Hi guys,

I own currently what is at my signature, a 1986 305 TPI IROC auto. I have recently purchased a complete 1991 corvette TPI setup w/Auto tranny, complete tpi unit and computer. A couple of questions (or alot actually)

1. I now have Maf, which do I want? Maf or SD?

2. My intake is polished from plenum to lower intake which I really dont want to lose. The corvette engine came with everything including TPI unit, what can I swap over that is polished and not lose.

3. What computer do I use? I have the 86 cpu with a chip for the 86 TPI auto, and now have the computer for the corvette 350 TPI auto? Does it matter what computer just the Prom chip?

4. Will the corvette serpentine setup work on my car? If not how can I make it work?

5. Do I need a bigger radiator? Do I need a oil/tranny cooler? Do I need the dual fan setup as I only have the single?

6. Anything else anyone wants to chime in on is welcome!! This is my first ever engine swap. This engine is from a vette with 44K miles on her that got rear-ended. Do you think she needs any work on the block/heads? If so what should I get done to it?

What kind of gains am I looking at from going from my 190HP 305 engine to the 91 vette engine/tranny?

Again thanks to anyone that helps me out and sheds some light on the situation.....

 

If the trans (vette) is the origional trans for the car, it will no work in your f-body. The factory vette trannies have no provisions (holes) for the crossmember bolts to attatch to. All other 700r4/4l60's do have the holes you need. These holes cannot be drilled as there is no "meat" there to drill into. Check this bfore you proceed.

 

You can use either intake.

If you are going to use the SD system, you'll need to use the '91 ECM and sensors. If you stay with the MAF system, you'll need to use the '86 ECM. The '91 ECM has a bit more potential, since there is no intake flow limit and more program area to modify. The one caveat is that the Y-car ECM is designed to be mounted under the hood, IIRC.

Obviously, the early ECM will require use of the early PROM. The '91 ECM will require use of the '91 PROM. You should be changing the program anyway, but that will come later.

A single fan will work fine under most conditions. The stock '86 radiator should work fine as long as it is clean and not obstructed. An auxiliary oil cooler and transmission cooler are always helpful under demanding conditions, regardless of the engine size. You can get by without them, however.

 

Thanks guys for the inuput.

Vader, will using the 91 ECM and chip affect anything else? Will the computer not recognize things like VATS or will it work with no modification at all?

 

You will have to satisfy the VATS code in the ECM (there was no separate module in '19). The '91 ECM and programming wil also not support (and not need) a cold start injector.

The easiest way to skirt any operational problems is to burn a custom PROM, disabling VATS, setting the fan parameters to keep the engine cooler, setting the CTS parameters to allow use of a 180°F thermostat, and using the modified VE tables found in later program binaries. This will also allow setting of the TCC lockup to optimal for your axle ratio and vehicle weight.

Even if you used the '86 ECM and wiring harness, you would need to install the '91 (larger) injectors and program the better MAF tables from a later binary. You would have a choice of using or abandoning the cold start injector. Coolant and fan temps would still be adjusted, and the common problems with the '86 TPI code would have to be fixed, like the false MAF codes, poor TCC lockups, false lean codes, etc.

I would vote for using the MAF if you are not planning to go wild with the engine. If you plan to run tall gears and at significantly higher RPM (which is not particularly well suited to a TPI) you should run the S/D scheme and plan on frequently burning PROMS as the modification list changes.

As I see it, either way you'll be burning a PROM or pulling a lot of extra wires to satisfy the '91 ECM and PROM.