Knock Retard. - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

Reply
 
 
 
Thread Tools Search this Thread
Old 06-22-2009, 02:53 AM   #1
Senior Member
Posts like a Turbo
Thread Starter
 
Bwayney's Avatar
 
Join Date: Feb 2009
Location: Indiana
Posts: 260
Thanks: 0
Thanked 0 Times in 0 Posts
Bwayney is on a distinguished road
Red face Knock Retard.

So how does your engine actually aquire KR?

Do stock supercharged cars naturally have it? Or does just changing the pulley small give it to you?

I have a stock 2002 SSEI and i have a 180* T-stat and ZZP 1.0 PCM.

How much knock retard would i have around because i never have scanned for it?
Bwayney is offline   Reply With Quote
Old 06-22-2009, 05:38 AM   #2
Senior Member
Posts like a Northstar
 
Nobotada84's Avatar
 
Join Date: Apr 2009
Location: Indianapolis, Indiana
Posts: 699
Thanks: 0
Thanked 0 Times in 0 Posts
Nobotada84 is on a distinguished road
Default

Good question. KR is still one of those things I havent quite wrapped my head around, but there are a lot of good threads here on the forum devoted exclusively to that. To my knowledge a car doest't have any KR stock and fresh from the floor. Its like you said only when more boost is added i.e. a pully swap, that is if you get to small of a pully, that your in danger of aquiring the dreaded KR and the potential to chip a piston head. For 2000+ bonnies I believe you can go as small as a 3.5" pully and be relatively safe, but its always good to do some supporting mods, (upgraded exhaust, intake, etc.) Just so your car performs better and handles the extra boost better as well.
Nobotada84 is offline   Reply With Quote
Old 06-22-2009, 11:40 AM   #3
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

KR is derived by the PCM when it reads the noise on the knock channels from the two sensors. The amount of noise is monitored and when it reaches specified amounts the pcm retards timing. This retardation is known as knock retard or the retarding of the timing to stop predetonation/knock
BillBoost37 is offline   Reply With Quote
Old 06-22-2009, 02:43 PM   #4
Senior Member
Posts like a Corvette
 
Nighthwk12's Avatar
 
Join Date: Feb 2009
Location: Jersey Shore
Posts: 1,511
Thanks: 0
Thanked 0 Times in 0 Posts
Nighthwk12 is on a distinguished road
Default

Working on what bill said. If you are modding your car you know the 4 cycles of your engine. on the power stoke for optimum power the spark plug lights up a few degrees before top dead center of the compression stroke. When you engine is knocking the gas being compressed ignites before the safe ignition zone of compression stroke. So to combate this the PCM electrically retards the spark. so the spark ignites farther into the compression stroke. This keeps your engine in one piece but you do loose power. Simple things can be done by you to stop predetination. You a higher grade gas. If you are boosted should be using 93 anyways. ON the 2000+ the 3.8 sometimes get carbon deposits which cause hot spots to start predetination. A head gasket but on wrong can cause an over hang in the cylinder causing a hot spot.
In short owning a boosted car turbo or blown you will always be fighting KR Check on ZZP'* tech articles some good stuff there.
Nighthwk12 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
knock knock knock L27Buick 1992-1999 7 09-17-2004 04:23 PM
Knock Knock, engine knock? Spiral 1992-1999 5 05-23-2004 10:08 PM
Knock Retard....Fuel Starvation....Torque Management ??? 2000SilverBullet Performance, Brainstorming & Tuning 35 04-10-2004 09:08 PM
What is Knock Retard? Wolfedog50 Performance, Brainstorming & Tuning 9 08-31-2003 09:45 PM
KNOCK RETARD Forced Induction 22 04-29-2003 01:36 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:43 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.