Knock Knock

[Don Dada]

Hey guys i know some of you get high spikes of knk on the pfc and generally cosider it as noise or might be a badly tuned cell if it is persistant

My problem is opposite....i am actually hearing knk and the pfc shows no major increase in value ie. say between 3-4000rpm at boost building time i can hear it rattle and values will show anywhere from 15-20, up from about 10 and under which seems to be "normal" values.

From reading here, values up to 30 seems perfecty ok and i was going by that to tune my car but it seems like that cannot apply in my case

Ive gone so far as to add up to 31* on full load and only saw a spike of 20 once or twice and to me it should be knking a shit load more with that kind of advance....and its not consistant either, some logs will show no increase at all.

On the flip side i decreased timing to 19* on full load and didnt get any random spikes, but the overall values were the same

My first thought was the sensors were fu#&d but i hooked up a safc2 i had lying around and what do u know it registered high knk between 3-4k when i could actually here it rattling and also approaching red line but i couldnt hear that one.

So basically i just want to get an idea of what you guys think......It seems to me i have to keep it under 15 ish which doesnt give me much room to play with???

Anyway i have logs if any one is interested and i would also like to see a log of a similar set up just for reference

Mods> Rb26 stock turbs,,pods & cai,, 3" exh. no cat,,13.5psi on 95oct timing set to 20* on cas

[DVS JEZ]

Be very careful. Ur playing with fire abit here. If u can hear the knocking from inside ur car that is pretty serious and will be doing damage.

Seems like ur standard knock sensors arent up to scratch. If u can get it on a dyno it would be good so atleast u can be under the bonnet listening for detonation.

What afr are u running at full load?

Is 95 the best fuek u can get?

[Don Dada]

Yea man i know

I havent check the service manual but is there any way to check the sensors ?

There are no tuners here with knk sensing devices and they are really bogus in my book thats why i bought the pfc in the first place to have some sort of detection

95 is the best we have here too and i'm running 11.0 afr from 4k up

[DVS JEZ]

What sort of timing are u running at full load?

Keep it safe with the timing.

If u have access to a dyno when the driver is ramping it up on full load have earmuffs on and ur Hav ur head on the inlet side of the engine and close to the rockers.

Unfortunately this will be the only safe way for u to do it.

[paulr33]

use temp adjust

take out -10 deg

floor it from 2000rpm to redline

do you hear the same rattle?

if so drive train / engine noise / mechanical noise

if you dont hear the rattle it could be detonation

i would be suprised if you would hear audible detonation and the PFC wouldnt pick it up

the only logical explanation for this to occur and plausible would be dead, mangled, fault knock sensor

certainly possible

[paulr33]

ah i just read the 95octane bit

hmmm thats no good

given the rb26 in std trim needs 98 minimum

as soon as you add boost, more timing etc

it would make sense that it's detonating

i would like at some form of anti-det killer

ie 100octane, meth injection, mixed injection etc

it sounds like youll always have this issue given 95 penis is std in your area

i know if i ran my car on 95 penis it would be unhappy

[The Dan]

You're missing the point somewhat, you don't run the maximum timing until it pings, then back it off to make it safe, you run the maximum timing for torque and when torque no longer increases when you add timing, you stop. 15 degrees may be all it needs to achieve it. Having 20 or 30 degrees in the same spot is not going to make you go any faster, in fact, probably slower

[Don Dada]

use temp adjust

take out -10 deg

floor it from 2000rpm to redline

do you hear the same rattle?

if so drive train / engine noise / mechanical noise

if you dont hear the rattle it could be detonation

i would be suprised if you would hear audible detonation and the PFC wouldnt pick it up

the only logical explanation for this to occur and plausible would be dead, mangled, fault knock sensor

certainly possible

To tell you the truth this is what giving me the shits right now...I'm runnin a retard map right now basically around 19* and sometimes i hear a vibration/rattle sometimes i dont.

I wanted to pull more timing but im not sure how low i should go...wanted to try about 15-16* is that safe?

I really am not sure if its a drive train/ somethin loose noise but it did lessen to an extent when decreasing from 30* to 19* probably because the car is making less power so less vibration/ stress etc. i really dont know ..... i even went under the car to chech for loose shields etc but every thing seems in tact the noise comes from around the shifter area

But in any case shouldnt the knk sensors go crazy with a 30* advance??

Heres the log 4hiiiii.txt

Dont know if i did that correct .ha ha

Edited March 10, 2011 by Don Dada

[Don Dada]

You're missing the point somewhat, you don't run the maximum timing until it pings, then back it off to make it safe, you run the maximum timing for torque and when torque no longer increases when you add timing, you stop. 15 degrees may be all it needs to achieve it. Having 20 or 30 degrees in the same spot is not going to make you go any faster, in fact, probably slower

I thought that was the general rule to tuning but never the less i understand what youre saying but thats hard to do when it gets tuned on the road.

