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Scanmaster and Knock results

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radtech

New Member
Joined
Sep 19, 2006
Messages
76
I just installed my Scanmaster 2.1 I have an 87 Turbo T w/the following:

TA49 turbo set at 16 lbs.
crappy 91 octane Arizona fuel
Reds 93 chip (tuned rich)
42 lb injectors
HP fuel pump/hotwired

After running a couple 0-100mph runs, the KR was 820/ 13.2
This looks to me that I'm getting some SERIOUS knock???
I don't see any other factory guages that would register knock
Can sounds/runs smooth, but I think I need some race gas ASAP????
Thanks guys,this was my first attempt at the scanmaster run
 
can you hear any pinging or engine noise? I was getting 13ish degrees of knock and just so happened to be my brand new Walbro 340!!
 
i would imagine that it is real knock. runnin 91 octane on a 93 chip. and i think red's chips have too aggressive timing as it is. not sure on that one though. do u know what timing the chip has in it?
 
No I don't know what timing it's set for. I would never know there was knock from the sound of the engine. Never hear any kind of noise under WOT at all[/I]
 
when the knock occured did it build slowly like 1,3,5,9,13 or did it jump right up. knock normally builds gradually, false knock like exhaust banging or tranny shifts jumps up fast out of nowhere! hth
 
TA49 turbo set at 16 lbs.
crappy 91 octane Arizona fuel
Reds 93 chip (tuned rich)
42 lb injectors
HP fuel pump/hotwired

After running a couple 0-100mph runs, the KR was 820/ 13.2
This looks to me that I'm getting some SERIOUS knock???
I don't see any other factory guages that would register knock
Can sounds/runs smooth, but I think I need some race gas ASAP????
Thanks guys,this was my first attempt at the scanmaster run

the best advice i can give u is if u see the car registering knock, go easy on the car so the headgaskets do not pop! what kinda boost gauge do u have? if its factory i would recommend gettin an aftermarket one because i used to have knock issues, thought boost was at 16 since digital gauge couldnt register anymore. turns out boost line off compressor melted and popped off, overboosted bad. clamped boost line, then it popped off in another spot. clamps everywhere now!!!

"I think I need some race gas ASAP????"
by the sound of this statement, i think ur ready for some alcohol injection!!!
 
I only saw the high knock number when I recalled my Scanmaster readngs

When recalling readings, hit both recall and mode buttons together to see the mph at which the o2 and knock were recorded. That can help with diagnostics.
 
There are two things I would look into. First what type of boost gauge do you have and is it working properly. Second, you should consider a modern day chip that will account for the poor fuel sold today as well as a chip that you can program. This way you can adjust fuel and timing according to your setup.

I have heard some older Buick owners say that you will never hear knock as the computer is cutting the timing back so quickly. Not sure I necessarily agree with this but you need to get gauges that you can trust in order to eliminate this in the future.
 
Roll the boost back a bit. That chip at 16-17 lbs recorded light knock on 93 octane for me. I assume 91 isn't enough octane for that chip.

Do you have an adjustable fuel pressure regulator?
 
I have heard some older Buick owners say that you will never hear knock as the computer is cutting the timing back so quickly. Not sure I necessarily agree with this but you need to get gauges that you can trust in order to eliminate this in the future.

im pretty sure ive heard knock before, one time i heard it and i had my helmet on too:eek: then i looked down and the KR started to rise!
 
I do have an aftermarket boost guage as well. I don't believe I have an adjustable fuel guage. How would I know if it is the adjustable type??? How BAD is 13 for knock anyway? I can't "hear" any knock.
 
adj. fuel pressure regulators will have a nut and a screw sticking out the top of them. and it is at the end of the fuel rail under the hood.

13 degrees of knock retard is pretty bad, if it was real knocking going on. at lower boost like 15-16psi it is not as likely to damage the engine as 25psi, but it still can! definitely turn the boost down and i would recommend getting a modern chip from somewhere like turbotweak for 91 octane.
 
if you got it on a recall and didnt see it while at wot then i would say it was from letting off the gas at wot my car will register high numbers when i recall after a wot run even though i didnt see any on the run. its from the engine banging when letting off. did the car keep pulling or did it fall on its face
 
I do have an aftermarket boost guage as well. I don't believe I have an adjustable fuel guage. How would I know if it is the adjustable type??? How BAD is 13 for knock anyway? I can't "hear" any knock.

To answer your question. 13 is bad if it is true knock. You should consider 4 your limit and really zero is your target. If it is false knock then you have nothing to worry about. As stated in this thread already you want to watch for the gradual progression as knock starts and keeps getting higher. If it just jumps to 13 out of no where than it is most likely false knock.
 
I'm gonna watch the guage while running on boost next time. I wasn't watching it, but doing a "recall" once I got back to my house. Just bought some 110 octane for insurance. I think I'll put 5 or so gallons into a 3/4 full tank of 91. This way, maybe I'll be at 96 or so. Any opinions on how much race fuel (110) I should use per tank of 91???
 
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