Knock only at 4000 RPM even after reducing timing

[brycedrue]

Weird issue here, KR logged onlt at 4000 RPM. Not even full throttle, even reduced timing

[blindsquirrel]

If you decrease timing or increase octane, or both (preferably), and the 'knock' does not change, then it is not spark knock, it's coming from something else that the sensors are picking up.

[brycedrue]

That's what I think it is. I'm leaning towards adjusting the knock tip in tables. Maybe the throttle transition is causing the issue.

[brycedrue]

Should I desensitize tip in TPS or tip in RPM? Both? I already tried to desensitize global gain by 20%

[smokeshow]

Zero info on the hardware..

[brycedrue]

P01, ls1 w/lsa supercharger

[smokeshow]

P01, ls1 w/lsa supercharger

I could tell you what the problem is...but you won't like the answer.

[brycedrue]

What's that?

[smokeshow]

LSA and cathedral ports and not friendly with each other, adapters be damned. The hardware simply is not compatible. You'll always deal with some tip-in leanness, stumble, knock, or intake backfire. No way around it.

[brycedrue]

Soooo "Turn off knock sensors and enjoy" is what I'm hearing lol 😆

[smokeshow]

If nothing else is bothering you, then by all means. lol

[brycedrue]

I've seen the adapter plate issue before. When the ole' ls1 gives up, I'll do a 6.0 with ls3 heads to make things easier

[blindsquirrel]

Will the aftermarket EVER solve this problem? Do they even know it is a problem that needs solving? Do they care? Hell, Brodix just announced a new small valve head for 3.80" bores... but it's still fking cathedral port. Thanks guys. Thanks a lot. <golf clap>

This is why I have stopped collecting parts for my LSA junk. I have everything but a lid and front drive stuff. Good blower, all good bearings, new coupler, new LS9 fuel rail (driver's side inlet), good used cleaned/tested LSA injectors, heat exchanger & pump... anybody passing through here on I-20, we can meet up and you can have it all for a song. Not literally for a song, but you know what I mean.

[smokeshow]

I asked Paul Yaw to address it. He said it would cost him $250k for injector hardware development that he'd never get a return from - the average guy doesn't care enough.

I can accept the transient performance from a quality injector with an on-axis injection cone given the LSA is on its native rectangle ports. But port adapters, forget it.

[brycedrue]

Small bore ls3 head?

[smokeshow]

Small bore ls3 head?

Definitely an option. They are pricey though...starts to chip away at the lost-cost perk of the LSA.

[blindsquirrel]

...and only fit down to LS1's 3.91 bore, will not fit the smaller 5.3.

[Alvin]

Are you sure there are no knock sensor codes present on this one? Are any knock sensor codes "turned off"

This looks how they behave when it has a knock sensor code pending or present. I didn't see one in the log.

[brycedrue]

Thanks for responding. I have never seen a knock sensor code on the car. Just a few evap and mass air codes. Oh and a 1637 alternator code

[brycedrue]

Are you sure there are no knock sensor codes present on this one? Are any knock sensor codes "turned off"

This looks how they behave when it has a knock sensor code pending or present. I didn't see one in the log.

I posted my tune file