I have a '88 Corvette L98 (A4). I also have access to a complete TPI setup off a '90 IROC L98.

My plan is to take the IROC TPI and port the plenum and base and either polish the whole setup or have it powder coated. Then I can make the swap on a weekend.

I believe the fuel rails are different, but I dont see that being a problem cause I can use my original rails. I also realize that the EGR provisions are different so I will be doing an EGR delete (or can I transfer my EGR to the IROC base)?

I know the '90 IROC unit doesn't have the cold start injector, whats involved in adapting that to my '88? Will my stock TB work?

Is there is any difference in the base between my '88 unit and the '90 IROC unit, such as mounting holes that will make the swap difficult if not impossible?

Thanks for the help.

 

The 88 is MAF
The 90 is SD
And the computers are different.

 

As long as I keep my MAF that shouldn't make a difference should it?

 

http://www.hotrodlane.cc/Streetstories/choosingtpi2.htm

 

The base mounting holes are different.

RACE ON!!!

 

OK. thanks for your replies. I'll guess I'll have to go to Thirdgen and see if I can sell this sucker.

thanks again

 

I think you should be able to enlarge/elongate the center mounting holes in the center of the intake manifold and you should be able to use it.

If not, how much do you want for the setup?

You would need to have your chip reworked to eliminate the cold start injector.

The plenum would have an extra vacuum port to run the map sensor.

 

Insane1,
I've had a couple people tell me that the manifold could be modified to fit.
I think I just might give it a try. Even if I can't get it to work, It will be costing me more time then money.

 

Check around on thirdgen.org, those guys know those swaps inside and out.

 

I bought a 89 prom to solve the cold start problem. GM deleted the cold start & put it on the prom in 89. I think the manifold & other parts should bolt on. you can use your computer. Just plug the map sensor vacume source, you don't need it with your MAF system. The EGR should transfer as well. Use your 88 parts & hook it up the same as your 88. your throttle body will work. Dont go for a 58mm TB. It wont help & will lower low end tork. you might consider an accel super ram set up. I picked up 5 mph in 1/4 mi. It is smog legal all states. you can buy a new one on ebay for $1200, but can find used ones for less. Good luck with your project.

 

Thanks TPI,
Thats some good info.

 

Sorry if I seem a little dense, but I want to be straight on this

To sum up and see if I have this clear.

1. I can delete the cold start on my '88
2. I can delete the EGR

(No. 1 & possibly 2 will require chip reprogramming)

3. I can use my '88 throttle body even with out the cold start provision

4. Plug the MAP sensor vacuum source since I don't need it with my MAF system.

5. If I elongate/enlarge the center mounting holes on the manifold, it should work with my aluminum heads.

Am I missing anything?

 

 

I installed a mini ram which delets both EGR & cold start. It ran fine with the original computer & prom, no programming. Then I replacer the mini ram with a super ram (California smog test- passed) EGR was hooked up & working, no cold start. I then bought an 89 prom. It ran better cold & returned to idle RPM faster. (cold in Ca is warmer than many other locations) I have not done custom programming yet because I want to install headers first, but it runs fine without reprogramming. It may or may not have more power with a custom program. I used a hypertech off the shelf prom & it did nothing except keep the fan running at a lower temp, but no improvememt in performance. ECM custom tunning is esentil if you make major mods like stroking, cam,& head changes that increase air flow significantly. you MAF will compensate to a degree for minor changes in flow so your stuff should work. I may be wrong, but I think the gen 1 motors 1955 to 1991 are all the same including bolts for intake manifold. In1992 the LT1 was introduced. TheL98 & LT1 are the same except the center 4 intake bolts are at a different angle. Some after market manifolds are machined for both angles and can be used on both. I still think your 90 manifold will bolt on because they are both gen 1 motors. Please let me know if I am incorrect. If I'm wrong, it is easy to modify the bolt holes. Conversly, you could modify a LT1 orLT4 intake manifold to work on your L98 but the water channels must be modified as well. Let us know how it works out

 

Thanks for all your replies. When I get started on this I'll post updates with some pics.