hi i have a s1 rx7 running a 12a bridgeport and rejetted nikki carb...
i was wanting to fit a ida but the are way to $$$$ for me so i have been looking at idf and 36mm drla etc and a 40drla 48dhla and ive got really lost and unsure what would work on a rotary with to much messing around.. i know ill have to jet it and sort a manifold... i dont care if its side draught or down draft i just wanting to ask whats the next best thing to a ida??? and is 36 idf two small etc etc etc help please

 

45 is the smallest you should be using on a stock port 12a, and even then they say is still restrictive..... so in your case a 48 should be the smallest you use since your bridgeport. IDF is similar to IDA except theres a choke mechanism and the venturies are smaller than the 48 IDA. Best choice would be a 48ida with over bored venturies 43mm maybe, then a 48dco with bored venturies too. If you are patiant and look on the for sale section of the forum you will come across the carb and manny for you. Or better than that is post a thread (want to buy) for your application with a max purchase price and maybe someone who is holding onto one of these prized carbs will sell it to you.

 

Most people don't bore their own venturis.

I'd just get a 48 IDA. A 48 IDF or DRLA would be fine, but the manifolds are pretty rare. A Lake Cities or Atkins style (non-wraparound) sidedraft manifold with a 48 or 50 DCO (or 48 DHLA or 47 OER, etc.) would be pretty sweet, too. Fact is all the carbs I just listed cost the same new (500 USD, except the Dellortos which are NLA). There was also the old dual 36 DCD setup, which apparently worked pretty well, but good luck finding one. I don't know of any other Weber-style carbs that could easily work.

 

I would stay away from DHLA or delloto 48. Weber 48 IDA parts are easy to get

 

i can get 2nd hand 36mm or 40mm idf for $50nz and other side draughts for $100 to $350 but ida is $1100 new zealand $$$ Look up www.trademe.co.nz and have look at what new zealand has to offer its is our ebay..... or go on you tube and put in 1978 rx7 s1 12a. and see my red rx7.... so could i use a pair of 36mm idf? mmanifold is no problem as ill build one to suit. (joys of my job) i cant buy a manifold for any carb for my rx7 as its a 12a 6port bridgeport from a 1985 cosmo.

 

what if i used two 36mm idf ?

 

Ah, you didn't mention it was a 6-port.

If you can make your own manifolds, there are a bunch of different options. Dual 40 IDFs would be interesting and flow really well. I've also seen dual 40 DCOEs. Is it overkill? I dunno, but it is a bridgeport, after all. You could also do dual progressive carbs, like DCDs.

 

dual 40s, then build a "proper" side-draught manifold to suit. i think that's the money shot!

 

thanks guys.. im thinking that dual 40 idf would work ok and look very diffrent hanging off side... should get them in without cutting bonnet... 40doce? sidedraught if usedshould be mounted stright forwald as if you lay the accross engine then they flood or miss when you turn manily to right. so why dont peope mount them stright (like were turbos sity in rotors) as long as manifold lengh is same then?????............... SO before i do it any last words on having two 40 idf on a 12a bp? or if im having two would i use a 36idf for primary and a 40 idf for secdonary. does any1 know how much a std 40idf can flow as the factory nikki flows only 450cfm

 

If I'm understanding correctly, you're talking about mounting the carb with the air horns pointed toward the front of the car? If so, that seems overcomplicated to me. Weber-style carbs don't really have fuel-slosh issues in my experience.

I would use dual 40s. Having 36s on the primaries would only really be beneficial if you set up a progressive linkage, I think.

I don't know the CFM rating of the smaller Weber carbs, and it depends on what venturis you use. However, the stock Nikki only flows 313 CFM at 1.5" Hg, and dual 40 IDFs would certainly flow quite a lot more than that, maybe more than a single 48 IDA (which is 600+ CFM at 1.5" Hg depending on the venturis).

 

does anyone know what a single 40 idf flows??? sorry for all the questions you guys are being great help, thanks again