Spark knock
Thread Starter
Staging Lane
Joined: Apr 2008
Posts: 66
Likes: 0
Spark knock hello all. I have a 67 camaro with an LQ4. It has LS6 intake, throttle body and injectors. Mid length headers, stock 317 heads and just installed a Texas speed 224r cam package. Running through a 4l80e trans with stock converter to 9 inch ford with 3.89 gears. My tuner is telling me he is getting spark knock in the higher rpm range which is equating to 309 rwhp on a mustang dyno. Does this number seem low to you guys?? Also, the fuel system is more than adequate. What would cause the ecm to continue to pull spark out up top?? I had 91 octane and he is now replacing with 93. Any advice greatly appreciated for tuning this out.
TECH Junkie
Joined: Dec 2012
Posts: 3,614
Likes: 1,326
From: Iowa
Especially with a swap, start looking for false knock. A loose header, tight header clearance that makes it beat against the floor, etc
Also, as with any knock check for BAD GAS!! Even if it gets plenty of fuel, if its crappy fuel...you'll have crappy results
Lastly, if this is an engine out of a junkyard truck that sat with the hood open in the rain, or got neglected in general, I would pull the intake and inspect the knock sensors and harness themselves. LS valley covers are known to get water in them and ruin the sensor.
I guess I should have answered your question first...yes a 6.0 with a cam making only 309 seems very off to me. Best of luck!
Also, as with any knock check for BAD GAS!! Even if it gets plenty of fuel, if its crappy fuel...you'll have crappy results
Lastly, if this is an engine out of a junkyard truck that sat with the hood open in the rain, or got neglected in general, I would pull the intake and inspect the knock sensors and harness themselves. LS valley covers are known to get water in them and ruin the sensor.
I guess I should have answered your question first...yes a 6.0 with a cam making only 309 seems very off to me. Best of luck!
aside from the spark knock, the 317 heads equating to near stock 9.4:1 compression ratio, 4l80, mid-length headers, and 9 inch rear, wouldn't that eat a bit more of the parasitic/drivetrain loss? on top of that through a mustang dyno which reads lower? if adding anywhere between 12-17% would put it around 350-360ish?
TECH Junkie
Joined: Dec 2012
Posts: 3,614
Likes: 1,326
From: Iowa
I would think with the bolt ons, it should be 325-ish probably 350 tire with the cam
With the cam it should be more.
Can you tell us how much timing is commanded and afr at what RPM?
How much is the KR pulling back out of it?
With the cam it should be more.
Can you tell us how much timing is commanded and afr at what RPM?
How much is the KR pulling back out of it?
the performancetrucks.net forum shows a few stock LQ4s dyno'd 230-240 on a mustang dyno and about 250-260 on a dynojet. stock auto ls1s dyno'd around 280-295ish on a dynojet as perspective.
edit-also are you using the truck pcm that your tuner's using to tune with? if so, I read that the truck tune has a very aggressive torque management and knock retard settings.
edit-also are you using the truck pcm that your tuner's using to tune with? if so, I read that the truck tune has a very aggressive torque management and knock retard settings.
TECH Junkie
Joined: Dec 2012
Posts: 3,614
Likes: 1,326
From: Iowa
the performancetrucks.net forum shows a few stock LQ4s dyno'd 230-240 on a mustang dyno and about 250-260 on a dynojet. stock auto ls1s dyno'd around 280-295ish on a dynojet as perspective.
edit-also are you using the truck pcm that your tuner's using to tune with? if so, I read that the truck tune has a very aggressive torque management and knock retard settings.
edit-also are you using the truck pcm that your tuner's using to tune with? if so, I read that the truck tune has a very aggressive torque management and knock retard settings.
Trending Topics
^true but the OP is still running stock compression ratio. coupled with the 224r cam and his tuner, would add like, what, 35-40whp? again, going back to my question on whether the 9" rear and 4L80 trans and mid-length headers not LT headers would be robbing his horsepower numbers. in the end though, OP, run the car at the track after the spark/knock retards taken care of and see what she runs. hell my old fireturd build ran pretty decent times on stock compression ratio (317 heads) but I never bothered to dyno it.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
Staging Lane
Joined: Apr 2008
Posts: 66
Likes: 0
It doesn't help that the tuning is being done in 90% humidity. Thanks for the discussion. I appreciate everyone's opinion. Converter and heads are on the wish list or just throw a supercharger on in the future since the compression is so favorable.