Always getting knock Retard
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Always getting knock Retard
Hi
my friends Camaro SS
has a strange problem
he bought a rebuilt motor *short block* from a local guy here
built LS1 348ci set up for nitrous
Custom Nitrous Camshaft 228/230 571/573 LSA 114
Rest of the setup
ETP 215 62cc
FAST 102mm
102 bigmouth
headers
11.1 CP
3200stall
3.73 gears
The car is a good daily driver, it's tuned and sound great
and the mid range TQ is huge
But the problem is it doesn't stand timing, it has to be in the 17-18° in timing so it doesnīt sense Knock Retard in WOT and it doesnīt pull jack **** after 4500 rpms
AFR is 12.5 threw the band, but if you give it more timing it just KR, we tryed give it racegas but it didnīt change anything it just KR if we gave it more timing.
I think it isnīt false knock, because i can get KR out by going down in timing.
the car went at the track like this and it went 13.1@105
So the question is
What can be wrong here ?
could it be
1. the Camshaft is built this way
2. the camshaft is degreed wrong
3. something wrong whith tuning
???
Baezi
my friends Camaro SS
has a strange problem
he bought a rebuilt motor *short block* from a local guy here
built LS1 348ci set up for nitrous
Custom Nitrous Camshaft 228/230 571/573 LSA 114
Rest of the setup
ETP 215 62cc
FAST 102mm
102 bigmouth
headers
11.1 CP
3200stall
3.73 gears
The car is a good daily driver, it's tuned and sound great
and the mid range TQ is huge
But the problem is it doesn't stand timing, it has to be in the 17-18° in timing so it doesnīt sense Knock Retard in WOT and it doesnīt pull jack **** after 4500 rpms
AFR is 12.5 threw the band, but if you give it more timing it just KR, we tryed give it racegas but it didnīt change anything it just KR if we gave it more timing.
I think it isnīt false knock, because i can get KR out by going down in timing.
the car went at the track like this and it went 13.1@105
So the question is
What can be wrong here ?
could it be
1. the Camshaft is built this way
2. the camshaft is degreed wrong
3. something wrong whith tuning
???
Baezi
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This can be a big problem with the auto cars with aftermarket converters. I would think it was something that should be corrected in the tune. Also, the knock sensors have to be torqued properly for them to read right. Those would be the two things I look at first. The tuning info can be found in the PCM section.
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What are the knock sensor sensitivites set at in the tune? I dunno what OS you are using, but perhaps try to find the original settings for that car / model year and reflash those. If they are stock, decreasing sensitivity - to a point - might be the only remedy.
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
How aggressive are your KR tables for reducing timing?
Have you got enough fuel flow / injector?
Is there some mechanical issue that is causing false knock?
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
How aggressive are your KR tables for reducing timing?
Have you got enough fuel flow / injector?
Is there some mechanical issue that is causing false knock?
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
Last edited by macca33; 07-11-2011 at 11:17 PM.
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What are the knock sensor sensitivites set at in the tune? I dunno what OS you are using, but perhaps try to find the original settings for that car / model year and reflash those. If they are stock, decreasing sensitivity - to a point - might be the only remedy.
It's set at stock
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
Not hearing knock no only showing KR in the log
How aggressive are your KR tables for reducing timing?
stock
Have you got enough fuel flow / injector?
they are LS7 injectors, but maby some settings are wrong, that was one idea i got
Is there some mechanical issue that is causing false knock?
the motor is new rebuilts and sounds fresh
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
It's set at stock
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
Not hearing knock no only showing KR in the log
How aggressive are your KR tables for reducing timing?
stock
Have you got enough fuel flow / injector?
they are LS7 injectors, but maby some settings are wrong, that was one idea i got
Is there some mechanical issue that is causing false knock?
the motor is new rebuilts and sounds fresh
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
thanks
Baezi
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I don't remember the process for fixing it in the tune. Thats why I said its in the PCM section. You are gonna need to search around that section until you find one of the threads that tells you how to fix it.