Spark Advance

Have a stock 305TPI with factory Prom/tune. Running 98ron fuel , would like to increase SA particularly down low/mid range. Considering 2/3 degrees + then monitoring through road testing. Have a wideband to monitor AFR.

Interested in in experiences of others while endevouring to increase power in what is essentially a stock vehicle.

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Originally Posted by Yellow Camaro

Have a stock 305TPI with factory Prom/tune. Running 98ron fuel , would like to increase SA particularly down low/mid range. Considering 2/3 degrees + then monitoring through road testing. Have a wideband to monitor AFR.

Interested in in experiences of others while endevouring to increase power in what is essentially a stock vehicle.

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98 RON is closely equivalent to our 91-93 octane pump fuels here in the US.

I played with these TPI cars quite a bit and running 91 or better they typically liked about 4° more timing than the factory 6° recomendation. Throttle response and torque increases a bit but the HP really does not increase much. These engines like about 34-36° of total timing above peak torque. Be careful in the 2,400-4,000 rpm range at WOT because that is where the TPI runners are boosting the VE and cylinder pressures are higher.

Thanks for your reply. However , intended to leave base timing timing and adjust spark advance map. It is reassuring that a 4Degree increase can be achieved fairly safely on higher octane fuel.

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Originally Posted by Yellow Camaro

Thanks for your reply. However , intended to leave base timing timing and adjust spark advance map. It is reassuring that a 4Degree increase can be achieved fairly safely on higher octane fuel.

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I understand that part. I just wanted to let you know in the past what I had done on bone stock cars that otherwise did not require PROM changes.