off the shelf carb info needed.

[warwickben]

yes i posted this in the frist gen section to try to get the most out of this.


hey guys i just have a few simple question.
iam hoping sterling and jeff20b would be willing to chime in to.

i tried writing this post 4 times and kept starting over.

iam gonna be making my own tubular intake, and i want some info on carbs.
i know sterling is the man when it comes to moding the stock carb's. but in a heated post what i got from it, he believes a turbo setup on his carbs destroys the work he puts in to them making them better plus all the turbo prep that is needed.that and if i do go turbo i could get carb hats ect ect cheaper for off the shelf carbs.

so i deiced id go with a off the self carb from x brand. my best friend works with a few people that can get me all most any carb at a good deal which is a plus.

my question's are these.

what cfm carb should i go with for a na 12a?
what type of carb/brand would you guys say i should go with.
can i use the same carb down the road if i ever go turbo? since people have gone turbo with a stock carb i believe the answer is yes.
what do i need to do to the carb for it to work for a rotary?
where should the omp lines go,would i be able to tap a few holes in the intake for the omp lines(do they go to the stock intake on a 80 12a? feel dumb about this one)

what else do i need to know?

[PercentSevenC]

For blow-through? 48mm Weber/Dellorto for simplicity of setup. Holleys are another option, and there is some blow-through information available for them (theturboforums.com is a great resource).

For NA? 500 CFM Edelbrock Thunder Series. Getting it to work on a rotary is just a matter of tuning. They have adjustable vacuum secondaries, too, which is pretty awesome. Just be careful that your manifold is tall enough for the carb to clear the water pump housing.

OMP lines can go into the manifold. Jeff20B installed some brass fittings in my LIM for them. If you go turbo, remember to clamp the lines so they won't pop off under boost. You will have to either figure out an OMP lifter rod or wire it open. Or if you prefer, you can always just premix.

Oh, and as far as carb hats go, don't expect to find them any easier with an off-the-shelf carb. On the contrary, it's easy to find Nikki carb hats: just go to Robert! I couldn't find any carb hats for Webers or Holleys at all when I looked (well, I did find one Weber one, but the inlet was in the wrong orientation). It's all custom, it seems. Robert will make you any carb hat you want, but his Nikki hats are the cheapest, IIRC. I settled on making my own due to lack of fundage.

[warwickben]

if i dont make my own intake would the racing beat intake be a bad idea would it work with that carb?
iam really a carb noob, would i have to run lines since its has vacuum secondaries. or is that all ready setup on the carb it self.
the rb intake all ready has a vac line for breaks id all so have to tap for timing advance and the omp lines correct?

[PercentSevenC]

The Racing Beat intake works fine with Edelbrocks if you use a spacer (I forget the required thickness, it's either 3/4" or 1"). The vacuum secondaries take their vacuum signal from the carb itself. No need to tap for vacuum advance, just tee it off the brake booster hose. You will need fittings for OMP lines, though, since the Racing Beat intake is meant to be used with Racing Beat's modified Holleys, which have the OMP lines going directly into the float bowls.

[warwickben]

i was thinking of ways of saving cost instead of the full kit from rb. would i have to worry if the oil is not going in to the carb?

why do alot of people bash there full carb setup ?

[FC Zach]

When you do decide on which carb you are going to use and are still interested in a carb hat let me know. I ran a K&N plenum on my RB Holley, didnt use it long at all, and then decided to go with a regular style filter. I also have the little fitting for the OMP line to go into the fuel bowl if you decide to go that route, I didnt need it since I pre mix.

[orion84gsl]

i was thinking of ways of saving cost instead of the full kit from rb. would i have to worry if the oil is not going in to the carb?

why do alot of people bash there full carb setup ?

You will need the OMP hooked up properly and running unless you decide to use premix. The OMP delivers oil into the combustion chamber to lubricate the seals that the oil can't get to through the regular oiling system. Your engine will die a quick painful death without that.

Alot of people bash the RB holley because it's a Holley. It is not designed to run on a rotary engine. It's modified to but isn't meant to.

[PercentSevenC]

Yeah, I can't say I'm a fan of Holleys. If you're going to go with an off-the-shelf 4-barrel, Edelbrock is a better choice, IMO. However, Edelbrocks are trickier to boost prep and there's not as much information available on that subject for them, so Holley is probably a better choice for blow-through. But even then I'd rather have a boost-prepped Sterling Nikki or a 48 IDA/IDF.

