Big Boost!! Full Results!! 1 Mistake!! Compound Turbo 4.8L!!
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- čas přidán 12. 09. 2024
- 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?
Love the longer video with the in depth analysis. Something about a compound setup just sounds mesmerizing, almost demonic 👍🏻
I want to see one with a supercharger - best of both worlds!
P
I like the idea of all the brains u put in it pretty much cool
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!
Your like Engine Masters on steroids. good job Richard. I'm enjoying your content.
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...🤣 🤣 🤣
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...
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.
Kyle Milligan happy there are Guys Out there who like dyno results as much as I do
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
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
did you miss the part about these being the turbos I had laying around?
@@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.
@@BoostForBreakfast thnx for the advice
@@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. 🤦♂️
@@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.
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.
love the longer detailed format man. Glad you got to play and we were entertained
Thnx-should be like this going forward!
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.
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.
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)
:)
I have it vs an S475 I ran on this motor
@@richardholdener1727 new to the channel so may have missed it :)
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
@@richardholdener1727 I seen the comment. The secret is out hahaha
Results the same, just power comes on later in the powerband
I pressed “ like” times🤣🤣🤣. Thank you for doing experiments we would never dare do.
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".
My favorite part if this is trying to picture the engine bay that this fits into...
2nd time I'm watching this series, appreciate the knowledge you've given us!
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.
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
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.
That's the purpose of compound turbo, to spool faster. Besides 8 cylinders will spool a single turbo pretty well
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.
Hydrocarbon82 fully agree, and my comment below touches on that a bit.
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.
Sequential might be a better choice for an LS-just harder to plumb
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.
I should be receiving my compound setup short block from the machine shop next week. 🤙
We appreciate all you do.
😼Hey Richard, when you get done with compound turbos. Do a boosted engine with 12.5:1 compression. With whatever fuel it takes.
S rage that works
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
Very interesting setup - thank you. Better audio would make a huge difference in the overall video quality.
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
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.
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
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.
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..
THAT DIDN'T WORK
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.
William Moody I would love to but not much support for them
Thanks , very interesting vid . I’m glad you fixed the 4.8 lt and got it all working ! Looking forward to the next vid !
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.
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👍
And love your videos! Keep em coming! I'm learning a lot!
Double the pressure, double the fun. Don't forget lower egt with Compound turbos.
Love that braille welding!
Ridiculously good tech here Richard, thank you!!
Thank you for watching
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.
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
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 :)
Yet another very informative video. Glad to see you love your work (play).
Keep up the great videos.
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.
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
I'd love to see an optimized compound setup, with intercoolers after each stage, on proper built motor.
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.
Lots of info to digest.
Looks like you put alot of work into this one. 👍
It was a lot of building, fixing the motor, testing and editing, but that's how we learn and have fun.
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
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?
Love the grassroots breakdown, beats the big corp shows
BW s280 and s400 make a killer combination on a 6.0.
I would like to see a compound setup with a procharger style blower and a turbo!
I'd love to see this as well. Seems like a perfect "have your cake and eat it too" scenario.
@@scottrussell2281 honestly it usually is the exact opposite of that. This would be the correct system, but he has all the wrong sizes between the turbos and the big turbo has to small of an exhaust.
What we need to see is an lsa blower with a turbo
The trick would be figuring out the pully ratio so that you don't max the procharger too early and get the big turbo to spool faster. Screw and paddle blowers work for this, but their lifespans are drastically shortened due to vein deflection from so much pressure on the inlet side. In the end we're asking components to do things they were never intended to do.
@@ARK842001 see the problem with a centrifugal supercharger paired with an even larger turbo is that they are both rising boost curves so they really wouldn't be that great until you got all the way to the top. Ask the Duramax guys who tried it. It in the end just kind of sucked.
849 HP is nasty on a compound setup. IDK why people dont often do it since it is very efficient
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.
With a a setup like this im looking for : Higher low end power/ longer high end torque/ and continuous shift boost.
Talk with Gale Banks on this Turbo set up. I'm almost certain you can crack 1000 horsepower reliable threw Gale's information.
You need have the small turbo feeding the big turbo. Then have the big turbo feed the engine.
I know I saw the compound test I must have missed this one 👍
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.
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
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.
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 CZcams 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.
as explained, there was a reason we didn't add more torque down low but it is certainly possible
@@richardholdener1727 When I said the torque curve was glorious I'm referring to how long and flat it was, not the amount.
@@johnparrish9215 no worries, you can shape the curve nicely with dual controllers on a compound
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.
The hand gestures kill me. Lol
why can't he just stand still
Because...*waves arms* EMPHASIS! It’s like yelling, but without caps.
