Is this phantom knock?! ...Driving me nuts!
 

Hey guys,

I have been having a lot of issues tuning car recently. I just went to speed density and seem to have that calibrating near-perfect. The fuel trims look good, and the car drives great!

The issue I am having is that under 250-260ish load anywhere from 5100-6000RPMs, the car starts picking up knock. My AFRs are good, and timing seems to be ok, so I don't know what the issue is. A little info about my setup:

Buschur 2.1L 10:1 motor, BS delete, with fully built head, GSC S2 cams, hand-ported (not flow-benched), Torque Solutions solid mounts throughout, Full-Race T3 manifold, HTA3582R Turbo, Buschur double-pumper, and PTE 1200cc injectors.

No matter what I do with the timing, I can't get the car to stop knocking, and my AFR's seem too good to be the issue. Is my engine just noisy? I'm tuning on 93 oct BTW.

I have attached a few logs as well as my timing map.

Thanks!

Timing looks high for 10:1 and 93 and 26psi of boost. I'd be half of that or less in the lower rpm range, where you are 5's I'd be 1 or 2 normally.

I think it's running 26-14.5= 11.5psi at that point, wouldn't it? It's a SD setup with OMNI 4-bar, GM AIT. Maybe I've been reading the boost wrong. My Defi gauge is way off too if that's the case. :x

Something looks off with the map sensor reading? Look at the loads your hitting against the map sensor reading. That is unless the speed density is set up all wacky

I never run it absolute so I didnt even think about that. If its 11psi its fine. What does the DEFI say? Less than 1 bar I presume?

Aaron

try out the gsc s2 mivec map it think from english posted in the mivec tuning thread. that helped out my knock with gsc s2's a ton. also i agree you seem to have a lot of timing.

Ok, so I double-checked everything, and I have my OMNI configured correctly in my ROM. I didn't however change the formula in Evoscan for logging boost though!!! *dumb me...

I just updated the formula. The car, according to my Defi gauge is running about 17psi.

The reason my timing is so high is because when I started low, the car was knocking like a bastard! I gradually increased the timing, and this is where my car has been best-case-scenario. Only issue is: IT'S STILL KNOCKING!

Aaron, I tried the map you sent me, but had no luck... Also tried lowering my timing again, and it knocked even quicker...

Did you verify the actual wideband gauge readings against what evoscan is logging? Post up a pic of your fuel map

Yes. That is correct. If you'd like to PM me your e-mail, I can send you my whole ROM. :updown:

How long have you had your solid mounts? My car was able to be beat on prior to me building it and adding the Avid solid mounts. Now that I have no balance shafts, a built motor, and solid mounts I cant seem to get rid of knock around 3800-4500 regardless of what is done to timing, afr's, mivec, etc. Does your car vibrate rather badly around the rpms its knocking?

I've had the solid mounts for about 2-3k miles. They were on the car before this build. The car def vibrates a lot at idle, and when driving down the road I can feel it in the steering wheel, so I guess so. Hard to say how bad though just becuase of how loud everything is. LOL. I guess if I were to take it for a ride and really pay attention, I could give you a better answer to that. :p

Check your pm, I'll take a look at your rom ;)

Just wondering because Im also trying to narrow my knock issues down. Mine happen during the moment of motor vibration though. I hope its something simple with your tune and you get it all worked out man. Good luck.

Problem found! Intake rubbing slim radiator fan... making enough vibration for knock ;)

Thanks guys!

Good to know man :) I sent another email just now to by the way.