i have a 6-port 13b engine from an 86 SE that i want to put a carb on.

what kind of manifold/carb setup is good to use?
cheap please, thats the whole point.

can i fit a stock manifold and nikki carb from a 12a?
i know the holes will be off since the 12a is 4-port,
but presuming there is adequate coverage, i dont care how bad the airflow is as long as it runs.
just a fun project.

can i use the stock lower intake manifold and do something custom for the upper part to mate to a carb?
(something cheap i mean. hahaha)

when going from the EFI setup to carb, i will have no computer running the ignition. i have a friend who is willing to donate the dizzy from his 85 GSL-SE (early 13b). will this work? would a 12a distributor work as well? can i use the stock 13b ignition coil setup or should i use whatever coils were on the GSL-SE the distributor is coming from. do 12a's have the same ignition setup as the early 13b? (could i use coils from a 12a)

is there any other concern when switching from EFI to carb? hmm stepping down the fuel pressure perhaps?
would that be accomplished by the carb or what? i know the stock nikki has a return line, so im figuring it has some sort of pressure regulator.

oh yeah.. heres a good one. the injector bungs...
the two in the manifold i may be able to ignore since i might be using a different manifold, but the two in the block i must do something with. tap the holes and stick in a threaded plug?

the oil injectors are bye-bye as well, but since ive already done that before i know what to do.
this engine has everything removed. no emmisions, no extraneous coolant lines, not even to the heater core.
no vacuum spider, no solenoids...
just intake and exhaust air and coolant hoses to the radiator.

what is the sissiest material you can make an intake manifold from? could you use regular exhaust pipes?
could you use high temp plastic? (perhaps just for the upper intake, since the exhaust manifold is right under the lower intake part. but with proper heat shielding...)

good grief. that was a book. thanks for your patience,
i appreciate all helpful information, but please...
no opinions on whether fuel injection is better than carb. i dont care.

 

Racing beat upper manifold for use on the lower stock manifold. DCOE type carb will bolt up to it. Will need a fuel pressure regulator. 81-85 12A dizzy. I'm not sure if the GSL-SE will work. I actually didn't know it had one. When you've bought everything to switch to a carb you would have spent less money buying a used Haltech E6K(I think thats the one). With the newer E11 coming out I'm hoping more used ones will be for sale.

 

Atkins rotary and MazdaTrix also have a setup.
You will have to use distributor form a G1.
Have fun man it is a fun setup once you have it tuned. It give you the feeling of the old Detroit steel

 

thanks fir the info. i always thought it had the electronic ignition system as well, but my friend swears up and down its got a distributor. we figured that a distributor from a 13b would have to be better matched than a distributor from a 12a.

Quote:

Originally posted by FPrep2ndGenRX7
When you've bought everything to switch to a carb you would have spent less money buying a used Haltech E6K(I think thats the one). With the newer E11 coming out I'm hoping more used ones will be for sale.

now didnt i just get done saying i dont care?
it would be REALLY cheap just to leave the stock computer in there, but then i kinda wanted something different for a change. since i never had a carbed engine before i thought i would try one on.
but again.. thanks for looking out for me. i appreciate the concern. i am indeed hoping the E6k's get cheaper with the release of the E11, since that is what my other rx-7 will be getting... eventually... maybe.

p.s. what is DCOE?
dual camber overhead evaporators? hahaha
i know nothing about carbs.
i will look at mazdatrix ... thanks again

 

Its a type of carb. Weber 48 DCOE is the desired one if you get a side draft carb. Its what I have on my car. An IDA is a down draft carb and very popular also. Check out the link in my sig to see a picture of the carb I'm talking about.

 

All first gens cars run a distributor, including the GSL-SE. the 79s (and I think the 80s) use points ignition (really old school).

 

whats the deal with side-draft / down-draft?
is it just a fitment/cosmetic issue, or is there some reason why one is better?

 

Ignition systems are pretty much all compatible. In my '74 REPU I run an '86 13b, electronic ignition dizzy and coils from an '83 12a, and a 48mm Weber side draft carb.

Side draft carbs lay sideways across the engine. The intake ports go straight out the side. Down draft is mounted vertically. you can look straight down into the intake from above.
If you look at this web page http://www.mazdarepu.com/board/viewt...?FID=1&TID=250 the third picture down is my truck with the hood held up by a wooden stick. If you look closely you can barely make out the carb laying across the top of the engine. Down lower there is a pic of a downdraft with 2 intake horns sticking straight up.

 

Oh yeah, and to plug the injector holes in the block Racing Beat sells a plug kit for like $12. I have it in my truck and it is very good quality.

 

That's funny!

Weber's an Italian company, so whatever it stands for, it's probably in Italian.

 

you're kiddin me?!?!?!
italian for real? wow. i did not know that.
i woulda figured it was american.

thanks. that is great to hear.

 

those are some bad-*** pickup trucks =)