I'm with the guy who wants to see lower rpm boost. The whole point of compounds is to get boost lower in the rpms. 4500 from an ls isn't that great. I bet with a properly sized small turbo that big charger will come on way earlier
we can make a lot more low speed torque by adjusting the controller for the small turbo-just didn't want the load in torque on the dyno-but you can have it on the street or track
Would like to see a jy 5.3 with a quality ring set pushed on low torque with this setup to see what the gen3 & gen4 rods and stock crank can handle. When these things start to let go
You're the guy who loves detonation...
@@justinbryant237 Or maybe he knows how to tune.
@@wheezin_the_juice the Gen 3 properly tuned in fueled will make an excess of 1000 crank horsepower then the rods will start to bend roughly about 1300 a 1400 horsepower on a Gen 4 then the rods break. The tuning the tuning the tuning the tuning the tune is extremely critical
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.
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.
this combination of turbos will do that-we just didn't want that much torque on the load in
How about two compound setups (4 turbos), one compound running off the left bank, and vice versa, going into dual 4 barrel.... With nitrous. And methanol... On e85
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?
in the teens-13-14
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.
i have not tried one
Looks like you didn't really need the 3rd waste gate. But maybe bigger gates for the other 2
I'd really like to see a built bottom end that can handle all the benefits of a compound Turbo System. I'd like to see it make power like a motor twice its size. I really think you need another wastegate in between the small turbo and Big Turbo or bigger Gates. that way you can turn the spring pressure up on your small turbo to the same level as your big turbo or close to it. The 7 lb Springs are probably being blown open before that turbo even make 7 pounds... so you're not even getting the benefit of the small Turbo.
all the boost as indicated-we can raise the boost up on the small turbo as much as desired-we just didn’t want the load-in torque
I would just love to see what the setup can actually do versus you holding it back and I do realize why you're holding it back... it needs a built bottom end that can handle it.
Richard what about sequential turbos rather than compounds . Same setup. Instead of running the s480s outlet into the 7665 inlet take both otlets And y them together.
Sequential is cool but hard to get the switch over and requires a lot of tubing and valves
I've always wondered what the power difference would be .
If I were to do it I would use 2 throttle bodys on the outlets with out any springs making it so air can flow one way freely and if it try to flow back naturally it would close. Everything else I would keep the same. Pressure would work its self out look triple turbo diesels .
I'll tell you what your 4.8 made more power than my 5.9 with s488 . Gotta love rpm and free flowing heads.
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?
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?
we usually don't run them on the dyno but have not tested them with sensors are you described
The ONLY thing I dont like about compound turbo's iis reliability.. Too many extra variables that take effect. Compound supercharger/turbo setup seems much more reasonable, reliable and makes more sense in the grand scheme. The turbo driven off the exhaust and the supercharger driven off the engine, sounds like the combo!
neither is really necessary on a LS
I wish I lived closer, I'd help with audio, motors would sound sooooooo goood....
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
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
Great video Richard! Turbo boost is thought as free HP by using the waste exhaust of an engine. All forms of boost use crankshaft HP. You once mentioned of running a second engine, to supply the exhaust to feed a turbo(s), to determine the amount of crankshaft HP consumed by a turbo system. Did this experiment ever happen? Thank you, Tony
I have not but that would be cool-the turbo uses very little power-basically just the back pressure-much less than superchargers at the same boost level
I wonder if you could possibly get a close estimate if you ran the engine with turbo and measure the back pressure. Then run the engine N/A , then replicate the same amount of back pressure on the N/A engine that the turbo engine has. Of course the Hp would be lower so you would have use it as a percentage of Hp loss per.
Excuse me if I made that sound confusing! lol but im interested to see also!
@@JohnnyAnderson1 you can see the effect of back pressure if we eliminate it with the right turbo, but its 20-30 hp compared to 200-300 hp at high boost with a supercharger
😂😂
@@richardholdener1727 IMHO your estimated 20-30hp loss is a little conservative. I'm in agreement when you minimize the exhaust to intake pressure ratio, that hp will increase. However, exhaust back pressure is still a load on the engine, not the same load as a blower with all the rotational mass of the rotors, frictional losses and inefficiencies. Maybe in the order of 1/2 the hp loss of a belt driven blower?
I like the concept behind this but my only problem is with application. Unless you are building a rear engine setup or you're dropping this in a dump truck/18 wheeler, you can't mount this system in a race car or truck and have any visibility. Your system is great for proving the benefits of compound boost but needs work when it comes to fitment in everyday applications.
it only had to fit the dyno-we would plumb differently for a specific chassis
Everybody was kung fu fighting
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.
+1
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.
I'd have tried to get that small turbo to light up at lower rpm... it's probably too large.
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
I want to see a compound Turbo on a hellcat long block thru a holley intake.
