88iroc-Z

iTrader: (1)

I have a 88 iroc-z with the tpi L89 and am wanting to turbocharge this car.

I have built many turbo kits for imports, I currently have a turbo celica that I was going to re-DO a setup up for but thought I might try and use some of my parts on the iroc

the reason that I want to go with a single turbo setup is because I would like to mount the turbo on the driver's side of the engine comartment so that I can retain my A/C hardware.

Some of the parts that I have are:

Prescision GT32 turbocharger which I have had ceramic coated
(rated to 660hp)
A turbosmart 38mm external wastegate
Turbosmart dual-stage boost controller
Innovate widebane o2 sensor


I also have the stock manifolds which I would like to modify for this project as well as extra"practice" GM manifolds

I would like to modify these manifolds in the same way as I have seen some modified for the twin turbo setup where the turbo flange is welded to the top/forward part of the manifolds and, in my case a wastegate flange.Although I plan not too close the original opening that goes to the exhaust, so that I can use as an inlet for cross-over pipe from pass. side manifold

Only difference on the pass. side is that I would like to leave the passenger side manifold stock and just weld shut my Y-pipe where it goues to the rear and use the Y-pipe as a cross-over pipe to my other manifold, which should bolt-up like it did before.

So, I guess my questions would be:

1. Is my turbo big enough?

2 where can I route my exhaust after-turbo?

3. will this work properly?

thanks for your help/advice
-Daniel

junkcltr

iTrader: (1)

It sounds like you are trying to flow both banks exaust through one manifold to the turbo. That is a lot of exhaust for such a small pipe. I wouldn't try it, but it ?may? work. Seems like it would have very high back pressure.

Other than that, it sounds fine. That turbo may be big enough. It all depends on what you want for a powerband.

88iroc-Z

iTrader: (1)

As far as power band I am not really in need of all out top end, I do realize that this motor already lacks top end power considered to other motors which is really not that big of a problem for me.Although I would prefer the widest power band available.
I would like to get an almost instant throttle response and a quick spool up, which I think I would get from this turbo, but as you said it may be too small.

Are there any other problems related to turbo size other it restricting upper RPM hp?
Would it be to small that the increased back pressures or increased EGT's would damage of be unsafe for my motor?

Also I have heard of some setups that just run off of the exhaust from one side of the engine, would this be a better platform/alternative comared to running off of both manifold through all of the excess plumbing?

I would guess that it is not better.
But I am open to knowledge/suggestions, or any other input from others

and you mention that the piping being too small,
What if I run a bigger "cross-over" pipe?
Would that lower turbine temps negatively?
Or, is there a shorter or better route?

JoBy

You can use the stock passanger passenger side manifold and a stock sized cross-over pipe. That is no problem as it only exhaust from half the engine.

The problem is the drivers side manifold if you want to mount the turbo near the front of the engine. The pipe between cylinders 1 and 3 is only disigned to flow 1/8 of the total exhaust flow. If you can mount the turbo flange close to the cross-over pipe then it is not a problem.




This is a picture of the old Martin Turbo Systems exhaust manifold.

88iroc-Z

iTrader: (1)

I was planning on trying to use the stock manifolds from the L98, with these would it be possible to mount the turbo flange between cylinder's 3&5?

I have also seen some turbo setups that do not modify the manifolds at all, rather they just run exhaust piping from both manifolds to the turbo in a location in the front corner's of the vehicle.
I know that this would involve alot more piping as well as fabricating a bracket to keep all piping and turbo secure, would this be a better option?

I know that EGT's would be lower since the exhaust gasses have a longer path to travel, but wouldn't that work out good with the turbo I want to use, since the restriction of the turbo itself would raise the egt's?

88iroc-Z

iTrader: (1)

bump....

calebzman

iTrader: (3)

That's what I did, but I used Corvette manifolds and modified them.

88iroc-Z

iTrader: (1)

thank you very much this answers ALOT of questions that I had.

As far as turbo Size I will try and run my GT32 and then possibly upgrade later to a larger JY turbo, would something like a Powerstroke, or a cummins work well, or do deisel's have different types of turbos?

83 Crossfire TA

iTrader: (2)

I don’t know on what planet a GT32 is going to move enough air to make 660hp, but taking a quick look at the compressor map, figuring you running a 2:1 pressure ratio (14.7psig boost), the turbo will only move about 39lb/hr at 60% efficiency, which at that PR on an L98 will run out of breath at around 3000rpm. At lower boosts it looks much worse.

If you mount it on the driver’s side? Not a clue, there really isn’t room for it on the driver’s side. Possibly run it around the passenger side or under the crossmember. Otherwise just run the turbo on the passenger side and run the exhaust under the AC, there’s room. With a little creativity you could get a 3.5” pipe through there.

Not the way you’re looking at doing it now, I’d suggest doing some reading of older threads on the topic around here, there’s plenty of info here and you could prevent reinventing the wheel.

It’s not as big and issue as you think it is… the biggest thing is to prevent increasing and decreasing cross sections unnecessarily. That will end up causing more issues then anything else. Real world, there used to be a mustang turbo kit that has been used at over 600hp that had all if the exhaust gas going through a 1.75” section