picked up a 80688 holley 1050 to try

As long as I am n/a while I test the trans I want as much hp as it can make as is.While I was at summit store I could not stop myself but I just went for a new trans cooler.This carb looks like it will do nice with my
446
Victor head 340 cfm at .630
Victor intake
10/1 cr
112 lsa 109 ICL .260 at .050 roller
I got the trans cooler in so I hope to be driving soon.[video to fallow]
Holly carb
ps: I would use my 850 but it is a bit small I think and 17 yrs old,never cleaned

Are you foot braking or using a trans brake? That is a 3 circuit carb. like most racers use for a trans brake car
I would try it first no matter what your doing and go from there
It will probably work well

The carb is 2 circuit gen 3 version as in the link.No trans brake 5k stall 9" 3.73 28" tire.I may only get out 2 times to the track so the rest will be street driving.

Your correct, I looked again and it only has two sets of replaceable bleeds per barrel

No big deal.I made sure it was a 2 circuit and I am selling my 1250 3 circuit[s]that I have on the blower and will get another 1050 or use my 850's when the blower goes back on.

I have to admit. That sounds like a pretty decent carb for a really great price. Lots of nice features. It's about time someone started cutting racers some slack. Good luck with the new bling.

Smokin price and hopefully easy to tune in...........If I can help in any way hit me up...........

Thank you for helping so many.I got the car running after all winter on the 850 I know works good and now going to the 1050.The new trans cooler and fan are in also. idle video old carb

The carb had a anti corrosion liquid in it so I used the acc lever to pump it out2 squirts and the rest came out after I filled the bowls with fuel and started it.This was 3 pumps and 2 cranks almost not throttle given so I know it is rich confirmed by the exh o2 at 12.4 a/f.The floats are at 3/4 so later I will lower them to 1/2 per instructions.I had to seal the new trans temp fitting with ptfe paste. 1050 ootb idle
ps: the idle air bleed is 57 I may go to a 70 like on the 1250's I had on the blower.

This thing must be pulling on the acc squirters.The fuel % goes up as I push on the throttle in neutral in the garage and steady pt throttle/rpm a/f is stable at rich down to 10/1 a/f with 12/1 at just past the idle circuit.I blocked the power valve to start then put smaller jets in to be sure it was none of those 2.I have some tube squirters to put in.The float is at 3/4 so I still need to lower that.

LOL I just realized I didn't tighten the jets I put in.

Shouldn't affect idle quality but those idle bleeds could come up accordingly and of course based on the ifr sizing........I start at around a .067-.068 idles and .026-.028 on highs w/ .040 ifr's...........

Thank you.My idle is doing ok 15/1 at cold start and richer as heat gets in.I need to lean the hs air bleed from the 32 in it to maybe 40 to start and see how it goes.Just to be clear it gets rich as rpm and throttle opens
ps: the jets were tight I checked.
ps:Even if I get it to lean out the avg will still be too rich.[thinking hard on this 1]

I could really use some ideas on what to check!
Power valve gasket even though it is plugged w/blank.
Metering plate machine marks leaking past gasket?
Wrong gasket but came with carb?
I can't block the pump squirter by myself and see the o2 gauge while it is running.Thanks for the help

I am hoping for the keep it simple that it is just the floats and will check this in an hour.

You will think hard while correcting a Dominator. 4150's are cake compared to doms. 40 is too much in the hi speed. wouldn't go more that 32 from what i have seen. Sounds like your T-slots need jetting down and idle airs need leaning out. Mixture screw play into the mix as well. I finally gave up and sent mine to Dom. Dom can get ya straight on that.

keep the float level down too. it can throw you off too. no higher than half way up the glass.

My experience has been that "most of the time" rich part throttle operation when using a 4500 carb can be noticably improved by reducing the size of the t-slot feed hole in the main body.

That's where I'd start.

I also prefer to use a PV on the primary side......... Like a 6.5.

Thanks I will look into that.I need jets to adjust so I will have to get some.The float helped just a little but it still went to 10/1 air fuel by 1/3 throttle.

check this out
https://www.tapatalk.com/groups/racingfuelsystems/transfer-slot-restrictor-picture-t1392.html#p13086

i would add a t-slot restrictor and see how it acts. also, I wouldn't put a 40 hi spd bleed in it.

I looked at the specs...... I think the stock jetting is likely pretty close.

I'd start with t-slot restrictors....... Something like .065 to start, and idle air bleeds about the same.
Maybe knock the primary jets down one or two sizes.

