SAFCII knock Sensor

[gtstii]

Hey all,

Has anyone here looked into using the SAFCII's knock sensor seriously?

I've looked at the SAFCII manual which is downloadable from www.apexi.com (US site) and have set it up correctly. I usually have a reading of 0 which can go up to around 15 - 20 on a 35 degree day.

It seems to work ok, and gives higher values when i would expect them (ie. cheap fuel, hot day) but what I wanted to know is WHAT CONSTITUTES KNOCKING?

When should I be alarmed? Is it like the power FC output where I think 60 is when knocking is occuring??

any help appreciated

[hippy]

also i'd like to know how to build a knock sensor display thingy ?? some kind of warning light ??

[Busky2k]

Yeah its really weird. On hot days, the knock count can go right up to 30, idling on my SR20DET. In winter its never moves from 0. I have no idea why heat would cause these readings.

Always the best way to tell if your car is pinging is to do a peak recall after a hard run. If the knock counts are 20-30 over the idle count, then you have pinging. 100+, then I'd say its getting to worrying levels. However the ECU might have sensed knock and pulled the timing, so the high knock reading may have only occured for a split second or so.

Btw thanks for info on the SAFC II manual, its about time Apexi bloody put one up...

[JimX]

Knock is worse when it's hot because hot air assists detonation. Basically the amount the air heats up over-compensates for the amount it thins out over the same temperature rise and you get more/easier detonation.

[gtstii]

no probs - remember the apexi SAFCII manual needs the japanese language pack to be installed on adobe for it to work! (it's in english though)

So anyone know what would be a worrying level for knock?

[JimX]

If the manual doesn't say, then I would just assume they used the same scale as the PowerFC. Which would put your 20 at a very safe level.

[Busky2k]

Knock is worse when it's hot because hot air assists detonation. Basically the amount the air heats up over-compensates for the amount it thins out over the same temperature rise and you get more/easier detonation.

Haha yeah thats is true, but the SAFC is reporting 30 counts of knock during IDLE. Not at full boost or anything during hot weather! Strange... but as I said before, 20-30 counts over the idle count, and then i'd count it as knock!

Funny adobe requires the japanese language pack when there is not a shred of japanese in the PDF!

[JimX]

Oh, that may be cause for concern then Mine never gets above 40 or so even on a warm day at redline (PowerFC scale here though).

[gtstii]

busky 2k - have you calibrated it properly??

I know how we can get the answer - Access Auto Engineering in Vermont is the Australian dealer for Apexi items, I called and they said that they can give tech advice if you bought the item from a store in Australia.

These would be the guys to ask the question to, but i got mine second hand.

[Busky2k]

Yeah Its perfectly calibrated. Get knock readings at idle, but not at cruising when the temps are up. Makes no sense. I can even disconnect the knock sensor harness and i still get these wierd readings? LOL

Maybe I should give AAE a call, as I did buy my SAFC II new from hikari performance.

[hippy]

buying it from hikari doesn't mean they got it off them ... in fact i bet they get it directly from japan

[gtstii]

yeah, I'm sure hikari got them in from japan directly, you prob need to have bought it somewhere like autobarn or something

[Busky2k]

Really? Damn you're probably right. Ah well...

[EnricoPalazzo]

Is it possible to build a knock sensor? I need one!

[EnricoPalazzo]

I found one on autospeed.com, but its not a visual display, but a hearing one. not wat i want.

[EnricoPalazzo]

send me the instructions of the safcII and ill make sure u correctly installed it.

[hippy]

i'm sure theres some kind of knock sensor u can make .. i remember someone telling me about it ... anyways i'll go find a manual for a safc ... i'm sure we'll need it LOL ... i want to be able drive home from your place hahaha ...