Is there really a benifit to seting timing at 8 DEG from 6?
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Supreme Member
Joined: Jan 2000
Posts: 1,180
Likes: 82
From: Mississauga, Ontario Canada
Car: 1987 GTA
Engine: 5.7
Transmission: T5WC
Axle/Gears: 3:27
Is there really a benifit to seting timing at 8 DEG from 6?
Self explanatory...I think
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1987 T/A GTA 5.7L, Bored .020 and ported for .202 valves, edelbrock headers, flowmaster exhaust, JET STAGE II chip, Comp CAM, Adjustable fuel pressure, Airfoil, K&N filter, B&M stage 2 shift kit, and a home depot ram air(Hey it looks good and it works)
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1987 T/A GTA 5.7L, Bored .020 and ported for .202 valves, edelbrock headers, flowmaster exhaust, JET STAGE II chip, Comp CAM, Adjustable fuel pressure, Airfoil, K&N filter, B&M stage 2 shift kit, and a home depot ram air(Hey it looks good and it works)
TGO Supporter
Joined: Jul 1999
Posts: 10,907
Likes: 5
From: The Bone Yard
Car: Death Mobile
Engine: 666 c.i.
Depends. Most TPI cars suffer from "detonation". Part is because the engines tend to be older, part just because of the design of the TPI system.
The problem is, once the "knock sensor" detects ANY KNOCK, it starts to pull out timing...a lot of timing. So you may find a stituation (very common actually), where you add 2* of advance, but the ECM pulls out a LOT MORE because of the increased detonation detected. The net result is you end up with less effective total spark advance and decreased performance.
The best way to handle spark advance (and control the knock sensor) is within the eprom. Not what guys want to hear, but its the truth. Then you can control the EFFECTIVE total spark advance you are getting. And you can add it (the spark advance) where you need it and avoid adding it where you don't want it.
FYI, there are places in the RPM/Load range where you can add a lot more spark advance with absolutely no problems. It definitely helps with throttle response. Unfortunately, there are places you can't either and additional spark just triggers the knock sensor.
On EFI cars, these "mechanical" tricks just are not that effective. They cause more problems often than they solve.
The problem is, once the "knock sensor" detects ANY KNOCK, it starts to pull out timing...a lot of timing. So you may find a stituation (very common actually), where you add 2* of advance, but the ECM pulls out a LOT MORE because of the increased detonation detected. The net result is you end up with less effective total spark advance and decreased performance.
The best way to handle spark advance (and control the knock sensor) is within the eprom. Not what guys want to hear, but its the truth. Then you can control the EFFECTIVE total spark advance you are getting. And you can add it (the spark advance) where you need it and avoid adding it where you don't want it.
FYI, there are places in the RPM/Load range where you can add a lot more spark advance with absolutely no problems. It definitely helps with throttle response. Unfortunately, there are places you can't either and additional spark just triggers the knock sensor.
On EFI cars, these "mechanical" tricks just are not that effective. They cause more problems often than they solve.
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