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Inconsistent knock. Can't catch it!

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Newlogics

20+ Year Contributor
1,106
18
Jul 23, 2002
San Leandro, California
Hi guys.
Something rather weird happens to my GSX (according to my logger)
I get 0 knock through the whole powerband at WOT with timing generally at 17* , but at partial throttle, every once in a while I get nasty knock sums. It seems to mostly happen at about 4-5K rpms with throttle under 50%.

Once my knock sum went all the way up to 37 and timming pulled to 13* ! The phonomenon isn't consistent though. I can't just reproduce it whenever I want to by meeting all the conditions (RPMs. partial throttle etc...). I've tried playing with SAFC low throttle settings and other stuff, but I can't pinpoint the cause.

Also, since I get 0 knock at WOT, do you think I should up the boost ? It's at 15psi right now, 'cause I don't have injectors and FMIC yet. (I'm running mutt turbo (T04E compr. housing).
 
I had those exact same issues. What is your base timing set to? also how old are your plugs? Try adding fuel in that area. for some reason I was experiencing the same problem as you. add maybe 10% in that area on the low table. Look at your throttle points very close or log the throttle points against the knock and be sure its actually lean on the low table just to be sure. i know most wont agree but look at your a/f gauge when this happens, see if its burried on the red side. mine was:|

edit

sorry didnt see you dont have injectors or a fmic?

im selling my 650's and irc street core if you are interested
 
Originally posted by jdmawd
I had those exact same issues. What is your base timing set to? also how old are your plugs? Try adding fuel in that area. for some reason I was experiencing the same problem as you. add maybe 10% in that area on the low table. Look at your throttle points very close or log the throttle points against the knock and be sure its actually lean on the low table just to be sure. i know most wont agree but look at your a/f gauge when this happens, see if its burried on the red side. mine was:|

edit

sorry didnt see you dont have injectors or a fmic?

im selling my 650's and irc street core if you are interested

My plugs could be old. I had my low throttle point set at 30%, and had fuel reduced by about 12% in that rpm range. I've increased the fuel to +5% and set low TP at 20%. I didn't get any serious knock after that, but I still see knock up to 15 at partial throttle at times. I haven't adjusted my timing, so it's stock.

As I said, the knowck is very random, and doesn't come on all the time. When it does though, I can feel serious changes in how car pulls. (Noticebly loosing power)

I've just bought FMIC, but I still need injectors.
Who much do you wnt for them ?
Also, I may know someone who would want your FMIC, how much ?
 
Originally posted by Newlogics


My plugs could be old. I had my low throttle point set at 30%, and had fuel reduced by about 12% in that rpm range. I've increased the fuel to +5% and set low TP at 20%. I didn't get any serious knock after that, but I still see knock up to 15 at partial throttle at times. I haven't adjusted my timing, so it's stock.

As I said, the knowck is very random, and doesn't come on all the time. When it does though, I can feel serious changes in how car pulls. (Noticebly loosing power)

I've just bought FMIC, but I still need injectors.
Who much do you wnt for them ?
Also, I may know someone who would want your FMIC, how much ?

PM or IM me
 
with stock injectors and intercooler. im not 100% sure what turbo you have, but i would stay around 15 psi. even that might be to much on a stock fuel system and intercooler.
 
Originally posted by jdmawd
with stock injectors and intercooler. im not 100% sure what turbo you have, but i would stay around 15 psi. even that might be to much on a stock fuel system and intercooler.

I do have 255lph fuel pump. And according to the logger don't seem to stress my injectors... I'll still wait till my FMIC arrives before I raise boost any higher.
 
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