How much timing?
02-17-2008, 10:01 AM
#11
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thats what im thinkin..i wonderin how in the hell some people can get alot more timing and not knock..i always keep 110 mixed in with my tank though..i dont trust pump gas and i dont like sprayin on pump gas
02-17-2008, 01:28 PM
#16
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Without a dyno for timing, im so demorilized on timing. Nothing really makes sense and there is nothing you can really trust for good timing (besides factory timing)
No matter what I do with my timing it makes no diffrence I can detect on my 5.3 with headers.
If you have a cam timing should be increased at low rpms as ve isnt as high at low rpms with a big cam, but as rpms rise ve will go up with a big cam and the engine wont need as much timing.
The optimal timing on the vortecs is about the same on LS motors, which I would think the vortecs would require more avarage timing becuase of the slightly lower compression ratio.
Anyway the optimal timing (what the pcm uses to calculate torque based on how far the acutal timing is away from it) for the 5.3 it about 28-29 @ 3600.
For as much testing as the factory does to thier engines I guess you can trust that the optimal timing in the factory tunes is the optimal timing. Trust 27-29degrees of full timing at wot, although it might require a higher octane fuel.
For headers, I havent seen any diffrence from them. I don't see any diffrence in airflow either.
No matter what I do with my timing it makes no diffrence I can detect on my 5.3 with headers.
If you have a cam timing should be increased at low rpms as ve isnt as high at low rpms with a big cam, but as rpms rise ve will go up with a big cam and the engine wont need as much timing.
The optimal timing on the vortecs is about the same on LS motors, which I would think the vortecs would require more avarage timing becuase of the slightly lower compression ratio.
Anyway the optimal timing (what the pcm uses to calculate torque based on how far the acutal timing is away from it) for the 5.3 it about 28-29 @ 3600.
For as much testing as the factory does to thier engines I guess you can trust that the optimal timing in the factory tunes is the optimal timing. Trust 27-29degrees of full timing at wot, although it might require a higher octane fuel.
For headers, I havent seen any diffrence from them. I don't see any diffrence in airflow either.
02-17-2008, 10:11 PM
#18
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I was running 27-28 at WOT on the stock cam without KR. I had problems when I originally started tuning getting the timing up much, but after I got the fueling nailed down better I had no trouble running more timing.
02-17-2008, 10:21 PM
#20
I run roughly 28* with just boltons and a 4.8... I don't get any KR.... IMO start out with a richer mixture to get the timing you want the adjust your AFR accordingly.... I have got my AFR spot on while it SD mode but when I enable my MAF and tune it it seems like I have less power.... Next weekend I am going to covert over the COS3 and be done with the MAF..... Do timing is slow increments...