View Full Version : E38 LS7 Ignition timing question
Age08
August 4th, 2017, 06:33 AM
Ran my car 08 Z06 on the dyno at a car show and it didn't produce the numbers that I was expecting of with heads milled 20' and a cam with .649In/.660Ex lift, 227/243 duration and lsa 115.
It put down 469hp/420tq @ the wheels, The airfuel was a little rich @ 11.3-11.6, and the ignition timing seemed low at 17.
I know there was atleast 1-2 degree removed due the IAT being at 30, but I still would except higher.
What do cam'd ls motors typically run 2134421345for timing @ wot?
wesam
August 4th, 2017, 09:37 AM
What dyno is this ? What fuel used ? this car should put 550 whp in dyno jet with 93 octane if tuned properly
Age08
August 4th, 2017, 10:39 AM
Mobile Dynojet, 93 octane, Thats what number I was excepting, I am still in the process of tuning the motor since I did mods, which were done only because I had the motor apart to fix the valve guides,
wesam
August 4th, 2017, 10:43 AM
According to those numbers i think you have one or two pistons not functioning properly
I would check for missfire then make a compression test
Age08
August 4th, 2017, 10:50 AM
If you look at the log, under wot it had no knock
I'm more so blaming tune, although the car doesn't smoke or run rough for a camed car,
the motor only has 8k miles on it.
wesam
August 4th, 2017, 10:53 AM
Even if you put 4 more degrees of timing and lean it out to around 12.6 it will not jump 80 whp where it should be
Some times for a camed cars it hard to notice the missing if there is one or more pistons missfireing so you have to check
Age08
August 4th, 2017, 11:00 AM
When I get a chance I will do a compression test and leak down test to compare that all cylinders are good,
Age08
August 6th, 2017, 05:00 AM
Did a compression test and was 210 across the board dry, all the plugs looked the same, wires all measure out the same resistance wise as well,
The only thing I found wrong was the two pvc lines that go top the dry sump were crossed, and there was some oil in the intake where the vent line comes in,
when the car was on the dyno it made no smoke out the tail pipe,
joecar
August 7th, 2017, 08:26 AM
From your log, MAP starts dropping as rpm gets high... is there a different filter you can try...?
Can you run cooler intake air...?
Keeping it rich, have you tried adding a few degrees of timing...?
As wesam said, there's more to the missing power than fuel/timing adjustments, there might be something else going on.
Age08
August 7th, 2017, 01:37 PM
I noticed that to with the map, there's a bigger filter which is a direct replacement that might help,
When it was on the dyno they didn't have a really big fan which could of contributed to the higher temps,
I don't see anything obviously wrong, beside the pvc lines crossed,
What I'm going to have to do is book some dyno time try a few things, the intake air may be one of the problems,
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