Hi all,

i rejetted the carb and now I have around 14:1 A/F in cruise (had average 14.7:1 and went up 2 jet sizes, doesn't seem to make a difference really now)

On part throttle accelleration I am about 13.5:1 to 14.5:1 and on
WOT i am at 12:1

does anyone have any recommendations on where all those values should be?

 

Depends on the engine and it's detonation resistance and ability to burn fuel. WOT at 13:1 will make more power(run premium) as long as it doesn't detonate...and some setups get away with 13.2:1. Cruise depends on what the engine can tolerate. 14:1 is decent, but the leaner you can run it the better the mileage will be. Generally though it's hard to get a carb setup to go more than about 14.5:1. Part throttle acceleration 13-14, depending on what it tolerates.

 

Yes

First off Why did you you change jets and not needels? I was under the impression that your mix was good under load...see post in

https://mustangforums.com/forum/clas...g-woheeee.html

As for A/F part throttle cruise you should be around 14.3 to 14.5 at 2500 rpm
part throttle acceleration should be around 13.8 to 14.1
and WOT should be around 12.3 at 1500 rpm and up to 12.6 at 4000 RPM

happy hunting

-Gun

 

67m302: thanks. so i'll leave main jetting as is, will try to lean WOT out a bit. might even put the 58's back as it cruised ok at 14.7-ish. My first thought would be to use smaller secondaries, but it might be the PV that makes my WOT so rich.
For the off-idle-hesitation. christ it is annoying. you think it's a crap car when you don't hit the throttle more. I'll keep trying with the cams. If that doesn't work, then **** it and I'll buy a QF mech secondary (with electric choke though)

GunJam: i'm on holley at the moment, not edelbrock. no needles (metering rods) here. i know it's confusing as I changed carbs at least 3 times this year already.
I have the edelbrock carb and my old weiand intake sold now. So no chance of that carb going back in again
But thanks for info as well. that's not too far off where I'm at the moment.

Kalli

 

Sounds like a plan. I find that 12.5 or so is about as rich as you want to run at WOT. Running richer than that will probably give you problems with ignition. Even though 14.7 is the ideal AFR, I find that when I get into the 15s, my car really does not like it. I cannot really run leaner than low 14s under cruise or I have hesitations. I suppose it is different for every engine/car. It took me just playing with AFR levels and feeling for what the car was doing to tell where it needed to be. If you are shooting for economy, that is one thing, but if you are shooting for power, I think keep the part throttle in the low to mid 14s and keep the WOT in the mid to high 12s.