I just wanted to ask you guys, if you go out of your way to find a smooth road to tune on? Cause i think im picking up some knock from the rough roads, then when i hit the freeway and do the same pulls i get 0 all the way through, witch pissed me off because i spent 2 hours screwing around on a road i thought was ok, because of miner imperfections, and suddenly its 0 on the freeway,

anybody else notice this, or do you guys tune on rough roads and its still ok?

 

My guess is that you have an aftermarket exhaust and while driving on the rough roads, your exhaust is rubbing / banging on your oil pan / TC. The bummer is the ECU will start changing your fuel map and pull timing....

 

ya i have an aftermarket dp, xs engineering to be exact, now i looked under there it seems like i have a pretty decent oil pan clearance, i dont know how much it bounces when hitting rough roads, but i was wondering if that happens to you with your aftermarket exhaust?

 

if your dp is banging around the easiest way to check is to take it off and look for rub/ding marks


could be different weather or gas too that's effecting your knock counts...I always tune on the same road and never really thought about the smoothness of the road affecting the tune. when your tunning are the knock counts all over the place or are they consistent and in the same rpm and load range every run you log??? cause if its consistent then I dont think its the road...just my .02c

 

ya thats the thing that bugs me, they are consistent on the rough road, but when i hit up a smooth road the knock seems to be way down. Its super messed up at times, im going to check my dp and see if its hitting, im leaning toward it being 91 pisstane, california just pisses me off, infact california is garbage now.

 

Interesting you should mention that. In my case, I have my downpipe rubbing against the lower tie bar (the black one). It's nowhere close to my ACD/oilpan/etc but I can hear it buzzing against the bar and if it DOES have a negative effect on timing, I'm going to get it off and get the shop to whack it a bit with a mallet or something so it clears properly.

 

I used thermal insulation on the pipe and crossbar so they weren't rubbing/clunking together anymore, it solved the problem without realignment or beating the snot out of it.

 

Good idea. I'm going to see if there are any shops open tomorrow and get some. In any case, thermal insulation of the dp is a good thing, from what I've heard.

 

Something else to consider:

You could have more vibration at a given rpm range because of the harmonics involved.

i.e. when jets fly over your house the windows rattle.

Even though it's consistent it could STILL be from the DP hitting the crossmember.

 

I don't have an aftermarket exhaust...only a test pipe and I get knock counts on rough roads.

 

thanks sophie that makes me feel a bit better, because im almost sure its the rough road, and my dp dosent even look close to hitting anything, no dings or scratches, because on a smooth road, i can almost do 5 consecutive pulls i mean doing the pull slowing down then re doing the pull and i hardly see anything over 4 counts of knock, and when i go to a rough road, i do a pull i suddenly see 9-12 counts , the weird thing is it always happens right after 6k rpms on the rough roads.

 

i've never gotten 9-12 counts though.
You driving over speed bumps?

 

what was the highest you have picked up?

 

Apologies for going off-topic here but I though I'd update on the thermal wrap 'mod'

The rubbing and clunking is gone, and the car seems to pull harder and more consistently than before. Not sure if I am just feeling things, but it feels smoother to drive.

However, I did notice that it comes very close or gently touches what appears to be the front diff/ACD, and I'm wondering if I should bring it back to get the mechanic to give it a love tap or two to increase the clearance so I don't inadvertently damage the ACD.

Jack, what do you think? Give it a bit of a tap?