89gmcs15

iTrader: (7)

I had mine in my bleeds for a season.. theyre still fine. If anything its a easy way to get the size set you need then put brass ones in for something under fuel?

ZONES89RS

iTrader: (25)

I was going to drill mine as needed and leave it, just step up a bit at a time, but that's because it's rich, a lean setup wouldn't work so well. Lol

Pop N Wood

iTrader: (1)

The problem with that is bleeds have a press in brass part to size the restriction. If you try to drill it larger the bit can catch the press in and pull it out. One guy on the web said he used a drywall screw to remove his restictors.

Pop N Wood

iTrader: (1)

Interesting. Might have to try those.

Drilling the brass ones is a lot easier if you chuck the set screw in a variable speed drill and set it to rotate slowly then hold the bit stationary in a pin vice. You have much better control over the pressure that way, the brass drills pretty easy.

ZONES89RS

iTrader: (25)

I was going to step up in size slowly enough to barely remove any material at a time. Not to say it wouldn't pull out anyway, but removing allot will usually catch.

89gmcs15

iTrader: (7)

I actually drilled and tapped a 1" shaft for the 10/32 screw and chucked the brass in the lathe and then used the tailstock bit to drill them. Still was a pain. Brass was better but I bought 500 nylon ones for like 5$.

krochus

iTrader: (1)

I think in gonna order a quick fuel slayer 750 tonight.


I could see the easily drill able plastic set screws being handy for figuring out how to start fairly close when ordering screw in bleeds

krochus

iTrader: (1)

UPDATE:

even though the carb is still slightly rich fuel economy is VASTLY improved. Before I was barely getting 12 today I filled and then refilled after making my 60mile round trip commute not hypermiling but not driving like a hoon and I got 16mpg out if this loop.

It's nice not watching the gas gauge drop like it's been drinking popov.

ZONES89RS

iTrader: (25)

I just filled up and went to the track after jetting down primary from 72 to 67 and 78 rear to 76. The. Stepped down the idle to get 14.5ish but after starting again it didn't want to fuel and I had to get it to 13.5. Driving has gotten allot better, but I still can tell when I'm in the low speed circuits off idle, before it cracks to use the primary jets, it's still rich, but not in the 11.0-11.3 like it was. So next step is using the wires from my new brush. Not sure how any to use but I may just see what 2 does.

The track trip and tuning will go against the mileage but it was 12ish before.

krochus

iTrader: (1)

Got the quick fuel in today and slapped her on.

Seems like it's gonna be a pretty good carb. Out of the box the AF ratios are pretty good. I think it needs to loose the power valve though as it goes pig rich at any throttle that causes much of a vacuum drop.

Also the idle mixture screws are hypersensitive and my wideband seems to fluctuate a great deal even cruising steady.

Bigger idle air bleeds perhaps?

89gmcs15

iTrader: (7)

I wouldnt ditch the power valve unless your going drag only. Theres replaceable bleeds in the powervalve that can adjust how much fuel it adds when it opens. Make sure its not the acc pump adding too much fuel with throttle changes tho

TXsilverado

iTrader: (18)

sounds like my quick fuel. I know that no 2 combos are the same, but all i heard was how close quick fuel is out of the box. i'm now 4 jet sizes over on primary and 7 jet sizes up on the rear of my quick fuel 850. 80 and 91. my idle mixture screws are also HYPER sensitive. a **** hair one way or another can mean a full point.5 of afr change.

if i lean up the idle to 14.5ish, it goes EXTREME lean 20+AFR at very light cruise, then richens up to 14.0 if i give it a little more throttle. i richened it up to 13.2ish idle and it cruises good now. a couple rich spots at light cruise but i'm getting tired of smelling it. WOT is dead on around 12.8-13.0.

i hope that watching your thread will help me learn to fine tune mine. keep the updates coming.

krochus

iTrader: (1)

I just got back from a quick "test n tune" (gotta love living in the country) and losing the powervalve just like with the Holley was a good move. The float level was also a little high so that got adjusted down too.

It cruises out real real well now. With part throttle AFRs staying well above 13.5 the whole time accelerating normally as in traffic up till the mains start to come on then it leans out further into the low 15range.

It's no longer going pig rich if I dig into the throttle a bit now. Sans powervalve it hovers around ideal up till I really dig in towards 1/2 throttle then it leans out a bit up towards 16. This however isn't an especial concern to me as if you're like me anything past 1/4 throttle is merely on the way to WOT anyhow!!

Speaking of WOT there's even more WIN! I'm up a total of 17 jet sizes over the 670 Holley and it's slightly leaner now than before around 13 screaming pretty hard. That's gotta mean that motor is sucking down enough extra air to make use if that much more jet! And that my friends are how little baby horsepowers are made

krochus

iTrader: (1)

Folks keep saying this but I've done away with the powervalve on two carbs now in about as many days and in each case the results were only positive.

Yes technically I can tune the amount of fuel it adds, but that amount would be pretty darn small Since getting rid of the thing completely has been getting me pretty close to ideal.

krochus

iTrader: (1)

A little carb ****

krochus

iTrader: (1)

After a few days with the quick fuel it looks like two things need to happen.

1 I need a bigger accelerator pump shot as I have a slight bog on the bottom in conjunction with rapid throttle change

2 and I'm not sure how best to address this (bleed or ifr) I'd like to take a little fuel from the idle low speed circuit. I'm slightly rich under the main jets and the idle mixture screws are super sensitive and closed pretty far.

krochus

iTrader: (1)

I went ahead and drilled the idle bleeds out to .077 from .070 this brought the part throttle a/f ratios into the mid 15's which is good yet surprisingly the mixture screws remain hyper sensitive and are out less than 1/2 a turn.

I also closed the secondary baseline slightly opening and compensated slightly on the primary. This was very productive in restoring chrispness to the throttle response. The tip in stumble was also reduced as a result.

I think I can now look into adding the powervalve back but it only needs a FRACTION of the fuel the factory .055" restrictions are providing

speedtigger

iTrader: (16)

This is pretty typical for a 4 corner idle carburetor on a small block.

I is very surprising to me that you can get anywhere near the WOT A/F ratio you need and still get clean part throttle A/F ratio with the power valve block.

What is your WOT A/F ratio? And, what jets do you have in the front and rear?

krochus

iTrader: (1)

72-82 jets (factory)

WOT AF starts mid 11's and cleans up to 13 or so at extreme high rpm.


With the power valve it was <11 at all rpm @wot and at any throttle that caused the PV to open the AF would shoot straight to pig rich and the car would fall on its face

The kicker with the mixture screws is this is just a two corner carb

speedtigger

iTrader: (16)

You have got a lot of strange things going on there for sure.