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timing ???

Old 01-05-2014, 12:06 PM
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Default timing ???

Is there a just right timing for these LS engines ? or a test n tune thing ?
Old 01-05-2014, 12:45 PM
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Test and tune. Will be different per cam, compression, ect.
Old 01-05-2014, 12:58 PM
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Originally Posted by jaywill
Is there a just right timing for these LS engines ? or a test n tune thing ?
The combustion chambers and the compression ratio will dictate for the most part. 26 degrees total is a nice safe starting point. Then add more to see if the performance increases.
Old 01-05-2014, 02:19 PM
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I started at 32*...bumped 2* up every pass until there were no more gains and then dropped it 1*.
Still a lot of tuning to do to the carb which may effect timing down the road....right now it's fat and happy....needs lean and mean.

If you post your specs, it will be easier/better for someone to give you a starting point.
Old 01-05-2014, 02:57 PM
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Originally Posted by jaywill
so you are saying start it at 26 and move up from there ?.. right now my timing is 32 total.. Initial timing 20 ramped up to 30 by 2000rpm. Drop down 2* between four and five
For some people, like me, the car runs the fastest at 26-27 degrees. Other people run as much as 36 degrees. You will have to measure it either at the track or on a dyno to know for sure. The thing is, running 10 degrees too little timing won't hurt anything. 10 degrees too much, on the otherhand, can break ****.
Old 01-05-2014, 03:04 PM
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Mine is 20* initial timing ramped to 30 by 2000 rpm droped down 2* between 4 & 5k then back tov32* on out...
Old 01-05-2014, 06:06 PM
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What is the reason behind backing off on timing a little in the middle of the power band? I see this a lot.
Old 01-05-2014, 06:57 PM
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It is supposed to promote power. So everyone does it.
Old 01-05-2014, 08:34 PM
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Originally Posted by ZONES89RS
It is supposed to promote power. So everyone does it.
I've heard this, and looked, but haven't found any proof. Maybe I'm not looking hard enough...
Old 01-06-2014, 01:22 AM
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my e85 combo has a specific sweet spot, few deg up or down and power drops a heap.
Old 01-06-2014, 05:24 PM
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I don't know how dyno runs are interpreted. Failing the ability to set timing at each and every RPM to tweak a peak, if I was to do it I would set up a series of constant timing advances, run each up through the RPM's and overlay everything to get a composite graph. I would then take the peak power at each point in RPM, get the timing setting for that and move to the next power peak. In that way I would (I think) get an optimum timing curve. That still wouldn't say why there was a sweet spot although I don't doubt that there is one everywhere.

However that's not what I infer from the discussions I've read here, everybody including MSD just seems to include this timing dip right about the same point with no explanation.

I called GMPP for my crate and talked to their guy. He said 6 degrees at 0 linear to 27 at 3000 and steady as she goes. That's where I'm at. BTW I am not a drag racer, rather an autoX'r.
Old 01-06-2014, 05:37 PM
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Mine is flat lined right now from 1000 on up, like the locked timing I used to run in my SBC solid roller motor.

Car 218.... pass #4 got out of groove and got out of it.

Old 01-06-2014, 06:02 PM
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9.0 at 153?!?!? Lol, we wish right?


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