Detonation fix?
Thread Starter
Advanced
Joined: Nov 2013
Posts: 61
Likes: 5
Detonation fix?
'06 LS2 75,000 miles stock except for Vararam CAI and SLP Loudmouth II mufflers. Premium only. Chevron. A bottle of Techron once a month.
I thought it was a heat shield rattle but it turns out to be detonation on moderate to heavy acceleration (3000-3500rpms and up). A little sputter with the noise.
Someone suggested new plugs and a tune (custom tune) will resolve the issue and get a performance boost.
Open to any and all suggestions?
I thought it was a heat shield rattle but it turns out to be detonation on moderate to heavy acceleration (3000-3500rpms and up). A little sputter with the noise.
Someone suggested new plugs and a tune (custom tune) will resolve the issue and get a performance boost.
Open to any and all suggestions?
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Are you logging and actually seeing knock or just feeling/hearing it or what exactly? Factory original tune?
If you're seeing it on logs I'd replace knock sensors just to be sure it's not those. Don't over torque them when you install the new ones (I think the spec is 18 ft lbs). It's a long shot, but they're cheap and easy to replace, so you might as well be sure they're good first
New plugs aren't a bad idea
It shouldn't keep knocking regardless, though. The way the factory computer works is after it sees a certain amount of knock it biases towards the low octane timing table. It takes quite a while for it to slowly work its way back to the high octane timing table.. so if it knocks a few times it really should be pulling the timing down far enough that it shouldn't keep doing it. That's why I ask if you're actually seeing it on logs or just think you hear/feel it.
Need more details before I can say much else. I fought false knock on mine for months. Found water pump bearings were going out, power steering bump bearings were going, alternator bearings were going.. all set the knock sensors off like crazy.
If you're seeing it on logs I'd replace knock sensors just to be sure it's not those. Don't over torque them when you install the new ones (I think the spec is 18 ft lbs). It's a long shot, but they're cheap and easy to replace, so you might as well be sure they're good first
New plugs aren't a bad idea
It shouldn't keep knocking regardless, though. The way the factory computer works is after it sees a certain amount of knock it biases towards the low octane timing table. It takes quite a while for it to slowly work its way back to the high octane timing table.. so if it knocks a few times it really should be pulling the timing down far enough that it shouldn't keep doing it. That's why I ask if you're actually seeing it on logs or just think you hear/feel it.
Need more details before I can say much else. I fought false knock on mine for months. Found water pump bearings were going out, power steering bump bearings were going, alternator bearings were going.. all set the knock sensors off like crazy.
Last edited by schpenxel; Nov 7, 2015 at 10:33 PM.
Thread Starter
Advanced
Joined: Nov 2013
Posts: 61
Likes: 5
I have assumed my Innova diagnostic tool that collects "live data" was the same as "data logging." If not then I am not data logging.
So I have looked at the Innova website. I don't think this device does nearly the job that HP Tunes. I also look at the HP Tunes site. It seems to me that getting HP Tune or similar product to data log (est. $400) and then have a tune developed for my specific vehicle and circumstances another couple of hundred dollars. But will it resolve the issue?
So I have looked at the Innova website. I don't think this device does nearly the job that HP Tunes. I also look at the HP Tunes site. It seems to me that getting HP Tune or similar product to data log (est. $400) and then have a tune developed for my specific vehicle and circumstances another couple of hundred dollars. But will it resolve the issue?
Last edited by Southmsfiveo; Nov 8, 2015 at 10:34 PM. Reason: More information to share
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
If the issue is your exhaust hitting the body or suspension, no HP Tuners can't fix that. Your car will pull timing to prevent knock before you actually hear it so it's odd that you would actually hear knock.
I'm suspecting that your mufflers are hitting, I'd suggest you get it on a lift and scope that out carefully - if you can do a drive on lift that's a lot better as it'll show you where things are sitting when the car is on its tires. That's what I'd do before I spent a lot of money on anything else.
I'm suspecting that your mufflers are hitting, I'd suggest you get it on a lift and scope that out carefully - if you can do a drive on lift that's a lot better as it'll show you where things are sitting when the car is on its tires. That's what I'd do before I spent a lot of money on anything else.