[warwickben]

do you have to have the oil going in to the carb or can i tap lines on the intake mani?

i wish there was a easy way to supercharge the 12a so i dont wast the money on the header i bought.

[PercentSevenC]

You have to get oil into the engine somehow. Whether through premix, fittings in the manifold or the carb's float bowls, it doesn't really matter very much.

There is an easy way to supercharge a 12A. Just buy one of Atkins' kits. It's not especially cheap, but then again neither is a turbo. It doesn't end up being all that much more expensive, really, especially if you already have a nice NA exhaust. But you are limited on power.

[warwickben]

i was leanin to the atkins'/camden super charger. today i went to a old school car show/ drag race. man it made me want to sell my car as a shell re build the motor put a blower on it and put it in a rat rod truck.

iam not that dumb i new you had to get oil in the motor some how wasnt sur eif it would be ok to just tap some lines on the intake ect.

[FC Zach]

It all basically depends on which setup you decide to run, but yeah you could simply just tee into the rotor housing injector lines. IMO it would be best to run the lines into the primary fuel bowl so that the oil atomizes and covers a larger area rather than from the center of the housing and on.

[FC Zach]

Just a curious question to those who critisize the Holley carbs saying they're not well suited for the rotary engine because it a Holley:

-Does an unmodified Edelbrock function properly without modifications?

-Or, if Holleys arent the best candidate then why arent more people running them? Or most importantly, why isnt RB marketing them??

I dont mean to come off as some kind of asshole, these are just some serious questions that I've had on my mind for a while. I've been running the Holley kit for a while now with no problems. Just was curious as to why there were ill feelings torward Holley carbs. I understand for the most part its personal preference but was your decision based on experience or was it just from someone elses failed attempt. I realy am curious cause I'd like to know if I wasted money on a glorified Holley when I could have just bought an "Off the shelf Edelbrock".

[PercentSevenC]

It all basically depends on which setup you decide to run, but yeah you could simply just tee into the rotor housing injector lines. IMO it would be best to run the lines into the primary fuel bowl so that the oil atomizes and covers a larger area rather than from the center of the housing and on.
He doesn't have oil injectors in his rotor housings. That's an '84+ 13B thing. Stock carbed rotaries have nipples on the carb for the oil lines that feed into the primary barrels.

I only have my personal observations with regard to Holley vs. Edelbrock, no numbers or anything to back them up. Just based on what I've seen, Edelbrock seems to be the better carb, or at least, the easier one to get right. I drove Jeff20B's supercharged FB, for example, which has an unmodified 600 CFM Edelbrock Performer Series, and I was very impressed. The idle, the cruise, the power delivery, were all very smooth and it had good power. Not to say that Holleys couldn't probably be tuned that well, but I do know that Jeff didn't have to do much to that carb to get it to run very nicely. Fact is, though, I'd rather have a Sterling Nikki than either of them.

To the OP: By the way, I forgot to mention OER as another option for blow-through. They're a pretty cool carb based on the Weber DCOE with some nifty improvements and factory boost-prepping. Though after having to remove and install my DCOE a few times with the RB wraparound manifold, I'm not sure I'd buy another sidedraft. The bottom nuts are a pain to get to. :P

[FC Zach]

I think im gonna give an Edelbrock a shot, I have a friend that messes with nothin but Edelbrock carbs so im pretty sure he'll let me use one for demonstration purposes. I'll update you guys on my results. Is there anything I should look out for after bolting it on, or is it simply just plug and play?

[warwickben]

i found a place to buy o.e.r
(http://www.zccjdm.com/catalog.php/azcarbum/dt43196/pd858216/O_E_R_Sidedraft_Carburetors_-__SPECIAL_PRICING_)
rob from rotary shack sell's the mani for around 200$ i think.

[PercentSevenC]

The main thing for Edelbrocks is to space it up high enough to clear the water pump housing. After that, it's just a matter of tuning, IIRC.

[warwickben]

what would i have to do to the o.e.r to make it run right on my car. what size would be good ect.

[PercentSevenC]

I'd get the 47mm. Making it run right is a matter of tuning.

[warwickben]

yeah figured that much. i was told with a 2-barrel its harder to tune for street is this true.

[PercentSevenC]

To some extent. There's a lot more you can do to tune them, so there's more to screw up, and they're usually not set very close to how we need them at the factory. Expect to buy at least one set of everything, and probably a couple sets of jets and air correctors before you get it right. Invest in a decent fuel pressure gauge and a narrowband at the very least, wideband of course being preferable.