getting some knock readings from data log --should I be worried?

Just logged my car launching from gear 1 from 0 to ~55mph

 

Data log shows a lot of knock. Am I logging it incorrectly? Or is there something I should be worried about?

 

Currently running Cobb AP OTS Stg1 91 ACN (to be safe)

 

Log is here:

https://docs.google.com/spreadsheet/ccc?key=0AtopqjJ3EQz4dDlQRlZuLTFHcFZGZjR5ZDJaR2wwbUE&usp=sharing

Yes, that's a lot of knock. You've got a long-term fuel trim of -4%. That alone could cause some knock. If anything you want the highest-load fuel trims to be positive, not negative.

 

--Dan

Mach V

FastWRX.com

Thanks Dan! Looks like I'm going to be flashing back to factory. What steps can I do to fix this?

Would not driving hard keep my engine in good shape?

start by telling us mods, gas and car info

My bad.

 

Car is completely stock (stock filter, stock everything) except for Exedy clutch and WRX flywheel. I've only been on stage 1 93 for 2 days, 91 for a week, and 91 ACN for another week after getting my AP 3 weeks ago.

 

If it helps, last time compression/leakdown yielded 130/130/125/125 psi, and 10% 15% 11% 13% december of 2011. Don't know what it is today.

 

RE: gas I'm using.

 

I've primarily been using Canadian Chevron 94 octane, even on my 91 tune and I drive around sea level mostly. I went to Seattle last week and ran Shell V-Power 92 octane on the OTS 91 tune. Have never felt my engine run smoother on that tank of gas. This knock is on a tank of 91 Canadian shell --might switch back to 94 Chevron and see if it happens again.

 

In any case, is it safe to run the OTS tune? Or would reverting back to stock prolong the life of the engine? I'll probably be driving grandma style from here on until I get a protune.

I'd try switching back to installed-but-stock mapping, and keep logging.

 

--Dan

Mach V

FastWRX.com

Driving stick?

 

That sort of knock reading can easily be induced by a hard shift from 1-2.

Yes driving 5MT. On another question, any of you think 1st and 2nd gear is too short?

Driving stick?

 

That sort of knock reading can easily be induced by a hard shift from 1-2.

 

Would a hard upshift cause the FBK to be recorded 1+ sec after the upshift is complete though? The logging interval isn't particularly fast (~3 samples/sec), but the initial -4 deg is recorded at 11.36 sec (~1 sec after getting back to WOT in the next gear), with the additional -2 deg being recorded at 11.68 sec (1.29 sec after the upshift).

 

I'm seeing what appears to be shift knock in my '05 OBXT, but the knock is being recorded within a couple tenths of a sec after upshifts. No knock appears in single-gear WOT logs @ same/very similar RPM (within 50 RPM) and identical or higher load, even when romping on/off the throttle rapidly in an attempt to get timing/load to change rapidly (which could induce knock, but doesn't on my car).

Try to do it again, but log fewer parameters to maybe decrease the interval and see if it happens again. Could just be a fluke....

^^ wasn't sure if that was mainly intended for OP, but I'll be using the RomRaider logger in fast polling mode next (17-18 samples/sec vs the AP v2's 3-4 samples/sec) to hopefully get a better picture. I get shift knock b/n 1-2 and 2-3, on avg 4 out of 5 pulls. Moreso when shortshifting at ~5k (which lands me around 3800 rpm in the next gear). When I shift at 6k+ (landing around 4500 rpm), I rarely see any shift knock, so I'm wondering if I'm just too close to the edge on ign timing in the high load / 3800-3900 rpm range.

I'll do it too

I see a lot of knock with the newest cobb stage 1 map. This learning view is from a 2006 spec b, with just a k&n drop in panel filter. The rest of the car is stock. He is now stage 2 and we tuned his car after installing the up and down pipe. No more knock. I would go back to stock and do some logging (you'll need a vag-com or tactrix cable). keep in mind the stock map does tend to knock some as well, but nothing like the cobb OTS map, from my experience.

I see a lot of knock with the newest cobb stage 1 map. This learning view is from a 2006 spec b, with just a k&n drop in panel filter. The rest of the car is stock. He is now stage 2 and we tuned his car after installing the up and down pipe. No more knock. I would go back to stock and do some logging (you'll need a vag-com or tactrix cable). keep in mind the stock map does tend to knock some as well, but nothing like the cobb OTS map, from my experience.

 

 

I've attached a couple logs from my Cobb Stage 1 map on a stock 06 LGT, manual...knock under high load. I'm going to switch to the Installed Stock map and try a couple more logs.

 

Edit - Logs 2 and 3 are Stage 1 91 octane, running 93 octane (I think exxon)

 

Logs 6 and 8 are Cobb stock mode....didn't get as good of pulls.

datalog2.csv

datalog3.csv

datalog6.csv

datalog8.csv