need some advise....kentucky slider or drifter prodigy

[Koshin]

alright, I am getting some inaudible knock whenever the weather gets warmer..I know my ecu is tuned for higher octane fuel because its a JDM car...the knock increases on the SAFCII the longer I drive the car when its warmer outside, Im not overheating...I have a nismo therm, koyo radiator...I know that heat does increase knock but its wierd because I dont get any knock during the colder months, none at all....Dont know if you guys have dealt with anything like this...It does backfire at times when its really hot outside but the only performance decrease is becasue of the pulled timing from the knock sensor...I was going to relocate the sensor to the firewwall to avoid this but I dont want to hurt my motor...if indeed it is knocking...I know the plugs are never whitish or even grey...My car runs rich so I dont know if its maybe a timing thing ?? but that wouldnt explaing why it doesnt knock when its colder or why my plugs arent burnt up...I dont know what I should do or where to turn next...I know you two dewds know these motors pretty well and figured Id call you out for some help....let me know something, just looking for a direction to turn next...thanks boiz

[DrifterProdigy85]

Its the way the knock reading of the SAFC is. Its really not that accurate. When i had the SAFC, i noticed that the knock would creep like that during normal driving but once you got WOT, the number would drop down really low and hold steady till it would have some knock and the number would spike for a second. All you really wanna look for is the spike in knock @ WOT. As long as you dont spike over 35 or 40 i think its ok.

[Koshin]

I know that I wanna basically look for spike in the knock at WOT. My bigger concern is why this is directly heat related?? On a hot day bro, this knock sensor will read as high as 80 knock at idle!! It isnt audible, I have heard it in other cars and know what to look for...It freaks me out and I check plugs constantly looking for any signs of knocking from the plugs. Its a little rich, as always...The car runs fine..I know the SAFC is junk, honestly Im gonna pull it out after work tomorrow..Id ont use it anyway, it just drives me nuts...

What would your next move be?? I am thinking of relocating the knock sensor to the firewall...only thing is, if it ever does need to retard the timing for anything...it wont and BOOM maybe...I dont know

Why on earth would the temperature outside effect knock that bad...no performance decrease other than the typical turbo loving the cooler weather thing...no undastand

Thanks DP

[Koshin]

nobody??

I find it hard to believe that no one else has a similar issue....maybe its just me

[Koshin]

WTF!!!! 10% throttle, 10% AFR and 64 knock....makes absolutely no f***ing sense...

figured Id snap a pick of it....no knocking is occurs, a knokc like that you would hear no?? checked plugs again, a little rich as always...

[DrifterProdigy85]

its just how the afc works. the knock reading really isnt very accurate at all.

[gmac708]

Just and idea.

Loosen up and disconnect belts. Make sure you are not hearing steering pump, AC compressor, alternator bearing.

Try that

[IanS]

First of all, your ECU is not really tuned for higher octane fuel. Japanese/Euro fuel is not really that different then the fuel we have here. The diference, depending on location, is as little as 1 point. People just think there is a difference because high octane in Japan is 100, but the truth is, the scaling is different.

There are actually two numbers - RON (Research octane number) and MON (Motor Octane Number). The RON simulates fuel performance under low severity engine operation. The MON simulates more severe operation that might be incurred at high speed or high load and can be as much as 10 points lower than the RON. In Europe, what you'll see on the petrol pumps is the RON. However, in America, what you'll see on the petrol pump is usually the "mean" octane number - notified as (R+M)/2 - the average of both the RON and MON. This is why there is an apparent discrepancy between the octane values of petrol in America versus the rest of the world. Euro95 unleaded in Europe is 95 octane but it's the equivalent of American (R+M)/2 89 octane.

Im not that familiar with the SAFC II. All I know is how many people have problems with them, especially with the knock checker. I know HKS used to make a really nice knock monitering system.

There will always be a little more knock as temps increase, are you sure yours is abnormal?

Is your spark timing over advanced? Do you have high compression internals?

