Okay this may be a dumb a$$ question. I am not running a EGR and have been told that the engine will require more timing. My understanding is to keep my physical timing mark (6*)and increase the timing in the prom for total timing. Is that right? I am at 6 BDC now, do I need to move it to 8 or 12? The car seems happy at 6 BDC, so I'm a bit confused on what I have heard. I plan on spending some major data logging time tomorrow.

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1988 IROC 350
Vette heads, SLP headers/Y-pipe,No EGR.

 

That sounds alittle bassakwards. When EGR is active, additional timing is added. The engine doesn't need the additional timing if the EGR is disabled.

 

If your not running EGR, have you disabled it in the code?, or just unplugged it?.
Just unplugging it, screws things up.
Find someone else to listen to.
There is plenty of EGR info., in past posts here.

 

You WILL need to retard the timing from a stock spark table, especially in the 30-70 kPa region with no EGR. Just finished remapping my non EGR 383 TPI motor. As Grumpy alluded to, if you do not disable the EGR function in the ecm, the ecm will make corrections to inj pulsewidth based on the EGR duty cycle it is commanding.

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Dave Zelinka