Tuning advice

[iBoostDSM]

I have a quick question, should I adjust my timing if I have a boost leak. I've had multiple accounts of 12.7 deg knock. Should I tune to get rid of if? I have an idle of about 10 inHG at an idle of 1200rpms or so. The only leaks I could find was a leak on the throttle body which I'll replace tomorrow. It's not that big either. I think the previous owner said he rebuilt the head, is ita possibility that I could have bad compression? I don't want this knock!!

 

[mindset]

No, your best bet is to fix the boost leak. Then see if the knock continues.

 

[iBoostDSM]

I have all of them fixed except the TB and there's no way that leak would raise my vac to 20 inHG. Anything else that would cause low vac?

 

[mindset]

Well first off your idle is fairly high. And a leak can cause that. With no leaks, your vacuum should be about -18/-20.

 

[iBoostDSM]

Ok well I'm going to have to look crazy hard for this leak because it's not in any common place.

 

[miguelmcv]

Ok well I'm going to have to look crazy hard for this leak because it's not in any common place.

I had the same problem, but I had no leaks at all, I used to have more knock when no boost was present, It was 12deg of knock with -2deg of timing.
The Problem........... Phantom Knock.
The Solution........... Set Knock to 2500rpm and 50% TPS.
I hope that helps.
Try that and report back how it goes.

 

[mindset]

Ok well I'm going to have to look crazy hard for this leak because it's not in any common place.

You just said it was at the throttle body? WTF

 

[iBoostDSM]

You just said it was at the throttle body? WTF

Haha well that ones not big so there's definitely another one somewhere.

And today I'll see if is phantom knock.

 

[Sp1kE]

If you have a leak at the TB and it is enough to raise your idle to 1200, then IMO it is enough of a leak to cause rich knock under boost.

 

[miguelmcv]

If you are knocking under boost, I don't think that's phantom knock, that's your boost leak.
But if you are knocking when no boos is present, Then that should be a phantom knock.

 

[iBoostDSM]

Yeah I know but I also adjusted the Bissau which I know is a no no but because of the vac my car would die if I didn't adjust it.

 

[mindset]

just fix the damn boost leak!!

 

[iBoostDSM]

I'M TRYING!!!

I fixed my TB leak and my idle vac didn't change, maybe by 1 inHG.