hi everyones !

i plan to buy Weber IDA 48 mm carburator for my

89 rx-7 fc, non-turbo, stock

eh, what do i need to buy to get that carb fit on my car

( intake manifold, air filter,... )

also only one carb on the fc ?

( need to buy only one weber carb ? )

thanks !!

can anyone list all the piece that are required .

 

I don know for certain if they come with a filter, but you will need an intake manifold. You can either keep your stock lower intake manifold and get a new upper manifold or you can get a completely new manifold that replaces the lower manifold.
And you only need one carb.

Why do you want to do this? You wont really get any more power, cold starts will be much more of a pain, and you will get worse fuel economy. The only real advantage would be less crap under the hood.

 

The down-draft IDA will need a whole new intake manifold. Remove all of the other crap related to polluntion control, get an air-cleaner and throttle linkage, and put a decent exhaust onto it, and you will be VERY impressed with the extra power.
You may not be impressed with the ordinary low rev, low load drivability and lousy cold starting.

 

I have a webered 2nd gen 13b 6port in my 79 1st gen. I'd probably beg to differ with Tom93r1 in that I feel it gives good power. The side draft conversions use the 6port lower inlet manifold, but the downdraft conversion is most common (here at least) with a single aftermarket inlet manifold. Mine has the carb fuel fitting on the engine side of the carb. Out of the box, and ida is just bare, with trumpets and cruddy choice of chokes and jetting. Try and find a complete 2nd hand or at worst a new kit. The inlet manifold should have a fitting for a brake booster vacuum hose, just make sure.
The installs we see here in Aust usually have the 6port actuators wired into open position.
IDA's are easily overpowered so a fuel presure regulator set for 4.5psi is a must. Ideally run the stock fuel return line. I use a K&N filter and have the charcoal canister and crank vent breathing into it's base (for legal reasons). The induction noise is also higher. Most people ditch the metering pump connecting rod and just use a cable tie to hold the pump part open full time - I feel this contributes to some fouling at cold idle probs, but a little throttle foot attention when warming up can overcome this.
Like both above said, cold starting sucks as there is not a choke function. But at wide open throttle, they are great.

 

This is a great mod for older FI cars where most of the components need to be replaced. The simplicity is silly and the power is great. The healthier your motor is the more efficiant the carb will be. You have to remember that with the carb everything is dependent on vacume. This will help a ton with the difficult cold start. You will need a low pressure fuel pump, pressure reg. carb, manifold, linkage, air filter, heat shield and airbox will help performance. I love mine, good luck.
John

 

Oops, I was thinking side draft when I mentioned intake manifolds.

Does anybody have any dyno numbers that can show there was any difference in power between FI and carb setups? I know the carb sounds alot faster, it sure has a loud growl at WOT. Performance I dont know, my problem could be that I still have a cheap restrictive exhaust.

As far as cold starting goes though, it is better than I would expect for not having a choke. Just turn on key, pump 5-6 times then crank with no throttle. Fires up right away but have to keep idle high for a couple minutes until things start to warm a bit. Not too bad but nowhere as convenient as FI.

 

I have several IDA's. For the OMP, heres what I did. I took the bracket (from a broken OMP), where the rod connects to the OMP. Modified a regular flat washer to fit the carb's shaft. Finally, tig welded the modified bracket to the flat washer. Used a welding rod to instead of the original OMP rod. For the carb, I drilled a pilot hole in the fuel bowl. Shorted stock carb's OMP inlet fitting and used JB weld to secure it. Modified the OMP lines.

Otherwise, you can leave the OMP fully opened except the engine will occasionally smoke due to excessive oil.

 

What would be the benifits of using the IDA carbs(TB's) and manifold over using the side-draft carbs(TB's) and manifold.
I know that for the street the sidedraft allows you to use the 6th ports, what would be the differences in power?

 

My thoughts:

pretty much, the 48mm IDA is the ultimate in carby fed induction for your 12a/13b. It is a racing carb that will give poor driveability on the street but rewarding results for the racer in all of us.
i guess you just have to weigh up what is more important for what you want.
Driveability, or a tough rotor that chews juice and revs hard!!

 

it is very interresting. Yea i agree that Weber carb are great. i want to get one. thanks for all your helpfull comments.

 

IDA's are great. I'm suprised a lot of people say they've had trouble cold starting them as mine always started right up. The only thing I ever had trouble with was hot starting due to heat soak but that was solved by putting in some phenolic spacers.

 

I have an IDA on my REPU that i drive every day and i dont have any truoble starting in the mornings. 1 or 2 pumps while turning over and she fires every time. It starts faster than it did befor with the stock carb. I would totally recomend it over the complicated FI system that the FC's had. It will make your whole engine much simpler to work on and diagnose problems, it will also add a tuning aspect. What i cant figure out is, If you look at all the high HP NA stuff wheather ti be 4 cyl. 8 cyl etc. the big high dollar guys a lot of the time will use individual TBI injection. The spoon honda guys is it and make a lot of HP. The IDA is as close to this as you will get without having to dump all the cash into the ECU, fuel rail injectors etc. Yes its a carb, but it flows almost identical to a 2 barrell TBI. Once again i am totally sold and i could tell a pretty big difference in pwr.

CJG

 

When I mean't cold starting problems, I meant as in from a dead cold engine in the cold... like approaching sub freezing temps, and keeping it idling without fouling was the trouble, not getting it to kick.

 

Oh ok, Sorry i didnt know thats what you were referring to when you meant "cold starting" I was just referring to the engine startability at ambient temp. I live in the pacific NW, temps here in the mornings are usualy in the 40's. Running hot plugs should ade the cold start problem, try the 3rd gen plugs in the 7 heat range, should be either BUR7EQ or BER7EQ cant remember, that should keep them from fouling so easy.

CJG