A/F readings, What do the experts think? Options

[Black22]

Hey all,

I've got a 1911cc motor with about 250 miles on it. KB pistons, stock cam and L-jet, with 1.8l heads modified to 2L valve sizes. Compression is 8.5:1. Running Brad Penn 20/50.

Car was recently running way rich and got VERY poor gas mileage. I hooked up with Joe Sharp, (thanks again Joe!) and he let me use his LM-1. I tried to dial my L-jet in and got pretty close. I've since purchased and installed an Innovate MTX-L AFR kit. Gauge works great! Here is my readings as of now and after MUCH tweaking this is my dilemma.

AFR stats:
Idle= 12.7
WOT= 9.7-10.2 (it will hit these readings regardless of RPM)
Decel= 14.8-15.9

Timing is set @ 7.5* @ ~900rpm with vacuum ports disconnected and plugged.

WOT seem rich still, but now my motor runs hotter. I know I'm leaning the motor out and should expect higher oil temps but I was running about 190-200 and now I'm running 210-220. I'm also running an external 72 plate oil cooler w/fan!

I've adjusted the timing to experiment, and had it at 9.5* adv. and it ran cooler at idle but the temp went back up while driving.

It seems I have some more adjustments to get it even leaner, but that's just going to raise the temps right? (IMG:style_emoticons/default/confused24.gif)

What do you guys think and what should I do (if anything) next?

[ChrisFoley]

You should get a CHT gauge.
Leaning out the mixture will have a greater effect on CHT than oil temp.

I want my oil to get up to 210F to fully burn off volatile impurities.
And I have to work pretty hard to get it that hot.
As long as you have at least 10psi per 1K rpm its not too hot.

I'm running BP 10/30 in my 1911 with D-Jet. No problem with oil temp/pressure or CHT. I've driven hard on 100 degree days and had no issues.

[rwilner]

::Disclaimer -- I am not a member of the expert community, only the peanut gallery::

Gas mileage is principally determined by AFMs at cruise, at least on the highway. What are you running at cruise?

My car likes 13.5:1....a good compromise between fuel efficiency and engine head temps. I agree with Chris -- if you're messing with AFR you should have a CHT gauge installed, otherwise you're guessing.

[Black22]

::Disclaimer -- I am not a member of the expert community, only the peanut gallery::

Gas mileage is principally determined by AFMs at cruise, at least on the highway. What are you running at cruise?

My car likes 13.5:1....a good compromise between fuel efficiency and engine head temps. I agree with Chris -- if you're messing with AFR you should have a CHT gauge installed, otherwise you're guessing.

At cruise w/ partial throttle just to maintain 70mph I'm around the 11.8 to 12.5 area depending on load.

I would love a CHT, but baby boy will be here in 2 weeks and Momma will kill me if I spend another dime on this ride! (IMG:style_emoticons/default/sad.gif)