Twin turbo? [Merged 11-6]

[Tecson]

Originally posted by allgripnoslip
i think ultimately you should go for a sequential set up, just like the fd3s , im not biased really!

Ultimatley, I will turn it to a sequential set up.

 

[allgripnoslip]

yay

 

[clownface]

Originally posted by Tecson
Maybe it's how the pic is angled but what the hell are you talking about. Each turbo is connected to 2 tubes each. The one turbo is connected to the 1st and 4th and the other is 2nd and 3rd. The exhaust ports for the turbo on the left is blocked by the right turbo. I just need to fab a y dowpipe. It was previously tested on a 1g and worked beautifully.

o, okay, its really hard to see them, i guess i was actually being blind, hehe, the wrap was blending in with the driveway or w/e that is to my eyes but now that you mention it i can sorta see what the manifold looks like better. Well good then, cause i thought you where a idiot,

 

[InferiorWang]

hmm...swap one of those t25's for a t28? Would that work as a sequential? I'm trying to think exactly how those work. Would be nifty, tho.

 

[Scrymerr]

Seemed like no one really supported you until they saw the pic. I'll see if any of the guys up here would know anything.

--Dan

 

[PieTSI]

Ya a lot of people on here will say things like...It would be really cool for a TT GSX, etc. But never actually attempt it.

 

[Tecson]

It seems funny that it works out that way dosen't it? Anyhow, I really appreciate the help. Thanks

 

[Defiant]

I don't see the water and oiling being the problem, I'm more curious how 2000ccs are going to pump enough air to drive both of those.

Now, with a couple of turbos off something like the old Yamaha turbo 750 motorcycle, it'd not only work (once the pumbing nightmare was dealt with), but spool at about 1800rpm.

My skepticism is undaunted, and the monkey's showing no sign of stirring.

 

[project94tsi]

Originally posted by Defiant
Yes, good luck indeed. And take loads of pictures for us.
Monkeys will fly out my butt before this thing gets built.

haha. you really have to look.

 

[TSi92]

Originally posted by talonted_one
Your pic looks like it is a very well thought out design. I know someone has already done a TT DSM but I can't find out who or where it was. I know its hidden in the bowels of ClubDSM.org in the Digest some where.

Good luck to you and we want to see your progress when you make some.

Doug Derby had a twin turbo laser. In fact his IRC nick was twinturbolaser

 

[szewczyd]

Originally posted by TSi92
Doug Derby had a twin turbo laser. In fact his IRC nick was twinturbolaser

That's the guys name who had these on his car. Was it ever finished? if you go to his website, it never shows them as being finished.

 

[Tecson]

Originally posted by szewczyd
That's the guys name who had these on his car. Was it ever finished? if you go to his website, it never shows them as being finished.

I spoke to him and he had it on for two years. He said it worked great but the spacing and it did run a little "warm". He gave me the specs on his and he directed me to a place where I can check it out.
Depending on the performance, I will probably not be using the set up in my car exclusivley. It's probably going to be a show piece more than a daily driver.

 

[ditchmagnet]

well, i havent read all of the posts cause it would take to long...but just wanted to say my boss used to have a 10 sec tt talon, with a 150 shot...thats all i have to say.

 

[kpt4321]

Originally posted by ditchmagnet
well, i havent read all of the posts cause it would take to long...but just wanted to say my boss used to have a 10 sec tt talon, with a 150 shot...thats all i have to say.

Does he now? Can we see pictures or slips?

 

[clownface]

Originally posted by ditchmagnet
well, i havent read all of the posts cause it would take to long...but just wanted to say my boss used to have a 10 sec tt talon, with a 150 shot...thats all i have to say.

WELL my boss has a 6x supercharged engine with a million shot of rocket fuel that runs 3's. On a 87 laser. hehe

 

[RiceKiller_TSi]

Originally posted by ditchmagnet
well, i havent read all of the posts cause it would take to long...but just wanted to say my boss used to have a 10 sec tt talon, with a 150 shot...thats all i have to say.

Thats nothing because my boss has a 90 Talon that runs faster than the speed of light with an alien made engine in it. His turbo uses negatively charged ions to produce black matter. I heard his car out ran a comet once.

