Causes of Detonation?
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From: Ottawa, Canada
Originally posted by SILVERLIGHTNING
Maybe the cats are plugged.
Do you use leaded fuel?
Maybe the cats are plugged.
Do you use leaded fuel?
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From: Ottawa, Canada
Originally posted by rh.223
http://www.factorypipe.com/Technical...Deto/deto.html more fuel less boost, is your exaust stock? less back presure=less heat. is the maf clean dosent take much. i had a bug leg mess one up. cold air is more dence,can cause deto. check
the fuel presure at the rails, fuel filter? good luck!
http://www.factorypipe.com/Technical...Deto/deto.html more fuel less boost, is your exaust stock? less back presure=less heat. is the maf clean dosent take much. i had a bug leg mess one up. cold air is more dence,can cause deto. check
the fuel presure at the rails, fuel filter? good luck!
I have checked the MAF and it is fine (Its a new SCT big air MAf)
The temps have been around 65 so I dont know if that is too cold for it.
I think one of my next tests is going to be to lower the boost and see if that helps. I was going to dump some race fuel in it but none of the suppliers have any yet.
I think my next steps are going to be..
1- Larger blower pulley (lower boost): See what happens
2- Put the smaller pulley back on the blower and run race gas :See what happens
3- With the small pulley on and with 94 octane gas, richen the tune and run pig rich and see what happens
Thanks for the input guys.
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From: Ottawa, Canada
UPDATE:
This was my game plan...
1- Larger blower pulley (lower boost): See what happens
2- With the small pulley on and with 94 octane gas, richen the tune and see what happens.
3- Put the smaller pulley back on the blower and run race gas :See what happens
Results..
2- With the small pulley back on (19-21psi) and with 94 octane gas, richen the tune and see what happens.
3- Put the smaller pulley back on the blower and run race gas :See what happens
To say the least I am very happy that the truck is now running perfectly! I don’t know if my findings can help anyone but I thought I would post them just in case.
Cheers guys, Jason
This was my game plan...
1- Larger blower pulley (lower boost): See what happens
2- With the small pulley on and with 94 octane gas, richen the tune and see what happens.
3- Put the smaller pulley back on the blower and run race gas :See what happens
Results..
1- Larger blower pulley (lower boost): See what happens
- Replaced the 3" supercharger pulley for my larger 3.5" pulley.
- This reduced the boost from (19 base 21 peak) to (14 base 16 peak).
Did a test drive and the detonation was gone! The truck felt slow after going down that much boost but the good thing was the detonation was gone.
Went home and on the computer used my Tuning software to modify the tune and advance Wide open throttle timing 2 degrees went for a test drive and the detonation was still gone.
So so far this testing leads me to believe that my problem is fuel related. I.E. not enough fuel for 20 psi boost when under load in 3rd gear.
- Replaced the 3" supercharger pulley for my larger 3.5" pulley.
- This reduced the boost from (19 base 21 peak) to (14 base 16 peak).
Did a test drive and the detonation was gone! The truck felt slow after going down that much boost but the good thing was the detonation was gone.
Went home and on the computer used my Tuning software to modify the tune and advance Wide open throttle timing 2 degrees went for a test drive and the detonation was still gone.
So so far this testing leads me to believe that my problem is fuel related. I.E. not enough fuel for 20 psi boost when under load in 3rd gear.
2- With the small pulley back on (19-21psi) and with 94 octane gas, richen the tune and see what happens.
I went into my program and added as much fuel as I could for wide open throttle (15%) I also decided to lower timing even more (to 10 degrees) just to see.
Went for a test drive and the detonation was gone!!!
Went back home and burnt 2 more programs. One with the timing set to 12 degrees and the next with it set to 14 degrees.
I tested both programs and the detonation was still gone.
So it looks like my hunch was right and the truck needed more fuel to cope with the load and Cyln pressure.
Went for a test drive and the detonation was gone!!!
Went back home and burnt 2 more programs. One with the timing set to 12 degrees and the next with it set to 14 degrees.
I tested both programs and the detonation was still gone.
So it looks like my hunch was right and the truck needed more fuel to cope with the load and Cyln pressure.
Testing not required since problem is solved by step 2.
Cheers guys, Jason
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From: Ottawa, Canada
Originally posted by Odellintulsa
What is your air fuel on the top end? THanks for posting Im hearing some detonation in mine too when I tryu and add more timing for the track.
What is your air fuel on the top end? THanks for posting Im hearing some detonation in mine too when I tryu and add more timing for the track.
My plan is to make about 5 tunes that do not detonate with varying mixtures of timing and fuel. I will then take those 5 or so programs toa local dyno and see which one makes hte best power. I will hook up a wide band at the same time to see what kind of A/F I am seeing now. I suspect them to be on the rich side but it seems that is what is required.
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From: Florida
Jason -
Glad to hear your detonation woes have been solved, The only thing I can recomend to you at this point is to run a wideband in the truck full time. I have had wideband in my boosted vehicles full time since 2002 and I can say it was the most important thing I have ever done for the life of my engines.
I have not blown one up yet <fingers crossed>
Bob
Glad to hear your detonation woes have been solved, The only thing I can recomend to you at this point is to run a wideband in the truck full time. I have had wideband in my boosted vehicles full time since 2002 and I can say it was the most important thing I have ever done for the life of my engines.
I have not blown one up yet <fingers crossed>
Bob
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From: Ottawa, Canada
Bob, I have been thinking about a wide band for some time now and I think I am going to take your advice and order one.
PS, Thanks for the support/suggestions during the troubled times.
PS, Thanks for the support/suggestions during the troubled times.
