Twin turbo? [Merged 11-6]

[kpt4321]

what if you had all 4 cyl spooling both turbos?

Doesn't matter, still sucks.

 

[clownface]

It's a diesel, the point is to make lots of power.

Diesel's run much more boost than you are used to, so they often run two turbos in series.

It's not at all what you want on a gasoline powered car.

Thats cool. I want big arse turbo diesel truck, hehe. How much more boost do diesles run?? like 30 psi? 40?

 

[nanokpsi]

Thats cool. I want big arse turbo diesel truck, hehe. How much more boost do diesles run?? like 30 psi? 40?

Shit, they run that much boost stock. A semi local guy around here has a series twin turboed cummings 2500. he runs 11.40s and 100 psi. So yeah, more than you

 

[DSMJim]

Thats cool. I want big arse turbo diesel truck, hehe. How much more boost do diesles run?? like 30 psi? 40?

Double that, like 60-80psi.

 

[hellotbone]

Jim have you been looking at my Rams boost gauge dreaming again!

 

[Eagle 5]

this could be a stupid idea and may not help any but why not somehow make the exit fo the frist turbo go right into the turbine of the 2nd turbo then to downpipe. so all flow form cylinders goes through first turbo, then out tis exit into next turbo, then to exhaust? i doubt there is room for it and this wya would most likely cause some kidn of problem as the exhaust gas has to go through 2 turbines, at which point they both may be making different amounts of boost.....

ok that idea probably would not work but, its an idea. if you want to do it becuase you can then do it. who cares whether or not it gives good performance. most of the people on this site are only about performance and if you dont do something the exact right way thats its been done many times before, they think its crap and shouldnt be done.

so i say do it just becuase you CAN and its something to do. wont cost you too much since you can make some of your own stuff. the people on this site are very helpful but sometimes they are a-holes about stuff.

 

[hellotbone]

This is how we do it on the Cummins Diesels and any other Diesel truck for that matter.

You see how it works thats the only way I can see it working on a 4 cyl. If you run just 2 turbo's and have 2 mani's feeding with 2 cyl I don't think there is enough ehx pressure to run it. However compound it like this and maybe you have a shot. The diesel truck this is on is a straight 6 and they are about 100 of them with this kit right now. Depending on how they are setup etc come run from 60 psi boost to over 120 psi of boost depending on the application. There is virtually no turbo lag in this setup and both turbo's are wasted so you will not over run the baby when it runs out of capacity. If you have ever heard one of these go there is nothing like it. 2 trucks now have gone over 1000 RWHP and just over 1800'lbs of torque. Its getting serious in the Diesel biz!

 

[Eagle 5]

^^^ thats like my idea only i didnt think of running the comp outlet of one to the comp inlet of the other. that would probably be the best way to make it work and work somewhat well.

 

[AWDLATIN]

 

[Tallen]

This is how we do it on the Cummins Diesels and any other Diesel truck for that matter.

You see how it works thats the only way I can see it working on a 4 cyl. If you run just 2 turbo's and have 2 mani's feeding with 2 cyl I don't think there is enough ehx pressure to run it. However compound it like this and maybe you have a shot. The diesel truck this is on is a straight 6 and they are about 100 of them with this kit right now. Depending on how they are setup etc come run from 60 psi boost to over 120 psi of boost depending on the application. There is virtually no turbo lag in this setup and both turbo's are wasted so you will not over run the baby when it runs out of capacity. If you have ever heard one of these go there is nothing like it. 2 trucks now have gone over 1000 RWHP and just over 1800'lbs of torque. Its getting serious in the Diesel biz!

Only problem is that this is not a diesel motor. Both engines have different demands and requirements.

 

[kpt4321]

^^^ thats like my idea only i didnt think of running the comp outlet of one to the comp inlet of the other. that would probably be the best way to make it work and work somewhat well.

Argh. People, please just stop trying to think of new and improved ways to make this "work."

First of all, running two turbos in series on a gasoline engine is a terrible idea, for lots of reasons. On the hot side, the turbine contributes to a huge drop in temperature and pressure; this is where the turbo gets its power from. If you run two turbine sides in series, then the first turbo will cause a huge pressure drop, which will cause the second turbo to get much less potential energy.

In addition, the second turbo will decrease the PR across the first, which will make it so both of them extract less energy from the exhaust.

You need to run the turbine sides in parallel.

On the cold (compressor) side, you also need to run them in parallel. The only reason that picture has themin series is because it is for a damned diesel, which wants 60+ psi of boost. One turbo simply has a difficult job of achieving a PR that high (5+). By running two turbos in series, you decrease the PR across each of th compressors, which makes their life easier.

However, because they are in series, you are no longer using two smaller turbos to create approximately double the airflow that one of them could push. Instead, each seperate turbo must be capable of flowing the air that you need, which means two big turbos. I presume you don't want to run two 20g's on your car, do you?

Can this damned thread die, please?

 

[Aikouka]

The reason that twin turbos suck has nothing to do with displacement, it's the law of physics (particularily the way flow capacity and size are related.) A twin turbo setup sucks on 2 liters and sucks on 8, compared to a single turbo.

