Knock Retard - Boost Forum

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Knock Retard
Friday, January 26, 2007 12:31 AM
Yea, so I'm seeing 5.9 degress of knock retard in 4th at wot sometimes. sometimes i wont see any. grrr

I have the interceptor scangauge and its awesome. ive noticed a couple things. anytime your over 4k rpms and decel, your ign adv is 22 degrees, atleast with mine. the second it drops below, it goes to 0. in 1st, 2nd and 3rd gear i have no knock retard. 4th gear sometimes i will sometimes i wont. 5th gear, well yea. all the time. intake temps for me max out at 136 degrees without meth. there are a couple readings i dont know what they do. we have pulse width, but it doesnt ever go over 22. there is a long trim b1 and a short trim. have no idea what those are.

So what could be causing my knock retard? I'm thinking it being lean.....maybe bad gas? grrr i dunno



2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |



Re: Knock Retard
Friday, January 26, 2007 10:28 AM
Quote:

UNTUNED


I'm gonna say thats the culprit right there

willing to bet you're running lean. Do you have the GM reflash?






Re: Knock Retard
Friday, January 26, 2007 11:23 AM
At 22ms IPW and 6200RPM's your injectors are running at 110% duty cycle.

You're running lean.

Get a tune and some bigger injectors.
Re: Knock Retard
Friday, January 26, 2007 1:25 PM
grrr

Yea I have the reflash. I figured it was my injectors cause I dropped 2 pulley sizes and it didn't feel any faster. Oh well time to get green tops lol....thanks guys



2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |


Re: Knock Retard
Friday, January 26, 2007 2:28 PM
get the 2.0 lsj injectors , they are 36lbs

once i put them in i was alot happier , my afr droped to 11.5 under boost , and knock was almost non-existent , and ive actually uped alot of timing also

also i droped the base fuel pressure from 50 to 30






Re: Knock Retard
Friday, January 26, 2007 2:36 PM
I hate it when people don't knock



Re: Knock Retard
Saturday, January 27, 2007 6:25 AM
IM STILL RUNING 310's with ALOT of HP tuning involved and WATTER injecton, i have

0-ONE count of knock retard. all the way to 7K. and am running somthing like 25 deg avd.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: Knock Retard
Saturday, January 27, 2007 6:23 PM
cool thanks guys

i took some more time and actually payed attention to it today. its actually lower than 22 haha....the highest i seen it was 19.2 so, Im not maxing the injectors out but I might as well be. i need to hook my meth back up.



2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |


Re: Knock Retard
Saturday, January 27, 2007 7:53 PM
Whinin(BLWN Z24) wrote:cool thanks guys

i took some more time and actually payed attention to it today. its actually lower than 22 haha....the highest i seen it was 19.2 so, Im not maxing the injectors out but I might as well be. i need to hook my meth back up.


Can you read duty cycle with what your using? If not how do you know your not maxing your injectors out? I was maxing 370cc injectors out with 7psi.



FU Tuning



Re: Knock Retard
Saturday, January 27, 2007 10:03 PM
John Higgins wrote:

Can you read duty cycle with what your using? If not how do you know your not maxing your injectors out? I was maxing 370cc injectors out with 7psi.



By this info, I'm guessing you take your ipw and times it by 5 to get duty cycle. I could be wrong, and probably am. 22x5=110 so i would think 19.2x5=96% duty cycle maybe i dunno.

Black00Ga wrote:At 22ms IPW and 6200RPM's your injectors are running at 110% duty cycle.

You're running lean.

Get a tune and some bigger injectors.





2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |


Re: Knock Retard
Saturday, January 27, 2007 11:03 PM
I used this online calculator.

I also mistyped my first post.

22ms IPW @ 6200 RPM = 113% Duty cycle
19.5ms IPW @ 6200 RPM = 101%

So you're injectors are still going static.

I think the rule of thumb is that you should avoid running injectors that will see anything over 80% duty cycle. You run a greater chance of having them fail.

Not to mention that running very close to 100%, the slightest variance, even somthing like air temp. can cause you to lean out even more.

Also, be careful not to beat on your car until it's fully warmed up, you ECU will command higher IPW's while your car is cold. That could be why you saw the 22ms before and are seeing the 19.5 now.

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