Fluidplay

Thought I'd start a fact finding thread here for those using a knock counter (Curtis or other) or for anyone interested in this. I've been playing with 91 and 100 octane gas and boost levels trying to minimize the number of occurrences I get under WOT.

EDIT: I also changed the FQS to -3 timing / 0 fuel

Hopefully we can compare these recordings with some constant variables related to car set-up, octane and boost levels and get some kind of consensus as to what's acceptable.
Here's what I've recorded on 91 octane running 15-16# boost. First off, under spirited driving conditions I get absolutely no knocks through all gears shifting at approx. 5500rpm. When I get a little more aggressive with running the shift rpm's up to about 6000 I get:
no knocks 1st and 2nd
1-3 knocks 2nd to 3rd
2-4 knocks 3rd to 4th
4-6 knocks 4th to 5th.
At WOT it ticks up...
no knocks in 1st to 2nd
1-3 knocks 2nd to 3rd
4-6 knocks 3rd to 4th
6-8 knocks 4th to 5th.
I've been trying to tune the WOT knocks down by making very small changes +/- in my A/F mixtures with little success.

Running 100 octane at 18# boost those numbers are basically cut in half. Would love to run 100 oct all the time...but at $9 a gallon.

I would be interested in knowing how you guys are eliminating these knocks if at all...or is it impossible to tune these knocks out of a modded car?

Please post your results.
Thanks

JohnKoaWood

retard the timing to loose the knocks... you can only do so much with AFR, the last few need to retard the timing to lose...

Fluidplay

Hey John, I forgot that...I did change the FQS to -3 timing / 0 fuel

JohnKoaWood

You might need to lose more timing...3% of 26 degrees isn't really much... I pulled 2 degrees additional to get rid of my last few knocks @ 15PSI before I pulled my car apart to rebuild the turbo...

Fluidplay

...you do that by changing the belt position?

JohnKoaWood

I do it using MaxTune and and Ostrich 2, you can also order chips with the timing retarded... I would recommend you get chips for the boost level, or get some tuning software and a setup like the ostrich... I can pull timing add fuel and burn the chip image with the car running and see instant results... I have gotten 5 tunes and runs in a half hour...

DONT change the belt.. it will change the valve timing, not just the ignition timing.. and that could be BAD...

Rogue_Ant

What AFR is your target @ WOT?

Also, the FQS switch pulls nearly 3degrees of timing, not 3%.

And Changing the belt won't effect ignition timing...


-Rogue

JohnKoaWood

Sure changing the belt would, but it would also change the valve timing, which would be bad...

He already has FQS set -3/0... I stand corrected, the FQS pulls 3 degrees not 3%... now I know, and knowing is half the battle....GOOOOOO JOE..sorry, I blew out my back today and am on drugs now...

eniac

E85 will lower your knock counts much more than 100 octane and it's only ~$2.12/ gallon(around here). After I installed my knock counter I ran 18psi on pump gas(94 octane) and the knock counter would go nuts under boost. I switched to my E85 tune and kept boost turned down with E85 and barely got any counts at all, just random ones here and there and a couple ticks every time I start the car for whatever reason.

Rogue_Ant

Changing the belt has no effect on timing. The distributer simply directs spark to the correct cylinder - actual timing is determined by the DME/KLR.


-Rogue

JohnKoaWood

In that the coil is controlled by the DME/KLR, BUT if the belt pulley is moved it will alter the timing, if the cam pulley were to be moved 90 degrees the spark timing would be 90 degrees out... and your valves would be digging into your pistons

but that is a trivial discussion as it is NOT advised to change the timing of the cam to the crank as that is what leads to valves hitting pistons... Only extreme performance cars need to be playing with the cam timing at the pulley using an adjustable pulley...

TO THE OP.. for this application the values of the DME timing table need to be changed, not the timing belt cam pulley.. DO NOT PLAY WITH YOUR TIMING BELT PULLEYS... get the chips changed... or just lower your boost...

Fluidplay

John - if only I had the tuning software/ability to change the timing and burn the e-prom myself, that would be a perfect scenario. Unfortunately I'm using a piggyback system for tuning, which at best is limited. One of the things I was considering, is doing a few dyno runs to get some graphed info., then taking that info. to someone who can program the chip to work with my set-up at a desired boost level.

Sound like a viable way to go? Not having the ability to correct this with my current tuning capabilities.

Rogue - my target A/F is low 12's @ WOT

eniac - though I haven't looked, not sure E85 is available here in So. Cal.

Edit: ok, California does have E85, the closet station is 50 miles away.

Rogue_Ant

The timing will only change if you move the rotor so far out that it is igniting the incorrect cylinder.
The rotor is fairly wide, to allow a large range of timing advance commanded by the DME.
This is not a small-block chevy, rotating the distributer does not alter ignition timing. I implore you to hook up a timing light if you don't believe me.


-Rogue

Rogue_Ant

At your boost (15-16psi) on pump gas, you should be shooting for a little richer AFR... Try 11.5-11.8, it should help your knock and give you a little more safety.


-Rogue

JohnKoaWood

If I were you, I wouldn't mess with the dyno... if the knock is bothering you that much and it would sure as heck bother me, I would pull the chips you have and take them to be altered, and not bother with the dyno session, spend the $100 or so on the chips instead...

Russel berry (MaxHPKit.com) can do this for you... not sure if authority or Vitesse can do the same, but I imagine so... Russel can also work just off the BIN file if you can have it pulled of your existing chips... call the dyno shop and ask if they can pull the BIN file off your EPROMs... that can then be e-mailed to Russel with your desired changes, he can then burn them to a new set of chips and send the chips to you.. granted for a charge of course...

You MIGHT be able to find locally to you a tuning shop that has the capability to work with your DME files, but there aren't any in my state much less close enough for me to take the car too, hence I bought a chip reader/burner, the ostrich and MaxTune SW.. I do it for myself, and once the car is back together will be investing in some dyno time to maximize the HP while eliminating the knock, and get the car tuned to run perfectly at 15 or so PSI..until I do a full rebuild this winter and get a bigger turbo... new exhaust..etc..etc..etc..