I have 47/51/55/61/70 air bleeds

I put a 47 in and it only helped 1/2 pt to 10.5 air fuel from 10.0

I put a 70 in and got 11/0.The main jet is 84 from factory.What is this telling us?
ps:I put 80 jets in and got 11.4 a/f

Early non-HP style 4500 carb where the only tunable part are the main jets.
This is a 3 circuit 1050 #9375.
I added a "high flow" metering block, which is nothing more than a block with a provision for a PV. The stock blocks have none.

Typical fat and blubbery part throttle operation for this style of carb was corrected by installing transfer slot restrictors.
I usually install changeable air bleeds in these old carbs, but on this one I left them alone.

This carb has very nice part throttle manners now.
Maybe not perfect for a lot if street duty, but vastly improved from how it was from Holley.

That help some.just fyi this is my carb.

I don't have a pin set to check the jet size

You could try the wire trick in the t-slot feeds to see how much affect it has.

Not a professional but i would use a 55 t slot jet, 70 iab 28 mab with float set mid way or slighy less and adjust screws to flavor. Usually 1 to 2 turns. Just my 2cents

Thanks for the t slot jet info and so I need to go bigger or smaller with my rich fuel mix?I see I need to reduce the tslot jet.

is that a set screw in the transfer slot feed or is it just a brass plug?

i put 8-32 set screws in a 4150 body and it looks similar...



But yeah, i would do the wire trick Fast68 just mentioned, quickest easiest way to test that change...

I will put all jets back to factory accept the pv and try the tslot in my next step.

set screw

I do have some set screws that I will check for the correct thread size and maybe I can drill them,I have a lot of pin drills
ps:Will I need to do both pri,sec side of the carb?

Do you have a 1/16" drill bit?

Is the T-slot restrictor bigger or smaller than that?

I will have to check and may take some time.I have to find my pin drill bits

IMO you wont get that cleaned up without the t slot restrictors. Mine ran way cleaner with t slots in the mid 50's. Those t slot orifices are way big. I just could not nail the tune down the way i wanted it, so off it went to Dom@Thumpercarbs.

Start with just the pri side to make sure it's having the affect you're hoping for.

Yes on the t-slot restrictors so here's my tune.......

.040 IFR'S lowered
.068-.070 idle bleeds
.026-.028 hi bleeds
.055 t-slots and .082-.088 jetting

You need a vacuum gauge to check for the best power valve and one that comes in as you crowd the throttle while cruising at a steady state speed........too high, rich too soon, too low delayed enrichment..........

Cool thanks!!

Thank you!!

Call me if u need help............

You want smaller on the t slot. If you dont have pin gauges, get some off ebay. You need to pin gauge the pvcrs as well.

I put you in my contacts,see how this goes.

my .075 slops around a little in the hole and the jets are press in it looks like

Drill and remove those then the holes are USUALLY sized for an 8-32 tap..........

TY!I had a holley tech on line and it was like pulling teeth.I did not get it solved on a press in part # I wanted to see if I could get.

looks like a nice carb for the coin...almost makes me want to pull the EFI off...

Say it ain't so.............

Has anyone pressed in a lead plug and drilled it?

I may have the tap 8-32 and I will get a drill bit just bigger than the hole in the brass jet.I figure I need the carb off for this.

I heard some have but best to drill n tap that way you can make changes easier and it's cleaner...........

I just got the drill and tap plus the drill to remove the press in jet.Thanks for the help and I will get back to you in a few days.

You got this...............

I took my time measuring depth and threads[8] on the set screw,drill bit,tap and the 5/16 8-32 screw[0152806] sits flush with the edge.I ordered 100 brass set screws from fasten all[2.65$] that will be in Tuesday and I can drill a few and give it a try.

when drilling brass, be very careful on the bit "break through", as this is the point that will be most prone to drill breakage. a lot depends on the feedrate, and the alloy content of the screw.

Thank you,I drilled and tapped a little holder for the set screws and is what I tested for drilling the carb and this should be stable for doing the set screws.

i chuck the set screws in my handheld drill.
last time i drilled some, i actually just put the drill bit in a regular vise, set screw in the drill, drill in one hand and the other hand spanned the drill and the vise to keep steady...

also, most common i think are 1/8" long screws for IFR's and 1/8" or 3/16" long screws for the t-slot

I may have gone 3/16 but the shoulder[on press in jet] would have made it very deep so 3 threads are shallow and 5 are full contact on the set screw.

I personally use 6-32 in brass and 1/8 in length and 8-32 in the same length then the 10-32's are longer of course..........