Why bother with seperate intake manifolds, except to make your life that much more difficult? There is no performance merit to doing that.

I didn't set it up as a performance design with two manifolds, but I already thought about a single manifold design last night, which would be better overall.

And if someone were to make a set-up that worked, we know that a smaller turbos combined should have a pressure increase once the two air streams are combined. So, even if you used a simultaneous turbocharger set-up, you should see a combination in pressure.

 

[Defiant]

I am also hell bent now because people are saying it cant be done. I will turn haters into believers, I hope!

Well, the winged monkeys in my butt are anxious to fledge.

 

[GSntncT]

Well, the winged monkeys in my butt are anxious to fledge.

:laugh: , and I thought I was an ass at times. I think for this guy at this point in time he has to options:

Put the hell up, or shut the hell up.

 

[kpt4321]

And if someone were to make a set-up that worked, we know that a smaller turbos combined should have a pressure increase once the two air streams are combined. So, even if you used a simultaneous turbocharger set-up, you should see a combination in pressure.

Two turbos in parallel do NOT add pressure when the air streams combine. If each turbo has 9 psi coming out of it, then the manifold pressure after the streams come together is 9 psi.

 

[Boosted98gsx]

Two turbos in parallel do NOT add pressure when the air streams combine. If each turbo has 9 psi coming out of it, then the manifold pressure after the streams come together is 9 psi.

This is where PSI vs airflow comes into play. While you will only get 9psi, you will also achieve (if using 2 of the same turbochargers) double the airflow.

 

[coltboostin]

yes, their is no gain in pressure with turbos run parallel. When you run them in a series though, the pressure rises a a multiple. that is how desil guys run rediculous amounts of pressure. What you do gain is airflow, which makes more power. 2 turbo's at 9psi will be pumping double the volume of air into the motor.

It is a matter of what I have time for, and right now time is an issue. 3 jobs pays the bills , but does not leave time for much else. We shall see, thansk for the links though.

 

[kpt4321]

What you do gain is airflow, which makes more power. 2 turbo's at 9psi will be pumping double the volume of air into the motor.

I hope you are not saying that 2 turbos at 9 psi will flow twice the air volume as one turbo at 9 psi...

 

[clownface]

Wouldnt two turbos making 9 psi mean that each turbo is doing like 4.5 psi or something?

 

[L2RTSiAWD]

Ok dead horse beaten enough.

 

[FireyIce01]

Was wondering what y'all thought of this idea. I was thinking about making a custom tubular header with dual turbo mounts on it (one for cyls 1 and 4 and a second for cyls 2 and 3) run a pair of small T3 turbo's with external 34mm wastegates.

Other than the fabrication required, do you think that this would have spool up problems, would a pair of T3's be able to support 50+ lbs/min of air (2.3L, 8.5:1,23psi, 1600cc injectors, walboro 255 pump, HKS 272/272 cams) Would this engine need more airflow, I haven't quite figured out the equations, as I put the numbers in for 4000 rpms and got appros 35 lbs/min and when I put the numbers in for 8500 rpms I got over 200 lbs/min which can't possibly be right, and as far as I can remember (I did this a couple nights ago) the only number that changed was the CFM that the engine would be flowing at the higher rpms... *shrugs*

For those that are wondering, the intent behind this is to have enough turbo volume to handle the power I want to make, while still having a small enough turbo setup to spool up before it hits 3 or 4 grand... was also thinking about having a small turbo pumping the air through a larger turbo as a secondary option, and perhaps run a intercooler between the 2, but that would be a plumbing nightmare in the compact DSM engine compartment, wheras I think I could manage to get 2 small turbos side by side.

Anybody have ideas?

 

[!^3]

Hmmm...well one guy tried it and gave up after realizing there was virtually no way of efficiently cooling the turbos with oil/water. That and you'd make more power with one turbo than two.

IMO, a built motor, nitrous, and a GT35R will serve you just fine

 

[FireyIce01]

Hmmm...well one guy tried it and gave up after realizing there was virtually no way of efficiently cooling the turbos with oil/water. That and you'd make more power with one turbo than two.

IMO, a built motor, nitrous, and a GT35R will serve you just fine

Yea, oil plumbing was something I was trying to figure out still, cause you can't run from one turbo into the next or you'd coke the bearings in the second turbo for sure... but if you ran an external oil cooler, before or after each turbo that would be a possible option... just means more fabrication... Will keep doing my homework, if anybody has any other info, or things that I need to watch out for, please lemme know

 

[blue1]

There was a thread on here or on DSMtalk that someone had tried this and was not successful either. 4 cyls apparently dont twin turbo for some technical,engineering,flow,rod length versus day of the week thing! if i could remember how far back it was i would point you to it it was quite informative and would possibly make you forget about trying it and not wasting time,money and effort. try the searches on both sites!! Good luck.

 

[Sharkcus]

A guy over at turbododge.com twin turbo'd a shadow. He recently took his site down, but you can get most of whatever is left at the following link:

http://web.archive.org/web/20030206233146/www.omniturbo.com/Turbo+Mopars+Home.htm

it might take a min. to load, but all the info is there.

In conclusion, I think he stated it was a fun project but did not get any substancial gains out of it that he couldn't get from a larger turbo.