SFAC-II knock level

[EJ253]

im not exactly sure what this is. the manuel doesnt really tell waht it is either.

sometimes mine goes up to ~81. can anyone tell me what this does and if thats bad.

thanks,
Greg

[johngriff]

It is a rating out of 200. So take the number, and divide by half.

81/2 40.5% knock.

Not good, sounds like you dont like your engine at all.

[EJ253]

what can i do to fix it

[sean350z]

Or your engine doesn't like you. I'd make sure you redo the set up of the knock sensor calibration on the SAFC again. Mine never gets above 15.

[sean350z]

Originally Posted by EJ253

what can i do to fix it

New engine

[sean350z]

Just kidding...I would make sure your SAFC is set up right, check your plugs for detonation, timing, etc.

[downshift_sideways]

Yea mine never went above 20 on safc2.

Dou you KNOW how to tune the safc2? with readings like that you can blow your motor.

Like me haha, Overtuned safc2 and sliding in the rain, hit the limiter hard and my knock was at like 1000+ haha....Blew it.

[PS13SILVIA]

On a cold night average knock on my S13 KA24DE with almost 190k is 0 to 13 and on a hot ass day it can go to 38 or so, my timing is set at 22 degrees BTDC and I mostly run 91 octane.

[EJ253]

i reset it. and now it stays between 3 and 7 usually. it doesnt usually go above 11. is that ok?

[downshift_sideways]

You should find out some more info on your safc2.
Deff not something to just mess with numbers.

Preset all your channels to you own liking.
and when your safc2 is on, its best to show all the sensors.
Throttle%,Rev,Knock,voltage, Etc....

[Flybert]

Originally Posted by PS13SILVIA

On a cold night average knock on my S13 KA24DE with almost 190k is 0 to 13 and on a hot ass day it can go to 38 or so, my timing is set at 22 degrees BTDC and I mostly run 91 octane.

These numbers sound about right for my SR as well.

Any unusual spikes over the normal amount usually means it's knocking. Numbers are usually 50+ when that happens.

[EJ253]

it only spikes up once and a while when i let off the gas and the RPMs go below ~850.

but is it ok if its constantly between 3 and 7 ??? keep in mind its cool. the numbers were all set by a respectable tuner a while back (with the previous owner)

[PS13SILVIA]

Also when you go WOT your knock values should go down lower than when just cruising around in closed loop....

[EJ253]

they do, they usually go to zero


**what does closed loop mean?

[PS13SILVIA]

Originally Posted by EJ253

they do, they usually go to zero


**what does closed loop mean?

Closed loop mode means that the ECU will compare the measured air/fuel ratio to the target air/fuel ratio and automatically increase or decrease fuel delivery accordingly.

Open loop mode, the ECU will still use the oxygen sensor to read air/fuel ratios, but will not adjust fuel delivery as in closed loop mode.

[johngriff]

AFC "tuned"? "Respectably"?

List of modifications.
*AFM type
*Engine
*Turbo
*ECU
*Injectors
*Level of boost

[gunluvS14]

i wouldn't even bother by the knock #. its a silly function.
how would you know your knock sensor is working properly. how would you know some other similar frequency produced around the engine bay were not picked up by the knock sesnor and throw off the knock count?

to be honest, i wouldn't freak out or depend on it.

[johngriff]

I would say the same, especially after reading that he "replaced" the knock sensor. What was the tourqe spec? LOL.

I just want to see the list of mods to see if it is stock, or modified to hell, in which case knock would be a moot point.

[EJ253]

its an S14 SR20, stock injectors, S15 T28 (same as stock turbo?), stock ECU, .75 bar

[johngriff]

hmm i wonder if its more airflow w/o correction.

[EJ253]

my AFRs were fine when i got dynoed. ~12

[johngriff]

+11.4 on pump is no good.

