Knock With Pfc

[Bennett]

Lets just all have a huge cruise right round australia

[barnoon]

lol the guilt-toy tour of australia, you need a bus and some roadies.

[Bennett]

the guilt-toy tour of australia

HAHA actually has a nice ring to it

[SLYDA]

Mine useda knock at around 100, now wont go past 12.. think something was rattling around in the engine bay.. as it also wasnt knocking on the dyno.

[andymoocow]

I know this thread is a few months old, but did you guys get your problems fixed by guilt-toy??? I am in the same boat here, engine does not have any problems on the dyno, but on the street its not very friendly with my engine light flashing from 6000rpm onwards. Car just been "re-tuned to clean it up" as they said, still SAME THING happening. Bummer.

keen to get this problem fixed soon!!! Any tips or help would be greatly appreciated, thanks

Andrew

[Darren83]

I did mine on a road tune, and during the tune, the tuner says the knock is below 10 on the datalogit. When he plugged in the hand controller, while i was driving home, at max rpm of 4k, probably 30-40% throttle, knock of 95 is shown as the peak. Even in mild driving styles, knock would go up to 50, like i mean really mild driving styles.

Compared to my SAFC2 i had earlier, the readings are much lower, ie under 10, and the occassional 20+. Im going to bring back to the tuner in a week or so to fix the problem, from what i have read from the previous posts, it doesnt seem to fix the problem? That there is always a varying difference in the readings in the datalogit and the hand controller.

Cheers

Daz

[Guilt-Toy]

I did mine on a road tune, and during the tune, the tuner says the knock is below 10 on the datalogit. When he plugged in the hand controller, while i was driving home, at max rpm of 4k, probably 30-40% throttle, knock of 95 is shown as the peak. Even in mild driving styles, knock would go up to 50, like i mean really mild driving styles.

Compared to my SAFC2 i had earlier, the readings are much lower, ie under 10, and the occassional 20+. Im going to bring back to the tuner in a week or so to fix the problem, from what i have read from the previous posts, it doesnt seem to fix the problem? That there is always a varying difference in the readings in the datalogit and the hand controller.

Cheers

Daz

that is bullshit. i have never heard of or seen a difference in the datalogit or hand controller for any values what so ever. they are getting the data from the same source!!

I think your tuner may not be reading the knock data from the datalogit correctly. maybe he is reading a AVERAGE knock and not the MAX knock like your power fc h/c recorded value.

make sure your tuner knows what he is doing. it was probly knocking its nuts off when he was tuning it.

[SKYRYAN]

Yep, in Perth I had a tune at a very reputable shop. Apparently lots of pinging so there was a lot of timing taken out and the car was a sluggish piece of shit.

Got a re-tune somewhere else just recently and they strapped a knock-box on the engine instead of using the stock/pfc sensors, and they heard no noise at all.

My PFC hand controller shows 20-30 knock at idle... so it must be f*cked. So much happier with a proper tune.

[paulr33]

those seeing high knock levels or wierd knock levels with datalogit vs hand contrller

you should only use one at a time, as they share the bandwidth on the FC bus

that is, dont drive around with the hand cntroller and datalogit plugged in logging stuff etc

only use one at a time, as if you have both plugged in, its possible during clock cycles

for the hand controller to pick up a value, and then in the next clock cycle, datalogit to miss it

and vice versa, so when logging only use one to view the "data" either hand controller or datalogit, not both at once

to those seeing a knock of 20-30 at idle

are you sure its a constant knocking

ie MONITOR, 1 CHANNEL, KNOCK, NEXT, then press UP

is the BAR GRAPH constantly

||||--------- like that at 20 to 30

or it is like

|------------ and the number underneath is 30?

the number underneath when you press UP is the max at any one time

so this may spike to 20-30 at some other time, its not the constant value

you can press RIGHT to clear this max value

[89CAL]

Paul, quick question... Might be off topic but might also help, lets just say its a semi valid question lol

whenever mine see's knock its usually one quick spot of knock not constant, It does have constant knock sometimes but not anything to be concerned about, only low values.

My question is how bad are these values of knock if there just one quick knock, and also are they more likely to be engine bay noise?

