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blackblowngto
August 4th, 2005, 08:21 AM
can someone list all the reasons why someone might be getting knock? can a lean condition cause knock? any help would be greatly appreciated.
TAQuickness
August 4th, 2005, 09:13 AM
Not sure if all the reasons can be listed :wink:

Being too lean
Bad Gas/low octane gas
Oil
Too much timing advance

That's just off the top of my head
blackblowngto
August 4th, 2005, 09:40 AM
oil is good, gas is good, spark is perfect. probably a lean condition then! tanks for the help
TAQuickness
August 4th, 2005, 09:48 AM
Not so much bad oil, but getting oil in the induction system.

What motor do you have?
BowlingSS
August 4th, 2005, 10:52 AM
What year do you have? It could be false KR... You could also have a pipe hitting..

Bill
GMPX
August 4th, 2005, 11:03 AM
Remembering your car is boosted, how much timing is the engine getting just before it knocks?. Have you logged the actual AFR's before it knocks.

Cheers,
Ross
joecar
August 4th, 2005, 11:58 AM
Compression ratio too high.
Running too hot.
Valve train noise.
blackblowngto
August 5th, 2005, 06:20 AM
blown ls1 in an 04 gto, mafless, and tuning VE tables.
Black LS1 T/A
August 5th, 2005, 08:02 AM
Why do you say "spark is perfect"? :)
What is your total timing at WOT? How much peak boost are you running? What is your static compression ratio?

IF you are blowing oil into the induction (it happens a lot with blown applications), it will degrade the quality of fuel going in and create knock.

Powerful take-offs (something our blown cars can have in the extreme) can induce lots of exhaust noise of launch. :x You won't even hear it over all the noise. Double-check for loose or banging exhaust.
blackblowngto
August 5th, 2005, 09:24 AM
i do have a very loose pipe as i just put a new exhaust system on, how easy is it for that rattle to be mistaken for knock? thanx for your help and awesome setup!!
Black LS1 T/A
August 5th, 2005, 11:50 AM
i do have a very loose pipe as i just put a new exhaust system on, how easy is it for that rattle to be mistaken for knock? thanx for your help and awesome setup!!

Thanks man... I need a different cam, I guess, to put more horsepower at top and flatten the torque curve. It's useless except at the track. :(

Absolutely, a loose exhaust can give you that problem!