? ABOUT KNOCK RETARD
? ABOUT KNOCK RETARD i got an 02 z. i just recently go a predator and did some diagnostic runs. no wot knock but twice i got alittle over a degree (1.3 - 1.1) of retard at part throttle. is this normal?
now i did the base tune and out of maybe ten wot runs to half of fourth gear, about half (5) runs showed about 1 degree retard at or when i was shifting (5700-6000 rpm) then it would go away after the shift. is this normal? maybey im just tapping the limiter? (i normally dont take my foot of the gas and just clutch and go....especially since the tune 3rd finally barks real nice!).
i put the power erichment up to .05 and havent messed with timing yet. im just trying to get a feel for where i stand.
thanks
jeff
now i did the base tune and out of maybe ten wot runs to half of fourth gear, about half (5) runs showed about 1 degree retard at or when i was shifting (5700-6000 rpm) then it would go away after the shift. is this normal? maybey im just tapping the limiter? (i normally dont take my foot of the gas and just clutch and go....especially since the tune 3rd finally barks real nice!).
i put the power erichment up to .05 and havent messed with timing yet. im just trying to get a feel for where i stand.
thanks
jeff
TECH Resident
Joined: Jul 2003
Posts: 834
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From: Marysville, OH
Re: ? ABOUT KNOCK RETARD I would not be to concerned with that KR. There have been posts on here with people that have had alot worse than that. I would try however to tune to achieve no KR. KR is the enemy and avoiding any amount is the best way to proceed.
Re: ? ABOUT KNOCK RETARD thanks for the input. now reguarding what youve said... with getting a hint of knock im at the max timing i can run? or do i fattin up the pe some more till it looks like 0 knock 98% of the time then do i try to squeek some more timing out of it? i would have gottin edit but if i did id never drive the car really just constantly change variables. thanks for the insight
jeff
jeff
TECH Apprentice
Joined: Jan 2002
Posts: 364
Likes: 0
From: Princeton, IN
Re: ? ABOUT KNOCK RETARD When your converter locks up at lower speeds and you give it a little gas I’m sure you will see a little knock, It puts a load on the car. If you have a t56 then you might have shifted to soon then tried to speed put in to high of a gear.
TECH Apprentice
Joined: Jan 2002
Posts: 364
Likes: 0
From: Princeton, IN
Re: ? ABOUT KNOCK RETARD
I would not be to concerned with that KR. There have been posts on here with people that have had alot worse than that. I would try however to tune to achieve no KR. KR is the enemy and avoiding any amount is the best way to proceed.
Re: ? ABOUT KNOCK RETARD '98 knock sensors are known to cause bogus KR
when they go bad, GM changed the sensor later.
A flat 3.9 degree value is a sign of this. Check
it out.
With TM removed by Predator, I also see KR blips
on upshifts especially with trans set for faster
shift & more pressure - you jerk the RPMs down
and the engine load / cylinder pressure up fast
and the timing is too advanced for it.
I'd prefer to keep about 2 degrees of timing pull
just during the shift but with Predator it is all
or nothing, unless you get a custom tune done.
Don't know what the stock TM acts like but with
just enough timing pull to keep KR from hitting,
you would get rid of the KR "tail" that persists
after a knock event and probably be better off
overall.
when they go bad, GM changed the sensor later.
A flat 3.9 degree value is a sign of this. Check
it out.
With TM removed by Predator, I also see KR blips
on upshifts especially with trans set for faster
shift & more pressure - you jerk the RPMs down
and the engine load / cylinder pressure up fast
and the timing is too advanced for it.
I'd prefer to keep about 2 degrees of timing pull
just during the shift but with Predator it is all
or nothing, unless you get a custom tune done.
Don't know what the stock TM acts like but with
just enough timing pull to keep KR from hitting,
you would get rid of the KR "tail" that persists
after a knock event and probably be better off
overall.
