1150 dominator Questions
 

I currently have the 1150 off of my motor going through it,and have some questions,as all my experiance comes from mechanical fuel injection.

Sometime during this carb's life the throttle plates have been drilled with a .125 drill bit,(all 4 blades,side closest to each 's respective metering block) the secondary side has since been plugged with a small bolt and nut.
What does drilling the blades acomplish,or what is it a quick fix for that could have been taken care of in some other fashion?
The carb,from what I can find online came from the factory with 95 jets squared,no powervalves.I ended up the end of last year with a 4.5 powervalve in the primary side with 88 jets (i do run a vacuume guage in the car,at idle it makes 5 inches of vac,in gear.),and 98's in the secondary side with no powervalve,trying to clean the idle up.
It's soaking in mineral spirits overnight,but can anyone shed any light on things I need to look for when I begain reassembling it tommorrow?

Also,someone has drilled and tapped an 1/8th inch pipe plug behind the powervalve well,into the area that the linkage resides,but has no plugs in it.This area should be sealed by the gaskets shouldnt it?Why the holes,and no plugs?


WHat a great site.
Thanks for your time.
Bob

Re: 1150 dominator Questions
 

Pictures of what I am trying to describe

the throttle blades,I have removed the bolt and nuts while cleaning

http://i166.photobucket.com/albums/u...lbertyjr/4.jpg

the holes behind the powervalves are my major concern,why they are drilled and tapped but had no plugs in them,so should I quit worrying about them and run it,or plug them?

http://i166.photobucket.com/albums/u...lbertyjr/3.jpg

http://i166.photobucket.com/albums/u...ertyjr/5-1.jpg

http://i166.photobucket.com/albums/u...ertyjr/6-1.jpg

Re: 1150 dominator Questions
 

The holes in the throttle blades are to fix an idle problem. On a race motor you shouldn't need them.

1150 don't come with power valves. I would block it off & jet it 95 or 96 square & see where you are .

The hole was probably drilled so the power valve could transfer fuel.

Not a carb expert, but this is what I think Lou

Re: 1150 dominator Questions
 

Some 1150 Dominators DO come with power valves. ...The 80556 is one. ......Some builders use them to keep the car more drivable when enriching the idle circuit on a throttle stop carb.......The idle holes in the blades look a little big,but unless you cannot set the idle down to an acceptable speed leave them alone. ....If the idle cannot be set with them open ,replace the blades ,Dont plug them with a screw!....the screw will disturb the air flow past the booster,not to mention the concequences of one falling out! .....Replacement blades are available from many sources and are easy to replace. ....My newest carb I'm running uses a PV in the Pri side with a 10 # spread from pri to sec. on the jets. ...I have not run it on the track yet ,BUT it is absolutly the most responsive 1150 I've ever had! ..I'll find out how good it is in a couple of weeks at Atco. .......Tom ...............One last thought,unlike constant flow fuel injection,where the answers are usually universal, if you ask 5 people how to set up your carb ,chances are you'll get 5 different answers!

Re: 1150 dominator Questions
 

This carb is a 7320,box stock calls for 95's squared,no powervalves.

I left the plugs out of the throttle body,(behind the power valve plugs)left the bolts and nuts that were in the secondary blades on the bench,sqaured the jetting at 98 (it's all i had on hand to make it square) I will get the 95's before I go out,and plugged both sides instead of power valves.

Started it tonight and got it warm,ended up with the A/F mixture adjustments out 1.5 turns each ( 4 corner ),which gave me the highest vacuume reading at 5 inches.

The throttle blades are pretty tight as I can not get a .004 feeler guage between the blades and the walls of the throttle body,which leads me to believe it is breathing through the .125 holes in the blades.

The idle varies from 1400 to 1100.To elaborate,if you whack it,after it comes down it is high,give it a few minutes and it drops,but it doesnt just come down clean,but idles pretty good once it does get down.

Thank you for your input,it still isnt perfect,but I do feel like I am closer than I was last year.

Re: 1150 dominator Questions
 

Bob, If you go on the Holley web site you can find a chart that lists the factory air bleeds for your carb.....I'd check to see if they have been changed in size ,especially the hi speed........ With all the other mods to the carb it's possible they have been changed as well. ...... Changes to the air bleeds can have a huge effect on jet selection.....The specific gravity of the fuel you're running will also dictate where you should go with the jetting. ....generally the higher the specific gravity the leaner you go with the jetting,but we're talking only 1 or 2 jet sizes .......Stay on the fat side to start ,better to look like a diesel on your first passes,than hurt a piston.......Tom

Re: 1150 dominator Questions
 

More questions about the same carburator,

It is an older 7320 without adjustable air bleeds, I bought new throttle blades from Chuck Nuyten, but they didnt want to discuss the carb because it is "only a two circuit"

My questions, if it idles through the pits, and is wide open against a chip on the tranzbrake, why would there be any need in an intermediate circuit?

