Questions: C0 Adjust?

[HAMMER]

SCApex Mountain -- 10lbs boost (at intercooler 8000ft) -- AFR 12s average

I pulled a brand new set of stock sparkplugs, only 30-miles on them, no idling, went from riding hard, straight onto the trailer. The dry black carbon indicates they are beginning to "cold foul"......WTF?

C0s all set to 0 during this time.

Cylinder #1 plug clean (normal)
Cylinder #2 25% covered in dry black carbon
Cylinder #3 50% covered in dry black carbon
Cylinder #4 100% covered in dry black carbon

Tonight I staggered the C0s to see if I can clean up those plugs
(at least in the throttle position and rpm range the C0s cover)

Cylinder #1 left at 0
Cylinder #2 lean -2
Cylinder #3 lean -4
Cylinder #4 lean -6

I'm thinking it’s the MPI intercooler design because it has a "jog" in it around the SC intake where it feeds cylinders #3 & #4.

These questions are for the guys that have messed with the C0 settings.

What do you think about those settings, too much, not enough ???

How many numbers does it take to make a difference, like in jetting ???

 

[powderlites]

CO settings

When using our control box some sleds run way better at -20 CO Even helps throttle response.
http://www.powderlites.com

 

[TurboJamie]

- 10 on my powderlites equipped sled. Clean out of the gate and nice tan plugs.

 

[KnappAttack]

The co setting only affects idle on my machine. CPR Apex turbo. 0 on co it will idle at 17:1. upped them to +5 and it idles at 15:1 on innovate and runs great. Touch the throttle and the co does nothing anymore, reverts right to controller and co settings don't come into play. Hammer, what are your cruising #'s like on the wideband? I wonder if we can lower them into the 13-14 range? I was running rich for break in at 10.6-10.8 range and now have leaned them to 12.0 and it runs much cleaner. Would like to go leaner but don't want to ruin anything to pick up 1-2 MPG. I shoot for 11.8 @ WFO which I can only hold for seconds at a time anyway due to extreme track speeds. Mike Knapp#17

 

[TurboJamie]

Mike I cruise on flat lands at 13.5 ish to 14.0 no problems for 2 season now, well 1/2 the second season riding anyways. Ran 3000 miles last winter 13-14 in the mid all winter long. Engine looked like brand new when we pulled it down Leak down is 6% across the board.

 

[KnappAttack]

Was that with your blower set for 10 Lbs on stock engine?

 

[TurboJamie]

That was with my blow yes. I am crusing the same way now with the powderliets front mount. I have 500 miles on it now 13-14 in the mid running northern ontario 100 mph trails. 12.3 @ WOT.

 

[HAMMER]

Thanks for the input guys !!!

This is how it was running that day, fresh stock plugs, C0s all 0s.

Adjusting controller settings any leaner and it dead-spots/backfires when going from hard deceleration back into hard acceleration

Idle (1)
Needle (3)
Main (5)
Boost (5)
Accelerator (3)
Altitude (5)

AFR probe has never seen leaded fuel and has been free-air-cal'd
13.5:1 AFR at Idle
11-12-13 AFR depending on throttle position and load while cruising
9.8-10.1 AFR under hard acceleration tapering into 11.8:1 AFR at sustained wide-open-throttle

Nitrous:
Bottle temperature 98*F
During 5-second sustained nitrous burst (.012 jet) it leaned the 11.8:1 to 12.3:1 AFR

Blow-Off-Valve:
Works just as expected stayes fully open unless above half throttle with NO compressor surge in any throttle position. Just cruising down the road boost at the intercooler is 4-5-6lbs, depending on throttle position and load. Moving the intake out from under the hood, adding an intercooler fan, and all my extra venting keeps the intercooler temperatures in the 40-50-60*F range. Intercooler temp jumps up to 100+*F after you stop and shutdown the engine.