Oft knock

[brady86]

So I have been running the stage 2 ots map since I got my headers (p and l) longtube el header and started running 93 stage 2 tune. I ran into knock problems and no matter what I did I got knock so I bumped it down to the 91 tune and still only use 93 and I still get some knock this morning it even dropped to .67 adv muiltipier. Should I just dump the ots and get a dyno tune or is there something that could be up?

[steve99]

Originally Posted by brady86

So I have been running the stage 2 ots map since I got my headers (p and l) longtube el header and started running 93 stage 2 tune. I ran into knock problems and no matter what I did I got knock so I bumped it down to the 91 tune and still only use 93 and I still get some knock this morning it even dropped to .67 adv muiltipier. Should I just dump the ots and get a dyno tune or is there something that could be up?

First try some different fuels, some fuels are better than others even though octane rating is same.

The difference between 91/93 tune is only timing above 5000 rpm, so if knock is below that running the 91 tune wont help.

http://www.ft86club.com/forums/showt...47#post2216047

note the picture shows the changes to the timing tables not the absolute values

more info read the links below on knock correction.

[brady86]

Originally Posted by steve99

First try some different fuels, some fuels are better than others even though octane rating is same.

The difference between 91/93 tune is only timing above 5000 rpm, so if knock is below that running the 91 tune wont help.

http://www.ft86club.com/forums/showt...47#post2216047

note the picture shows the changes to the timing tables not the absolute values

more info read the links below on knock correction.

I have been trying a couple different types of fuels sometimes I get slight knock while others I get tons. It seemed to improve a lot on the 91 tune though did not know they were the same until 5000 maybe it is because of the longtube header on the el tune.

[steve99]

Originally Posted by brady86

I have been trying a couple different types of fuels sometimes I get slight knock while others I get tons. It seemed to improve a lot on the 91 tune though did not know they were the same until 5000 maybe it is because of the longtube header on the el tune.

is your header a plm long tube ie nameless copy ?

Their are cam tables for that

[brady86]

Originally Posted by steve99

is your header a plm long tube ie nameless copy ?

Their are cam tables for that

Is is a p and l header not namless copy

[wparsons]

Do you know where the knock is happening in the RPM range? If it's in the ~2500-3500 rpm just edit the tune to pull some timing out. I get knock there on the 91 tune with 91 octane fuel, and it's fine on both 91 and 93 octane tunes with 94 octane fuel.

It happens the worst for me stuck in traffic with the AC on, but will also happen driving around town if I load up the engine too much at low revs with a lot of throttle.

[jprice130]

Now that the summer is in full swing, I too am seeing lots of knock (even on 93 gas) that didn't happen in the winter and spring. It mostly happens to me in load ranges between 0.6 and 0.9 and between 2500 and 4000 RPMs. High load (greater than 1.0), WOT pulls aren't an issue for me at all.

This is more likely to happen when I'm in stop and go traffic or am driving from stop light to stop light. When you're sitting idle at a stop light for a while, intake temps sky-rocket until you take off and get air flowing. This means your initial acceleration from the stop light is going to be sucking in some pretty hot air.

To help with this, I've updated my tunes with more aggressive IAT compensation (Steve99 has a good link for this). This will pull more timing when intake temps are high, but "normal" timing will automatically return as soon as intake temps are down. The stock and OFT tunes have some IAT compensation, but I feel that it could be more aggressive to better combat high intake temps in stop and go conditions.

[brady86]

seems like a lot more work then I want to do for just a flash tune maybe I should go get a dyno tune by jay perry. and just use my oft for clearing codes and data logging

[jprice130]

Originally Posted by brady86

seems like a lot more work then I want to do for just a flash tune maybe I should go get a dyno tune by jay perry. and just use my oft for clearing codes and data logging

I hear you on that, but the other thing I'll mention is that the OFT tunes generally run less timing in the mid-load, low RPM range than the stock tune (which is where you'll be for partial throttle acceleration in stop and go traffic). The OFT tunes don't really add much timing over the stock tune until you get to higher load and the mid to high RPM ranges.

A dyno tune from a reputable tuner is always a good thing, but you'll want to make sure your tuner is taking a close look at partial throttle performance at low to mid RPMs, because I bet that's where most of your knock is coming from right now.

[JB86'd]

Originally Posted by brady86

seems like a lot more work then I want to do for just a flash tune maybe I should go get a dyno tune by jay perry. and just use my oft for clearing codes and data logging

Why don't you start by data logging and posting a datalog up here so we can all figure out where the issue is..it could be a simple fix. Unless you'd rather go spend hundreds of dollars on something you can do yourself.

[brady86]

yeah on the way to work on highway i went to pass and bam went from 1.00 to .68 and it stayed like that rest of the trip.

[brady86]

alright so very strange on the way leaving work it dropped all the way to .51 and I had enough pulled over and went to flash to a stage 1 and for some reason i wanted to try a 93 octane stage 2 over 91 octane stage 2 ( i do run 93) and reflashed it and drove home 40 min got on it plenty of times to make passes did get small amounts of knock down low but stayed at 1.00 the whole ride home i am very confused i did take logs and will try to get them up.

[brady86]

http://www.datazap.me/u/brady86/2nd-...2?log=0&data=1
this is a 2nd gear pull on the 91 octane stage 2 tune

[brady86]

http://www.datazap.me/u/brady86/3rd-...og=0&data=1-14

this is 3rd gear and looks like hell