What happens when you replace a stock chip off 1989 350 5.7 TPI GTA with a stock chip off 1989 305 5.0 TPI?

 

I would expect that the engine would run very rich at WOT,, due to the error in the rating of the fuel injector size.

 

depends on whether or not you're talking about a manual or auto 305 bin (the 350 bin is likely auto).

the two will at least have different injector constants (no big deal and very easy to adjust. the ECM will correct for this, but will throw your BLMs off, which is uncomfortable for some).

if the tranny setups are different between bins, much will be different, like:

- idle tables (autos typically idle lower throughout the tmp range)
- anything related to TCC (tables/constants)
- shift light tables/constants
- iac throttle following
- tranny-related flags
- startup tables
- etc

also depends on the bcc of the bins.

 

The injector constant difference can not be corrected at WOT, yes, the ECM will try to correct the part throotle AFR by adjusting the BLMs, but nothing is corrected for WOT running,, the engine will run rich.

Unless you dial down the fuel pressure, but then going lower on fuel pressure from stock is a bad idea.

And of course, the tranny must be the same type between the two cars, otherwise there could be some big problems.

 

I believe you're mistaken. the injector constant controls BPW across the board and is *meant* to be changed/different with different injector ratings. 22# injectors in the L98 calls for a different injector constant than 19# injectors in the LB9. Hence the difference between the two in the bin. ;-)

 

oh, and this should be in the DIY PROM board.