Question about knock

[TheShit]

Question about knock on a gen3 coyote.

Did a pull in 2nd gear to the middle of 4th. 2nd gear and 3rd gear had -2.0 knock until I hit 7k rpm and it went to 0.5. Then when I shifted into 4th gear, it felt lame, and the log shows 8.0 to 9.0 knock.

What would cause 4th gear to encounter so much knock compared to 2nd and 3rd gear?

I'm running the v3 jt trim with the 3.6 pulley.

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[Joshinator99]

Question about knock on a gen3 coyote.

Did a pull in 2nd gear to the middle of 4th. 2nd gear and 3rd gear had -2.0 knock until I hit 7k rpm and it went to 0.5. Then when I shifted into 4th gear, it felt lame, and the log shows 8.0 to 9.0 knock.

What would cause 4th gear to encounter so much knock compared to 2nd and 3rd gear?

I'm running the v3 jt trim with the 3.6 pulley.

The taller the gear you’re in, the more load on the engine and the higher your chance of knock. You’ve got too much timing or not enough octane. Or both lol.

 

[TheShit]

The taller the gear you’re in, the more load on the engine and the higher your chance of knock. You’ve got too much timing or not enough octane. Or both lol.

I dynoed with this tune and octane booster. And it did fine.

I'm runnig that same tune but with a different octane booster and it apparently isn't enough.

 

[Pistol_91]

This morning i did a few pulls and had 9 degrees of knock. Drove around a little bit and did 2 more pulls and it went away in the same gear. I chalked it up to be shit gas since i havent drove the car in about 4 or 5 days

 

[Zrussian13]

Question about knock on a gen3 coyote.

Did a pull in 2nd gear to the middle of 4th. 2nd gear and 3rd gear had -2.0 knock until I hit 7k rpm and it went to 0.5. Then when I shifted into 4th gear, it felt lame, and the log shows 8.0 to 9.0 knock.

What would cause 4th gear to encounter so much knock compared to 2nd and 3rd gear?

I'm running the v3 jt trim with the 3.6 pulley.

9° would be a lot of knock to come on all at once after it was pulling fine in the lower gears. Did the knock come on right after the shift? And I assume this is a mt82 car right? If yes to both I'd be leaning towards false knock.

 

[K4fxd]

I've been seeing lots of knock lately. My dragy shows -1400 DA I chalk it up to that but I'm N/A.

 

[Joshinator99]

I dynoed with this tune and octane booster. And it did fine.

I'm runnig that same tune but with a different octane booster and it apparently isn't enough.

Not uncommon for cars to be fine on the dyno and then be lean and/or knock once it hits the real world since the actual load on the engine is higher on the street/track (vs dyno). And changing brands of octane booster can absolutely have an effect, they’re not all equal.

PS: E85 fixes that problem. ;)

 

[TheShit]

9° would be a lot of knock to come on all at once after it was pulling fine in the lower gears. Did the knock come on right after the shift? And I assume this is a mt82 car right? If yes to both I'd be leaning towards false knock.

I added more octane booster and ran it again, and the computer liked it. It was -2 or -2.5 all the way through the upper end of 4th gear.

 

[Zrussian13]

I added more octane booster and ran it again, and the computer liked it. It was -2 or -2.5 all the way through the upper end of 4th gear.

What type of octane booster are you using?

 

[junits15]

+9 is wild, thats saying the borderline timing is around 9 degreed off from where it should be.

If octane booster fixed it that means its real knock too, you sure you're not having a fueling issue? That's a pretty large discrepancy.

 

[horsepower addiction]

+9 keep it up and you will be building a engine
Is there a reason why you’re not on e85?

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