Galant VR4

[iceminion]

Ok guys, this is for my 91 GVR4.

I have been saving up and doing this one right, I have the following ready to be installed:

TRE Stage2 Transmission, welded diff, taller 5th
(Switchable Transfer case w/ shifter, 2wd/4wd from the cab)
DNP T3 Mani w/Tail44 wg
SC6152s
GM Maf w/translator
Chipped ECU for the 780cc injectors
SAFC2 for fine tuning
Bar and Plate FMIC
And soon to be in my possession 280 cams with springs

Driveline mods: 4-bolt w/4WS, KYB AGXs w/ground controls, Complete ABS delete (ran all new lines, SS Flex lines, New 2-piston calipers, 5-lug converstion.

Not sure what I am going to be doing with the block, its a 2.0. I really know that I should get a 2.3 or 2.4 but thats not in the budget yet. I have been told that alot of the fun I had with my old small 16g would be gone forever due to my "large" turbo (please no comments from MAP and their Borg Warner s300).

I want to have my cake and eat it too. I want this thing to spool fast, so I was looking over NOS kits (yeah, I know its a brand, I just like saying it that way) and I am scared, I dont want to do it.

How about this: a remote mounted T25 before the muffler and after the rear diff? There would ovbiously be a cutout/dump right before the T25, probably activated by the stock wastegate actuator.

what do you think?

I am familiar with the details: remote oil and water pumps/tanks/coolers.

Will I need to isolate the turbos from each other? under low RPM boost, will the air from the T25 seep backwards through the SC61? and will the SC61 blow backwards through the T25 under high RPM boost?

thanks, and no flaming for thinking outside the box.

[FattyBoomBatty]

You need to look carefully at pictures of dual turbo systems on turbodiesel pickup trucks, or maybe 3rd gen rx7's. You can plumb it so one will blow into the other and not flow backward and such, but I think you'd want something larger than a t25 in terms of flow capability, because even if you have the big turbo, the way it works is that somewhere, all the air either intake or exhaust will have to flow through at least one side of the t25 and you will be restricted.

[iceminion]

I can solve the problem for the exhaust side, it will only flow through both turbos when the t25 is boosting, and when the sc61 reaches full boost the cutout will be completely open, and then the t25 will be basically not be in the equation anymore.

the only problem that I can see (for now) is that having 2 inlets to the pressurized intake side.

But thanks, ill look into the rx7s' setup

[Kevin 1G Drummer]

You would probably want to put the smaller turbo a little closer to the engine. By the time the exhaust gets that far back, most of the velocity of the exhaust gas will be gone, plus, you'd have to pressurise all of the piping going up to the 61, so that would kill the spool time of that turbo.

[iceminion]

Thanks for the feedback, I have read up alot on remote mount turbo systems, here are my thoughts:

This mod is cheap, and does not affect any of the previous mods in any way whatsoever, a slight modification to the exhaust and intake pipe is it, if it turns out to be a dismal failure, then it is a failure, but guess what, I dont think it will.

I have read up on remote turbo systems and they seem to work out great, there seems to be a great amount of what I like to call "automotive superstition" behind remote mount turbo systems, as I understand it the exhaust is leaving the engine at the same rate no matter what, there will be slight differences because of heat, the colder the exhaust gas the smaller the mass, so less air = worse spool time.

ok, so this T25 may not spool like it does on a stock 2g, I am still pretty sure that it (remote mount) will still spool faster then a 14b on a stock 1g.

I am really excited to do this, I hope to prove all of you wrong, who knows, maybe I have stumbled on to something here, because there is no way to fit 2 turbos under the hood of a 1g easily, this may change everything.

[Hoffer00]

Let us know how it works out.
So we all can:seeya:

[JET]

I would say just spend $300 on a 2.4 block, much easier and cheaper. Run higher compression pistons if you want better spool, those 280 cams aren't going to help either :P

[iceminion]

Correct me if I am wrong, $300 on a 2.4 wont get me close to having a drivable engine.

right now I am planing on re-ringing the stock engine, and honing it out.

hopefully the motor can be put back together for around $300 (head gasket, ARPs, rings, bearings, misc gaskets)

I have always wanted a 2.4 and plan on getting one, but I cant see it happening for less then 1500 if i do it myself, and 2-3 grand if I have a shop do it correctly.

my plans for this twin turbo setup are simple and cheap, most of the supplies involved I already have, (wastegates, TBs, piping, exhaust) the only things I dont have are the turbo, and the pumps, and mini radiators.

Thanks for the intrist, and I will keep you all updated.

[JET]

You will need some type of cutout to open up after a certain RPM, otherwise that T25 is going to be a huge restriction in your exhaust. It is going to have to be really fast acting. Then you need some way to control it by RPM.

Maybe if you drive a tiny turbo off 1 cylinder then use the other 3 to drive a bigger one? LOL

[iceminion]

Here is a diagram of what I was thinking.

this will involve a second throttle body BEFORE the GM MAF, this is to keep the SC61 isolated from the T25

the t25 inlet feed will also be before the GM MAF

so it goes Intercooler > isolator TB > T25 inlet coupler > GM MAF > Stock TB

all shutters/isolators will be controlled by wastegate actuators, so I will have like 4 boost controllers, but I dont care, I like a challenge