I plan to use this ECM in a turbocharged small block Chevy using a 1000CFM Holley Throttle body. Has anyone used or can you use a Typhoon PROM for this application? Would it be better to use a 90 - 92 Firebird PROM and would the 749 be able to read it? What might work?

 

You would be better off with the '90-'92 8 Cyl Firebird MEMCAL. The cylinder select value in the CALPAK portion of the MEMCAL is the important part.

Can then use the $58 code that the Typhoon uses in the PROM.

RBob.

 

This may be beyond my computer expertise. Please explain the difference between the PROM (90 - 92 F'Bird), the MEMCAL, and the CALPAK. I know the V8 value has to be selected but does this require a reader and program like Tunercat? Are the MEMCAL and CALPAK a part of the PRIM? If you would rather email privately rather use 3rd Gen postins you can email me at j.panter@charter.net. Thank you for the response.

 

Check out the sticky above called: Memcal, Prom, Calpak

It has a pic along with short descriptions of the various parts. Feel free to post further questions.

Welcome aboard.

RBob.

 

RBob
Checked out the sticky thread and understand most. Question: is the cylinder select function in the CALPAK a programing issue or how is it done?

 

The cylinder select in the CALPAK is done by resistors. It is hardware.

The cylinder select in the PROM is done by a calibration term. It is software.

They both need to be correct for the particular engine.

RBob.

 

I have talked to Tony at FAST and he is pretty sharp. He doesn't believe that the PROM froma 90 - 92 F Bird will work in the 749. He suggested that I use a Typhoon PROM then select 8 cyl and set it up for 36 lb injectors rather than the stock 30 lb (4.88 lbs/hr. At 48 lb of FP that should be good for near 600hp using .5 lb/HP. Thanks for your input.

 

Why are you taking advice for a stock GM ECM from someone that does aftermarket ECMs?

Does he know the difference between a MEMCAL and a PROM?

RBob.

 

Rbob I had srarted some dialogue with Tony before I started this with you. I questioned whether he would be willing to make a PROM for me to get this thing started. They do this and sell that service. The ST/Ty site has a good listing of all the PROMs used by their cars, however I called the local GM dealer and they can't get the PROMs any longer so that could be a problem (Getting the data) What I am now gathering from you is that the Firebird PROM will work in the 749 but I need the Typhoon mapping in it.
Is that correct? Could you modify the Firebird PROM for me? If I use the 749 ECM I''m going sto have to buy the service to make it work!! Let me know.

 

Here is the best plan:

Get a '90-'92 Camaro or Firebird V8 TPI MEMCAL

Get a Moates adaptor (G1 I believe)

Have the $58 (Sy/Ty, Sunbird, GrandAm) turbo code burned/flashed into a PROM (EPROM, Flash Prom, whatever is available).

The Moates adaptor will plug into the ECM in place of the MEMCAL. The V8 TPI MEMCAL will plug into the side of the Moates adaptor. The PROM (w/the $58 code) will plug into the top of the adaptor.

The key is that the CALPAK portion of the MEMCAL sets the ECM hardware for the proper injector firing. It is based on the number of cylinders. Will a Sy/Ty MEMCAL work? Sure, but it won't be correct. Will a '90-'92 TPI MEMCAL work? Sure, and the injector firing will also be correct.

RBob.