I was reading a book about Holley carbs and the section on air bleeds said larger high speed air bleeds cause the mixture to lean out. I thought larger air blleds caused the fuel emulsion to speed up and actually richened the mixture. Any carb experts know for sure?

I am not a carb expect but I know the answer on sizing. The smaller the air bleed, the richer the mixture...the opposite of jets. It was explained to me that as the bleed gets smaller, the carb "sucks" harder and adds more fuel. The explaination may be off, but the result is correct!

I am not a carb expert but I know the answer on sizing. The smaller the air bleed, the richer the mixture...the opposite of jets. It was explained to me that as the bleed gets smaller, the carb "sucks" harder and adds more fuel. The explanation may be off, but the result is correct!

The air bleeds are actually a controlled vacuum leak. The larger the air bleed, the larger the hole in the air bleed, the larger the vacuum leak. That larger leak will cause the carb to be less able to pull fuel. A carb works on vacuum, so if you take away the vacuum, it can not pull as much fuel....hence it will get leaner. If you change the idle air bleed, not only will it affect the idle mixture, but it will have an affect all the way through the rpm range. The high speed air bleeds will only affect higher rpm. Hope this helps explain it.
Eddie

We were typing at the same time.

Thanks for the info guys.

Hi, I just got back from Racetalk.com and they recommend .025 main air bleed instead of the .037 stock that the 8082 Dominator comes with. They say stock the 8082 is rich at low main jet use and lean at wot and the smaller air bleed along with smaller main jets will fix this problem. Good luck for anyone else that's been having trouble with this.

This might be good advice...but the Holley books I have read say that if you are changing the air bleeds more than 4 sizes, something else is likely wrong. If you want to check with another source, I have gotten solid advice on the Holly tech line.

Air bleeds don't always act how they are supposed to. What exactly are you trying to fix (symptoms), and how do you know there is a problem (plugs, wideband, dyno, etc.)?

I'm trying to fix a fuel mixture problem. All checking has been with plug readings. At first it was very lean with stock 88 jets but worst at wot. With 98 jets now, wot is pretty good but cruise is rich. The bleeds are cheap and easy to try. Maybe, I won't go all the way to .025 on the first try.