SA main table change for modified L98
Thread Starter
Instructor
Joined: Aug 2004
Posts: 108
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SA main table change for modified L98
I have increased boost pressure from 6 to 8 psi, changed injectors from 22 to 30, installed large tube runners, ported intake manifold and 52 mm throttle body plus a few other things. My car is a 91 Vette with L98.
At the moment my main SA table is the same as in the the ANTH bin with 4 degrees subtracted of the entire table. I have some knocks inte the 65-85 kPa and 1800-2200 rpm region, knock retard up to 5 degrees.
How should I change the main SA table? I could subtract a few degrees in the region mentioned above. But perhaps the entire table should be shifted due to increased breathing instead?
The stock main SA table has a large “dent” which I read somewhere is due to the long narrow runners, perhaps it should move to lower rpm or shifted to lower MAP for my setup? Any thoughts? At idle MAP is about 42-43 kPa for my setup, not quite sure but isn’t about 35 kPa on a stock L98 engine?
Robert
At the moment my main SA table is the same as in the the ANTH bin with 4 degrees subtracted of the entire table. I have some knocks inte the 65-85 kPa and 1800-2200 rpm region, knock retard up to 5 degrees.
How should I change the main SA table? I could subtract a few degrees in the region mentioned above. But perhaps the entire table should be shifted due to increased breathing instead?
The stock main SA table has a large “dent” which I read somewhere is due to the long narrow runners, perhaps it should move to lower rpm or shifted to lower MAP for my setup? Any thoughts? At idle MAP is about 42-43 kPa for my setup, not quite sure but isn’t about 35 kPa on a stock L98 engine?
Robert
Burning Brakes
Joined: Dec 2002
Posts: 1,088
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From: Lakeland fl
I would remove just enough timing from your problem areas to eliminate the know counts, plus maybe 1 degree. You could go through the whole table like this, upping timing until knock is detected, then subtracting till its gone- plus a little.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 108
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Yes, that is exactly how I have done it so far. After a while I started to think that perhaps someone found a better/quicker way of doing it. I think my setup is fairly common so I thought perhaps someone out there knew how the SA table would change. Meanwhile I'll work with small changes and eventually I'll get there 
Thread Starter
Instructor
Joined: Aug 2004
Posts: 108
Likes: 0
comp, do you mean scanner tool or stuff on my engine? I built my own ALDL adapter and wrote my own scanner program. Not long ago I started to use Datamaster which has some nice features like the histogram... but perhaps I misunderstod your question?
Thread Starter
Instructor
Joined: Aug 2004
Posts: 108
Likes: 0
I have access to an emulator through my work but I felt I did not want to add more equippment that could fail during WOT. I "play safe" and burn new EPROM for every change. At work I flash ECUs in new trucks on the fly. Nice, no doubt!
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