[chuckies76ta]

Need a little help verifying air bleeds please.
Quickfuel carb 1050 3 circuit, QFT-FX-4710.



My understanding is that it's always idle air bleed is the outer most bleed then next to that, essentially in the middle is the intermediate bleed and then closest to the vent tube is the high Speed air bleed. Is this correct? Thanks

[Tom Vaught]

Originally Posted by chuckies76ta

Need a little help verifying air bleeds please.
Quickfuel carb 1050 3 circuit, QFT-FX-4710.



My understanding is that it's always idle air bleed is the outer most bleed then next to that, essentially in the middle is the intermediate bleed and then closest to the vent tube is the high Speed air bleed. Is this correct? Thanks

That is correct: Outside to Inside: Idle, Intermediate, then High Speed.

What orifice sizes are you reading for those three positions?
Front of carb and rear of carb.

Tom V.

[chuckies76ta]

Thanks Tom: I appreciate your help. Now whats odd is literature says: Idle air bleeds # 47, Intermediate bleeds # 85 and High speed bleeds #38.

What I have is : Idle air bleeds #36, Intermediate bleeds # 85, and High speed bleeds # 31. Seems the air bleeds are same as the 4700 2 circuit carb.. This is a brand new carb this season. Front and rear of carb are the same sizes.

Maybe that's why this carb likes to idle and run kinda rich. I had a call into holly tech, but they seem busy at the moment.

[PAUL K]

Holley tech is hard to get a hold of. .038 seems large for the HSAB. Are you sure it's not .033?

.036 seems a bit small for the idle. Atleast the intermediate sounds about right.

[steve25]

I always thought that the 3 circuit carbs where not preferred for drag race usage?

[chuckies76ta]

Originally Posted by steve25

I always thought that the 3 circuit carbs where not preferred for drag race usage?

Thanks Steve.

I have read the same thing, but at the start of the season I could not find a 2 circuit anywhere. They had this Quickfuel 1050 at local supplier so I grabbed it.

[chuckies76ta]

Originally Posted by PAUL K

Holley tech is hard to get a hold of. .038 seems large for the HSAB. Are you sure it's not .033?

.036 seems a bit small for the idle. At least the intermediate sounds about right.

Thanks Paul. On my carb the HSAB are #31.

I'm gonna try get ahold of Tech today, see If I can get through. Our WOT is around 12.5 to 12.9. Not so worried about that side of it. I'm a little more concerned with the idle air bleeds.

[chuckies76ta]

Just got of the phone with Tech at Holly and said to try a little higher Idle air bleed like 40 or 41. He wasn't sure why they are different from spec sheet. Said leave rest alone if it's working good at WOT. May have been changed somewhere at some point. Anyhow, Thanks for the replies guys.

[Tom Vaught]

I have seen quite a few at 42 but I would try the recommended 40 and then 41 first.

Tom V.

[chuckies76ta]

Good to know. Thanks Tom

[Vengeance Race Engines]

You may find it will need to be bigger on the idle bleed. Application specific of course, but 46's are my starting point in any dominator I build, and are often left there. The idle bleeds directly effect required throttle opening and mixture screw adjustment which will aslo be a big factor in how fat it is. It's all relative and one change will not usually fix rich conditions. Hi speeds are usually 28-32. Tune for power, NOT a generalized AFR reading.

[chuckies76ta]

Ok Thank you. Have some bleeds on the way. Could only get the 45. Summit didn’t have 46 or 47. Gonna start with the 40 and work my way up see how it goes.

Thanks again

[Vengeance Race Engines]

Originally Posted by chuckies76ta

Ok Thank you. Have some bleeds on the way. Could only get the 45. Summit didn’t have 46 or 47. Gonna start with the 40 and work my way up see how it goes.

Thanks again

Air bleeds, unlike jets, do not respond very well with minimal changes. .002" in an air bleed will usually convince most people it had no effect. Just something to keep in mind. Pay close attention to throttle blade opening at idle. The bigger you go, the more you can back off the idle screws. I say screws because you should be adjusting both front and rear evenly. Optimally the right air bleeds will have you using less than 2 turns on each screw, also allowing the mixture screws to be within 1 1/2 turns. I am also a fan of a power valve in the front only. Hope this helps.

[Tom Vaught]

Originally Posted by Vengeance Race Engines

Air bleeds, unlike jets, do not respond very well with minimal changes. .002" in an air bleed will usually convince most people it had no effect. Just something to keep in mind.

I will not contradict a Holley Tech Rep's suggestions in a post, but as I stated I think it will need additional air bleed diameter.

Proper Air Bleed selection is based off of learning what your engine application
wants, not what others run.

Tom V.

[Vengeance Race Engines]

Originally Posted by Tom Vaught

I will not contradict a Holley Tech Rep's suggestions in a post, but as I stated I think it will need additional air bleed diameter.

Proper Air Bleed selection is based off of learning what your engine application
wants, not what others run.

Tom V.

Most usually don't when they don't have enough experience to be able to make those decisions. No offense, of course.

[chuckies76ta]

I Thank you guys for taking the time to post information. I understand how these carbs work and also no offence taking here. I just needed some confirmation as to where it should be it relation to sizes.. I have no idea why the bleeds are changed from factory spec, except maybe someone messed with them. Looking back now when I purchased this unit some of the packaging was missing. I was a little to gullible and excited when I bought it and realized it the other day when I was checking it. Oh well, live and learn. Move forward. Thanks again.

[Tom Vaught]

My comment was not directed at you at all.
Same for Vengeance Race Engines.

Every Holley tuner/ "advisor" has to begin some place.
The Holley phone guys, have to start someplace on their learning curve too.
I learn every day and I have been doing carbs for a while. Since the early 1960s.

Tom V.

[chuckies76ta]

Yes, I realize that Tom. All good here. Just grateful for the help.