i am tired of my maf problems, and the fact taht the maf hardly flows any air at all, i have an 87 iroc with a 350 and i would like to know what i need to convert to speed density, i know that the plenum is different so i plan on getting a 90-92 style plenum to hold the map sensor, is the only difference in the plenums the place for the map sensor? what is everything i need to convert to speed density? how hard is the conversion?

 

moving to the tpi board, you should get more help there.

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ICON Motorsports

1st & 3rd
MM Black Diamond 538 F&AM

 

Go here, he did it..... http://www.ece.udel.edu/~davis/z28/

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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, Wonderbar, 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/

Member - The Tidewater Trans Am Club, Norfolk VA http://www.geocities.com/ttacva/

 

I thought we were in the TPI board. Where the hell am I? Somebody turn the lights on, I can't see!
hEllo!?!?!?

 

LOL OK, the MAF doesn't flow enough, how much flow do u think u need?? What are your mods and what else are u going to be doing??

Most of the time when there is BS with an MAF, it is something that u wouldn't think of and doesn't cost much.

 

Ok, I'm actually gonna answer his question.
1. You'll need to rip out the engine harness and modify it. If your not sufficient with wiring, you can send it to Howell at www.howell-efi.com
2. You don't need a new plenum. Get a map sensor and mount it on the firewall and run a vacuum line to one of the vacuum ports in the back of the plenum. I'm using an '86 plenum on my SD setup.
3. You'll need the 730 ECM and PROM. Everything will plug in correctly if you sent your original harness to Howell to be modified.
4. I think your VSS is currently a two pulse. With the 730 ECM you'll need the four pulse unless there is some way to modify it in the PROM.

That's about it. The hardest part is pulling out the wiring harness. I really don't think the swap is necessary if you have an operating MAF system. If you're starting from scratch, then SD is the way to go. Whatever problem you're having now can be fixed much cheaper than converting. There are others on this board who have MAF sytems with no problems.

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'88 IROC TPI 355, '69 truck 4-bolt, fully balanced, 9.75:1 compression, fully ported '70 truck heads(for now), Harland Sharp 1.6 Roller Rockers, Comp Cams CS 252AH-12, ported '86 TPI converted to speed density, Crane AFPR, Flowmaster 3in. exhaust, Edelbrock TES headers, all emissions equipment is still intact, plan on burning my own chips, many more mods and parts on the way as time and money permits =(
Best E.T. with TBI 305: 16.11 @ 82mph
Haven't been to track with new motor
If you have any questions on converting from TBI to TPI email me at jdkchevy70@yahoo.com
In memory of Dale Earnhardt, I'll miss cheering for that black #3 on raceday!!!

 

I don't believe the MAF has that much of a flow problem. TPI specialties flow tested a stock MAF at 529cfm then they removed the screens and got 711cfm then they removed the fins and got 750cfm. I think this is more than enough for a slightly modified 350. I know the computer limits airflow seen by the MAF but that can also be reprogrammed to match the higher flowing MAF. I am not saying this is better than SD. I am saying that you are able to get more from your MAF system than you might think rather than going through all the trouble of doing a swap.

Jeff

 

Amen brother! TPIS, AS&M, SLP, and Lingenfelter have built scary fast cars using MAF TPI. I don't know why MAFs get such a bad rap. Mine is 16 years old this month and going strong

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-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons

 

Actually, he doesn't need to rip out the entire harness... there are some repinnings that need to be done and some new wires to be run and others to cut out, and I may be missing a few things, but the entire harness doesn't need to come out. Believe me, I've seen Mike Davis' car personally and he still has it where he can change back to MAF in about 20 minutes when he wants to. He's using the original harness that came with his 85 IROC.



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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, Wonderbar, 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/

Member - The Tidewater Trans Am Club, Norfolk VA http://www.geocities.com/ttacva/

 

IROCZ88 Writes:
> Ok, I'm actually gonna answer his question.
> 1. You'll need to rip out the engine
> harness and modify it. If your not
> sufficient with wiring, you can send
> it to Howell at www.howell-efi.com

What, do you have stock in howell or
something? How can you honestly tell
someone that they have to "rip out" the
wiring harness to do these SD conversions?



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My Z28, ZZ4swap, TPI EPROMs

 

He built an interface out of some portions of another harness (pigtail) and a header (the "receptacle" that is mounted on the ECM PCB).

I think another good way to do this would be to cut all the wires that need to be re-terminated about 6" from the connectors that go into the ECM. Then, install a good mil-spec connector on each end of the cut. You could then make an intermediate cable with the wires crossed, jumpered, or whatever you want to install various styles of ECM. Just my .02.