I can always put in the shorter.The length of the jet may have some effect but nothing I will notice.

It's more about being too long ESPECIALLY in the ifr's but the emulsion holes should be ok...........

I will make note of that.Ty

nice holder you made for drilling the screws. i forgot to mention that also. a guy can do a lot without needing a mill or lathe, but in my opinion, a drill press is a must.

Nice. I used a cordless drill spun backwards and a pin vice to drill small set screws as well.

I did the same thing myself and also made a guide to hold the tap's straight while tapping the holes, being a machinist has it's perk's.

My 24" drill press will not hold anything under .100" But I had practice when drilling my oil restrictor for the heads with a small drill

tap guides are a great thing to have also, and are easy to make as well. if you don't have one handy, or the tapped hole is at an angle in the piece, here is a simple way to do this.

take a drill that has a shank size that fits your hole to be tapped snugly. put that in the chuck of your press with the flutes in the chuck. [you don't have to tighten the drill as you would when drilling the correct way.] using the backwards drill to position your hole, FIRMLY clamp your work piece to the table of your press so it can't possibly move.

clamp your tap in the drill press chuck. lower the quill to your work. then using both hands, turn the chuck with one hand while applying slight, downward pressure to the feed handle with the other. this will allow you to get some starter threads in your work. after a few revolutions, hold the handle firmly in position. DO NOT allow it to move. using your free hand, loosen the chuck with the key, allowing the tap to stay in the work piece, while allowing the quill to be raised. you can now tap the piece by hand. it will be straight because it was lined up by the hole in the piece and the chuck.

a machinist does have it's "quirks".

yes, we are a quirky bunch

I put in the t slot a 57 from a 80 and no change.This still goes to 10/1 a/f at steady state rpm 3k.Any ideas?
timing 32 locked/checked steady

Driving it or just in neutral?

if when driving.......Put the pv back in and take out a bunch of jet.

Smaller ifr.

Bigger iab.

One thing at a time

Just in neutral.I will take out a bunch of jet next.The richness is progressive if that helps

I wouldn't spend much time tuning a drivability issue..... Without actually driving it.

The main jet was it I went to a 72! pri side is all.

11.9 off idle 12.8 steady state 3k rpm now I think I can drive it and trust it.

I would shoot for, and do 14.5 AFR or leaner at light part throttle cruise below 2700 RPM in high gear
That really helps keep the spark plugs clean
Anything richer than 13.8 AFR or lower at part throttle cruise seems to be more responsive but sometimes the butt dyno can be fooled by sensations

I may as well change the sec jets with a 78 from the 94 in there the way things are going.I am checking things over to drive it in a day or 2.Thanks for the info Cab.

Not to get too far ahead of myself but the emulsion jets[3 top,bot,middle]looked small like in the .020 but are not replaceable?Could this be pulling in the extra fuel?
ps:When I change the jets in the sec side tomorrow I will check the e jets

IF they really are .020 I'd plug the middle and drill/ream #1 and 3 to .026 and go from there...........

I will check them with pin drill bits around lunch time.Should I try to get the main jet back to the 84 in this process?Having to drill the metering plate I don't think I can block any very well.

I will drive the car but not far likely tomorrow and Not change much till then but I want to plan ahead.Thanks for the help all of you.

The e jets are just bigger than .025 top 3,blank,.025.I take it I should just adjust the main jet to get a/f more in line?

how many total emulsion holes? 5 ?
so - .025,.025,.025,blank,.025

yes but not the exact size,The dril bits are miss packaged.The .028 bit is only a .024

On straight banjo 1050's .082-.084 on the primary should be close I would think and .090-.092 has worked on the sec. side w/the pvcr's in the .080 range..........Then there's the t-slots and if they're not exposed at idle then I've been between .065-.070 on idle bleeds and .026-.028 on highs w/.040 ifr's...........It's a damn juggling act for sure..........

I found some old 66 an 70 jets and will put the 70 in pri side n take out the 72 and this should help a/f and be more in line to drive so about the sec,Should I lower those from the 94?I would think so before I drive it?

The 84 is too rich!I am down to a 72 going to a 70 on pri side.

The ifr is a 46[fyi]changeable.

I think Dom puts .040 ifr in just about every dominator. A .040 from a .046 should clean it up.

Thank you!I will have to order some tho.

Fix the emulsion..........2 at .026 till then you will chase your tail.............

A .024 was loose in the hole so I think I am there but I don't have a .026 bit to check
ps:I will keep looking for a .026 and a .040 drill bit and maybe use some e jets fron another metering block to drill and put in the ifr.

