FortuneLS

i concur

PHLSingle

Clint -

You're right, the thread starter started asking about running the EXHAUST from one turbo into the other. That is compound charging....

See Picture:


That certainly looks like the exhaust from the 1st turbo is getting fed into the bigger turbo.

sc3boost

thats what i was talking about, but both turbos will have there own air filter.

so is this fairly new or have the diesel guys been doing this for a while. and no one has done it to a gas engine...................



also most members are really knowldgeable about lexus/toyota/turbos etc, and there are the guys like me who know enough to get by, and i'm always looking to learn more, but then there are guys like me that also get swell headed and think they know everything,and we all know no one knows everything. (no offence to anyone)

when i first signed up i read 5 threads that said one thing and 7 post that said another.

i say that the mods shoud erase all the bs threads that will misslead someone into thinking that something is what it's not.

Dramon

However, what i was reffering to and more realistically is you have one turbo capable of flowing 50 lbs at 17 psi. And you have two turbos capable of flowing 25 each at 10 then yes you will produce the exact same hp considering all other variables equal.

Flow and pressure are relative but they are not the same thing. with same pressure the flow CAN CHANGE, without chaning anythign inside the motor And yes I agree with you in your example.

sc300tt

No. He never said running the compressed air into the intake of the next turbo.. He said running the exhaust into the next turbo, which has nothing to do with compound charging, although it is setup this way. You could easily have run the setup with both compressed outlets running to the intake manifold of the engine. The setup shown has nothing to do with improving spool.....50psi...90psi? Is anybody here running anything remotely close to that? Is it setup for spool improvement? NO! Is there a small turbo running in front of the larger one? NO! Compound turbos have nothing to do with this argument. They are meant for one thing......big pressure ratios.

sc300tt

Of course you agree, because I am right. Even you're above example is wrong again!! You're statement that twins will make more HP over a big single at a given boost level is completely and utterly WRONG!. It completely depends on the setup. Period. Number of turbos, does not matter. Are you hearing me? You are wrong. WRONG! WRONG! WRONG!

PHLSingle

Easy killer....let's start off by stating I am NOT saying doing this to your Lex or Supra...whatever - however.....Let's be honest - he didn't exactly know what he was asking about - just an idea he was having. And more or less...he was thinking about what I posted.

Have you even built a system like this? Been in a truck with twins like this? Seen dyno charts from big single vs this setup on a diesel? Yes, apples to oranges - that is because NO ONE has done it on a GTE motor...only in the diesel world with big motors moving around alot of air.

Does it improve spool on a diesel over a big single? Yes...
Is there a small turbo & large turbo working together? Yes...

Any other questions? Besides finding room accepting the 100lbs of turbos and pipes you'd hang off the side of your motor?

Dramon

You are completely and utterly WRONG!! I have been and just did say SIMILAR and SAME hp numbers throughout the entire times i've been posting.

Last time I chekced same hp did not mean more. You're jumping all over me for things that i'm not even saying.

The entire point of what I said was that you can run the twin setup at lower boost to achieve the same results. And yes I am correct. Why are you so deadset on a specific boost level. Boost levels dont mean crap becuase it all depends on the turbo and it's compressor map. And I never said that twins will make more hp over a big single at a given boost level. Read what I said, and when youre done, read it again becuase apparently youre not grasping it.

Maybe you need to take a few deep breaths and chill before you post becuase I never said that more turbos make more horsepower ever. And I know it completely depends on the setup, I know all this. Youre pulling arguements over things that I never even said.

sc3boost

guys i was always under the impression that every turbo has it's advantages and dissadvantages,

a small turbo on a 3L engine might spool at 2000rpm and give the impression that the car is farster than it actually is, and a big turbo will make mega hp but it might start to really spool at 3000-4000rpm, so the engine with small turbo will jump off the line faster, but will get smoked a couple feet into the race. am i right???

and i have another question if a big single turbo makes 800hp, and a TT makes the same 800hp, would'nt the TT spool faster (depending on the turbos)even though they have the same power

what you guys are arguing about is useless unless you get a single turbo car and another with appropriate twins and let them race.

sc300tt

Do you see something contradictory about your statements? First you say that twins will achieve the same results at lower boost than a single, and by "same results" you are implying same hp because there is no other definition for "same results" in this context. Then you go on to say that boost levels dont mean crap, yet you just made a statement regarding "lower boost". Then you say you never said twins will make more hp over a single and a given boost level, but by your first quoted statement above, you say twins achieve similar results at lower boost, which would mean that at equal boost, they would have to make more hp.

