Apexi Pfc Questions

[Bill]

So I have a Apexi PFC in my R34 GTT.

Tonight I had a couple too many vodkas so I was in the co pilots seat as my wife drove home.

Being bored I was playing around with the hand controller (get that smirk off your face) and came accross the knock sensor reading.

The bar graph for the knock sensor seems to get 1/3 accross the screen under boost.

Is this good or bad?

When does the knock sensor start to retard the motor? When it starts moving or when it reaches 100% ?

Edited December 23, 2005 by Bill

[PlasticStan]

So I have a Apexi PFC in my R34 GTT.

Tonight I had a couple too many vodkas so I was in the co pilots seat as my wife drove home.

Being bored I was playing around with the hand controller (get that smirk off your face) and came accross the knock sensor reading.

The bar graph  for the knock sensor seems to get 1/3 accross the screen under boost.

Is this good or bad?

When does the knock sensor start to retard the motor? When it starts moving or when it reaches 100% ?

<{POST_SNAPBACK}>

The Apexi PowerFC doesn't retard the timing at all when it senses knock, your supposed to do that yourself with your right foot .

[Bill]

your supposed to do that yourself with your right foot .

<{POST_SNAPBACK}>

ahhh there in lies the flaw in that cunning plan

still,

Is it bad if the graph is not at 100%?

Edited December 23, 2005 by Bill

[R31Nismoid]

depends what the value is.

[paulr33]

covered the powerfc faq but anything over "60" is considered warning and it will flash the engine light. around 20's is probably ok, it can pick up road noise and other noises including engine knocking as its a microphone

[Bill]

Ok, my values are.

Standard Boost (0.5 bar) 27

Full Boost (1.0 bar) 68

Both runs done uphill going through 1st 3 gears.

Should I be worried about that reading of 68?

Also, Im not sure what gear I was in or what rpm I was doing when I hit that 68 as I had my eyes on the road and not the controller. Would a bit of wheel spin and/or hitting the rev restrictor between 1st and 2nd (yeah I know, clumsy me) have influcenced that figure?

Edited December 25, 2005 by Bill

[Bill]

Also, question on injector duty cycle.

At what figure do you need to consider changing the injectors / fuel pump? Im getting a max of 74.6% on 0.5 bar and 78.1% on 1 bar boost.

[paulr33]

a knock of 60 you may wish to get looked it, does it happen every time? can you re-produce it easily? do you know how to use map tracer? 1.0 bar is way too much for the standard turbocharger (if you are using it still) and it will fry the exhaust wheel. Try around 10psi ish for the 34 stock turbo. inj duty seems ok you only need to be worried when it flatlines or sits high up for a period, ie 98% at 5400rpm and stays like that. fuel pump unsure as it won't affect inj duty i don't believe, ie: if its leaning out you won't be able to tell from inj duty

[Busky2k]

I'd try removing -2 timing across the board in one of the Settings menu. I cant remember exactly what it was called, but its the 3rd or 4th item in the right hand column. Problem is, it reverts to 0 again after you restart the car.

[West]

a knock of 60 you may wish to get looked it, does it happen every time? can you re-produce it easily? do you know how to use map tracer? 1.0 bar is way too much for the standard turbocharger (if you are using it still) and it will fry the exhaust wheel. Try around 10psi ish for the 34 stock turbo. inj duty seems ok you only need to be worried when it flatlines or sits high up for a period, ie 98% at 5400rpm and stays like that. fuel pump unsure as it won't affect inj duty i don't believe, ie: if its leaning out you won't be able to tell from inj duty

<{POST_SNAPBACK}>

How do we use map tracer Paul?

[paulr33]

its in the powerfc faq in my signature, use that and then watch when the engine light flashes to work out what cell is causing the 60 knock to be reached, then adjust the timing for the cell

[MattSR]

Its much easier to do if you can get someone to drive while you look at the hand controller.

[Bill]

Ok I spent some time playing round with it today.

Air Temperature High 20's.

a knock of 60 you may wish to get looked it, does it happen every time? can you re-produce it easily?

Ok, with a lot more playing round and using the graph mode I found:

1st 3 gears can be floored to 7000rpm and the highest reading is usually high 20's to low 30's. 4th can be up to high 40's as ypu close in on 7000rpm, but can spike higher than this if used at lower revs while going up a hill.

5th is weird. Sometimes low 30's but spiked to 166

Seen a couple spikes in 5th in the 90's to 120's as well.

According to the 10sec rolling graph these spikes in 5th seem to only last for an instant then drop back to normal. Sometimes the warning light will flash sometimes it wont. Is it normal to just happen for a sec then stop?

Should it keep doing it? Could it be a dodgy sensor or some interfearance?

So... 1st 4 gears seem ok (under 60) if you dont take it past 7000rpm.

4th and 5th will spike over 60 but a hill is usually involved (espically in the case of 4th)

Im taking a stab that the extra effort going up a hill changes the load point for that rpm sector, which is why it can spoke sometimes and not others?

So.... If Im right there, I got to work out what load point at what rpm sector it is and adjust those particular ones only?

do you know how to use map tracer?

Never tried it. But you guide looks fairly clear. It looks like a two person job for that though.

1.0 bar is way too much for the standard turbocharger (if you are using it still) and it will fry the exhaust wheel. Try around 10psi ish for the 34 stock turbo.

I usually cruise around on .5 bar, only up it to one occasionly.

Im getting a different turbo when funds permit.

One thing I noticed from the dyno, the stock turbo will hold 1 bar till 4400rpm, then tapers off to 11psi at 7000rpm.

inj duty seems ok you only need to be worried when it flatlines or sits high up for a period, ie 98% at 5400rpm and stays like that. fuel pump unsure as it won't affect inj duty i don't believe, ie: if its leaning out you won't be able to tell from inj duty

Ok, thanks. Never seen the injector duty exceed 78.x %. The AF printout from the dyno starts at 13, then drops to 12 at about 3400rpm then declines gradualy down to 11.6 at 7000rpm.

That sound ok?

Thanks for all the info so far

Edited December 26, 2005 by Bill

[Bill]

Anyone?

[paulr33]

The engine light will flash when you execeed knock of more than 60, it will flash i am pretty sure 3 times 0.5seconds apart and that's it. if its constantly or repeatedly doing it then its knocking above 60 more often.

to debug the 4th 5th knock find a hill

watch the map tracer (not in trail mode) and look at the dash cluster.

follow the map tracer whilst driver is driving along the map path, it should flatline along load point 14-15ish up the hill and begin moving across as revs increase. as soon as you see the engine light come on look at what point it was on the map tracer. repeat a few times to ensure you are looking at the right cell point. then count how many cells across and how many down. my guess is R10 L15 which is Rev point 10 (10 across) and load point 15 (3/4 down the left side). then once you have narrowed it down the right cell you can goto settting, ign map and move the same cell point and look at its ign timing, you can then take out one or two degree's at this point and try again. you should be able to smoothen out the knocking within a few tries

[Spook's_Skyline]

after i had my powerfc installed, i was getting very high knock after the first tank of petrol i put throught he car after the install

i noticed the dash light coming on and checked teh controller and it was hitting 120+ for the knock value

babied the car around for the next tank of fuel

got a retune (new exhaust) and still occaisionly saw readings of 60-90

a couple of tanks of fuel later, and i dont see a knock of anything higher than 20/30 now

im guessing the car was just working through the last of the bad fuel as nothing else has changed . .. .