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Current spark advance table

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Old 07-07-2005, 10:34 AM
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, LT1
Transmission: TKX, 4L60E
Axle/Gears: 3.42, 3.23
Current spark advance table

Heres kinda where i'm ending up with the SA table. For those of you not familiar with my setup, its a 350 bored .040 over with SRP inverted dome pistons (mirrors chamber), 64cc aluminum trickflow heads, and a custom camshaft (230/245 @ .050 , .530/.545 lift on 114lsa 112ica).

Overlap is around 9.5 degrees, compression ratio is 9.14:1

Blower is a vortech S-trim, with a 3 core intercooler (front mount - infront of the radiator).

Singleplane manifold, with a monoblade vortec throttlebody, 1205 gasket port, and 42# ford injectors. The motor seems to like more spark than less. I'm actually surprised at how much spark it seems to want in cruise, idle, and decel areas. I'm still experimenting with WOT.

-- Joe
Attached Thumbnails Current spark advance table-v10-spark.jpg  
Old 07-07-2005, 02:53 PM
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Re: Current spark advance table

Originally posted by anesthes
I'm actually surprised at how much spark it seems to want in cruise, idle, and decel areas.
If you have a good oil pressure guage, try an easy to duplicate highway run of ~50 miles, then on another day with about the same ambient temps/hum, try it again with say 36d of cruise timing, and compare oil pressure readings. Cruise tuning takes alot of time to fully optimise, while the coolant temps might seem exactly the same, there's alot of heat in the piston domes, oil, etc., that take time to stabilize. A typical cruise timing run for me, is like 200 miles in one direction, and then come back with the *new* changes, doing a mileage check each way. And even with that when going on a long trip, I'll still try different calibrations.
Old 07-07-2005, 05:50 PM
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I'm impressed that you're able to run that much timing at 600rpm at all loads. I'd have thought 23 degrees at 100kpa would have been too much. What's your idle set too?
Old 07-07-2005, 08:57 PM
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Car: '88 Formula, '94 Corvette, '95 Bird
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Axle/Gears: 3.42, 3.23
Originally posted by JPrevost
I'm impressed that you're able to run that much timing at 600rpm at all loads. I'd have thought 23 degrees at 100kpa would have been too much. What's your idle set too?
Idle around 900rpm at about 55kpa, 14hg if you go by the mechanical gauge. Cruise really depends. A light tps cruise could be 70kpa, a 0tps cruise could be 40 kpa.

-- Joe
Old 07-07-2005, 09:00 PM
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Car: '88 Formula, '94 Corvette, '95 Bird
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Re: Re: Current spark advance table

Originally posted by Grumpy
If you have a good oil pressure guage, try an easy to duplicate highway run of ~50 miles, then on another day with about the same ambient temps/hum, try it again with say 36d of cruise timing, and compare oil pressure readings. Cruise tuning takes alot of time to fully optimise, while the coolant temps might seem exactly the same, there's alot of heat in the piston domes, oil, etc., that take time to stabilize. A typical cruise timing run for me, is like 200 miles in one direction, and then come back with the *new* changes, doing a mileage check each way. And even with that when going on a long trip, I'll still try different calibrations.
I see what your saying.

Cruise timing at 36, 32, 28, etc just caused a surge or stumble. I spent forever playing around with VE when it seemed to really just want timing.

-- Joe
Old 07-08-2005, 12:20 AM
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I hava a similiar cam 230/245 ,544/,576 on 112lobe and 9.0 in comp but with bigger cubes and it likes timing...

My SA is not far from yours .... but at cruise I'm at 45deg, 100kPa 35deg, closed throttle 32deg.........Still tuning it.............

/N.

Oh, I found the problem with the files I send you, let me know if you want them I can Email you them again (in *.zip format).........
Old 07-08-2005, 08:45 AM
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, LT1
Transmission: TKX, 4L60E
Axle/Gears: 3.42, 3.23
Originally posted by gta324
I hava a similiar cam 230/245 ,544/,576 on 112lobe and 9.0 in comp but with bigger cubes and it likes timing...

My SA is not far from yours .... but at cruise I'm at 45deg, 100kPa 35deg, closed throttle 32deg.........Still tuning it.............

/N.

Oh, I found the problem with the files I send you, let me know if you want them I can Email you them again (in *.zip format).........
Hi,

That would be great! The screen shots were very helpful, but the files would be even better. Thanks again!

What did you end up using for your o2 mv threshold?

-- Joe
Old 07-08-2005, 11:02 AM
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Re: Re: Re: Current spark advance table

Originally posted by anesthes

Cruise timing at 36, 32, 28, etc just caused a surge or stumble.
Might try tinkering with the AFRs some.
Not to mention that with one of my tunes, I got the best mileage at 13.5:1. Not always is leaner better for cruise (can be, but, there's no rule that it will be).
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