Knock With Pfc

[DECIM8]

Heres my advice, BTW I got the PM you sent me..

Go trash the shit out of your car I bet you wont see knock over 30-40.. I found it strange to be doing this... Its obviously something funny in some cars.

You'll notice knock, it sounds like a shitbox trying to climb a hill in 5th. Mine eventually went away - I have no idea how! I think it was the lifters making noise after I put the cams in and the standard knock system freaking out a little. I did put a thicker oil in and dont look at the knock sensor any more. It has no blown up yet.

Edited April 8, 2009 by DECIM8

[Taso84]

Guilt toy, Im not trying to undermine you or anything, so dont go psycho on me, but what lead you to believe that a "tuned" engine will knock at a different frequency to a stock engine. From what most ppl say here, their knock happens not under foll boost at 6000RPM but under slight load in a high gear at about 2000-3000RPM going up a hill on a hot day.

Ie what im trying to say is that under that scenraio a tuned engine and a stock engine wouldn't be performing materially differently.

Also, if as you say the knock of a highly tuned engine would sound different to a stock engine, this doesnt explain why the knock value is still coming up on the PFC. Perhaps the "real knock" is a different frequency to what the PFC is showing but i would still be concerned that a large noise (consistent with stock engine knock) was coming out of my tuned engine consistently for a certain situation (ie above).

Before u reply Guitl-toy, know that I am not saying u r wrong or ur thery is flawed, I'm just trying to understand the underlying reasons behind ur theory and to answer some of the scepticism that others may have about what ur saying.

Cheers

[Guilt-Toy]

Guilt toy, Im not trying to undermine you or anything, so dont go psycho on me, but what lead you to believe that a "tuned" engine will knock at a different frequency to a stock engine. From what most ppl say here, their knock happens not under foll boost at 6000RPM but under slight load in a high gear at about 2000-3000RPM going up a hill on a hot day.

Ie what im trying to say is that under that scenraio a tuned engine and a stock engine wouldn't be performing materially differently.

Also, if as you say the knock of a highly tuned engine would sound different to a stock engine, this doesnt explain why the knock value is still coming up on the PFC. Perhaps the "real knock" is a different frequency to what the PFC is showing but i would still be concerned that a large noise (consistent with stock engine knock) was coming out of my tuned engine consistently for a certain situation (ie above).

Before u reply Guitl-toy, know that I am not saying u r wrong or ur thery is flawed, I'm just trying to understand the underlying reasons behind ur theory and to answer some of the scepticism that others may have about what ur saying.

Cheers

Usually when a tuner tunes your car he is not going to tune it in 5th gear labouring the shit out of the engine at 2000rpm is he? thats why it knocks. If he did tune it in 5th gear he could get rid of that knocking but you would lose response in other gears at the same part of the map because timing would be retarded and you would have shitloads less mid range and possibly top end as well.

the reason why this happens is because you are in 5th gear the ecu is hovering over that part of the map for a long period of time, after a second or so it will start to heat up and make some noise, If it is only reading 30 - 50 knock at those load levels then it would be nothing to worry about, if you see over 100 every time you go there then try avoid those areas and get your tuner to listen to the car on the dyno to see if he can hear anything, if nothing could be heard then you should ignore the knock readings.

this is a whole different issue then what we are talking about ? i thought we were talking about knocking on boost at mid to high rpm. Every tune i have had back before i started tuning has experienced this low rpm high load knock. Sometimes it can be removed with just a few deg of timing being trimmed other times you cannot remove it at all.

why would you want to hit boost in 5th gear going up a hill and labour your engine ? probly not the best idea anyway.

If you are confused about what this thread is about then here is a quote from the thread starter - 1st post

hey all recently had a pfc installed in my 33 gtst, now wen my car is at full boost and usually around 6200rpm the engine light will flash on and off which i kno is the power fc sensing a knock over 60, it doesnt always do it tho. I took it back to the tuner and he said that he has done a real safe tune (191rwkw) and did a couple more power runs to make sure, and sed coz my car has done round the 170,oookm that is prob just something elses knockin/loose in engine and engine is not at detenation. oh and i hav seen the knock go over 100. Car mods: pfc, fmic, 3.5cat back, walbro pump, pod filter, platnium plugs. Any help would be appreciated cheers jarad

[sunnycoast]

Interesting readings guys...getting my car tuned weds...usually knocks at 39 max...see what my tune does and let you know.

Chris

[Taso84]

Guilt toy, are you still coming to melbourne? Wouldnt mind bookink myself in for a knock check on ur gizzmo thing

[Guilt-Toy]

Guilt toy, are you still coming to melbourne? Wouldnt mind bookink myself in for a knock check on ur gizzmo thing

ohhh crap sorry I missed his. No I aint going to Melbourne. you should call Trent @ Status and he will be able to check it out for you.

[Dose Pipe Sutututu]

go clutch dump your car around a corner is 2nd, mad knock!

I've seen it go past 110, but on the dyno no more than 20~30