I parted out an 85 TPI car. I have the motor-trans unit and all wiring (I didn't cut a single wire, and got way more than necessary), ECM, etc... I was just doing some reading and I realize I did not snag the relays off the firewall (the car is long gone now). I believe these are the MAF burnoff relay and power relay.

So, I would like to convert this unit to speed density and put it in an 89 TBI car.

I know I will need:
-Another coolant sensor
-Speed density ECM and prom
-Fuel lines, sending unit and pump

- TPS- can I use the one off the 85 TPI or my 89 TBI?
- MAP sensor is a different p/n, but can I still use off the 89 TBI?

IAC valve- TBI part no. is the same
MAT sensor - TBI part no. is the same

Have I missed anything? Can someone help me out with the interchange of these couple parts?
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Or should I just sell this motor tranny combo and put that towards a mini or superram? If so, what is a fair price for a complete (minus two relays) 85 TPI 700R4 setup?

All you experienced guys help me out. I have a couple of 400 blocks, but no good cylinder heads to speak of as of yet. I would eventually like a mini or super, but maybe I should take small steps instead of one big leap. Thanks.

 

The 85 TPI setup has no MAF power or burnoff relays, just a burnoff module. Where it is depends on what kind of car you pulled it out of. T/As had it mounted to it's own bracket which was bolted to framework underneath the dash. Camaros had the module piggybacked to the ECM. When you pulled the harness you would have had to unplug the connector from the burnoff module when you unplugged the ECM as there is only about 4 inches of slack between the three connectors.

There are some 85 TPIs out there, but they are getting few and far between now, but of the ones that are left, you should be able to find someone who will pay a little bit more than what one would pay for an 86-89 MAF setup or even the 90-92 S/D setup. I would say $600 to $700 would be fair, that is, if it is COMPLETE. Really the biggest differences are the 1)the burnoff module ($961 at the dealer for a new one), 2)the antiquated "870" ECM, and 3)the wiring harness.

You can convert it over to S/D if you want, it's been done, just a question of how bad you want to do it. At the very least, if you do keep the 85 setup, convert it over to the "165" ECM. There is a link on my web page below to Mike Davis' page where he shows in detail how to do both swaps, from the "870" to "165" ECM swap, and the MAF to S/D swap. Good luck.

Also, the TBI and TPI TPS's are different.
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Kevin Irving
85 Trans Am WS-6, 305 TPI, custom burned '86 PROM with '87 "165"ECM, Accel Supercoil & 8.8 Wires, Rapidfire #2 @ .055", MSD 6AL, 1.6:1 Roller tipped rockers, Homemade AFPR, K&N cone, no airbox, Aluminum Driveshaft, Wonderbar, TB Coolant Bypass, Ported Plenum, Descreened MAF, Syclone Fuel Pump, JET Airfoil, Mobil 1 synth in all but transmission.

http://www.geocities.com/transam85tpi/

[This message has been edited by Kevin Irving (edited June 21, 2001).]

 

I just finished converting my '85 Y body to SD. TPS will be fine, there is no MAP sensor on an '85. One thing to be aware of is that the '85 harness has only 1 injector ground, not two. Both black/white wires in the C/D connector should go to the injector grounds. If you have any other questions, email me!

Chris

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408cid 1985 Corvette
http://www.mojosgarage.com

 

I do have the module that piggybacks the ECM. And like I said, the harness is more than complete. I got everything for the whole engine bay without snipping one wire.

Maybe I'll just convert to the 165 ECM. I have the page you referred to bookmarked already and have read through it, but that was a couple of months ago. Better go hit it again.
Thanks for the input guys.

I probably won't do this until winter when the car will be garaged. I think I will go over the whole TPI unit and clean it up, new gaskets, O-rings, removing some material from the runners, plenum, etc before then.. Would a local speed shop be able to flow test the injectors, or will I have to send them out? Anybody else have any suggestions for me, like details that are easily forgotten?

What if I wanted to use a 400. I have two choices of cylinder heads as of now (only because they both are freshly rebuilt)
L03 heads
Some 3998997 castings are 76cc

Will either of these heads be worth the time it takes to put them on the 400 and swap it in with the TPI? I will have to visit the prom board to learn how to burn chips. Probably need bigger injectors. Need a suggestion on the cam. Is this a gay idea, or should I just wait until I get some decent heads? I want the cubic inches, but I know I need better flowing heads. I guess I just want to know if with what I have can I make more power with the 400 than the 305 and still keep some driveability?

Thanks for all the help guys.

 

My 408cid car is very driveable. The idle is nice, and the power is ungodly. The downsides are the major bucks I have into it, and it's very difficult to keep cool.

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408cid 1985 Corvette
http://www.mojosgarage.com

 

I know. Eventually I plan on a 406 with superram. But I'm building a house and I have a 5 month old daughter. I just ordered a kit from PSC yesterday, but I can't drop a few grand on this car all at once. I want to have the entire suspension done (just about done, still need SFC's and torque arm) and the 1LE brakes done (waiting on the damn 10132829) before I start sticking high dollars into the motor and tranny.

That is why I want to know if I can do anything with the heads I mentioned on a 400. If not, I'll just leave the 305 in and change the bumpstick, port the heads and slap on the TPI after I clean up it's passages. But if I can use the 400 with either of these heads and do better with the TPI than the 305, I will.

L03 heads on a 400- I don't recall the cc of these heads offhand, but I'm pretty sure my comp. ratio would be pretty high. I don't believe they flow anywhere near what a 400 needs at higher rpms, and that is fine because as is, it is just a nice weather weekend car and I don't need to see even 4500 rpm, maybe even that is wishful thinking LOL!

The 76cc heads, Probably low enough comp ratio to run pump gas, I know they are smogger heads, but like I said, I'm not taking it to the track. I just drive it around on weekends.

If anyone thinks I could use either of these sets of heads on a 400 with the TPI and be happier with it than with the 305, let me know what you think. I know the heads are not anything special at all which is the only reason I am asking if I should waste my time with this. Thanks.