I need help (Detonation with High Compression)
Thread Starter
Burning Brakes
Joined: Jun 2002
Posts: 996
Likes: 0
From: Frisco Texas
I need help (Detonation with High Compression)
I have 55cc chambers on my 98 cnc heads. I am getting detonation out the **** when in OD with the converter locked. Right now my converter is set to unlock at 1% throttle increase.
When the converter is unlocked the car runs like crazy! On highway driving trying to pass someone it sounds really bad 14 degrees of knock. Any of you LS1 Edit guys every had this problem? How did you fix it?
My solutions are:
Octane Boost - Can I use 2 cans each fillup
Colder plugs, running 12 to 1 compression
Electric Water Pump - Increase cooling and take load off motor
NOW THE EXPENSIVE STUFF
Larger headgaskets - I have the stock head gasket now, how much bigger can I go? (Reudce Compression)
Different Cam - I have a even split 224 now, may goto a 224/230
Dished Pistons - Reduce compression (I will also change rod's and crank 383 stroker maybe)
Sell my heads and get some AFR heads
BLOW THE MOTOR AND GET A LS6 Motor
When the converter is unlocked the car runs like crazy! On highway driving trying to pass someone it sounds really bad 14 degrees of knock. Any of you LS1 Edit guys every had this problem? How did you fix it?
My solutions are:
Octane Boost - Can I use 2 cans each fillup
Colder plugs, running 12 to 1 compression
Electric Water Pump - Increase cooling and take load off motor
NOW THE EXPENSIVE STUFF
Larger headgaskets - I have the stock head gasket now, how much bigger can I go? (Reudce Compression)
Different Cam - I have a even split 224 now, may goto a 224/230
Dished Pistons - Reduce compression (I will also change rod's and crank 383 stroker maybe)
Sell my heads and get some AFR heads
BLOW THE MOTOR AND GET A LS6 Motor
Le Mans Master
Joined: Oct 2001
Posts: 5,577
Likes: 3
From: Southern Maryland Maryland
Re: I need help (JoeyG)
After thinking about your problem I just can't see why you would run that much compression with that small of a cam. My cam has alot of everything you need to run high compression, duration, overlap, ICL. Can you do a cranking compression test and that will tell us alot. The last time I checked my car was ~230s. I'd be willing to bet its alot higher....
Phillip
Phillip
Safety Car
Joined: Mar 2002
Posts: 4,928
Likes: 1
Cruise-In V Veteran
St. Jude Donor '09
Re: I need help (kumar75150)
Is the cam installed straight up or is it advanced...4* ??? If it's advanced 4* you could back it up (retard) which would reduce your dynamic compression.
Putting in a thicker gasket might increase your knock as it will increase the quench.
Putting in a thicker gasket might increase your knock as it will increase the quench.
Thread Starter
Burning Brakes
Joined: Jun 2002
Posts: 996
Likes: 0
From: Frisco Texas
Re: I need help (Phil97SVT)
After thinking about your problem I just can't see why you would run that much compression with that small of a cam. My cam has alot of everything you need to run high compression, duration, overlap, ICL. Can you do a cranking compression test and that will tell us alot. The last time I checked my car was ~230s. I'd be willing to bet its alot higher....
Phillip
Phillip
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Le Mans Master
Joined: Oct 2001
Posts: 5,577
Likes: 3
From: Southern Maryland Maryland
Re: I need help (cscollis)
I would retard the cam 4 degrees, install a Hypertech 160 T-stat, and throw in some Sunoco 94. If knock persists you need a bigger cam to bleed off the compression. I would go into the low 230s with a tighter LSA.
Phillip
[Modified by Phil97SVT, 10:34 AM 4/28/2004]
Phillip
[Modified by Phil97SVT, 10:34 AM 4/28/2004]