Also, box stock jetting is 95 sqared, I currently have 100 squared in it, and it wants more. What are your opinions about putting power valves in the carb (the motor only pulls 4.5" at idle) say 8.5's so that they are always open, and lowering the main jets so I can get back some adjustability out of it as 100 jets are the biggest I own,or can you buy 100+ jet sizes, all I have found is the alky jets up around 130, and read somewhere that the alky jets were a different thread pitch? Or have I got something screwed up to need someting so far away from the factory jetting? I am running Sunoco 110 gasoline (110 octane) at 7.5 lbs of fuel pressure.

I set the throttle blades with a feeler guage to get them the same, then adjust front and rear idle speed screws the same, to keep it squared, and the four corner air fuel needles I keep sqared, all the way in then out about 1 1/2 rounds is where they are now for the highest vacume reading.

Re: 1150 dominator Questions
 

Bob,Check the size of the main circuit air bleeds, they should be .028". ....If they are larger, it will lean the carb. ........Also,you havn't said much about the engine....The relativly low octane fuel you are using brings up the question of the engine being over carburated...........If the engine /cam head combination does not produce enough air flow at the booster,the resulting poor signal will not pull adaquate fuel thru the booster. .....I've usually found this to be the case when jetting changes are 3-5 jet sizes above stock,and the car still shows lean. ..........Tom

Re: 1150 dominator Questions
 

Thanks for the reply Tom,

The motor belongs to my sponsor, and it was bought 3rd person, It was all new, we did pull the pan looked at the bearings etc... but we only know what we were told about it. I will dissasemble it this winter to check, but what we have been told about it and the person is a reliable source, he has nice pieces.,before they freshened it he has using it for a nitrous streetcar shootout deal

477 big block chevrolet

10.2 compression,

Comp Cams http://www.compcams.com/Cam_Specs/Ca...?csid=551&sb=2.

Edelbrock heads http://www.edelbrock.com/automotive_...erf_rpm1.shtml

I didnt get the cam card till last week, had been setting the valves at .028, have since re-set them at the specs Comp calls for,.022 .024, made no differance in e.t.

Ignition is an MSD 6al,2 step,blaster coil,msd magnetic pick-up distributor at 36 degrees,(locked), running autolight 3935 gapped at .035

Staging it on a 4800 chip, shifts at 2.75 seconds into the run which is 6800, goes through the lights (1/4) at 7400, powerglide trans 1.76 low, 4.88 rear gear pulling 14x32's car weighs 3250 with me in it, runs 10.30's to 10.20's depending on the weather.

Personaly,I think the motor is lazy,it's consistant,but doesnt have the hit I think it should have say if you tried to do a chirp. Maybe Im just remebering my small block.

I will bring my guage pins home tommorrow from work and check the air bleeds.

Re: 1150 dominator Questions
 

That carb is too big for the motor specs you list and that is why it is lazy.....A 10-1 477 that runs 10.30 will go faster with a smaller carb. A 1050 would be about the maximum carb I would try to use on that engine/car combo.

Re: 1150 dominator Questions
 

I'd try an 850 on that motor. .Not enough compression,or rpm to justify anything larger. .........Probably would work if it was still on nitrous,but way to big without it...........Like Rich said ,It'll probably pick up a bunch of ET with a smaller carb..........Tom

Re: 1150 dominator Questions
 

How about on a 10 3/4 to one 540 with .714, .714 cam etc? Is the 1150 to big? That's what I'm using.
4000 lb pickup, pump gas, 10.72 @ 122 best.

Re: 1150 dominator Questions
 

Floyd, I'd bet your short times ,probably up to the 660' would pick up considerably. ......I've seen guys use way to big a carb and have success,but I've also seen many who struggled with the problem Bob is having. .....Bottom line is you have to try different carbs to see which is best for your combo..........A while back,.I tried a 1050 on our S/ST AMC Spirit which has a very healthy 401 in it. 13 TO 1, big roller ,ect .....It picked up about 1 mph ,but lost over 2 tenths in ET! , compared to a good 850 carb. ......Tom

Re: 1150 dominator Questions
 

Tom, the price was right on the 1150. A buddy of mine had it and wasn't using it, so there you be. I can borrow a 1050 and try it. Jet it the same 94 sq and see if there is any difference.
Thanks,

Re: 1150 dominator Questions
 

Tom, OT, I just got one of them F.A.S.T. air fuel ratio recorders, their instructions leave a little to be desired. Do you know how to adjust the carburetor to get the desired numbers? What are the desired numbers?