[Flybert]

Originally Posted by gunluvS14

i wouldn't even bother by the knock #. its a silly function.
how would you know your knock sensor is working properly. how would you know some other similar frequency produced around the engine bay were not picked up by the knock sesnor and throw off the knock count?

to be honest, i wouldn't freak out or depend on it.

People like me know that it works great because I've seen it first hand.

Example #1
2nd track event with s13 SR and first time with SAFC2. Stock sidemount intercooler on stock boost. Hot as hell day. Track was Streets of Willow. 91 octane. SAFC2 calibrated properly and motor timed properly to 15 degrees by way of removing CAS and lining up marks AND using a timing light.

Beginning of day was a learning session where we learned the lines of the track, how to drive side by side with people, etc. No knock because we didn't push it so the intercooler didn't heat soak. 2nd half of the day was full hard hot laps. After a few laps the intercooler heatsoaked and I started seeing spikes of 80-100. Pulled it in and decided to go get some 100 octane from the pump to mix with the 91. I went back out again for the next run group and ran full hard again. Despite having a heatsoaked intercooler, the knock levels remained normal.



Example #2
Same setup as example #1 with 91 octane. First track event with new motor. Drift event at the balcony at willowsprings. Took a few laps in the morning. Knock levels normal. Gets hotter as we get towards noon. Take a few laps and see knock spikes to ~100. Go back to the tank and get some 100 octane to mix with the 91. Take a few hot laps and knock levels are back to normal.



I have a ton of other examples with different setups on different boost levels with different turbos, injectors, MAFS, enthalpy tune, etc. If i see spikes of knock, it's always because of two things.

1. There's only 91 octane in the tank.
2. Not enough 100 or 110 mixed in with the 91.

SAFC2 knock sensor always knows what's up.



WHY PEOPLE SHOULD READ EVERYTHING I'VE WRITTEN

Late 2004/early 2005 is when I got my motor from phase2. It had 165-170 compression across the board. I only ran stock boost from those two examples I mentioned above. After that I've been running GT28R's on 1 - 1.2BAR both of which ran fine and never seized or died on me. Here is a list of every event I've done with my SR. The first two were on stock boost. The rest were on 1 - 1.2 BAR on gt28r. To this day, compression is still the exact same. My car is so reliable that I drive it to and from the every event with no problems. I even drove it out to laughlin, nevada from LA for the formula d pro-am event. I cruise out to every event now with 91 octane with boost set at stock and then turn it up when I get there and put in 100 or 110 leaded. The less 91 in the tank, the better. The SAFC2 knock monitor is priceless to me for obvious reasons. I give my car the beatdown and it just asks for more.

3/05/05 Just Drift at the Balcony at WSIR

5/23/05 SpeedTrialUSA HPDE at Streets of Willow at WSIR

7/25/05 Just Drift/Drift Association Drive Fest Competition at Walt James Oval at WSIR

7/29/05 Private-Events.net at Buttonwillow Raceway Full Course

9/25/05 Drift Day Competition 5 at California Speedway

12/18/05 Just Drift Private Practice Day at the Balcony at WSIR

2/26/06 Just Drift Top Drift Battle Round 1 at the Oval at WSIR

3/5/06 Drift Circuit 3 at Qualcomm

5/20/2006 Just Drift Top Drift Battle Round 2 at the Balcony at WSIR

6/17/06 Just Drift Practice Day at the Balcony at WSIR

7/2/06 Just Drift Practice Day at HTM at WSIR

7/30/06 Just Drift Top Drift Battle Round 3 at HTM at WSIR

9/23/06 Just Drift Top Drift Battle Round 4 at the Oval at WSIR

10/15/06 Just Drift Top Drift Battle Round 5 at HTM at WSIR

11/17/06 Formula D Pro-Am Nationals Practice Day in Laughlin

11/18/06 Formula D Pro-Am Nationals Competition

[EJ253]

im running 91 octane. should i use octane booster too?

or should i only worry about it at the track?