jeffswav

I have a Holley Comander 950 MPI Kit. I have been using the narrow band sensor until now. I have just recieved my wideband kit and I am just woundering about the target numbers for marine engines. From past experence with narrow band the engine desired to be a much richer fuel mixture than advised in the book. I can set the target from 10.00 (rich) to 15.00 (lean). I have a 500HP 489 stroker with one of RMbuilders roller cams. Anyone have a good starting point for target numbers? I have 8 different RPM inputs and 8 map inputs from 400 to 4500 RPM.
Thanks,
Jeff

GPM

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BenPerfected

I nice thing about the ability to measure is you don't have to make the engine overly rich except at higher RPM's to WOT. We expect to finish polishing on our 1150 Dominator's jetting next week. In the boat, we expect to be at about 12-6-12.8 at 5500 RPM to WOT using 3.5 PV's. From 3000 - 5500 RPM (PV's closed) our target is 13.6-13.8. At idle in gear, we should be at 14.5-14.7 by changing the idle air bleeds. We also check the plugs after a 2-5 min mid-range run and then stagger jet until the plug color is equal. With our set up we will be 2-4 jets smaller in the front.
What are others doing? I feeling like we are still wasting fuel in the mid-range.

JasonSmith

Find "tunertec" on here. He can help you out.

jeffswav

Thanks, good info

Mr Gadgets

Jeff,
I have a datalog file from my EFI.. It is always a tune in progress, but it should give you an idea of what to sneak up on. The motor is a 565" NA, with 65# injectors..

Have fun!! Tuning is always a great excersize for the brain.

OSO wont let me upload an Xcell file.. send me your email and I can fwd it to you..

Dick

articfriends

iTrader: (1)

I aimed for 14-1 to 14.7-1 from idle to 2000,from 2000-2800 I aimed for 13.5-1 give or take a little,from 3000-4200 I aimed for12.8-1 to 13-1 then I went to 12-1 anywhere above that when not in boost and 11.4-11.6 under boost,remember you might end up with a tank of gas with a bunch of ethanol in it so don't try to tune as lean as possible you will have no safety margin since you get no exhaust feedback/correction.
My son has been going to local college tech program for ase automotive training and they had a alchohol spectrometer tester,he took samples from every local gas station and there were some as high as 16-18% (speedway/admiral),I'm not sure how strictly they keep the mix at 10% BUT if the samples came up high obviously no one watches it real close,Smitty

BenPerfected

Mr. Gadgets,
I your wouldn't mind, i would like to have a copy of your file [email protected].

Smitty,
Are most blown applications richer than NA or are you just being safe?....I have zero experience with blower motors.

Ray (Raylar),
Where do you set your the fuel mixture on your higher HP 496's?

At 12.5+ after a solid run at WOT the plugs are still dark brown...even on 5 & 7 and 6 & 8.

TWIN-SPINS

on the 525 upgrade he wants it set 50psi key on engine off

jeffswav

Thanks for the good info on O2. The upgaded program alows you to set a target and alow the PCM to add or subtract fuel. I will see how that works. I empty my tank completly in the fall. I disconect my fuel line from the fuel rail and pump the remaining fuel into a 5 gallon can and put it in the truck. Then I start fresh in the spring. I blew my engine a few years back, it destroyed the tops of all the rod bearings.