this weekend i am going to try and get my car back on the dyno to tune my mikuni (44phh)..
what is the optimum air/fuel mixture that i should be shooting for?

this is on a 6-pot 13b.

 

11:1 is just rich enough to keep you out of trouble.

 

Does the air/fuel mixture stay constant through the RPM range? Or will it run rich at an idle and lean out as the RPMs increase (thats what my cousins 3rd gen does accoriding to his A/F gauge)? I dont really get all that jazz yet...But I need to learn What do the ratios mean also?

~T.J.

 

yes it can fluctuate according to rpm and is injector dependent. it seems rich at idle and stoich toward redline is typical but i'd think the opposite would be a safer scenerio.

 

At wide open throttle www.sevensonly.com has seen on their tyno that 12.5:1 has most power.

 

Just my $0.02. Nikkis tend to go rich at hi rpms. Its in the design. So if you rejet to fix this you can end up dangerously lean at mid range RPM. Tread cautiously.

 

coincidentially, sevens only is where i get my car dyno'd.
i brought it there last weekend , but they didnot have any jets for mikuni's so i will bring it back this weekend when i get some..

the strange thing is that their wideband o2 was acting a little weird.. my car is running rich as hell. i get 10 miles to the gallon right now, the exhaust reaks of gas, when my a/f guage was set up it was reading rich as hell (i need to weld a bung into the headers that i am using now to hook that up again), and the current jets in there are what we use around here for p-port 12a's that run at wide open throttle.. anyways, i put it on the dyno, and the wideband said that my a/f was between 14 and 15...

???? that cannot be right????

edit.. i pulled off my old headers to change them this weekend. the insides were black. another sign of running rich as hell.. the o2 sensor was black as well..

 

after tuning the carb (going through what jets i had around) i ended up with an a/f ration of about 12.7

what do you think of that. close enough? or should i [can i] try for better.

i am now running 200 main ful jets and 200 main jets.

any suggestions (if an adjustment is necessary) are always appreciated.