When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi,
I seem to get knock at higher revs and sometimes not where expecting.
Stock LS1 5.7 241 heads Gt45 turbo Efilive M6
Could i be getting real knock here with equivalent to your 93 gas (our 99 is your 93)
COS3 using PE to reduce timing after 100KPA
Any help appreciated
Regards
Gav
agree its super rich and 14.5 degrees at 135kpa (~5psi) is very low. id also double check all your exhaust isnt flopping around hitting things and making noise.
Agree , definitely need to eliminate anything mechanical making contact and "noise " that the KS is picking up, are your KS settings stock ? Can desensitize them a bit and still have safety . What fuel ? Shouldn't need WM injection at that boost , although mine starts around that level . Not a tuning expert but tuned mine and helped out some friends with hp , don't know efi live. Haven't tuned stock cam and boost before but it could lead to higher than expected cyl pressure than most of us have dealt with. I would try and get the AFR to 11.5 ish although I didn't see KR from 11:1 ratio. Can't tell, if you're logging g/cyl but you need that info to remove timing a degree at a time in the correct areas until you see no KR. I believe it helps to keep coolant temps as low as possible for a small edge in keeping knock away , keep at it , you'll get there
Agree , definitely need to eliminate anything mechanical making contact and "noise " that the KS is picking up, are your KS settings stock ? Can desensitize them a bit and still have safety . What fuel ? Shouldn't need WM injection at that boost , although mine starts around that level . Not a tuning expert but tuned mine and helped out some friends with hp , don't know efi live. Haven't tuned stock cam and boost before but it could lead to higher than expected cyl pressure than most of us have dealt with. I would try and get the AFR to 11.5 ish although I didn't see KR from 11:1 ratio. Can't tell, if you're logging g/cyl but you need that info to remove timing a degree at a time in the correct areas until you see no KR. I believe it helps to keep coolant temps as low as possible for a small edge in keeping knock away , keep at it , you'll get there
At 5 pounds of boost you almost don’t need to do anything. I don’t usually get into 11afrs until 16-18 psi.
Your tune is already way below anything I’d expect to even think about knocking. I’d suggest throwing some race fuel in or a can of octane booster. If the knock goes away then I’m wrong and it’s real knock. If it stays the same then you have external noise activating your knock sensors.
Hi,
wow thanks all for advice.
pre turbo install couldn’t get this engine above 24 degrees using our 99 Ron your 93 equivalent.
my turbo manifolds are tight in engine bay.
i do log grams cyl and drop timing in those areas of knock which I did after starting this post and rich ended up aft at higher revs a tad and log showed no knock….
should I leave timing and lean out afr on boost to 11.5?
regards
gav
mine is 5.7 stock compression so probably higher than most 5.3s?
That’s an overly conservative tune IMO. It *shouldn’t* hurt anything if you throw 2 degrees at it and lean it out to 11.8 or so.
Do plugs show any signs of detonation? I’ve never even run a knock sensor on a turbo LS. Signal was always too noisy to be useful. (not that they aren't a great tool when working correctly).
This is how I have mine setup. NA my EQ ratio is .87 Lambda after peak TQ till 100kpa, then I slowly ramp it richer the more boost that comes in and settles to .78 Lambda
I do the same thing with timing, which is really soft right now below peak TQ to help keep the SBE LS1 alive. I need to add a little bit down low, because it spools alot slower than it should with twin 58's. The cam has a lot to do with that too though.
From your log, it looks like you are maxing your air mass at a low boost. I had to scale my tune by 75% to be able to use the entire table. I made a custom PID that shows how much boost at any given airmass which has helped me a lot in shaping the spark table. After doing that, 1.20 g/s equations to 15lbs, which is the most I'm comfortable running on this setup considering what it made N/A.
But if your COS pulls timing based of boost, that might not be an issue for you, I've only used HPTuners.
06-21-2024, 06:41 AM
More knock 