Point blank., you are making utterly incorrect statements. But please, attempt to prove me wrong by explaining the way twins "achieve the same results at lower boost" in a scientific form, talking about compressor efficiency, mass of air, air temps, etc. I need a good laugh.

CleanSC

Sure you did. Post #35:

sc3boost

that **** was funny

dramon you got caught red handed.

Dramon

I'm still not seeing where I said they'd make more hp.

I said that they'd flow SIMILAR air.

similar does not mean more.

Two smaller turbos can flow similar air to a single bigger turbo at lower boost levels. Granted the turbos have to be similarly sized. Of course two t25's wont flow the same amount compared to a t88 at lower boost, but i'm pretty sure two t04e's would flow about the same as say a gt35/40 at lower boost levels.

sc300tt

Sorry, this thread is driving me bonkers.

Yes, there is a small and large turbo working together, but this setup is not to achieve improved spool. It is setup that way because modded diesels run over 50+psi, which is over a 3:1 pressure ratio which is where turbos fall off dramatically in efficiency. I remember the thread on Supraforums about all this, and of course, nothing ever came of it. Why because it doesn't offer a spool advantage. If it did, you would see it used in racing. It's not a very difficult setup and it's not new technology.

Dramon

I said that that boost levels dont mean crap in reference to your stating that the twins have to be running the same amount of boost. They dont. It is possible to flow the same air with 14 psi as it is with 17 psi on two different turbos. It dpeends on the compressor map.

"Then you say you never said twins will make more hp over a single and a given boost level, but by your first quoted statement above, you say twins achieve similar results at lower boost, which would mean that at equal boost, they would have to make more hp. "

And in some circumstances I suppose yes they could make more hp, but thats not even the point I was trying to make. All i said was for the most part at lower boost twins can push the same air as a bigger single. I never said anything about them making more hp at equal boost levels and granted the larger single isnt way too much bigger than the other one yes they should. And in that case you could just turn the boost up on the single and you'd be even again. AND IT ALL DEPENDS ON THE TURBO. HOW BIG THE BIG IS, HOW SMALL THE TWINS ARE. It was a general statement that for the most part is correct granted the difference isnt too extreme. And in some cases yes two smaller twins could make more at the same boost as a big single. But in other cases the higher boost on the two twins could put them out of their efficiency range.


It all depends on the VE of the turbos. The benefit of smaller twins versus a bigger single is faster response time due to inertia. but a bigger single has better VE in it's range, typically. Ultimately you're trying to figure out what will get the most volume of air in the chamber at the fastest and coolest rate And that can depend on a number of things..Like, a twin GT25/30BB versus an archaic T78..The GT's will spool faster and run cooler assuming they're within their VE curve when compared to the t78 running high boost.

Though you could take that arguement and compare t25's to a GT35RS and it'd be the complete opposite. I'm sorry about my statement earlier and I revise it to twins can flow same air at lower boost. On that same note Two t78's flowing at exactly half boost will make the same volume as one t78 flowing full boost. Assuming the efficiency is identical at that boost level, which it's not. Though if you found two smaller turbos with a similar ratio of boost to volume multiplied by two as the single t78 at that efficiency range then yes it'd be correct.

This arguement is retarded. And not becuase i'm right or youre right. Just becuase I think that we're argueing about the same thing. Quit trolling and giving me this you better watch out becuase youre a newb and i'm a vet crap on the forums. Just becuase i'm new to this forum doesnt mean i'm new to cars. ****, last time I checked we're all here becuase we like sc's.