what's the best aftermarket carb setup?
 

Guys I'm thinking of going with a RB modified 465 holley for stockports. Its 533 bucks, but it sounds like RB knows what they are doing. Anyway, Does anyone have that setup that can tell me how it runs? I already have the RB manifold with a badly tuned carter carb on it. Runs slow eats gas BAD.
How does the RB holley run? Revs high, fast better HP? I want to put the best setup I can on there. Anyone think I can spend 533 or less for an even better setup?



BTW I already have a RB exhaust, so bad exhaust flow isnt slowing me down.

Stock Ports?????
 

If your porting is stock, then you are not likely to see enough horspower gain to justify what you are doing, in my opinion. No doubt someone here will disagree, of course. A Dellorto will give you all the power you can get with stock ports, and certainly better fuel mileage than a Holley. You can probably find one on here for $300 or so.

http://www.gruntled.com/Dellorto/

If you are just driving on the street, and want something that is smooth and reliable, take a look at my post here, post number 10:

https://www.rx7club.com/1st-generation-specific-1979-1985-18/help-needed-do-you-know-what-kind-carb-463299/

i have a holley not rb modified and it makes a noticable difference, holleys are very street able (more low end torq) i have no complaints, i just need to tune mine

Anyone else have an opinion?

Holleys are great unless you like to turn left.

Not an opinion, but a very important question to help you get better advice...

What is the intended use of your RX-7? drag, auto-x, road-race, street, mixed, what? This will make answering this question a little easier for the experts on here... I assume street, but please clarify.


Cheers,
-Bern

Best carb setup for an FB?

Hands down, a pair of carburetors from an EX500 with 105~115 mains (depending on enviroment and mods) or 120~125's if ported. A good machine shop can build you a Y like the one in the link below for about $45, the carbs you can get for $20~50, $100 factory pro kit, 4" of radiator tubing at about $.90 an inch, 4 hose clamps at about $.25 and piece, and some RTV sealent at about $3 a tube...you'll end up with a carburetor assembly superior to a more traditional webber setup that you can completely dial in during your 30 minute lunch break (I'd like to see a reletive noob do that with a nikki, holly, webber, dellortowhatever, or mikuni auto setup) at an actual fraction of the cost. What can be better?

http://www.twowheeledpassion.com/cvk2.JPG

I built that Y to mate a set of eX carbs with 120 mains to my 2.6l MKI Supra. As soon as I can get hold of an FB lower intake manifold I'm going to build a similar aparatus to mate the same carbs to it.

WTF!

What is an ex500? Bike?

I must know as much as I can about this.

Yes, Kawasaki EX 500. I choose these for my projects because the EN454, 500 Vulcan, and E500 have been produced in such mass numbers for nearly 2 decades that you can find the carbs for about a dime a dozen...you can get excellent shape carbs for $20 shipped if you look in the right places.

I would stay away from other I-Twin bikes, though...Suzuki's GS 500 and yamaha's several I-Twins have all used smaller carburetors.

all in all...you'll have a hard time finding ANYTHING better than motorcycle carburetors...and you absolutely will not find anything simpler and easy to work on.

interesting!

Instead of a "Y" pipe, why not just run them straight to the intake ports, almost like a peripheral port?

When I can get around to tinkering with FB and FC manifolds I will most likely do just that. The y pipe is really not a great solution for my problem with the toyota, but it was the most effective way to place them. I had to use a cressida carburetor manifold and then the y-pipe. I was trying at first to arrange individual throttle bodies, then merge an I4 setup to the I6 engine, then the I4 carbs to the cressida mani, but each one had clearance issues. The BIGGEST issue is with the distributor...you can't see it, but the distributor is almost right under the carburetors and right dead nut in front of the #1 intake port...plus this car has it's cooling system routed through the intake manifold and that added a whole other complication.

With the RX7 I can't see any reason why it can't be setup to run one carb per rotor. The make-shift mani that I've made to bolt up to my 13B LIM simply has two runners, one off the forward ports and one off the rearward ports, and I think it will work quite nicely.

get a sterling (modified nikki)!!!

-cheap (about $350),
-flows around 450 cfm
-you can go around corners
-streetable

i plan to get one in the future, so i've done quite a bit of research on em

yea right, try getting a sterling....I've been waiting over 8 month and still "not ready" or "almost ready to ship".

Thanks for all the help guys. To answer one question, I have a street setup. I want my car to be quick, but I dont plan on racing it just yet. That moto carb idea sounds cool. Anyone else have experience with a minuki, holley weber etc. that they could contribute. Can you compare the carbs?

carbs
 

Had quite a few setups and never had problems with any of them. lately i have being running 36 DCD webbers and love them. Got a holley set up, (RB), that I keep around just to change from time to time. Ran Holley before and the only problems come in the cold weather. :allcho:

I've had many Holley's and they are really tuogh to tune right! I had a weber 48 ida from racing beat but I guess racing beat doesnt do much to these carbs as far as modifications go, they basically are the middlemen and just sell these carbs. Mikuni set up so far seems to be the best choice for my large/wild (ito) street port 12a.

You get the basic on the 48. 51's are supposed to be modified.

holley's are not hard to tune.... unless you DONT get a double pumper. get a 600cfm double pumper (4150 model) and just jet it down to your specs. done. no "modifications" neccessary.

I'll second that. Years ago (1959!!!!) I bought a Sprite and put a Judson supercharger that made it into a REAL car. But the holley carb crapped out on hard righthanders, so I fabbed an adapter and installed a carb from a Hardly Abelson 74 that I found in the trash barrel at the MC shop, and that thing was great! It just worked! Solid brass, balsawood float and all.

B

Are you saying that a 600 double pumper will make a (NA) stock or street port motor run hard??

The best carb is the once that you can sell for the most money so you can buy a sweet TWM throttle body, 2 TII injectors (or bigger if needed), a fuel rail, and a Megasquirt to control it. O ya, you'll need an EFI fuel pump and regulator. And some common GM sensors.

Seriously though, if you are set on a carb setup go with a Weber DCOE. They are the most versatile and best looking/sounding. Once you learn how to tune it you'll love it.

I run a DCOE 48 on my 12a stockport with RB streetport exhaust and direct-fire ignition. It needs some tweaking (just got the car recently and it was never tuned right) which I will do soon. Still I am very happy with the performance. I will be switching over to the EFI setup that I described earlier in my post before next spring.

only thing that sux about the twm throttlebodies is they only use 2 injectors... so later if you go turbo or even big port and you need more fuel, you have to run TWO large injectors which can create problems in tuning. but if you do plan to keep it how it is... then i agree.

wackyracer: you can use a 600cfm DP on both a stock port and streetport, turbo 12a, turbo 13b, whatever you like. a very versatile carb.

Dont know about the turbo set up but with N/A and streetport, that carb is just way too big. It will run but there is a difference between "work" and "works well".

BTW: This thread is about carbs, not F/I or T/B. ;)

any experience with these and boost?