 

[LandoAWD]

...cut it out, guys.

Anyone can dream.

 

[kpt4321]

From a technical standpoint, this is a terrible idea. Especially with twin T-25's.

A T-25 spools at what, 2600 rpm or something on a regular DSM? You're attaching twin T-25's with stock sized turbine housings, and stock sized turbine wheels. In essence, you are providing the same amount of exhaust gasses with twice the flow area, and twice the turbo to move. It's going to spool a hell of a lot slower, we're probably talking 4000 rpm here. That's a good enough reason in itself not to do this, spooling after 4000 rpm makes a car pretty much useless on the street.

In order for a twin turbo system to work correctly, it has to be engineered very carefully. Now, single turbo systems need the same attention to detail, but you don't notice that because the work has already been done for you. On the other hand, the work has not been done for a twin turbo system. If you really wanted to do this right and make it work, you would need to spend way more time setting thing up than you have.

The system you have there would be equivelent, in terms of lag and boost response, to something larger than a FP Red or a GT35R. We're talking bigger than anyone on this website uses.

On the other hand, in terms of power potential on a 2 liter motor, you're talking much less, probably in the 400 horsepower range. Nothing to laugh at, no, but also not nearly enough to justify the insane amounts of lag. I don't feel like doing the power calculations now, but I may do them later tonight and come back to this thread.

Even if the system was set up correctly, twin turbos are inherently less effective than a single. When you do not have the packaging constraints of a V motor, or a packed engine bay, you will be able to make more power with less lag on a single turbo. A 4G63 does not have these constraints, as in either case the turbo will be mounted in approximately the same place with the same manifold style and size. Thus, a single turbo is always going to make more power and/or spool faster.

 

[Tecson]

Originally posted by kpt4321
From a technical standpoint, this is a terrible idea. Especially with twin T-25's.

A T-25 spools at what, 2600 rpm or something on a regular DSM? You're attaching twin T-25's with stock sized turbine housings, and stock sized turbine wheels. In essence, you are providing the same amount of exhaust gasses with twice the flow area, and twice the turbo to move. It's going to spool a hell of a lot slower, we're probably talking 4000 rpm here. That's a good enough reason in itself not to do this, spooling after 4000 rpm makes a car pretty much useless on the street.

In order for a twin turbo system to work correctly, it has to be engineered very carefully. Now, single turbo systems need the same attention to detail, but you don't notice that because the work has already been done for you. On the other hand, the work has not been done for a twin turbo system. If you really wanted to do this right and make it work, you would need to spend way more time setting thing up than you have.

The system you have there would be equivelent, in terms of lag and boost response, to something larger than a FP Red or a GT35R. We're talking bigger than anyone on this website uses.

On the other hand, in terms of power potential on a 2 liter motor, you're talking much less, probably in the 400 horsepower range. Nothing to laugh at, no, but also not nearly enough to justify the insane amounts of lag. I don't feel like doing the power calculations now, but I may do them later tonight and come back to this thread.

Even if the system was set up correctly, twin turbos are inherently less effective than a single. When you do not have the packaging constraints of a V motor, or a packed engine bay, you will be able to make more power with less lag on a single turbo. A 4G63 does not have these constraints, as in either case the turbo will be mounted in approximately the same place with the same manifold style and size. Thus, a single turbo is always going to make more power and/or spool faster.

WOW That was amazing!
Well if the set up I have now won't be effeciant, How about one small turbo for the fast spooling and a larger one that waits til the smallerone is done and it takes over. Kind of like the sequential deal. I agree that two stock turbos won't cut it but what about the other option?

 

[RiceKiller_TSi]

Originally posted by Tecson
WOW That was amazing!
Well if the set up I have now won't be effeciant, How about one small turbo for the fast spooling and a larger one that waits til the smallerone is done and it takes over. Kind of like the sequential deal. I agree that two stock turbos won't cut it but what about the other option?

I like this guy ^^

 

[kpt4321]

Just to expand on my earlier post:

Due to compressor speed limitations, the T-25 is really only going to be capable of somewhere around 18-20 psi. That number is taken from the compressor maps of a couple comparable turbos, since I can't find a T-25 compressor chart. You get the idea though.