For some help, mine only usually knocks when I have it on high boost (12psi) and revi it out and do a quick change, between 3rd and 4th is probably the worse. Im guessing its just one little point on the map that is relevant with those two gears due to the revs achieved through the specific ratios of 3rd and 4th... I'm trying to make it sound smart haha but anyway. Should this knock be a concern? Seeing about 60 knock is not uncommon in this situation but it isnt done frequently.

sorry its a bit of a rambled question but any words of wisdom you want to throw up are much appreciated

Cheers

[Darren83]

those seeing high knock levels or wierd knock levels with datalogit vs hand contrller

you should only use one at a time, as they share the bandwidth on the FC bus

that is, dont drive around with the hand cntroller and datalogit plugged in logging stuff etc

only use one at a time, as if you have both plugged in, its possible during clock cycles

for the hand controller to pick up a value, and then in the next clock cycle, datalogit to miss it

and vice versa, so when logging only use one to view the "data" either hand controller or datalogit, not both at once

to those seeing a knock of 20-30 at idle

are you sure its a constant knocking

ie MONITOR, 1 CHANNEL, KNOCK, NEXT, then press UP

is the BAR GRAPH constantly

||||--------- like that at 20 to 30

or it is like

|------------ and the number underneath is 30?

the number underneath when you press UP is the max at any one time

so this may spike to 20-30 at some other time, its not the constant value

you can press RIGHT to clear this max value

Paul,

The tuner did not connect the hand controller when the tuning was done, and he did shut the engine off first before reconnecting the hand controller.

I just took it for a short drive, with -3 off the ign timing. Yes, the knock is considerably lower now, with max of under 30, as compared to fluctuating of 50's to 90's. When i first start the crank, its 94 lol.

Hopefully no damage was done, as i was only part throttle of say 30-40% with revs of 4k. Will ring the tuner up tomorrow and ask if he took the average or max values in the datalogit.

Cheers

[Taso84]

Interesting reading, so the PFC knock sensor does not read correct values.

Just wondering has anybody found anything to replace the PFC knock sensor with something that gives the correct value. If this is true then as guilt toy has stated, we are all probably running around underpowered.

Hopefully this is figured out ASAP. Just out of curiosity, if u advance the timing will this affect the AFRs?

I was always under the impression that the PFC used the factory knock sensor. Maybe its just the case that the factory knock sensor is getting old and is giving incorrect values??!! Usually the knock sensor is designed to pick up sounds at certain frequencies that coincide with detonation. I would have thought that the nissan engineers would have made the factory know sensor be able to pick up the correct frequencies. Since the knock sensors use some sort of coil to pick up the frequencies it might be that the coil has aged and is not working properly.

I wonder if anyone here has tried to fix knocking problems by buying from nissan a brand new genuine knock sensor. Would be interesting to find out if this helped fix the problem

Edited April 7, 2009 by Taso84

[Guilt-Toy]

maybe i did not make myself clear enough on this topic.

Nissan designed the RB25 to have 185ish kw @ engine to work with the standard ecu. They also designed the knock sensors to pickup knock frequencies for a complete stock engine. at 165kw at the wheels your knock sensors will be sending the correct data to the stock ecu with no problems!

Joe blow - YOU. gets to a point in his car modding career where he needs a power fc to take advantage of the modifications. These modifications include.

FMIC

turbo back exaust and high flow cat

high flowing pod filter with cai

boost pressure turned up from 8psi to 14psi

high flow turbino

cams

etc

etc etc etc rah rah rah rah

OR ANY OF THE ABOVE

So your new setup is going to make 195 - 260kw at the rear wheels +, but hey! lets rely on the stock knock sensor frequencies to pickup engine noise as knock and tune the car accordingly.

How about, lets NOT. Lets turn the knock sensors off and stop wanking about the knock levels your heaps fully sick power fc hand controller gives out, to impress all the wog bitch's and dickheads out there.

how about we tune the engine the way it is supposed to be tuned ?

Sounds better to me.

tell your tuner to turn the knock sensors off, run proper knock sensor detection device that he can listen to and tune the engine with the torque graph's on the dyno.

I aint here to tell people how to tune cars, but there are a sure hell of alot of people who got it all wrong and its hard for the tuner to keep his customer happy when the customer goes on the internet and believes all his mates and mechanic's down the road when they say "ohhhh 90 knock mate, your engine is going to explode!!!" bad tuner bad tuner bad tuner!! "call him a salmon"

Its not going to explode. maybe if you saw levels of 100 - 200 when comming onto boost EVERY time then maybe they can tell you something is up.

