Later in the year I want to get my little 12A Street-port and better carb. I am leaning towards the Holley mostly Because my dad knows alot of people who can tune it and parts are cheaper. The thing is Racing Beat has a 465 Holley but is it possible to get a bigger one or no?

 

yeah and for a lot cheaper,

1.By the correct 12a racingbeat intake mani from racing beat or mazdatrix, or find it here ont he forum or ebay.
2. Buy the carb through jegs as remanufactured carb. you can run any size carb you want, but for a stock application i would run a 600 or 650 vacume secondary carb!!! Tunning is the key without that your lost. And just because your dad knows a lot of people who can tune holley carbs doesn't make them an expert in the field of tunning a carb on a rotary. Keep that in mind

i have ran the 600 vacume secondary, 650 vacume secondary, 750 double pumpers. tunning the carb does not take a genius. So to answer your questions save your self the money and buy smartly not needlessly.

 

Holy cow, that's WAY too big! From everything I've read stock ports don't like anything above 500 CFM. You can run a 600 on a streetport, but you'll have to do some mods. 650s are only suitable for boost or bridgeports. My cousin tried an Edelbrock 750 on a supercharged streetported RX-4, and it was just too huge and ran poorly. He put an off-the-shelf Edelbrock 600 on it and it was great.

Some people think that bigger is better, but that is simply not the case. If you run a carb that's too big, you'll kill your intake charge velocity, resulting in bogging and reduced power.

The other thing is, the Racing Beat carbs are not the same as the ones from Jeg's! They have been modified to work better on a rotary, with things like center-pivot floats (can't remember all the things they do off the top of my head). The RB Holley 465 CFM carbs work fantastically, and I wouldn't recommend anything else for stock ports if you simply must go with Holley. Sterling carbs are still by far the best carbs there are for stockport rotaries, though.

 

Agreed. Even if you managed to get your engine to 100%VE all the time (which is impossible by the way) you wouldn't even be able to max out 465cfm worth of flow. The only reason 600s or 650s are run on Bridgeports, even though the engine's displacement doesn't change and VE still isn't 100%, is because people tend to build and run those engines at higher RPMs and for applications other than on the street.

If you're dead set on a Holley, it's RB Holley 465 or nothing. If you do something else, I'd be willing to bet that in the not too distant future your dad's friends will end up frustrated trying to tune it and you'll be back here at some point complaining about how your car sucks and wanting to drop in a v8 or something stupid like that.

I've got the RB Technical Manual/Catalog at home, I'll find out for you what they say they do to the carbs. They don't reveal everything, but I know they do make quite a few changes, some for convenience, some for reliability and some for driveability. OMP linkage attachment and barbs for the tubes is one mod they do that Jeg's carbs won't have, so you'd have to run premix. Centre floats were mentioned but you can get those seperately for most Holleys... and a few other things I can't remember off the top of my head.

If you're wondering what I'm talking about when I say "Volumetric Efficiency" or VE, read this thread from top to bottom, lots of great info there:

https://www.rx7club.com/showthread.p...ric+Efficiency

Jon