JohnKoaWood

I'm working on it, sorry all I blew out my back a week ago(twisted the wrong way moving a battery from my 951 to my N/A so I could move the N/A and take out my boat...another day of boating gone...), and have been layed up since... I have a pile of parts to put back on my car, and 2 more write ups to finish... I will try to get it wrapped up by this weekend, and posted.. I will work on the write up tonight once I get home...

I'm modifying the third one I bought right now (1st unmodified is in the car, 2nd is modified sitting on my table, 3rd is still sitting in it's box), and plan to post a DIY, and offer a cost plus core, or just cost for me to do the modification...

As soon as I finish the DIY I'll post it, along with anything else I come up with...

Also keep an eye over there, as I know it won't be long before I get my hand slapped for trying to do a favor...

Josh B

Hey John - don't mean to pester you but I sure am interested in this mod

JohnKoaWood

I'll get it done this weekend, and post a DIY with DIFY (do it for you) pricing...

Sorry, life has once again gotten in the way for me, but I will re-focus this weekend.. I have 1 modded that I still need to install, and 1 un modded in the box that I will do a write up with..

SORRY... please don't get mad at me...

toddk911

Would you only be offering the mod or buildnig them from scratch and selling?

Also, what is an accatable knock count?

Van

John, can I hijack your thread a little bit? I've been logging my knock via my Traqmate - so I can see where and when it happens on the track. I can say that pretty consistently I get one or two knock impulses once I'm full throttle exiting a turn (I log throttle position, too).

Think this is anything to be concerned about? I assume, because the knocks are pretty singular, that the computer is backing the timing off to reduce it... I suppose I could play with my octane and/or LBE and see if the knock counts change.

JohnKoaWood

Van, try playing with your FQS, go no fuel change, -3 ignition, I bet your knocks dissapear... but so will throttle response and top end...

I got 23 knock events on my tri home today...some spirited pulls on teh highway, usualy get 1-2 knocks on WOT shifts for a few reasons... mainly because I have advance my timing maps..and they still need refined to eliminate the knocks...

if your AFR s are good, and you have instrumented throttle position, air flow meter / MAF voltage and knocking you should be able to target ignition map modification (X RPM at Y Load.. retard timing untill you stop seeing the knocks...)

BUT

Your knocks may not be actual knocks unless you are seeing them at WOT... at part throttle there is little boost, and little tendancy to knock... you might just need to back down your WOT map at X RPM, when modifying my ignition maps I usually go in .1 degree increments... I advance untill I see knock, then I retard to loose the knock, then I go another .5 degree retard to avoid knock if I should get crappy fuel or have a problem with elevated IAT...

If you aren't tuning your DME..you should be able to rid yourself of the knock using the FQS to retard timing -3... see if it helps while being aware it WILL impact throttle response and top power...

Tod,
In a perfect world, zero would be good, Knock is bad for your engine, the environment, and over all performance...

That having been said...

Knock is caused by many different factors, to the extent that Porsche put the KLR in for just this function... at elevated manifold pressures, when HOT intake temps are encountered, all it takes is a bad ignition signal, or some contaminated fuel to destroy your engine... 1 Knock CAN kill your engine if it is bad enough, or timed at the "right" time...

Timing control is how Porsche chose to control Knock, when the KLR detects Knock, it retards the ignition.. This is OK... a few knocks here and there, at WOT especially at higher RPMs SHOULD be OK, but generally knocking should be avoided...

The Knock counter is a tuning tool.. it will tell you when you are pre-detonating fuel, I am using it to let me know if and when I am running my ignition too advanced, have gotten bad fuel, have IAT too high to be good, or if I need to get off boost...

Zero Knocks would be good, an could be done by not boosting, or running ignition retarded, or both... BUT that wouldn't be much fun would it?

