turbo to be pressurised every 1 psi on the intermediate pipe will be 2 or more on your normal boost gauge. This way you compare final to intermediate pressure to find what % of the boost the small turbo creates. And then to controll boost accordingly.

[@MrLightning54]

So aside from quickened boost response would this be any faster in a car at the same manifold boost pressure as a single correctly sized turbo. Very interesting, just wondering if there would be a reason to do this aside from a video like this.

[@delamin8r]

If you ever find yourself with a smaller small turbo and a bigger big turbo just sitting around, I'd love to see what that sort of combination could do. Seems like it ought to be possible to get 15-20psi boost around 2k RPM from the little one, and 1000+whp at the top end from the big one, which would be delightful.

[@richardholdener1727]

this combination of turbos will do that-we just didn't want that much torque on the load in

[@johnparrish9215]

Mr. Holdener, Diesel Power Source makes a VGT turbo in the S300 and S400 sizes. They say the turbine has a ratio spread from .48 to 1.10, it is controlled by the exhaust drive pressure. Have you ever tested a VGT Turbo?? Do you think Diesel Power Source would let you borrow one?? I'm sure they would, if it worked out they would make sales.

[@richardholdener1727]

i have not tried one

[@TheProchargedmopar]

Muffler shop in the woods using a park bench. My kinda place. 💪👍

[@richardholdener1727]

My Tail Gate Turbo!

[@Mr5gtt]

why not connect the primary turbo`s(small) wastgate reference signal to the exhaust manifold and the big turbo`s wastegate (the one actually controling ultimate engine boost)to the intake manifold and set the primary turbo`s wastegate spring pressure to the desired intake manifold boost.this way i think you would have balance between the turbos and maybe a 1:1 pressure differential in the exahust man and intake manifold provided the secondary exhaust housing doesn`t get restrictive?

[@dannythompson1948]

850hp???? Freaking insane! What kind of compression? I want to build a small block ford that can achieve this.. I have a 66 fastback I'm about to turn into a runner

[@josephscarborough23]

Can you do this again but with a intercooler and a aftercooler

[@jackmagnium6115]

849 HP is nasty on a compound setup. IDK why people dont often do it since it is very efficient

[@MrLandslide84]

I wish I lived closer, I'd help with audio, motors would sound sooooooo goood....

[@michaelyon7856]

I want to see a compound Turbo on a hellcat long block thru a holley intake.

[@finnroen2334]

Would it be an ide to put the wg for the big turbo on the primary pipes so the exhaust bypasses the hole system? Maybe there is no need to push exhaust to be wastegated through the small turbo first?

[@teacherm96]

Would this turbocharger set just be for trucks or heavy vehicles. How fast does this set spool up? Could the Holley set be used to set the boost control? What was the torque down low? Thanks

[@richardholdener1727]

it would not be just for trucks-it could be used for any performance application, it spools up quick with the small turbo, Holley can run an electronic controller and you can adjust the torque output as indicated in the video

[@sinformant]

Boost creep to infinity and beyond!

[@michaelrodgers6559]

I'd have tried to get that small turbo to light up at lower rpm... it's probably too large.