Wideband Readings and Knock?

I'm trying to figure out my knock issue if I have one? Have a TT chip setup for my combo 60 pounders 255 walbro pump (Good one not the bad one) I have the boost set to around 18 or so maybe 19 max running 93 have a scanmaster and a caspers knock gauge and a autometer wideband gauge. My question is do I need to be worrying or looking at the knock gauge and scanmaster KR for the knock numbers or just pay attention to the wideband since that is real time numbers? I have adjusted my translator per eric's instructions to 4 for the BLM's to stay at 128 which it does and have gone from 2 to 3 back to 1 on the Wide open throttle. Before I was getting 12.7 for an AFR at WOT with default 128 on the chip and 2 for the translator? I have adjusted the fuel curve on the chip from 128 (no change) to 136 +6.3 fuel curve but wideband was at 10.0 went to 132 AFR went to 11.0 went to 131 and it's at 11.2 give or take? But the knock gauge goes amber sometimes max red and same thing with the scanmaster readings? I could get 1.6, 2.3, 6.1, sometimes no knock at all? But I get nervous when I see the WB close to what I'm looking for on the correct numbers but the gauge and ScanM vary on the knock? It does seem like when I decrease fuel from the chip the WB numbers are getting to where I want them to be? Any suggestions? O2 is in good shape as well and all vacuum lines have been replaced? Am I safe or what should I be doing to fix this issue. To me decreasing the fuel in the chip at WOT would be bad so maybe it's either false knock or rich knock?


New Member
Having a scanmaster and wideband and not always getting the two to coincide myself, AND going off of you saying you checked everything else, I would go off of the scanmaster first. Get it dialed in. Then see what wideband readings are at that correct power/lack of knock and use that wb reading as a reference point. If you had more tech in the car, I may go about it a different angle, but that is a pretty basic setup for your issue. I had it to where I was running down knock and it was my fuel sender reading wrong and a 1/4 less tank of gas was causing it. Keep it simple til it requires a complicated approach.


Staff member
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You didn't give us a lot of info on your setup, to make any kind of educated guess on what's going on. For example: what kind of intercooler are you running? If you're running a stock intercooler, or stock location intercooler, you're running TOO MUCH boost for 93 octane and no alky.
Pay attention to your knock retard, get it to zero reliably by bringing the boost down. That much boost (or more)on straight 93 is possible with a good front mount intercooler. I personally run 21# of boost on straight 93 octane no alky, but through a large CAS brand front mount, and do it at an 11.3 AFR at WOT.
You've got to get a handle on the knock first thing.


Well-Known Member
False kr can be from your shift points, i.e. tire spin, etc. Tuning above 16/17#s of boost w/o some kind of additive like alchy or race gas, can be tricky due to ambient air temps, actual octane mix levels, the % of actual ethanol in the fuel, etc. Try increasing the octane level to see if the kr is eliminated.
Ok thanks I am running a stock location stock IC and I will turn the boost down about 3 pounds and see where that goes? No alky just straight 93 no additives. I was informed also that 1st and 2nd there really is no load until I hit about 3rd then that's when it starts getting crazy numbers. Also do I need to adjust fuel parameters on the chip either plus or minus fuel? Even after I turn down the boost?


New Member
Once you drop boost to make the sporadic knock you are getting to go away CONSISTENTLY, see what psi it is taking with zero issues. Let's say 17psi in 3rd, car warmed up. Cold runs after sitting, like you were at the track trying for the glory run, don't work for the street. The first flag I saw was the lack (no mention) of alky, stockish setup, and the 19psi you were trying to run. Once you get that, you go back to the basic increase of boost/fuel while keeping the knock at zero until you reach the threshold that the fuel can withstand. There are guys that CAN run 19 psi on 93, but they usually have heads, or compromise timing for boost, etc. Back to your original question of including the wb in all this, I reiterate, once you get the knock gone and the numbers close, bookmark the wideband reading for that level/adjustment and THEN you can start keeping an eye on wb for more minute changes. I would never abandon the scanmaster for the wb completely until I went to a wb only driven system. As always, that is just me and many others have skinned these cats many ways.
I turned down the boost counterclockwise about 4 turns will have to run it tommorrow and see where it is one turn should be about one pound of boost so I should be back to 15 or 16