black82gsl

iTrader: (3)

Ok, got my header with the race beat intake and the 465 carburetor on mt stock port 12A and from what I read its suppose to make a considerable power difference?
It doesn't even seem to be any better than my stock setup! I was wondering what jets are suppose to be in there and what the recommended a/f ratios are for that carb. Like maybe what jets come in it from race beat? It seems to have a noticeable difference on bottom end power ,but seems weak in the top? What could the problem be? The fuel pump is plenty and is set right so fuel isn't the issue. I bought the carb used and had to take it to our local hot rod shop to even get the carb to run right on my car so I don't know if some one had dicked with it in the past or what? Another thing is is the a way to be sure that this is an actual race beat carb and not just a normal v-8 4 barrel? One more thing the guy said there were these little "O" rings on the float bowl adjustment deal(i know dick about carbs) and he said there not suppose to be there so he took them off? What was that and is it suppose to be on there for this carb?

trochoid

iTrader: (6)

What fuel pump and pressure regulator do you have? My understanding is RB grinds the numbers off of the jets they put in their carbs, so the only way to tell for sure is to buy a jet gauge from McMaster-Karr. Then find someone who has a true RB carb that will measure their jets. EB did very specific mods to their carbs, I have het to find a thread where all of them are listed in the same place and I doubt that anyone knows the full extent of all of the mods.

Unfortunately there are a lor of psuedo RB carbs out there for sale that people have bought, tried to to mod and failed. They then end up sellig them claiming they are RB modded carbs. Since the engine runs ok ar low rpm but fals flat at the upper rpms, change the fuel filter.

RX-7 Chris

iTrader: (19)

My RB carb did not have the jet numbers grinded off, FYI.

Post up some pics of the carb and I might be able to tell. they have custom brackets for the throdle and oil metering.


That is what a new RB 465 looks like.

The problem is not enough fuel for the secondaries. It will be the Fuel pump like trochoid said if you have not changed it out. You need to be at 6 psi and the stock pump goes to 3 or 4 psi. if you do have a new pump then it could be the either something is clogged in the secondary curcut or the vacuum secondaries are not opening.

Has the carb been rebuilt?

DivinDriver

iTrader: (15)

A true RB carb should have added barbs for the OMP connection (Would be on the far side of that photo), and linkage points for the OMP linkage, right?

That doesn't mean it wasn't fooled with after leaving RB, though.

Super82

iTrader: (1)

Yeah make sure your fuel system is up to spec. You've gotta get about 6 psi and use a different, high flow fuel filter. As mentioned, the RB will have linkages for OMP.

FWIW, I have a RB 465 setup. I haven't installed it yet, it is sitting in a box in my garage. I plan on installing it after I get a few runs down the track with my new exhaust on. Then I'll report my results. I'm using a holley red fuel pump, and a fram G-12 filter. No regulator, but the holley red is set at 7psi and can be ran used with a holley without a regulator.

RX-7 Chris

iTrader: (19)

Here are some good links for you:
http://www.holley.com/data/TechServi...ech%20Info.pdf
http://www.holley.com/data/TechServi...Carburetor.pdf
http://www.holley.com/data/TechServi...ded%20View.pdf

The first link will really help you to understand a holley carb.

craigcorx7

I have the Rb 465 Holley and Rb header on my 12A with stock porting.As an example of jetting,Rb put .470 jets in mine (I live at 6200 ft.)and the car seemed a little lackluster.I installed .500 jets.My car ran much better.It would pull hills in a higher gear than before and accel.much better.Oh,and I did put a better fuel pump and filter on.I believe those #'s are correct.I did not change the secondaries.

RX-7 Chris

iTrader: (19)

The SP carb comes with 50 jets. I ended up keeping the 50s and going up on the AP jets. My car had a dead spot at full throdle.

With the 465 (and most 4160 carbs) you can not change out secondary jets because they are built into the metering plate. But you can get an upgraded metering plate that allows you to have changable jets. Also you can get a quick change secondary spring kit so you can change when the secondaries are opening.

Before you get into all of this, I would start with making sure everything is working the way it is.

RXnos1200

iTrader: (24)

"The fuel pump is plenty and is set right so fuel isn't the issue."