Does not work like that cos .002 can make a Hugh difference.........Get the right size bits and know EXACTLY where you r at cos this is not a guessing game............

OK OK!;)I can't get the 40 ifr till next week

Jegs had the ifr jet may be here Saturday so I can keep rolling on this.

You still have to pin every single one to make sure THEY did their job and I find I may ream a few to size every so often..........

Well I checked a lot of things to get to this pointI want to keep making progress.TY.

You are going the extra mile and it will pay off I promise you............

I found my pin drills!The emulsion are all .026
top .026,.026,.026.blank,.026 bottom
ps: so after all that I will set up the tune to yours,

Yes on the t-slot restrictors so here's my tune.......

.040 IFR'S lowered
.068-.070 idle bleeds
.026-.028 hi bleeds
.055 t-slots and .082-.088 jetting

You need a vacuum gauge to check for the best power valve and one that comes in as you crowd the throttle while cruising at a steady state speed........too high, rich too soon, too low delayed enrichment..........

Emulsion #i and #4 at .026 in addiction to the other stuff...........

Are you saying you want me to drill #4 emulsion blank hole to .026?

do your metering blocks have threaded emulsion holes?
if so, put blanks in all spots except #1 and #4. you can also do #1 and #3 though...

What he sad............if they are threaded, plug 2, 3, and 5 if not drill n tap em for 6-32 set screws...........

I plugged mine with a piece of lead shot.

For sure easier than drilling n tappin just not as clean plus a [censored] if you want to play w/different emulsion sizes and locations...........

I want to get going down the road at this point without fouling plugs is all.No mistake I will do more tuning on the metering plate and appreciate your help.

If you go all out on this thing and get it bad ass, not only will you learn how to tune each circuit but you will have a damn near EFI running car and plugs and oil will go many more miles than before GUARANTEED....................

Just to see what it would take I used a small fishing line crimp on sinker,pounded it flat to .090 and cut into slivers with a wood chisel to fit but I didn't try to pound it in.

I got to go around the block and things are looking good with the carb adjustments given so Thank you thumperdart!I have more to do but I can drive it to do so.The a/f was in the 13 to 14.5 but I had a 84 in the sec jet and will put in a 86 and see.

You are welcome and glad I could help ya out.............

I now have 88 pri 91 sec jetting and I am getting ready to put in the power valve and adjust the channel restriction.The car launches ok with a slight spit out the carb after the pump shot burns off and the engine temp was only 130.I will test the pv effect with a test launch and a hotter engine and check the plugs and go for a longer drive above 3k rpm to see the o2.
ps:The sec open at 1/4 throttle so it comes in early.

Bump for my info I need to read.

My question at this point is with t-slot jetting.I put in a .047 pri/sec and now I am fouling plugs.What jet would you go to to get an a/f from 11/1 to the 13/1 range?I was thinking of going to a .040 on all 4 with no pv and sq jetting.I took the air filter off and started having fuel fouled plugs.

I would think under 0.050 t slot would be getting on the too small .
IIRC my 1050 is 0.059 or a hair smaller. This is where I have it now on my 505 , may have been a hair bigger on my 440 . 505 pulls harder on carb . On the 440 it was #82F #98R , on the 505 I only needed to go #100 rear . It has a PV
Have you altered the IFR jetting , I took mine from 0.045 to 0.044 and lowered it . Was noticeable . I also increased to PVCR from 0.070 - 0.073
I do think I need to increase the T slot back a hair for street driving , though it is winter here and I will see how it goes as it warms up .
I am running the 1050SP sportsman aluminium 4500 .
Good luck . Knowing it will never be perfect I am looking for close , 90%

Tex

Thanks for the tips.I have the carb off and making some set screw jets [brass]If I was giving advice on this I would say check the pv gasket.I put on an 850 while I look hard at things,clean,think more of what I am doing.I work slow.

A good O2 system can be a great help dialing in carbs.
Especially pump gas big CFM carbs. like Dominator and 950+ CFM 4150 carbs.
With enough work you can make them motors real tire spinners

I have the o2 on the dash but with sun glare is hard to see sometimes.The o2 helps a lot.
ps here you can see the o2 is hard to see. Test launch a/f

Will your set up store data?
Mime does, Innovate LM1 with the RPM and LC1 add on for dual readings instead of one side only
Push record and read it later on the desk top or have some one watch it in real time with a lap top in the car

I am trying to use the video to record all info but I think it can plug into a laptop.I don't remember to turn on the camera half the time.lol