So, the power limitation is an issue of airflow that the motor will accept, not airflow that the turbos can put out. Twin T-25's at 18 psi could probably put out more than 500 horsepower worth of airflow (slightly over 50 lb/min, in my estimation). However, a 2.0 liter 4G63 is certainly not going to accept that much airflow, not within normal rev limits. At 18-20 psi of boost, you will likely not make more than ~ 400 crank horsepower. I wouldn't take 4000+ rpm to full boost for 400 chp.:thumbdown

On the other hand, this shows that such a setup would work great for a car with a larger motor. For example, a 3.0 liter V6 like the motor in a 3000GT or 300ZX would do very well in terms of power production with twin T-25's. You'd probably want to resize the turbine side still, though.

 

[Tecson]

Originally posted by kpt4321
Just to expand on my earlier post:

Due to compressor speed limitations, the T-25 is really only going to be capable of somewhere around 18-20 psi. That number is taken from the compressor maps of a couple comparable turbos, since I can't find a T-25 compressor chart. You get the idea though.

So, the power limitation is an issue of airflow that the motor will accept, not airflow that the turbos can put out. Twin T-25's at 18 psi could probably put out more than 500 horsepower worth of airflow (slightly over 50 lb/min, in my estimation). However, a 2.0 liter 4G63 is certainly not going to accept that much airflow, not within normal rev limits. At 18-20 psi of boost, you will likely not make more than ~ 400 crank horsepower. I wouldn't take 4000+ rpm to full boost for 400 chp.:thumbdown

On the other hand, this shows that such a setup would work great for a car with a larger motor. For example, a 3.0 liter V6 like the motor in a 3000GT or 300ZX would do very well in terms of power production with twin T-25's. You'd probably want to resize the turbine side still, though.

I'm not going to stick with t25 for long.
What are your thoughts on the sequential turbos?

 

[kpt4321]

Originally posted by Tecson
WOW That was amazing!
Well if the set up I have now won't be effeciant, How about one small turbo for the fast spooling and a larger one that waits til the smallerone is done and it takes over. Kind of like the sequential deal. I agree that two stock turbos won't cut it but what about the other option?

Thank you. I'm glad to see that you soaked it right up!

The problem with sequential turbos is exhaust routing. In theory, you could build a sequential setup which would spool faster than a single and still be able to make the same power (or make more power for the same spool characteristics). The problem is that, unlike a regular twin setup, you don't just put half of the exhaust gas through each turbo.

With a sequential turbo setup, you have to set up the exhaust so that it is initialy going through the smaller turbo, and then as the boost pressure increases a diverter valve will open and send the gas through both turbos, and then through the larger turbo only. This is similar in design to a wastegate, but you want it set up so that in the end most or all of the exhaust is going through the larger turbo (which means that a standard sized wastegate will not fit).

So, the real issue at this point is setting up the exhaust. You need a fairly complex system that looks like a regular manifold, but then goes through some kind of transfer device, from where it could enter the two turbos.

This is a fun discussion!

 

[kpt4321]

Originally posted by Tecson
I'm not going to stick with t25 for long.
What are your thoughts on the sequential turbos?

Sheesh! Patience!

 

[Tecson]

Originally posted by kpt4321
Thank you. I'm glad to see that you soaked it right up!

The problem with sequential turbos is exhaust routing. In theory, you could build a sequential setup which would spool faster than a single and still be able to make the same power (or make more power for the same spool characteristics). The problem is that, unlike a regular twin setup, you don't just put half of the exhaust gas through each turbo.

With a sequential turbo setup, you have to set up the exhaust so that it is initialy going through the smaller turbo, and then as the boost pressure increases a diverter valve will open and send the gas through both turbos, and then through the larger turbo only. This is similar in design to a wastegate, but you want it set up so that in the end most or all of the exhaust is going through the larger turbo (which means that a standard sized wastegate will not fit).

So, the real issue at this point is setting up the exhaust. You need a fairly complex system that looks like a regular manifold, but then goes through some kind of transfer device, from where it could enter the two turbos.

This is a fun discussion!

Through a sequential set up, with enough air; won't the smaller turbo stop being effective and just allow air to flow though? and that's when the larger on take over?