KR and Misfire on procharged G8, need help

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Today i performed a WOT run on my Procharged G8 and noticed few things that i didn't notice before because i had no hptuners: First, seems like I'm getting around 3 degrees of KR around 5200rpm and because of it and also getting misfire in cylinders 2,5, and 6. Besides that i also noticed that an IDC of 97%. The car has the following modifications:
* A procharger D1SC (about 11psi of boost)
* Snow Performance Stage II Water/Meth Kit (75%meth, 25%water)
* Kooks 1 7/8" LT Headers and exhaust

The car was dynotuned with the previous mods and made 575rwhp. After this last dyno tune I install a Circle D 2800 stall converter and a FAST LSXR 102mm intake and it hasn't been re-tune since this new mods.


To the facts, i already pulled some timing because i was getting kr's on those offending cells. Seems like i pulled too much timing on those cells, i could get rid off more timing but seems like the timing will end up been too low (5degrees in some cases). So my question is it possible that im running too lean or what could be the cause of this? Does switching to a FAST intake requires a full re-tune?


Attached is the wot log and the tune, any help will be deeply appreciated.

P.S. I'm getting bigger injectors.

[murphinator]

is it possible that im running too lean or what could be the cause of this?.

only way to know if your too lean is to get a wideband on it , you have a lot of dough in that setup to not spend a coule hundred bucks on wideband and know if your rich or lean

97% duty cycle is maxxed out , can you lean the pcm fueling out to gain duty cycle and increase your meth to hit your afr target ? I have never tuned anything close to that setup or meth at all but from reading about it that what I would think would be the quickest way to get fueling in control with what you have. Hopefully some more experienced guys can chime in here

I think I have read that misfires are hard to get rid of with more radical setups with aftermarket cams ,convertors ,etc...

a couple observations about your scan

set your histogram to + to see max values instead of average - you are getting 4* kr

your 02 sensors arent switching much at times when I would expect to see them switch a lot

[[email protected]]

Interesting, thanks for your feedback, im learning as i go. I have an LC1 but i just haven't installed it yet. Thanks also for the scanner tips, yes i noticed a max of 3.7 kR, i have to look into the 02 sensors not switching as you expect.

[murphinator]

hopefully you get some replies soon from some tuners more familiar with your setup but in the meantime at least you have something to look at. nothing worse than no replies to a post

[[email protected]]

experts chime in please!

[DSteck]

I'll try to look when I get home. If you have stock injectors, then you're skating on thin ice.

[[email protected]]

I'll try to look when I get home. If you have stock injectors, then you're skating on thin ice.

Thanks DSteck, im running FAST 57lbs/hr injectors, im supposed to receive today the Ford Racing M-9593-LU80 injectors. I'll be switching to those because im going with an E85 setup sometime in a near future. Speaking of these injectors, how difficult will it be to scaled these injectors if i don't have the injector data from Greg Banish DVD?

[DSteck]

Find a way to get the injector data. There's a thread on here about scaling that'll help you adjust for the IFR limit.

[[email protected]]

Find a way to get the injector data. There's a thread on here about scaling that'll help you adjust for the IFR limit.

I found a thread here to scale IFR by 56.3%, will give it a shot. Thanks and appreciate for helping on this.

[DSteck]

Scaling by 56.3% is dumb. Scale by 50%.

[[email protected]]

Scaling by 56.3% is dumb. Scale by 50%.

Heheh, ok.

[G8-4-speed]

Another note, if your running 11 lbs of boost, go 50/50 on the water injection. The water will give you more knock protection which is what you need. Water size nozzle are you running with your Snow Kit?
Are you running a BAP? You need one.
You may need to move down your cold modifiers in closed loop and add more proportional fuel to get your o2 to switch.
Change your injectors first since that will change everything.

[[email protected]]

Thanks for your input

Another note, if your running 11 lbs of boost, go 50/50 on the water injection. The water will give you more knock protection which is what you need.

Will give it a shot.

Water size nozzle are you running with your Snow Kit?

A Single 625ml/min nozzle, Am i need to go to a dual setup?
I'm pretty sure the car is making 600+rwhp right now, and this nozzle is only good to about 600rwhp, maybe im already at the limit?

Are you running a BAP? You need one.

Yep, a KB 40amp, been running it for almost 3yrs.

You may need to move down your cold modifiers in closed loop and add more proportional fuel to get your o2 to switch.
Change your injectors first since that will change everything.

Not sure where to make these changes but will tackle when change the injectors, got them today. I still need to find the injector flow data for the M-9593-LU80's in order to scale them.


I really appreciate your guys inputs.

[[email protected]]

I'll try to look when I get home. If you have stock injectors, then you're skating on thin ice.

Any chance on looking at it?

[DSteck]

-Need to know what injectors are in the car.
-Need wideband data.

[[email protected]]

-Need to know what injectors are in the car.

FAST 57lbs, yeah i know, no flow data.

-Need wideband data.

Will gather some this week in a new log file.