hotimport18

i recently bought a rb holley intake for my 84 gsl ive been looking at carbs on ebay an im confused about what options i need....they have mech or vac secondary's ? ....manual or electric choke? can anyone explain what i should be using...thanks

trochoid

iTrader: (6)

RB mods stock Holley carbs to work on a rotary. If you don't know how to do those mods, buy one from them.

jim_chung

iTrader: (2)

Trochoid,

You know I revere your wisdom and knowledge but I don't think you're helping the guy's confusion.

I think he wants to go with a stock carb in which case better off with vacuum secondaries that open depending on the vaccum signal or load on the engine and mechanical choke since all Fb have the in cabin choke lever and cable ready to connect.

We know that RB is supposed to modify their carbs to make them run better on the Rx7 but I wonder if that's more about marketing. I had one of their modified Dell'ortos and I think the only true mod was the accelerator pump gasket being thicker than stock and drilling more holes in the emulsion tubes. I currently run a stock Holley and have zero issues with driveability or economy.

trochoid

iTrader: (6)

Well, if that's the case, I have a 600 cfm vacuun secondaries and a 650 DP with manual choke that I will be more than happy to get rid of. Both carbs need jetted and a few parts to conect the throttle cable. I'll sell either one for 125+ shipping and the new owner wil be on thier own when it comes time for intall and tuning.

jim_chung

iTrader: (2)

Don't you think that 600 cfm might be too large for what I assume is (original poster's) stock Fb? The RB Holley is rated at 465 cfm and even that is a little large I believe (for stock porting).

fcdrifter13

I had a 650cfm Thunder Series(lol) edelbrick on my old car and all It wanted was more, the motor was stock port and stock everything else. But it seems like everytime i use a quadrajet based carb I have to use a larger CFM on identical motors.

t_g_farrell

iTrader: (1)

The dellortos also came with the MOP nipples mounted in the carb. It worked out of the box on stock engines as sold from RB. If you tried an off the shelf Dellorto DHLA ( or weber DCOE) you would be spending a lot of time jetting it, drilling the emulsion tubes, adding the MOP nipples (or going to premix).

RB did similiar things for the Holleys. Jets, MOP nipples, float changes etc.

The big thing is that these things work out of the box when bolted onto a stock engine from RB. If he tries to take a stock Holley 465 CFM carb and slap it on his manifold it will not "just work" and I expect that is his confusion.

speedturn

iTrader: (1)

"RB mods stock Holley carbs to work on a rotary. If you don't know how to do those mods, buy one from them."

I agree with trochoid completely. Plunking any old Holley down on a rotary will not run smoothly until it has been modified to suit the way a rotary behaves. I am not trying to dis you Hotimport18, but it doesn't sound like you have the skills or experience to do the carb mods yourself, so you will be much happier in the long run if you pay the money to Racing Beat and buy a carb that is guaranteed to run right on your rotary.

Siraniko

iTrader: (13)

Actually, RB came with 2 styles of dellorto carbs: 12-A and 6port. IIRC, the 6port dellorto didnt come with MOP nipples on the carb since the ports are located in teh block and intake manifold.

t_g_farrell

iTrader: (1)

Yeah, I was ***-uming 12a but he has an 84. Good call.

Midwest 7's

iTrader: (4)

should have got a 2 barrel.

teddyrx2

iTrader: (33)

Guys, back in the day i was running the 600 vacume secondary with no problems then moved up to the 650 vacume secondary on a 12a. now im running a 13b with the 600 vacume secondary with no problems. Tunning a carb on a 12a or a 13b is no big deal just takes some time. If you your going to run 475 from RB you minus well save the money and stay stock, it would be a waste of time and a waste of time.

Buy a 600 vacume secondary or 650 Double Pumper from Jegs re-man for about 200-245 bucks and go at it.

teddyrx2

iTrader: (33)

Why a 2 barrel

hotimport18

thanks for all ur opinions guys !

Midwest 7's

iTrader: (4)

because they are simple and make awesome power.
im talking weber, delorto, mikuni.

nopiston_racer

iTrader: (2)

im running a holley 600cfm 4brl right now on my stock ported 12a. the carb was rebuilt for rotary use but im still having issues tuning the carb for the car. its giving me a rough time starting b/c its always flooding, and once im running i have constant flames out of the tail pipe and just yesterday i had a flame come out of the carb. im still tuning the carb but i cant seem to get it to stop pushing so much fuel. also when i mash the gas the car will bog out so u have to ease the gas to accelerate and once im at around 4k rpm the car losses its acceleration. just giving him a little heads up that a larger carb can cause issues with the running and starting of the 12a if ur still running stock ports.

jim_chung

iTrader: (2)

Finally, someone who understands that bigger is not always better!

I'm running the CarTech draw through turbo system on my 12a at 6 psi boost and its only using a 380 cfm Holley.

teddyrx2

iTrader: (33)

Bigger is not always better but I have never heard of a shop building a re-building a carb for a rotary. There is just no way, dunno. But what ever to each his own

hotimport18

holley makes a 4bbl 450 i think im going to go with that

Midwest 7's

iTrader: (4)

racing beat use to do special work on the dellortos.
drilled the imulsion tube and a special thick accelerator pump gasket, as well as the omp inlets that any modded carb has.
i dont know if anything special was done to the mikunis, some company modded them as well, cant remember the name. thats why most every mikuni you see has those cut up ram tubes to fit in their tiny air cleaner.

josh...just josh

what exactly is done to the holley to make them rotary worthy? I know that the use some different type of float bowl to keep it from starving under cornering but what else?

sgieldon

Stock Port Specs
steve