DIY PROMDo It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.
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1987 Vette and Camaro for 5.7 TPI both used 7165 ECU. But I recall Vette is aluminum heads and Camaro is iron. Is that correct? If so the timing in Vette chip may be too aggressive. You may be able to retard at distributor to get it closer to Camaro? Also the trans in chip must match.
If the 7165 ECM's are anything like the 7730's, there's probably a parameter in the cal similar to "Spark Latency Time Correction vs RPM". IIRC, This parameter deals with the different diameter distributor caps. For a given engine rpm, the tangential velocity of the large cap HEI rotor is faster than the small cap rotor (due to the larger diameter). The spark timing takes this into account within the ECM. The ANHT (90-91 Corvette) and the AUJP (90-92 Camaros) have different values. Not sure the impacts of neglecting to adjust this.
It should work fine if you have VATS in the Camaro. All vettes had VATS in 1987 but not all Camaro's. I used to swap my Vette and Camaro chips back and forth before I started tuning my own chips and I never had a problem.
__________________ 1988 Formula 5.7L/6sp 3.91 gears,10.6 cr, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, Superram, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT, E-Tec 200 heads, SDPC Vortec manifold, ZZ-409 cam.
Best ET 12.17
Best 60 FT 1.754
Best MPH 113.1
RWHP 369
RWTQ 399
Well, if you're running 2.73 axle ratio out back, I'd change it to at least 3.42. IMO, you'll get more bang for the buck than anything you do to the engine (for equivalent $ spent).
1987 Vette and Camaro for 5.7 TPI both used 7165 ECU. But I recall Vette is aluminum heads and Camaro is iron. Is that correct? If so the timing in Vette chip may be too aggressive. You may be able to retard at distributor to get it closer to Camaro? Also the trans in chip must match.
Ronny,
Why would you want to retard at the distributor? For the 7427 (all i've been studying on for a while) your suppose to (Courtsey of Fast):
Next it is time to setup the timing table. For a mildy cammed engine I typically setup the distributor at 6* advance and set the corresponding initial timing setting in the ECM at 6*. This allows for quicker starting with a cold engine but does not put excessive drag on the starter at other times. The initial timing on the distributor and in the PROM MUST match or it will mess with the whole timing advance curve.
Isn't retarding the timing @ the distributor lying to the computer essentially negating any reason to do the above regardlessly?
I assumed he was not into burning his own chips. My first chip was a hyper and it suggested advancing SA at dist a couple degrees, maybe three. So, I believe hyper chip only did the fueling. Ideally he purchases correct GM chip or get into tuning and pull correct one of off Moates site.