With that said it makes a very noticeable increase in pwr from 19* to 30*

Paul...as i said the safc2 picks up the knk so i would think it actually is hearing knk from the sensors, but remember it can be calibrated so its probably just more sensitive than the pfc ...thats why i didnt really go down the road of it being buggered sensors.....even though i'll run some diagnostics on them this wkend

Edited March 10, 2011 by Don Dada

[The Dan]

Some of our cars run 10 degrees BTDC at peak torque so they won't rattle. 15 is still a fair bit depending on load etc. You can't tune timing accurately on the road.

[rob82]

Some of our cars run 10 degrees BTDC at peak torque so they won't rattle. 15 is still a fair bit depending on load etc. You can't tune timing accurately on the road.

If this is a competition about who's is smallest - some of my cars runs 1-2degrees BTDC at peak torque!!! How small is that!

And as for PFC knock sensors - they generally work ok, but there are numerous R33 Rb25's that I have tuned that detonate both audible and through the cahssis ear and dont show signs of knk on the hand controller!

And you cowboys tune using that knk feedback!!!

[The Dan]

If this is a competition about who's is smallest - some of my cars runs 1-2degrees BTDC at peak torque!!! How small is that!

And as for PFC knock sensors - they generally work ok, but there are numerous R33 Rb25's that I have tuned that detonate both audible and through the cahssis ear and dont show signs of knk on the hand controller!

And you cowboys tune using that knk feedback!!!

No, this is not a competition or I would show you maps with 0 degrees. I was merely telling him that 15 degrees is not as low as he thinks it is

[DVS JEZ]

No cowboys. Just ensuring while tuning there is no knock.

[Guilt-Toy]

think of an engine as a woman. there are many ways to get her to bed, once you get experienced enough you work out the fastest and best way

But dont expect a guy to tell you his secret, he dont want you taking all his women... took me a while to understand why experienced tuners keep their knowledge to themself's like they do.... but i would have it no other way now.

[Don Dada]

Yea Anthony i get ya

I rememer some years back when you wanted to start a thread on tuning pfcs for everyone to share their experiences but it was unsuccessful due to the same fact....

Well if its worth anything to you guys i'm not even in Aus so when i do get the hang of it you could feel comfortable that i wouldnt be taking any food from off ur plate. ha ha

Sau has been the source of ALL my info and i've come really far in terms of maintaining/upgrading/tuning skylines and Rbs and i'm grateful for that especially when an experienced mechanic here can watch ur plugs and say you need a fpr because they dont look orange enough

Or when one of the better tuners add 37* on full load on a set up like mine and says it be ok, its a safe tune....shit! that made me order my datalogit the next day!......

So guys i'm gonna get to the bottom of it and i cannot rely on getting any good info locally so any help is appriciated whether you feel you want to share it in public or by pm me

[wolverine]

think of an engine as a woman. there are many ways to get her to bed, once you get experienced enough you work out the fastest and best way

Hi Anthony, it's alcohol isn't it?!?!

It reduces knock and lowers the ladeez resistance.

[Guilt-Toy]

here, every tuner locks his tune. but sometimes, very very rarely a tuner forgets to lock the ecu, like yesterday, i had a Nissan Patrol come in the workshop with a GT47 turbo, the customer said the tune was shit and car ran badly...

I was expecting to have to flash the ecu's firmware to unlock the ecu, but NO this one was unlocked!!! How excited was i!! it happens very rarely if not never, it felt like i won lotto!!

I checked out the tune and it was complete utter rubbish, the guy tuned the car like a microtech is tuned, the fuel map was pretty much flat and the motec was tuned on boost compensations... it made lots of horse power but any clown can tune a car to make horse power....

I realise now that these guys lock their tunes mainly because they dont want people to know how bad they are??

I dunno but i never locked my ecu's untill i came here. Don't take this the wrong way but no real experienced tuner will come on the forums and give out usefull information that will fix your problem, its a f**ked up situation and i never used to agree with it. You might have some cowboy's who tune cars for fun tell you what to do and try and help but you never really learn anything untill you knuckle down and learn for yourself.

where are you located?

[Guilt-Toy]

Hi Anthony, it's alcohol isn't it?!?!

It reduces knock and lowers the ladeez resistance.

Actually alcohol injection is a power adder, its the 50% of water that *really* helps with knock

[Don Dada]

Yea as i said i do everything my self as i like the challange and dont mind gettin dirty....

I dont really expect to get my problems fixed over the interweb i just like to get opinions from you guys who have much more experience than is available locally......

And i wouldnt point fingers if something fu@k up as i think i have enough knowlege to pick sense from non sense

Any comments on the log???..... i have lots more

and where is Trent btw i know he's generous when it comes to sharing piss/ basic info like this

[karma_syke]

think of an engine as a woman. there are many ways to get her to bed, once you get experienced enough you work out the fastest and best way

But dont expect a guy to tell you his secret, he dont want you taking all his women... took me a while to understand why experienced tuners keep their knowledge to themself's like they do.... but i would have it no other way now.

LOL what,

they keep it secret cuz thats thier trade, duh, this is a skyline community helping eachother and sharing their experiences and knowledge, what your implying flies in the face what much of SAU stands for.