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Knock sensor 1

21K views 27 replies 12 participants last post by  __V__ 
#1 ·
Playing with my cobb AP and I switched one of my views to knock sensor 1. My value is around 86-88 and low of 81 and high of 90. I have no idea what a good range is? My friends sti has a knock sensor and supposedly if it goes over 3 it's bad. I'm utterly confused here and I can't find any helpful sample data in google for our cars.

Any tips from a pro?
 
#2 ·
His "knock sensor" is a knock ratio. If you see a kr of more than 3 hes right, its bad. The AP on this car doesnt have a KR pid to watch as far as I know.
Ian at COBB told me to monitor cylinder 1 timing correction. If it stays at 0 or goes +, then your good.



 
#4 ·
Mine goes - negative, quite a bit on the 93 map...
 
#11 ·
Adding timing is good, it means your fuel and tune are solid.
Pulling timing is bad, it's basically reducing power to keep your engine safe

Sent from my C6916 using Tapatalk
 
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#15 ·
Depends on the area. California only has 91, yet I have found a couple places out there with 100 on tap. Also, E85 is becoming more popular, pop some of that in with a tune and your good to go haha
 
#19 ·
Adrian,

We have lots of fuels to play with in the U.S. That's part of the problem! Here, our posted pump octane rating is the average of ROM & MON. For the same fuel, the U.S. octane rating is 4-5 less than it is in countries that use AKI (Very similar to RON). Additionally, in most areas our fuel is 10% ethanol. Of note, some of our refiners make specialized high octane gasoline both for off-road/racing and some legal for street use (Sunoco offers over 20 specialized fuels). This is rarely available at the pump but can be legally obtained at prices about double our usual $4.00 a gallon.

We are possibly within a couple of years of having leadless aviation gasoline available from Swift Fuels and possibly Shell. Then this entire question will become mute.
 
#21 ·
What octane map are you using? What gear is that in? Is it possible to take a log?

This car likes to add in timing when it is "happy". You can monitor timing corrections in all 4 cylinders individually, but I use #1 as a general reference. Typically, consistent negative timing corrections means that the mapping is too aggressive for the fuel being used or mechanical condition of the car. A negative correction here or there would be normal. But if you have consistent negative corrections, use a lower octane map until you can get higher quality fuel.

Ian
 
#22 ·
Any negative values means motor is sensing knock and is pulling timing to keep the motor safe (from detonating).

Why don't some of you do some datalogs, drive in 3rd or 4th gear and do some WOT pulls? I will be logging some more later today and posting results - but I am in cali so only 91 map till I get to a 100oct station later next week.
 
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