timing, masters of the LS please.....
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From: Broken Arrow, OK
timing, masters of the LS please..... Good day...
I know I do not post on here much, i usually do not have to because of all the smart people already doing so and making brilliant suggestions.
I have a 383 (4" stroke) LS series motor, MS4 and stage 3 heads from Texas speed -2.04 intake, 1.60 exhaust. BBK ported intake, 90mm tb, OLSD, step headers, 4" exhaust. 4:11 in rear with yank 4000, 28" tall tires. 11 to 1 comp.
AF is 12.9 to 1. and the following is NA
I started timing at 28wot went 11.55 @ 117 mpn (3 runs)
Went to 27 11.60, then 11.55 again, one MPH increase to 118mpn (2 runs)
so I tried to go the other way.......
29 netted me 11.30 @ 118.8, then 11.22 @ 119.xx
The question is I noticed that most people use 26 to 28 wot on these LS series motors, and ChevyHighPerformance got best power at 36 deg wot on their carb LS. Am I missing something? I have no knock logged. Is there something with my combo that may require more timing? Maybe even more then 29?
Please help o masters of the LS world...
Grim
I know I do not post on here much, i usually do not have to because of all the smart people already doing so and making brilliant suggestions.
I have a 383 (4" stroke) LS series motor, MS4 and stage 3 heads from Texas speed -2.04 intake, 1.60 exhaust. BBK ported intake, 90mm tb, OLSD, step headers, 4" exhaust. 4:11 in rear with yank 4000, 28" tall tires. 11 to 1 comp.
AF is 12.9 to 1. and the following is NA
I started timing at 28wot went 11.55 @ 117 mpn (3 runs)
Went to 27 11.60, then 11.55 again, one MPH increase to 118mpn (2 runs)
so I tried to go the other way.......
29 netted me 11.30 @ 118.8, then 11.22 @ 119.xx
The question is I noticed that most people use 26 to 28 wot on these LS series motors, and ChevyHighPerformance got best power at 36 deg wot on their carb LS. Am I missing something? I have no knock logged. Is there something with my combo that may require more timing? Maybe even more then 29?
Please help o masters of the LS world...
Grim
TECH Apprentice
Joined: Jan 2008
Posts: 366
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From: Gladstone, Queensland, Australia
All depends on the valve timing, overlap and dynamic compression all play a big part in timing. The More overlap generally the more timing you can run.26 to 28 sounds about right.But stay with 29 if that is your best mph and et. Next time try 30 and see if you gain more mph,
LS1 motors are very efficient and tend to need much less timing than typical SBC's and while you may make a few more hp at 32* compared to 26 or 28* for most people its not worth risking their engine over so most will settle for a few less hp for a bit more longevity.
There are a lot of different parameters that will dictate how much timing a specific setup will like. Trial and error both on a dyno and at the track will tell you exactly what the engine does or does not like. So, you're doing it right! As expected, higher timing will put you closer to detonation, so you really need to be running some quality high-octane gas to know what the engine really likes. It may like more timing with 100 octane unleaded vs. 92 octane pump gas just because of possible knock issues. You just need to do your testing with the fuel you'll run consistently. Be sure you run some higher octane fuel when you start running N2O if you're currently on pump gas.
Let me know if you have any additional questions or concerns.
Thanks!
Trevor
Texas Speed & Performance
Let me know if you have any additional questions or concerns.
Thanks!
Trevor
Texas Speed & Performance
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