fast01

iTrader: (16)

I posted a while back that I thought I was experiencing false knock and wanted to learn the process to reduce the sensitivity of the sensors. Well, as per some of your suggestions I pulled the timing to around 16* in the cells affected (was at 18*) and filled up with about 8.3 gallons of 100 octane unleaded mixed with 93 and 2 bottles of octane booster. No more knock. I guess it wasn't false after all! Thanks guys for not letting me do something that may have cost me dearly in the end! Now my question is; Is 16* of timing too low for an LS6? It seems like I should be able to run a bit more timing than that. The only changes I made to an out of the box LS6 long block are MAC mids and catted Y with some minor computer fiddling.

98redorangeta

iTrader: (10)

I dont ahve an ls6 but my ls1 has about the same amount of timing in it it seems low but thats what it takes for it to not detonate. Glad you did things the right way and didnt just turn the knock sensors off thats how **** goes boom.

fast01

iTrader: (16)

I know the "boom" thing very well. Sometimes I jump in and do stupid **** that costs me in the end. I guess you can teach an old dog new tricks, I'm learning! Then again, in the past there were no websites like this where you could draw on other peoples experiences and apply it to your own application. Kudos to all!

technical

Which cells were affected?

RedHardSupra

iTrader: (1)

16 is kinda low, what cam/heads/compression is it? do you have any logs? is it in one specific place or is it in a whole big area?

fast01

iTrader: (16)

The KR is from around 4400 RPM right up to 6000 in the 90-100kpa rows (?).
It's a factory 2003 LS6 long block (405 hp), 10.5:1 compression I think. I thought that was kinda low too. Any suggestions? I don't have any logs right now and if I did I'm a computer moron and wouldn't know how to post them anyway! Lol!

technical

Which table are you looking at? The spark table should be airflow based, not pressure correct?

If you meant .90 grams/cyl then yes 16* seems real low at 4400rpm.

fast01

iTrader: (16)

Yeah, that's what I meant. I'm on a work computer and don't have the tables in front of me. Any suggestions as to why I need to go so low? I haven't been to the track yet this year, so I don't know if my times are being affected yet.

technical

I noticed a SLP MAF mentioned in your sig. What tune are you using? Did you calibrate for the MAF? You could be running lean because of that.

fast01

iTrader: (16)

Oops! Never updated my sig. I put the stock MAF sensor back on, but I'm currently running SD (MAF fail set to 0). It seems that the car is actually running a bit rich. I don't have a wideband, but the readings on the stock 02's are in the 900-920mV range. That and the black tail pipes lead me to that conclusion. I recently ran some Seafoam through to see if it was maybe carbon build up. No luck there! I'm stumped.

brad8266

iTrader: (23)

16 degrees is way too low for a near stock motor.

fast01

iTrader: (16)

Anone have any idea why I'd have to bring the timing back that much? I'm at a total loss. I'll be swapping throttle bodies this week, I'll check for oil in the manifold, but I've got the updated PCV tht's not supposed to have that problem.

brad8266

iTrader: (23)

Try going back to stock timing and run some 100 octane and see if it knocks.

fast01

iTrader: (16)

What the heck, I'll give it a try. I don't think I should have to run super high octane to prevent knock with only 10.5:1 compression though.

brad8266

iTrader: (23)

Yeah you souldnt have knock with 93 octane with that motor. You might need to have your fuel system/intake tract cleaned out or possibly have a bad sensor somewhere.

technical

Are you running in closed loop or open loop?

fast01

iTrader: (16)

I'm pretty sure closed loop, but I'm not entirely sure how to be tell. I know it's a newbie question, but I never claimed to be anything but; How can I tell?

technical

The quickest way to tell, if you're using something like HPT or EFI live, is to monitor the fuel system state. That will specifically tell you OL or CL. There are settings for when the car will enter CL, but I don't know the code number off hand. It looks something like this, "Closed Loop Temp Enable."

fast01

iTrader: (16)

Thanks! I'll check that on HP Tuners. Do you think that will make a difference? Do you think the fact that I have LTFT's disabled will make a difference?

muncie21

iTrader: (14)

Stock LS6's should run 22-25* at WOT. 16* is more like FI territory.