Re: 1150 dominator Questions
 

A/f meters are great at showing you where the ratio is in relation to the car on the track. ....BUT correcting the fuel curve can be tricky. ...Most of the real experts I've talked to recommend 12.2 to 1 as a safe a/fr to shoot for ,but the car may want to lean out more as you progress down the track,and some cars work better with a much richer ratio at the starting line...........Jetting ,air bleeds and ignition timing all come into play. ...That why its best to establish a base line on the dyno before tuning on the track. .......If the a/fr is in a safe area, I'd start by moving the ign timing to see if it is covering any jetting deficencies...........Tom

Re: 1150 dominator Questions
 

Thanks, Tom,
I'm just looking to keep it consistent and try to keep up with the changes in the weather.

Re: 1150 dominator Questions
 

Ok here is the latest.
Tom the air bleeds have been messed with at some point in this carbs life. I only brought a small selection of guage pins home, the largest being a .030, and it will fall in and wiggle, I have a few 1050's to choose from,thank goodness for friends, so we will try it next friday night with less carb. Any particular list number I should look for?
I went ahead for the sake of nothing better to do, and added 7.5 power valves, and pulled the jets back to 95's, and it idles continuouse By that I mean the rythem prior to today would change as it idled, meaning {roll your "R"s} rowd rowd rowd rowd rowd then it would change tone for a few seconds and eventualy go back, now it just sits there with the rowd rowd sound never fluctuating, it ran for 15 minutes just now.And didnt build heat over 175.
I will get the 1050's on it and see what it changes. Thanks for all your help.

Re: 1150 dominator Questions
 

A 9375 is a good 1050 to look for and try.....They run well and jetting should be 92's as a baseline. Anywhere from 88 to 94 is a normal jetting range on those. Holley's generally do the Holley "gurggle" and it is pretty normal.....If it holds a steady rpm without sinking it is ok....If it loses rpm after it runs a while and goes back up after you rev it a few times...it's too rich...fixing that is not always just a matter of an adjustment.......Too big a carb or cam or both often slows a car down......

Re: 1150 dominator Questions
 

Got my meter put on this morning, it is way fat, 9.8 idle. Gonna drop back to 92's and then wait to make a pass at Phoenix next Thursday and go from there.

Re: 1150 dominator Questions
 

Well my changes did not work. Luckily one of my friends with a 1050 showed up. It happened to be a 9375 too. Bolted it on after the first time trial, and didnt even have to re-set the floats. Put the car back into the 6.50's (1/8th mile) picked up 1 mph, but the differance in throttle response is night and day. I used to have to realy get after the pedal to do the burnout, but not now,almost overwound it in low,backed off and shifted,let it pull down then got back in the gas in high gear and almost overwound it again. I think I have the 1150 traded off for a 1050,will find out later this week as I have to give the current 9375 back.

Thanks for the help. The car is much happier.

Re: 1150 dominator Questions
 

She is a hotrod again,

Talked with one of the big carb guru's on the phone for a lil while this afternoon, he talked me through this 1050 carb. It was loaned to me, with the option of trading the 1150 I have been running. I made my decisions, and set it up on the bench as a 3 circuit for the time being, put it on the car and she started and idled. Gained one and a half inches of manifold vacuume over the 1150. I added a round on each of the fuel / air screws from my bench setting for my highest reading ( out 2.5 turns each). I set the throttle blades at .020 t-slots showing prior to installation, and never changed them, also did not drill the blades. She idles at 1400 rpm clean. Goes against the chip clean, free revs clean, The exhaust note is so different my teenage daughter Sami came out to see what I had changed, and the neighbors eyes sure got large when she black tracked down the driveway. We will see how she runs friday night here in Tulsa, before heading to Sallisaw on saturday.

Thanks everyone.

Re: 1150 dominator Questions
 

What's the difference between 9375 and 8896?

Re: 1150 dominator Questions
 

479 :)

Re: 1150 dominator Questions
 

Ya got me on that one.
Now, what is the difference in the carburetors?

Re: 1150 dominator Questions
 

The metering setup used by Holley. And the HP versions are different from the older style as well. Different bleed sizes, different # of emulsion holes. The best out of the box was the old style 9375, less emulsion, smaller MAB's, open intermediate bleeds. Newer ones can be made better....

Re: 1150 dominator Questions
 

Thank you. I'm picking one up today to try out. I don't know which number it is yet. Dave Lang of Fuel Curve West built it and he say's it's a good one.

Re: 1150 dominator Questions
 

It's an early 9375. Dave told me to run it just like it is with 88's square. The change jets if needed.

Re: 1150 dominator Questions
 

You guys need to be talking to David Cook at DC Carbs in Texas... that boy has done 3 dominators for me over the years for 3 different classes... these carburetors were perfect out of the box... he has also taken another 1150 that I bought from a well known "CARB GURU" and made it much better... try him out... and his pricing will not kill you either... the number I get him at is 281-300-8637... you won't be sorry