What are the main difference between the TPI setup on the '85 TPI systems and the 86 and newer?

(A friend is going to buy a thirdgen and wants to know.....)

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ZaphodB a.k.a Carl Andersson - zaphodb@faxancruisers.org
'89 Camaro IROC-Z 5.7L TPI - Mods under construction :-)
Ed Wright Fastchip Stage II/160 stat, Edelbrock TES Headers,
SLP Airfoil, K&N Filters, Accel 8mm wires, Relocated MAT, AFPR @ 47 PSI

The hardware itself, runners, TBI, plenum, intake manifold, etc, are identical to 86-88 setups. (except the intake manifold, its 85-86 specific). The wiring harness, and computer are used only in the 85 models, and are considered inferior to the 86+ computer.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

The main diference also is with the MAF and its control module. They are both separate from the ECM whereas 86-89 integrates the control module into the ECM. This makes the 85 version more expensive. I vaguely recall someone quoting a price of $1000 from the dealer, but I could be wrong. If he plans to modify, I would tell him to skip it.

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1989 IROC-Z 5.7L

One more thing, the plenum is different. The 85 plenum has a different exterior design, the grooves on the top of the plenum extend down farther than those of the 82-92 plenums.

Thats an 85-88 thing, the grooves on the plenum. 89-92 have shorter grooves.

Omar is right, the 85 ECM and MAF setup are different. The MAF Burnoff Module is $961 from GM, there is no aftermarket module available. In 86 MAF control was integrated into the ECM and used 2 $9 relays, one for power and one for burnoff cycle. The ECM in the 85, the "870" ECM is a dog, thanks to a LOT of help from Mike Davis (85MikeTPI) we swapped it out with the 86-89 "165" ECM, probably the best mod that has ever been done to my car. That burnoff module is a headache, I smile every time I walk out to my garage and see that thing sitting up on top of my toolbox. Details of how to perform the ECM/MAF setup swap can be seen at my page below. Good luck to you.

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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, MSD 6AL, Aluminum Driveshaft, TB Coolant Bypass, Ported Plenum, Modified MAF, Syclone Fuel Pump, JET Airfoil

15.556 @ 86.65mph, Nov 10, 2000.... I know it sucks.. but it will get better!

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