Does this clear things up a bit?

yes/no ?!?

[Equinox]

The knock sensor is simply a microphone. It picks up everything across a large frequency range. It is then up to the ECU to apply a band-pass filter to this signal to filter out everything outside the range in which knock will occur on the engine. It then filters out everything which doesn’t occur near TDC.

It then calculates a knocking value based on the amplitude of the filtered signal coming from the knock sensor. This is where the error occurs as anything with significant amplitude near TDC will be picked up by the knock circuit as knock.

The best way is to install an aftermarket knock microphone and either listen to it directly with headphones or graph its output on an amplitude vs. time graph. The baseline engine noise can then be seen and any spikes will be the ones which need attention.

Edited April 7, 2009 by Equinox

[Guilt-Toy]

all different engines / combinations have a different sound when knocking, if you were to listen to a XR6 turbo when it pings, its very easy to pickup and cracks pretty loud, when a smaller engine will sound different

once you mod your car and push the engine harder it will knock differently to how it would if it was standard and it will have lots more engine noise. The power fc is not smart enough to filter out the knock to engine noise at the best of times.

[some_cs_student]

Too much giant black text in this thread

Guilt-toy, if you ever come to Melbourne I wouldn't mind a quick re-tune (not a full on expensive tune as that's been done before, only PowerFC though...)

[geraus]

my knock is wierd ,i just had a tune from status tunning it sits at 17 sometimes it goes to 36, its wierd... even on low boost.. is this normal????

[Guilt-Toy]

my knock is wierd ,i just had a tune from status tunning it sits at 17 sometimes it goes to 36, its wierd... even on low boost.. is this normal????

yes. your tune is fine!

[drf76]

maybe i did not make myself clear enough on this topic.

Nissan designed the RB25 to have 185ish kw @ engine to work with the standard ecu. They also designed the knock sensors to pickup knock frequencies for a complete stock engine. at 165kw at the wheels your knock sensors will be sending the correct data to the stock ecu with no problems!

Joe blow - YOU. gets to a point in his car modding career where he needs a power fc to take advantage of the modifications. These modifications include.

FMIC

turbo back exaust and high flow cat

high flowing pod filter with cai

boost pressure turned up from 8psi to 14psi

high flow turbino

cams

etc

etc etc etc rah rah rah rah

OR ANY OF THE ABOVE

So your new setup is going to make 195 - 260kw at the rear wheels +, but hey! lets rely on the stock knock sensor frequencies to pickup engine noise as knock and tune the car accordingly.

How about, lets NOT. Lets turn the knock sensors off and stop wanking about the knock levels your heaps fully sick power fc hand controller gives out, to impress all the wog bitch's and dickheads out there.

how about we tune the engine the way it is supposed to be tuned ?

Sounds better to me.

tell your tuner to turn the knock sensors off, run proper knock sensor detection device that he can listen to and tune the engine with the torque graph's on the dyno.

I aint here to tell people how to tune cars, but there are a sure hell of alot of people who got it all wrong and its hard for the tuner to keep his customer happy when the customer goes on the internet and believes all his mates and mechanic's down the road when they say "ohhhh 90 knock mate, your engine is going to explode!!!" bad tuner bad tuner bad tuner!! "call him a salmon"

Its not going to explode. maybe if you saw levels of 100 - 200 when comming onto boost EVERY time then maybe they can tell you something is up.

Does this clear things up a bit?

yes/no ?!?

all i want to say i agree with Guilt T-ripper lol, powerfc knock sensor should be used just as rough guide with some common sense

[W0rp3D]

my knock is wierd ,i just had a tune from status tunning it sits at 17 sometimes it goes to 36, its wierd... even on low boost.. is this normal????

I know trent uses a K-mon so as the informed people in this thread have said its not relying on the factory sensors but a very good bit of kit that is better than the factory sensor.

I also asked him about knock levels on the pfc hand controller and he told me that 35-45 is safe, even over that there is various other factors that can affect the knock display, i have seen as high as 111 but only once, unless high knock figures are happening constantly then it is most likely something else or maybe even your driving style (bouncing of the limiter will show up as knock) so i just use it as a guide and keep my eye on it for any constanly high knock levels.