What fuel pump and at what psi? good help and info in the previous posts ^^^^

Have you checked the float adjustment on both bowls yet? Just remove the site screws on the side of the floats and make sure it's good.

black82gsl

iTrader: (3)

bowls are perfect,had them done by a hot rod shop guy I know.
Have the summit brand fuel pump wich delivers 95gph at 7 psi and the holley regulator.
Carb is set right at 6 lbs and has all new lines and filters.
Also have the secondaries ran mechanically.
It does have the linkage for the omp.
Heres some pics of the carb,
I noticed every ones carb I see has a downward fuel inlet and mines straight out?
All the ones I see look different than mine? Is mine maybe just an old *** one?
Heres some pics

black82gsl

iTrader: (3)

Wait a minute speaking of mechanical secondaries.......The reason we did that was because the vacuum was only enough to pull the secondaries not even half way open and no gas would come out. I wonder if its to weak for my vacuum advance? That would explain the lack of top end power? In my car 60-85 was probably were it pulled the hardest in third gear and now it sucks but it will light the tires up much easier than before of a dig. I think I need to get a vacuum gauge on this beotch and see what its pulling. What should it be around?

RXnos1200

iTrader: (24)

I don't think my secondary diaphram had a vaccum outlet on my carb. I'll have to check my old pictures.

RX-7 Chris

iTrader: (19)

That is an older holley carb. It does look like a RB carb though. The fuel inlet must have been changed at some point. The angled one can be removed and replaced with the one you have.

A vacuum secondary holley carb can't really be changed over to mecanical secondaries. It will never work right. If the secondaries were not opening all the way then you could have put a lighter spring in. Also how do you know they are not opening? It will only under a load.

black82gsl

iTrader: (3)

They do work mechanically you can see the little nut and bolt on the linkage that makes them open. The car was really weak until we did that. I don't know about under a load but I could rev it way up and they would maybe open 1/4 way. Some one said I need that vacuum canister to keep enough vacuum?

RX-7 Chris

iTrader: (19)

You don't unless you have a large BP or PP. A vacuum canister would just be for your power brakes, etc.

black82gsl

iTrader: (3)

well I have the brakes and the vacuum advance ran of the same vacuum port on the intake,was thinkin maybe the brakes were taking a lot of the vacuum away since its like a 3/8 line and the advance is only 1/8? I have a 3/8 npt "T" with a 3/8 barb out one side for the brakes and a reducer with a 1/8 barb one the other which is then ran to the vacuum advance.

RX-7 Chris

iTrader: (19)

The advance should go to the vacuum port on the meadering block.

the problem you are having with the vacuum advance not working could be a torn ot misaligned diaphram. Have you opened the vacuum advance up?

black82gsl

iTrader: (3)

whats the metering block? no haven't opened it. so theres two dealio's on the dizzy are they both the same thing cause I have them both ran together with a "T".

RX-7 Chris

iTrader: (19)

the metering block is the piece that the main fuel bowl is atached to with the idle adjustments on it. it has one vacuum port on it. the two dealio's (vacuum advance diaphrams) one is for leading and one is for trailing. RP recoments that you just run the leading one.

black82gsl

iTrader: (3)

wich one is the leading one? one closer to the drivers side or passenger side?

84stock

iTrader: (5)

Running mech secondaries on a vac advance holley is just plain wrong. Your primary accel pump cannot provide enough for that. If you want them too open sooner buy a spring kit, and you'll never them open by reving and looking down them, there has to be a load. Trust me, I have ran more 4bbls on my 13b than you can imagine. I do plan on wiring something (don't know what yet) to my vac secondaries so I can get a read out of when they open. Usually if the vac sec don't open there is a reason. Do you have an open plenum spacer between the intake and carb?? Any vac leaks?

black82gsl

iTrader: (3)

no spacer and no leaks.whats the differance if they open mechanically or if theres a vaucuum thing that opens them as long as it opens? all the vacuum does is pull it open just like the vacuum would,but a lot better? I no carb guru but it seems like its the same deal as long as they open?

RX-7 Chris

iTrader: (19)

Drivers

The problem is a mechanical carb and a vacuum carb are completely different on holleys. it will never run right set up mechanically. A vacuum carb will open only when it needs to be open if it is working right. if they are not opening at all then something is not working or setup right.

If you need the spring setup, this is what it is:
http://store.summitracing.com/partde...5&autoview=sku
http://store.summitracing.com/partde...5&autoview=sku

I would still open it up and see if the diaphram is working and not ripped.

black82gsl

iTrader: (3)

It doesn't hold the vacuum I think it must be ripped. But now I think my apex seals went on my rear rotor the front has 225psi and the rear has 0. I am picking up a new motor today at noon. I don't the carb would have to do with a rotor going would it? When I rev it and look down the carb it would spray gas into the secondaries. Will it hurt the motor? The only thing I could think of being bad would be maybe they open and the fuels not there yet and it leans it out to much?

RX-7 Chris

iTrader: (19)

I don't thing the carb would do it. It was probably just a tired motor. The rear rotor seems to almost always be the one to go on these cars.