I am a new subscriber to the forum, although I have been following it for years.

I have a '93 6-speed coupe that I am considering adding a single turbo. I have thought about this for a while now, but following the progress of lcvette and JoBy (looking great guys) has motivated me even more. I am capable of fabricating all of the necessary exhaust and induction hardware. My main question comes down to tuning, as I have very little knowledge on this subject. Can it be tuned well with the stock ecu, or is an aftermarket ecu recommended?

Also, what do recommend for a turbo? I primarily use my car on the street and for road racing (very little drag racing) . I am interested in about 550-600hp max, and am a bit more concerned with low to mid range torque as opposed to high end power. I have seen several recommendations for the t76gts, but have also seen that this turbo is good to 800-900hp. Would this be appropriate for these power levels, or is it a bit too big?

Thanks in advance. This site has a wealth of information.

 

First of all, alot of what you are talking about for low and mid range can be had by changing the a/r on the turbine side. A smaller a/r will cause the turbo to spool up faster which is what you would want, but it will take away from the top end horsepower due to the fact that it does create more back pressure. I don't have any hard data with how much hp it will eat up, but the quick spool will be worth it for you.

As far as tuning goes you can have it done with the stock computer but there are some complications. I did mine with an Accel DFI Gen 7 and it worked just great. Modifying things on the fly with the laptop is a great way to do it. You can talk to Bruce and Rick(BaldTurboFreak) and they should be able to tell you more about doing repeated prom burns on a '93

 

on a sped density car I wouldn't consider trying to tweak it as the complications far outway the cost savings. with a maf system you will at least have correct airflow metering from the MAF sensor until you max its capability out which is somehwere mid 500ish G/sec. for a prommed setup.. do yourself a favor and go ahead and look into an aftermarket management system.. it will save you many issues in the long run and allow you to do alot of the tuning yourself.. it will also allow you up your injector size and the availablity to use Low Z injectors, interactive wideband O2 sensor, and a plethera of other features that you woukld be limited to on the stock control system. if you do this now you will ultimately save the money of tuning and other aspects you will spend money on trying to make the satock system work. I personally like the DFI, but others prefer XFI or BS3, for the money, you will need to decide which will suit your goals the best.. and then learn as much as you can about them to make your decision.. being that Brian and myself are running the DFI with single turbo setups on the corvettes.. That alone would push me into the DFI for the simple reason of available question answering here in the FI section from people running the same setup and system as you. other then that, Bruce or BTF might chime in with some other opinions, but I stand firm with my decision for aftermarket engine management.. after all you will find that the outlay for the larger components such as turbo, wastegate, BOV, intercooler, & tubing materials will pale in comparison to the fuel system, engine management, and all the other little things you never would have thought to add in to your budget. but if you start this project, you will need everything to make it work.. so figure your best calculation of outlay of money.. and then add at least 40% to be close to realistically completing it turn key.

good luck and have fun.. its a long and wild ride!

Chris

 

Agree with mmvette and icevett.
The factory computer seem to work ok with many many chip burnning and is a pain in the *** get it right with turbo. Mine 93 is already converted to a 2bar map. It runs pretty good but I am still not happy with the tune ( if some one happy with the 10-12psi) I say I would leave it alone . But I want a hell alot more hp. Therefore I feel the aftermarket computer is much more easy to do for what I want.

 

Bruce, I think you are crazy I'm gonna try 10 psi on mine and how we'll see what she does. I think I'll be happy with that for a while. I'm hoping that with my tax returns this year I can afford my new McLeod setup and my new turbo. Its so close I can taste it

 

I couldnt agree more. Ive done a good bit of different cars, and you just can't beat the programmabliity and on the fly adjustment of the aftermarket.

 

Thanks for the advice. I had assumed this was the case, but I thought I would check. I have never done any prom burning, but I have done a bit of programming with an aftermarket ecu, and it is relatively simple.

From what I have read, it sounds like you need a jumper harness (ie from Fast track performance) to interface between an aftermarket ecu and stock ecu to maintain functionality of the dash, gauges, etc.

 

It depends on how you do it. If you want to run the stock optispark then yes, that's what you'll need. Since the optispark has to be run through the stock computer. If you decide to move to a different type of distributor like I did, I only need the stock computer to run the gauges. My Accell DFI is totally independent.