I have asked permision to offer service for cost... and trust me, Not only will cost be reasonable, but varied in structure... (Modified, Modified with core, send your to be modified, or a kit to modify your own), all will most likely be very cost effective... If I am allowed, I will post it in the DIY writeup.. If not allowed I will post the DIY and find some other way to offer it outside RL, and not to be spoken off in RL... Like my SIG?

Van

The FQS is that little setting on the DME for altitude? I'm running stock everything (for my class) so there's not much else I can change.

Here's a screen shot of my data.

Each color is a different lap. The top graph is RPMs, the middle graph is the knock signal (from the KLR) and the bottom chart is the TPS.

You can see, this all takes place at turn 10 at Watkins Glen.

Anyhow, the blue lap had 3 spikes at WOT - red and green both had one count at WOT.

The datalogger is 20 Hz. And the blue counts happens in less than 1/2 a second.

My inclination is to not be too worried. Maybe some day I can log boost pressure, too.

(sorry for the large image size)

blown 944

Van,

What AFR are you seeing at those times??

3 counts per gear doesn't seem to cause any damage that I have seen.

You may try to add a bit of fuel through the FQS. There are 2 different settings above stock +3 and + 6. You can also pull a little fuel and timing via other positions.

My thought is that you may make just a little more power using the +3 or 6 setting and eliminate the counts.

Van

AFR is totally unknown (think I could log the voltage from the stock O2 sensor?)

I'll have to play around with those +3 and +6 settings some time. Unfortunately, I don't think I'll have this car back to the track until next spring.

Jeff N.

RE low RPM knock counting, I believe you can add a simple pressure switch that would only enable the knock counter on boost. This should eliminate off boost knock. Can't recall the name of the switch type off hand but they were pretty cheap. I think the 5lb one was about right.

theedge

You probably could log the stock O2 sensor yes, but that wouldnt really tell you much. They give you a small window around 14.7 and thats it.

JohnKoaWood

That and the fact that a stock DME ignores the O2 sensor input at WOT.. the NB O2 sensor isn't going to tell you anything of value...

ALL of your logged knocks are at 5400 RPM, WOT, within .5 seconds of throttle application... too bad you can't modify the timing map at WOT...I would pull some timing at 5000 RPM from the WOT table, and I bet you knocks go away...

What is your LBE set to? I'm betting 15 - 16 PSI..and you are running pump gas?

You have a few options... FQS is a 6 position switch on the DME, doesn't affect altitude compensation, it affects fuel and timing maps, but is affects the entire table, you are only having knock at 5400 RPM... all 3 laps show knock at the same RPM... I would switch to position 4 or 5... I'm betting you are at position 1... if you pull your DME, you should find a small black cap on one side... it might not be there... insert a small (3mm I believe) alen wrench and carefully turn clockwise...you should feel it click... but be aware you will be pulling 3% timing from the entire range of throttle positions and RPM..so she MIGHT feel sluggish...

Your knocks aren't that bad, but the fact that they all happen at the same RPM is of some small concern... can you run custom chips in your class, or do they pull the DME chips to verify stock setup? IF you can modify the chips, I would run your chip image, with -.2 at 5000RPM on the WOT ignition table... but that is only if you can run chips... or you could lower your LBE a little to see if it eliminates the knocks...

joeytoad83

ive got mine apart what do i need to connect to to get it to reset

JohnKoaWood

Connect pin 1 to the 2nd solder pad away from pin 4... momentary push button from radio shack will reset when pushed, I added a 220 ohm resistor to act as a current limiter...




I have almost finished taking pictures, and should be able to finish the DIY tomorrow, Sunday at the latest. while you have it apart add a 12V bulb on wires between pins 1 and 2, glue the mini bulb / led to the side of the screen (in the opening to the right side) and you will have back-light when powered on... I have managed to fit it all back together using a 2mm LED and micro switch, I now have brighter micro bulbs I am using in the write up..

joeytoad83

thank you, tiny things are a pain in the butt to solder