VersaTune User Forum

I've encountered some pulls where I have minor knock less than 1* and my AFR's will go richer by half a point from 11 desired to about 10.5. I know there are AFR tables for when knock is present and those are not set to be at 10.5 even though desired and actual hovers around that. Am I missing something?

During knock and depending on the duration, severity and load the AFR may go as low as the minimum desired AFR. So that's normal. Don't tune your car for when it's knocking, just adjust the timing and AFRs to make it not knock any more.

Would setting the minimum desired AFR table to let's say 10.8 have any effect with this as well? I say this because the knock I get it so minor (0.70 max) and not always repeatable

Lolmooses wrote: ↑June 30th, 2020, 10:54 pm Would setting the minimum desired AFR table to let's say 10.8 have any effect with this as well? I say this because the knock I get it so minor (0.70 max) and not always repeatable

It would but I'm not sure you are sure you want to do that. As I said, tuning for performance during knock occurrence is not something you want to do, just like tuning for performance at 2500rpm.

0.7 KR is indeed minor and should not trigger alone so low AFRs, are you sure that is actual knock and is not your traction control/stability system kicking in?

It's hard to say if it's real or not honestly. It's not super consistent during wot pulls. Sometimes it'll happen twice at different RPM's during a pull. Sometimes not at all. Seems to happen more often in 3rd. I can't say I've ever seen DSTC kick in during any of my pulls.

Lolmooses wrote: ↑July 1st, 2020, 5:36 amSeems to happen more often in 3rd. I can't say I've ever seen DSTC kick in during any of my pulls.

You will not see the traction control or stability control lights flashing if they only lightly intervene.
The fact that happens mostly in 3rd seems to confirm this though, or simply because the 3rd gear is shorter which allows more rapid movement of the engine when the torque is applied. In a longer gear the engine will shift and then stay steady for a longer period of time, and also the road noise traveling back to the drive train will be attenuated more.

But if it's mostly in 3rd and at different RPMs then most probably it's the traction control kicking in for some reason (even because of the road surface being rough and tires skipping when they meet a crack or bump).