99whitews6

iTrader: (2)

I have been trying to get rid of KR during some heavier load accelerations and I am only able to get around 18-19 degree of timing without any KR in the 4000-5500 RPM(havent taken it any higher) range. Does this sound right??

408CI
11.3 SCR
AFR 225 heads
23X/24X 63X/62X cam
Run 92 octane (10% ethanol)

I have heard that the aluminum AFR heads are more efficient but is this sound normal? My wideband isnt working right now but I do know that my AFR in this range was around 12.4-12.9 when it was working.

Also, I do have access to 93 pure premium (no ethanol). Would this allow me to run more timing and achieve more HP?

THanks!

Willem @ Fuel Injection Concepts

iTrader: (2)

its either false knock or just **** gas.. do you actually hear detonation?

99whitews6

iTrader: (2)

Nope. Sounds clean. I just need to figure out how to get rid of it. It only happens in this range too under load. Never anything under 4000rpms. Does it have something to do with the transition out of the VE table and into Open loop (or whatever it does)?

Any help?

SSpdDmon

iTrader: (10)

Is it when you mash the throttle or after you've had your foot in it from lower rpms (ie burst knock)? Before you chalk it up to crap gas or "false knock," I'd check into some dyno time. See what really makes power...'cuz it sounds like your spark curve is close to my stocker....and I keep reading a more efficient motor doesn't need as much timing. So, I'd say you're where you need to be as long as you're making power. Imagine that....the myth that all LS1's perform best at 28* timing is just that - a myth.

99whitews6

iTrader: (2)

Ok, if its burst knock, how can I tell? Will it always show up if I log PID burst knock because I have never has any reading in the Burst Knock PID?

SSpdDmon

iTrader: (10)

IDK...haven't logged the burst knock pid (yet). I was under the impression that burst knock was the result of a large surge of air (ie mashing the throttle from cruise) and KR handled everything when it showed up.

NoMoreFWD

iTrader: (1)

I would run the non ethanol. I'm in WI and live on the edge of 2 counties. 1 sells "the good gas" and the other has the reformulated ethanol stuff. Most people around here avoid the reformulated.

jimmyblue

iTrader: (11)

That .sig has high compression, great top end cylinder
filling and ****-water fuel in it; I think maybe 18-19 is
all the motor wants. You might want to push on it and
observe misfires as well as KR. I think ping might show
up in the misfires, if they are not already dummied out,
if it's strong enough to make crank jerk. Maybe need to
play with the KR settings to make ping's nature more
observable (not whack-a-mole; more like, tease the
mole for a while first). If upping spark brings on KR then
it is not likely false.

Best torque should always be found a couple or few
degrees before ping threshold. So maybe you want to
do a little quantitative performance logging and try
your 19 degrees, 17, 15, ... until you can see the
spark effect on engine output clearly; you want to
be in the middle of the "flat top" - ping on the right
hand side, and maybe the -10% point on the left,
timing at center will be both tolerant of drifts and
"as good as it gets"/

Or maybe more fuel, you're not looking at stock as
any kind of example for tuning targets. Again a
series of few-% increments would show you the
direction.

By way of performance, something you can do anytime
is find some Interstate that's quiet, put it in 2nd locked
up and just do "wind sprints" 2K-6K. Use Excel to plot
them overlaid and look at acceleration. Poor man's dyno.

Doc

iTrader: (9)

Motor mounts, exhaust all tight?

Slowhawk

iTrader: (12)

That timing doesn't look bad to me for your setup. Our recent 408 setup llike your only wanted 19 degree's of timing and made 540rwhp.

99whitews6

iTrader: (2)

Cool.

99whitews6

iTrader: (2)

I will look into the misfires later today. I do remember logging TOTAL MISFIRES a couple logs ago and I dont remember seeing anything higher than 0, but I will check again.

Can you elaborate a little more on playing with the KR settings? This is the last area in tunning that I am completely . The ONLY thing I have changed for KR is the "FAST KR RECOVERY VS. RPM", and I changed all the values to 0.031 across the board. I guess I really cant comment on how much it helped because I lowered the timing table in the same tune.

joecar

Will lowering lowering PE AFR in that RPM range make the knock go away...?

99whitews6

iTrader: (2)

I am still getting 4 degrees of KR like before and I only have 20 degrees of timing.

What things should I look at to try and correct this?

Steel Chicken

iTrader: (3)

what plug range you running? are they too hot for the application?

99whitews6

iTrader: (2)

NGK TR55's