Can spark plugs cause knock? I generally use the ngk brk7e's but the oriley's around me different have them so I settled for these worthless autolites that are iridium and I am 99.99% sure that's whats causing my knock. So the question is, can spark plugs cause knock?

 

Yes, if they are not in the correct heat range but it's more than likely a combination of things including your tune.

 

I am my own tuner, my tune is fine. Considering I am running methanol injection, retarded the timing all the way back to stage 2 timing and I am still seeing knock, I really think its the plugs.

 

what are you boosting?

what is your iat2 when in a 3rd gear pull?

As for plugs...

NGKs are junk when you mod this car

stop by napa auto parts and pick up some Autolite Copper 3922.

choose a gap between .032-.035... im @ .034 on a 3" pulley.

 

boost is under 20lbs depending on the rpms, roughly 17-19lbs. iat2's are under 120 degrees, i personally have always used the ngk bkr7e's and have never had a problem with them. I forgot the specific plug that I am currently using but I know that its an autolite xp and then some numbers, its iridium. Basically my only question though is can spark plugs cause knock, yes or no lol.

If spark plugs can cause knock, then im 99.99% sure thats why i am getting it.

edit: Steven - If I came off harsh or rude at all I apologize its almost 5am here and I am a little cranky lol. I don't like it when my car is running incorrectly lol.

edit: i believe these are the plugs im using autolite XP3923. Every 3-5k miles I change my oil and my plugs, I always use the ngk bkr7e's but the 2 stores locally didn't have them, guy recommended the above plugs and I got them, unfortunately I believe the suck lol.

 

nah you didnt come off grumpy at all lol...

stop by napa auto parts... go pick up autolites copper 3922 and gap to give or take .033...

that dont solve it, its not a plug issue lol...

you should be regularly changing your plugs regardless, since methonal does wonderous things to them over time

 

Indeed, as I said I change them every 3-5k miles when I change the oil. Just wanted to know if it was possible for spark plugs to cause knock. It seems logical to me, but sometimes my logic is wrong lol.

little update for ya, just picked up some ngk bkr7e's the same plugs I always use and am getting ready to toss them in, however I have one slight problem. I have no tool that will gap them. What do you guys recommend?

 

i have the autolites in mine right now cause none of the stores had ngk's in stock when i went to get them and i have no problems...ditch the irridiums and gap the new ones properly..

umm go back to the store and buy a gapper lol..

 

lol i just tossed the plugs in, gapped them at .035 however I still have knock.... I have no idea why, but I do. Car does run better however, i really didn't care for those plugs, but still in the end didn't solve the problem.

So the question now is why would someone have knock on stage 2 timing WITH methanol injection lol.

 

whats your mixture? you said you backed the high octane table back down to a gm stg2 mapping.

mind sending yyour log over?

 

The meth mixture is basically wiper fluid with 2 bottles of heet added, generally I have no problem with 20 degrees+ of timing with just windshield wiper fluid.

I am now running the gm stage 2 timing tables, copied and pasted them onto my tune and I am still seeing knock, with like tops of 15 degrees of timing. I am only getting like 2-3 degrees, but its still annoying.

Here is a picture showing it from the log.

http://s364.photobucket.com/albums/o...knocksucks.jpg

 

mind emailing me your actual log? I'm just curious

stevenflit@hotmail.com

thats weird man...

 

not a problem, sending a few logs over now.

 

cool... waiting on it

 

I am getting ready to go to sleep but this is really annoying me lol.

Edit: I am going to stay up for another like 30 mins and bs with you to see what you think, thanks again.

 

LAME i got like 1 or 2 degrees yesterday around 20psi. right about 6450 rpm 2nd gear. but im not fully tuned yet.

 

ya, knock sucks. But it really sucks when you have meth and your running stage 2 timing and your getting it lol.

 

looked at your first log

with meth on at 4000-4400 rpm roughly, you shouldn't be knocking w/ 17-18* i 3rd... though doesn't make much sense to me man lol...

though i did notice some lean spikes your getting in your first kr1 log...
your going from 50 idc to 93% in a matter of like 100 rpm lol... you got a wideband?
fix your P.E. if thats whats causin your wacky AFR. throw some more fuel at it if need be

if need be take it into the 10s... btw.. whats your pe enable TPS? I got mine set to 55% throttle through out the entire rpm, so my car goes into p.e. almost in sync with my meth.

dunno man... your logs seem so inconsistent...

if i were you, just take away 3* of timing after 3000rpm vs .88 g.cyl to play it safe for now.
you cant just load a stg2 timing table due to your maf not being tuned. your g/cyl in relation to rpm at wot differs completely from where gm placed all their timing for wot.

 

I do have a wideband, check the sig =P. I get 11.3 to 11.5 afr. My idc's seem fine to me...check out newplugs.hpl for that 3rd gear pull idc's seem fine.

edit: heading to bed, will check back soon.

 

it was just the first log that was all wacked w/ spikes...

the rest was fine...

i dunno man... i out of preference use pure methonal that I get from a local race shop. then I mix it w/ distilled water... 50/50 mix

try richening the car up from 3-5k; it should take to more timing. after 5k where the hp and trq curve meet, start scaling it upwards to 11.6-11.8... **** even 12.4 if you wanna max it w/o a EGT guage...

 

ngk plugs are more than fine. the highest whp cars on this site run them all day every day.

 

I <3 my ngk plugs. These cars are really easy to install them on too thankfully lol.

So boys the next question is, what is causing my knock. I have tried several different tunes from different people with different levels of timing, and still no dice. I have no idea why im getting knock.

I am going out to data log the car right now, I will upload the log to whoever would like to see it. Thanks for the help and I hope we get this resolved soon.

 

Spark plugs make a huge difference. Back when I was figuring my car out (oct-nov 2006), I ran my car at the track with Autolite copper cores, 1 range colder, .035" gap. I was running 101 octane, and it was about 60 degrees out. I could only run 20 degrees of timing without getting any detonation, and I ran 14.4 @ 104 mph. I went to the track the next week, with a set of NGK 2 range colder plugs, also on 101 octane. I was able to run 25 degrees of timing with zero knock, and ran 14.1 @ 107. Temperature was about the same, 60 degrees.

 

Thanks, I appreciate the information. It appears that at 1.16 cyl airmass at 4800-5300rpms is where I was getting the most knock. I basically figured everything out, I really don't know what has changed besides the weather and the plugs but I have the car running the way I like it now. Thanks for all of your help guys.

Out of curiosity does anyone know why 1.16 cyl airmass at 4800-5300rpms would be where the knock issue is. I mean at 1.12 cyl airmass at the higher rpms it was fine and at 1.20 cyl airmass its fine, basically its just 1.16 cyl airmass that I get knock. Kinda odd, either way I fixed it by backing off a few degrees of timing and messing with the afr a little bit.

Thanks for the help, i <3 these ngk bkr7e's. Thanks all.