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Safe Knock Retard numbers?

4boostin

4boostin

New member
After owning an 87 Turbo Regal for 23 years, I now own a 98 GS, so I'm new to these supercharged cars. I recently put on a 3.6 pulley with a stock tune so far. I have an Aeroforce gauge and wanted to know when to be concerned with KR. I realize that zero is the ultimate goal, but in general, at what point do I risk damage to the motor?? So far I have only seen 0.7 as the highest number under full throttle up to 80 or 90mph....running 91 octane, which is the highest octane pump gas here in Northern Utah. There is a local station where I can get 100 unleaded if needed.
 


Well, I'd be more worried at 4* or higher.

Every degree of knock equates to about 5-7 crank HP due to the pull in timing. There is a KR sticky IIRC in the engine section...if it isn't there...search for my thread titled Safely Modding Your 3800...it had every important engine related sticky on this site in it. Plus a lot of other useful info since your new to modding these cars and it could most possibly point you in the right direction.

If you can't find it on here...just google it :D
 
ive hit 10* on my car and not blown it up. its not really how much it can take anyway. sometimes a fluke knock spike of 4* will blow a piston while a 10* spike it will survive just fine. sometimes it comes down to luck, so trying to keep it as low as possible is the key.
 
Safely, and long term under 3, nothing over I'd say. It can go higher for sure, and nothing will happen...once and a while you might get lucky if it goes higer like that all the time. But for sure its not good.

And yes, 0 is the goal. :th_thumbsup-wink:

~F~
 
Also, one thing to keep in mind, the lower the pulley sizes, the more the KR compounds....it will try to come on sooner since the cylinder pressure goes up exponentially when you get down to the 3.0 range.

I guess what I'm saying is, 2* on a 3.6 is NOT the same as 2* on a 3.1, 3.0 etc.
 




it is n/a. i think i did have a vacuum leak issue caused by my fwi, and i have since fixed that (i think). my ltft's were stuck at 16.4, but now they move. they are just bouncing around at really high numbers. which means i am running lean? i think?
 
vailskier3 said:
it is n/a. i think i did have a vacuum leak issue caused by my fwi, and i have since fixed that (i think). my ltft's were stuck at 16.4, but now they move. they are just bouncing around at really high numbers. which means i am running lean? i think?
Click to expand...

Yup, positive percents means it is running lean and adding that percent of fuel.
 
I think we hit 12*+ one time in a s1x cammed car. A few things go wrong too quickly and **** happens. Still runs fine.
 
ive pegged out my sensors before. pulled all the timing out where the car would not even accelerate. no chipped pistons but i would not recommend doing that.
 


I personally think Vail's tune is just way off. I was doing the 16.4 dance after s1x cam install... before I did some MAF tunes..He doesnt have a DP .. so I dont think its the dreaded +16.4 fuel dump cat test issue.
 
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