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Why does spark table look jagged?

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Old Aug 13, 2006 | 09:17 AM
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Default Why does spark table look jagged?

I have been working on my own tuning with HPTuners on my modified LS6. The car hasn't been giving me what I want in the 1/4 so I went scanning and determined my spark advance probably isn't optimal.

I am trying to learn as much as I can before making changes and I noticed that my High Octane Spark Advance table is pretty jagged looking. My car was previously dyno-tuned so I downloaded a stock .bin file and it looks the same way.

Can anyone explain why this is? Is it this way for a reason or can I smooth it out?

Thanks!
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Old Aug 13, 2006 | 09:41 AM
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It shouldnt be jagged, look at the stock ones most are smooth. At any point in time the engine moves consistently from point to point in relation to power output etc, so your spark should do the same.

Ive seen plenty of jagged spark maps, its usually because the tuner has done a quick tune to get the results they want and not dialed each cell in carefully. Just hammer it with the smooth function from time to time as you develop the tune.
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Old Aug 13, 2006 | 11:06 AM
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Originally Posted by ringram
It shouldnt be jagged, look at the stock ones most are smooth. At any point in time the engine moves consistently from point to point in relation to power output etc, so your spark should do the same.

Ive seen plenty of jagged spark maps, its usually because the tuner has done a quick tune to get the results they want and not dialed each cell in carefully. Just hammer it with the smooth function from time to time as you develop the tune.
Thanks! That's what I figured but wanted to be sure. I already smoothed mine out so now I'll go load it on the car.
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Old Aug 13, 2006 | 11:41 AM
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Only thing to watch when you smooth is that you average out the cells, this means your optimal timing may get reduced. Conversely your on the edge timing may be increased over the edge.
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Old Aug 13, 2006 | 12:06 PM
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Originally Posted by ringram
Only thing to watch when you smooth is that you average out the cells, this means your optimal timing may get reduced. Conversely your on the edge timing may be increased over the edge.
Thanks: I am only smoothing by hand....

I put the STS turbo system on the car this spring. Not seeing the mph I expected at the track. It was a lot worse in hot weather. The car felt flat in the higher gears so I scanned it and found I only had 12 degrees of advance under boost. Looked at the tables and max timing for boost was 14 plus I was starting to pull timing with IAT in the mid 90's. This was a heads/cam car tuned on the dyno prior to my installing the turbos and to make matters more complex, my starting tune after installing the turbos was sent to me by a guy who has tuned many boosted cars, but it was set way conservative.

Since I figured this out, I have E-mailed with Rick at STS and with my local tuner who did the H/C and dyno tuning. They have both given me advice (that tracks - whew) on how to set up the timing for the turbos. At this point I am blending the HO Spark Advance table that was on the car with the H/C (ran like gangbusters and no KR) into what I now want the area for boost to look like. I expect this will give me the best performance and a smooth transition to boost.

I'm going to load it on in the next hour and go driving to see how the car feels while scanning and make sure the knock sensors are quiet. If that looks good then it is back to the track Wednesday night.

Thanks for the help - I'll let you know how it works out.

Last edited by RalphPZ06; Aug 13, 2006 at 12:08 PM. Reason: typo
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