What would cause a car to knock?
#47
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my cams are 264 in, 272 ex. i have extra 272 intake that i'll be installing soon.
#48
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Naji, i'm not going to blame it on the cams just yet . too many things to consider. plus i am a ricer . i want more powwwwwer!!!!
#52
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I created this iginition map for my friend's car. It is based on input from the prior logs, the map that Bryan sent me (Thank you, beer is on me if we ever meet), and the timing that I run on my 91 maps.
It is a pretty tame timing map.
According to my logs the car loads up to 240-260 and then tapers to 200-220 and ends redline @ 180-200.
What do you think?
It is a pretty tame timing map.
According to my logs the car loads up to 240-260 and then tapers to 200-220 and ends redline @ 180-200.
What do you think?
#53
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I created this iginition map for my friend's car. It is based on input from the prior logs, the map that Bryan sent me (Thank you, beer is on me if we ever meet), and the timing that I run on my 91 maps.
It is a pretty tame timing map.
According to my logs the car loads up to 240-260 and then tapers to 200-220 and ends redline @ 180-200.
What do you think?
It is a pretty tame timing map.
According to my logs the car loads up to 240-260 and then tapers to 200-220 and ends redline @ 180-200.
What do you think?
#55
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nj1266,
I'll pm you one of my more recent maps this evening, don't have access to them at the moment. I've been round and round with knock, in my case the bulk of it was due to a bad injector, but I also think georgia 93 octane is not that great, the cars I have tuned on the dynodynamics all seem to end up with timing similar to what I am currently running so I'll shoot you something to take a look at when I get home.
I'll pm you one of my more recent maps this evening, don't have access to them at the moment. I've been round and round with knock, in my case the bulk of it was due to a bad injector, but I also think georgia 93 octane is not that great, the cars I have tuned on the dynodynamics all seem to end up with timing similar to what I am currently running so I'll shoot you something to take a look at when I get home.
#57
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Fuel- That brings me to another question. I looked at the log before I sent a rom and saw what the wideband said the AFR's are. However I know at least with a IX that they dont match up with the target map with lean spool active. Are you sure that the WB is trustworthy? Just going by fueling you should be at least 1/2 point leaner or more by the target AFR with lean spool if it were a IX (at any rate). Something to double check as well Naji, it might be lean a little.
#58
Fuel- That brings me to another question. I looked at the log before I sent a rom and saw what the wideband said the AFR's are. However I know at least with a IX that they dont match up with the target map with lean spool active. Are you sure that the WB is trustworthy? Just going by fueling you should be at least 1/2 point leaner or more by the target AFR with lean spool if it were a IX (at any rate). Something to double check as well Naji, it might be lean a little.
1. Change the IC pipe clamps to t-bolt clamps and do a boost leak test.
2. Log, check for knock. If knock still there
3. Change spark plugs to BPR8ES
4. Log, check for knock. If knock still there
5. Flash the utterly conservative map that I am working on
6. Log, check for knock, if still there
7. Go back to stock cams
8. Log, check for knock, if still there
then the best piece of advise I can give is screw 91 octane gas and mix to get 93 octane. That is what the car is supposed to run on in the first place.
Last edited by nj1266; Feb 6, 2007 at 01:14 AM.
#59
I just want to update this thread. Today we got a chance to log the car. We changed plugs to BPR8ES and gapped them to 0.025. Then we went out and did 4 back-to-back WOT logs. The spark plug trick seems to have lowered the knock sum to about 6-8 counts dependening on the run. The good thing is that the KS is repeating itself in the same range; 5000-5500 rpm. That is where it starts and then it tapers down from there. There are also 3-2 counts in the logs, but I am not concerned about those.
Here is my question. When the KS hits @ 5-5.5K and then goes down are the Knock sums that are declining residual from the original or are they new KS? The chart below shows that KS hits 6 counts @ 5500 rpm and then falls down to 2 by redline. So do I remove timing/add fuel in the 5500 rpm range only or do I remove timing/add fuel for the entire KS area?
Overall, I am optimistic that we are heading in the right direction. Next step is to change the stock clamps to t-bolt clamps and do a boost leak test. Then we will log again and see the results.
I am also thinking of going to BPR9ES plugs. But that raises the issue of fouling the plugs in daily driving.
Here is my question. When the KS hits @ 5-5.5K and then goes down are the Knock sums that are declining residual from the original or are they new KS? The chart below shows that KS hits 6 counts @ 5500 rpm and then falls down to 2 by redline. So do I remove timing/add fuel in the 5500 rpm range only or do I remove timing/add fuel for the entire KS area?
Overall, I am optimistic that we are heading in the right direction. Next step is to change the stock clamps to t-bolt clamps and do a boost leak test. Then we will log again and see the results.
I am also thinking of going to BPR9ES plugs. But that raises the issue of fouling the plugs in daily driving.
Last edited by nj1266; Feb 9, 2007 at 10:38 PM.