[Koshin]

to my knowledge the motor is stock...as ive never had it opened up, it runs fine...13.08 @ 104

Im getting rid of the SAFC, Im taking it out tomorrow....seems like a hunk of junk

As for the HKS knock monitor, I have looked for one and cant find one in good shape...they havent made it for years...thanks boys

Ill keep an eye on things and let you know if anything else changes

Just and idea.

Loosen up and disconnect belts. Make sure you are not hearing steering pump, AC compressor, alternator bearing.

Try that

I thought about that but after listening to everything, it wasnt nessesary...the only abnormal noise the car makes is a alight timing chain rattle becasue it needs a tensioner...which Im replacing tomorrow..

Im gonna relocate the knock sensor to the firewall as well...

[Blown240sx]

Asnwer a few questions

Knock related to heat

Knock will increase as cylinder temps increase. On a Hot day your fuel and intake air is going to be warmer. The warmer the mixture in a compressed cylinder the easier it will combust (Diesel engines are a good example Low octane so it take a little heat/pressure to ignite it). Higher octane helps with this pre igintion situation. Now if your cylinder temps are hot enough with the extra heat of the fuel and air it causes a more likely chance of detonation. Not always but it does increase the chance. This is why you usually want a good cold air charge and in race car situations they even run Fuel coolers at times. Colder the more dense and less likely chance of detonation.

As for SAFC being junk. I think if you set the knock numbers like you should it should read just fine. The Power FC have no issue with it. Go into the etc and go to knock set and set it on a hot day at operating temp and see if your numbers dont look more reasonable.

Knock sensor also doesnt just pic up engine noise it can pick up anything that would transmit sound through the motor. Like loose motor mount or solid mounts, something rubbing the motor, or anything that would send a vibration through the motor. My friend had shot motor mounts and it made his knock levels jump at times for no reason.

[Koshin]

Im gonna reset the knock sensor on the SAFC for today becasue its hot...I am goin to look into some other stuff as well...thanks guise

[DrifterProdigy85]

Your still gonna find that no matter how long you drive, the knock will still increase. But it would drop down pretty close to 0 once i went WOT.

[Koshin]

this is the case...

thanks guise

[Blown240sx]

Your still gonna find that no matter how long you drive, the knock will still increase. But it would drop down pretty close to 0 once i went WOT.

I never saw much over 15 normal driving when I had my Power FC. Even on a hot day.

[Koshin]

the sensor on the Power FC is far superior than the one in the SAFCII...from what I hear

[Blown240sx]

uses the same sensor.

[vanquish2]

Thats ok...I don't know anything about these cars.....its not like I fed you beer at a recent event....LOL j/k

I agree with prodigy. Heard lots of probs with the safc. If you can spare the change get the turbo xs knocklite. Uses better technology.

Maybe I missed this but did you say it losses power when you see the knock? If not its probably just your safc overreacting

just my .02

[DrifterProdigy85]

I run the Knocklite right now. It works good. and doubles as a shift lite.

[Koshin]

Thats ok...I don't know anything about these cars.....its not like I fed you beer at a recent event....LOL j/k

I agree with prodigy. Heard lots of probs with the safc. If you can spare the change get the turbo xs knocklite. Uses better technology.

Maybe I missed this but did you say it losses power when you see the knock? If not its probably just your safc overreacting

just my .02

I do owe you sum beerz buddy...I cant believe they stopped selling beer like that, crazy...

I was unaware of such a light...Im gonna research and probably get one...thanks for all the advise fellas

Rich

BTW, Kevin I wasnt leaving you out on the thread title just didnt know how much you were even on here....I these two dewds all the time on the SR forum

[Koshin]

I ordered one of those knock lights yesterday....it should work out

thanks again guys

Rich

[Blown240sx]

Thats ok...I don't know anything about these cars.....its not like I fed you beer at a recent event....LOL j/k

I agree with prodigy. Heard lots of probs with the safc. If you can spare the change get the turbo xs knocklite. Uses better technology.

Maybe I missed this but did you say it losses power when you see the knock? If not its probably just your safc overreacting

just my .02

Natural Response o the ECU is to retard timing when knock readings get high enough. Thus loss in power.