Knock detector vs. Scanmaster

[ttafan]

I just installed a casper knock detector in my TTA and took it for a test drive last night. After letting the temp get up above 160, from about a 3mph roll, I cracked into it on a long strait road near my house. I noticed that at WOT the guage went up to about the middle of the orange lights (about halfway to red indicating severe detonation). However my scanmaster only read about 0.7 deg. of retard. I tried it again after raising the timing on the Turbotweak chip from BL 125 to 126 on 1st and 2nd gear (about .35 deg of timing advance). I hit it again. This time the guage went to red as soon as I hit WOT on the downshift but my scanmaster only read 2.3 deg. of knock at the same time. So my question is..... what should I go by, the guage, or the scanmaster? Is 2.3 deg. of knock retard considered severe detonation?

[Quiky One]

2.3 is not considered sever detonation but should still be taken seriously. I, too, have both the gauge and scanmaster and the gauge is a lot faster at updating then the scanmaster. However, each gauge reads differently then others and each light could differ on the amount of knock produced. You could use either for monitoring knock. Just get used to one or the other and you will then know how much each light produces etc. Did Eric burn you a chip with the fast update patch in it? I'm not sure how much faster it updates but I'm thinking double. I'm sure someone could answer that.

HTH Jason

[turbota633]

..... I tried it again after raising the timing on the Turbotweak chip from BL 125 to 126 on 1st and 2nd gear (about .35 deg of timing advance). I hit it again. This time the guage went to red as soon as I hit WOT on the downshift but my scanmaster only read 2.3 deg. of knock at the same time. So my question is..... what should I go by, the guage, or the scanmaster? Is 2.3 deg. of knock retard considered severe detonation? [/quote]

Someone correct me if i'm wrong, but i think you needed to take timing out, not add it.....thats why your KR was higher the second time around.
HTH
-Joe

[Quiky One]

If you have knock dont raise timing. That will raise the knock!!!! What are your o2's at WOT?

[turbota633]

Do you have an adjustable FPR?...hopefully, if so what is your FP set at(line off)?.....Well if your O2's are low at WOT, which they should be at the very low of 750, turn up your FP. Like they say..."leaner is meaner"...but to a certain extent,at least if your richer as opposed to leaner you shouldn't have as bad of knock. Take the timing you added back out ...see if your KR lowers, although 0.7 isn't dangerous, if it is as high or higher then take a little more out. I loved the first chip i got from Eric, tuning it was fun and it gave me somethin to work with and to fine tune once i had my boost/FP in check. Also, whats your boost set at? and what are your other mods on top of the TT chip? Maybe knock the boost down a pound and see if the KR lessens.
HTH.
-Joe

[ttafan]

I know I should take timing down when knock is present. I was just tying to find out "what was what" since I have made alot of runs with the BL set at 126 and even higher previously with the same boost. 2.3 deg. of retard was common on the shift and I thought that was OK. I am just trying to figure out what guage to go by the scanner or knock guage. I'm thinking the guage is reacting quicker than the scanmaster. O2's are 800 so it's not lean.

[Razor]

The knock guage ties directly to the esc output so its readings are instant. The scanmaster reads what the ecm sends down the aldl 1.5 frames per second. So it is a delayed reading, and a reading down 1.5 times per second. Thats why the numbers on the SM blink..blink..blink.. etc..

The scanmaster reads what your ECM tells it.. so I go by what the ecm see's. If adding octane the knock goes away on your guage.. then you are picking up real knock.

The knock thats dangerous is the one that happens after the motor is in a sustained WOT condition. The stuff that comes and goes is not an issue.

If your chasing the possibility of getting knock.. the very last thing you do is up the boost or increase timing trying to figure things out. Drop the boost till its at nothing then work on squeezing the car.

hth

[ttafan]

Thanks guys. I guess the times I was running will be a little slower now that I know I need to back things off a bit. The Alky goes on next week and I have to start over anyway and I'll probably be able to turn things back up after that.

[turbota633]

Originally Posted by ttafan

Thanks guys. I guess the times I was running will be a little slower now that I know I need to back things off a bit. The Alky goes on next week and I have to start over anyway and I'll probably be able to turn things back up after that.

actually your times may stay or even be better, i've found that more boost isn't neccessarily better.

-Joe