Knock Retard Questions..

[iceman]

What causes knock in the first place ??

Is there an amount that is normal or when is KR too much?

I logged runs at the strip this weekend and last.. Last weekend I was pushing ~7.5 degrees of KR in third gear headed down.. It was suggested to me to try putting the stock MAF back on, so I did that, this week I was just shy of 6 degrees.

Last weeks conditions were 54 degrees and 55 percent humidity, this week was high 60s and 100% humidity.. any thoughts??

I have

DHP PCM
SLP Exhaust, cutout was open
GMS MAF, now back to stock maf
CAI

I'll post excel sheets tomorrow night

[kubiache]

Just in case you (or anyone else reading) doesn't know what knock is, it's when the combustion gasses ignite sooner than they're supposed to. If they're firing way too early they're actually fighting against the piston as it reaches TDC.

What causes it are things like the gasses getting too hot (from the engine being too hot, or too high compression), or for your timing to be advanced too far. Which since IIRC DHP advances the timing some, it may have been too much. Your timing advances at higher RPMs anyways, so if you're running at the track with 87 octane it could be firing off to soon and too quick. If you did that without DHP, it's possible that a bad EGR valve could cause it. I was getting 10* of knock before I took DHP back out though I never bothered looking into exactly what might have caused it..

[Monello]

Hey =P

KR is bad

there are SOOOO many things you can do, i mastered it. I had to battle KR so much when i had the Supercharger in my GA. But Autotap was my friend and helped me bring it to 0 to 2.

Steps you can take to start the KR.

Replace Fuel Filter
Clean Injectors
Replace Air Filter.
93 OCTANE, A MUST


Second Step

Colder T-Stat
Cold Air Intake, like fenderwell.
Remove the Hood Insulation, its only there to help control a fire =)

Third and Expensive Step =)

HEADERS!! This is the MOST proven way to battle KR, it helps SO much. It has been known to remove from 2 to 4KR.

Bigger downpipe with NEW cat. The stock Downpipe SUX, its very small, and the cat will go bad on these cars. A clogged CAT will reduce performance and increase KR.

Exhaust. SLP is awesome, Borla is too restricted.

forth Step

Mini-AFC, it allows you to adjust rich or lean conditions. If you let me see your A/Tap i can determine what we need to do.

Throw away your Granola Maf Sensor, its not ajustable, and the Mini-AFC does the same thing for 100 bucks, and AJUSTABLE!

Bigger injectors. I put 4.2L injectors on my old ride, and with the mini-afc, the car LOVED IT. I was able to have the perfect mixture of fuel, no KR and the car flew.

Last Step, and Expensive as a MOFO

Upper/lower intake
Heads

If you flow better, you get the air and gases out better. You will have no knock unless you are boostin or doin something crazy.

Anyways, hope this helps, if you have any questions, let me know.

Later,
Pat

[iceman]

Steps 1&2 are done, except for colder t-stat, no need for one. Car sits at 180 degrees all the time... 93 octane, cai, etc...

for what I have done, I don't need injectors, a mini-afc, blah blah, that's a waste of money. I'm pretty sure its the PCM but DHP has my stock one now so can't switch anymore :\

[Monello]

I gave you a list of things that need to be done to battle it. You can either do it or not. But if you dont you wont resolve your KR. And 20degree difference from a T-Stat makes a HUGE Difference.

Anyways, goodluck.

[H.O. Driver]

Have you tried 1 step colder plugs?
I have copper plugs (1 step colder) WAI, no-cat SLP, and DHP. I have no KR all across the board with 93 octane at 70*
I will ask Chris (GTPrix) when I get the chance to see if he has any other ideas. I hope you find the problem.

[iceman]

okee, well on the new PCM it's still there, and worse. 10+ degrees of KR going down the strip. Ideas anyone?? I'm going to change the plugs and install headers next weekend.. should I stay with stock plugs or get some colder ones ? Any help would be appreciated

btw, this was with stock MAF and GMS maf, cutout open & closed.. 10+ either configuration

[kubiache]

Did you get the crank position relearn taken care of?

Does your autotap tell you how many degrees your timing is advanced? Still a possibility that for whatever reason it's too far.

[iceman]

Didn't need a case learn this time because it was my stock PCM w/ the new DHP stuff.. as per Charles.

I have timing advance and like 8 other things recorded, I'll post spreadsheets tomorrow at work (no internet at home)

[Overclock This]

I would do Autolite 605's for you car if you are getting that much knock and are running higher octane

[GTspeed]

how do u know if u have KR? does it make the engine sound different? how do u check it without going to a shop or dealership? something u can buy that's not too expensive? i have flowmaster 40 series exhaust, just the muffler, cai, and pro-m maf. u think that might cause anything??

[iceman]

Ok attached is the data.. Time slips and logged data.

Here are the slips



and some KR/load/spark advance charts. That dip in engine load is going from 2nd-3rd gear.. 3rd gear just really really bogs

http://iceman.draepi.org/22904chart1.jpg
http://iceman.draepi.org/22904chart2.jpg
http://iceman.draepi.org/22904chart3.jpg

I really need to let the computer reset, I know you can't just go and do something like swap a MAF and expect it to react the same.. I'm going to do that this week and try to get back to the track asap for more runs..

[iceman]

oops here is the spreadsheet

[GTspeed]

Originally posted by GTspeed
how do u know if u have KR? does it make the engine sound different? how do u check it without going to a shop or dealership? something u can buy that's not too expensive? i have flowmaster 40 series exhaust, just the muffler, cai, and pro-m maf. u think that might cause anything??

can anyone answer this?? sounds like KR sucks, dont wanna hurt my engine.

[iceman]

You'll need a scan tool.

[Blackrider]

Originally posted by GTspeed
can anyone answer this?? sounds like KR sucks, dont wanna hurt my engine.

Well Knock can be a really bad but mostly in Bosted Engines. With you NA Setup and a few mods you shouldent be getting a deadly amount, You can Hear knock in its bad forum because the engine will make a pinging noise.

I'm Running about .6 higher compression and i was havign a knock issue but i solved it by Cleaning my MAF, I'm still getting a bit in colder weather but not much.

Owwww I cant wait for 11.5

[GTspeed]

well i just found out i live 40 min from a dyno! woo hoo!! im gonna go up there and check hp and tq and stuff. and they said they can give u an estimate in the 1/4, and check your a/f ratio and timing and stuff and make sure everything is right. i think im gonna do that too.

[iceman]

Thats great, anyone got any info for me?

[Black2K1GT]

I am in the same boat as Iceman, I seem to be getting a KR of around 6~8 degrees with 60% or more throttle. I was running 89 octane at the time. I have many of the mods that Monello listed in a previous post, but am still having the same issues. For a list of my mods http://www.n-body.net/registry/black2k1gt2/

I am now using 93 octane and giving the computer some time to adjust before I check the KR again. I will let everyone know if this helps

[Blackrider]

Doods Checks your Knock Sensor, Its Probably not the probelm but its some where to start. Even with my mods my Knock its not nearly that bad!