When you graduate from HS and they ask you what you wanna do with your life; what will it be Richard? A doctor? A lawyer? An accountant? "I wanna be the guy that builds and dynos engines all day".
Great setup! Interesting data. Nice work !
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
Kind of the wrong too for the job. Compounds are there to make bit low rpm and midrange power/torque. The response being fully lit by 4500 makes me think the compound is a bit of a moot point . Probably also needed some more wastegate before the high pressure turbine because the drivepressure across the high side turbine should be a lot closer to manifold pressure along with low pressure turbine being more equal to boost level between the low and high pressure turbo
The actual point of compound turbos is to use the small turbo to increase the effective displacement of the engine so that it will have the required exhaust energy to spool a very large turbo. I the Diesel World yes we use compound turbos to increase the mid range and low end torque/horsepower but this is just a side effect of what is actually going on.
@@compted10 no, thats the entire point of why you compound. turbo response at lower rpm. peak power will not change and in some cases increase running a large turbo or just the atmospheric turbo in this case alone. peak airflow is dicated by the larges compressor open to atmosphere
@@whatchu_talkin_john_willis no the point of the small turbo is to create the exhaust flow of a larger engine. The reason big turbos can make more power alone is back pressure control as well as the compressor cover restrictions.
@@compted10 no lol, that is the FUNCTION (IE how it works) not the objective (the goal you're trying to achieve) the objective is to increase engine power delivery responsiveness (IE quicker turbo response) and widen the usable powercurve.
@@whatchu_talkin_john_willis I think we are arguing the same point from both ends.
I know very little, but aren't you suppose to compound the smaller turbo ( which boosts faster) to the larger turbo to spool it faster? Cool set up.
play with compound supercharger/turbo. OEM are going that way as opposed to compound turbo. in your setup, the engine sees that 23psi back pressure. An SC creates no back pressure and has instant throttle response. the S480 might even be too small for that setup.
Good stuff brother keep up the awesome work
great video and information as always
I think the atmospheric turbo needs to be larger both the turbine and compressor side to move more air at a lower pressure ratio.
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.
Compound turbos size by compressor maps differential and expected boost result.
Set each turbo to run in the start and end of the compressor map highest efficiency bubble. Tune boost reference for each to be dead center of the efficiency maps and then reference will increase or decrease both turbos simultaneously in the optimum zone. Giving you the least back pressure. Your set up is barely using the first turbo and running the second one way out on the map if I had to guess. Shane from Mazworx is "THE TURBO AUTHORITY" I don't know who else is running 150psi boost out of twins making 3000hp in a 4 cylinder reliably all season. I found a video of him talking to HP Academy.
czcams.com/video/1pV_tLbZY0A/video.html
You can keep the same boost and bring the backpressure waay down for biggerer numbers!
On a side note, snows water/meth injection is pretty much equal to C16 race gas in knock prevention. If you use a two stage pressurized into the intake pipe and tune for the added fuel of the meth it's within 10hp of E85. People aren't really onto it yet, but it is definitely the answer. No need to worry about E85 anymore. A case of -20f washer fluid and a case of the yellow heet water remover fuel antifreeze if you want to raise the methanol content.
You can set up a relay for tank level, pump running, and a pressure switch. Run the meth by boost pressure so you can tune for it and not waste it when you have no need. Run the relay to your ECU and have it go to regular tune if you lose the 5v signal. Adding 6+ pounds of boost and timing, so a warning light won't cut it. You'll smoke a Piston before you can let off unless you program for the signal. Like ref 7 equals tune 1B. I would definitely like to see that set up with the balanced turbos with -20 washer fluid and a can of yellow heet. I bet it is a viral video
I imagine this is mentioned below, but your high pressure turbos wastegate (the small turbo) doesn't have its "atmospheric" reference. You shouldnt reference the post IC line only, you need to connect to the mid charge pipe. The top of the gates is seeing dyno room pressure, not its inlet pressure. The delta of pressures makes this system work correctly. Would love to see this happen again with these updates!
Interesting from an academic perspective, but with modern turbo's there doesn't seem to be much value in a compound setup (for low boost applications.) That intake vs exhaust pressure difference is pretty bad and no doubt robbing a load of power.
Would have been good to see what the power curve on just a single large turbo would have been. No doubt capable of supplying the required mass flow.
Are you trying to sign? Or what is that spastic flailing suposed to be?
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
The hands bro the hands.
Corey Cripps articulate and gesticulate
Glad you got this thing working. Probably not viable for the weight and complexity but sure is cool to see
sometimes I just need to have fun! That usually just means spending a lot of extra time and money!
@@richardholdener1727 I know that struggle
thank's from Brazil !
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My right ear thanks you.