blindboxx2334

iTrader: (2)

Of course i know that, less flow=less power. I just wanted to see if a few of the ITB guys could chime in on what diameter throttle bodies they've got goin on under the hood... If all goes as planned, i'd like to have a 13b with a itb setup (fabbed by me, something ive wanted to do for a while)


So i guess what im really trying to get at issss, i have a set of 05 cbr600rr TB's.. the bore dia is 40mm. Im starting to think that they wont be big enough, esp. since i saw how big the tweakit ones are (45-50mm)... the 100rr TB's are 44mm, which still seem a little small as well... I havent looked into the gsxr ones, but am going to do so after i start this thread.

Oh and if it helps. I plan on going with a large street port, injector size still undetermined (need to read more on that), and have hopes of doing 200+ hp.

thanks for any help..

edit: also, so from what i see on the tweakit kit, you dont need a tps?? i know that miata tps's will work with these cbr TB's.. I confirmed this when i took it off my 00 NB when i was cleanin out the miata's TB one day, the female part on the tbs and the male miata tps plug almost went together, the snap deal was differnt, and i didnt wanna break it trying to force it in.. but i know if i used a whole miata tps setup and wired it correctly, i could make it work that way, provided that the wiring was somewhat the same as the fc3s tps system.. I imagine life would be easier with one, in terms of tuning and air to fuel ratio.. Correct?

j9fd3s

iTrader: (3)

ive got a 48IDA on my 12A P port. depending on the intake manifold, i'd say 48 is about the minimum.

shoot the stock FC is 3x45mm....

blindboxx2334

iTrader: (2)

damn. good to know. looks ill be looking for a set of goldwing or gsxr TBs then!

diabolical1

iTrader: (3)

you mentioned you'd be fabricating it yourself, so i'll assume you're not really interested in aftermarket units/kits already available.

if you're going with a custom, 4-throat route, then i'd say start with the throttles from the CBR1000RR that you mentioned. i'd tend to think 44 mm may be at the smaller end of the right ballpark for a 13B. i think it's a good place to start. obviously, manifold design will be crucial to strike a decent balance/power curve.
considering that he's trying to go with 4 throats, do you still think 48 is the minimum size?

blindboxx2334

iTrader: (2)

im only trying to go 2. its not hard to split the 4 itbs. since they're just bolted together... or would you recommend going 4 with a slightly smaller bore?

Im not new to ITB's ive done my research and such.. I just know they're not as popular on rotaries. and the only real thing ive had to base it off of is the tweak it kit.. 2 tbs with atleast 48mm at the manifold.


hmmm.. 4x44mm or 2x 48mm(minimum).. im curious now to see if a 4 throater would also and provide enough of a power gain.. i might have to experiment =)

also thanks for the input

-xlr8planet-

iTrader: (3)

cbr is 4x40
tweak it is 2x45

if you ever figure out the injector flow of the cbr injectors, PLEASE let me know

blindboxx2334

iTrader: (2)

I’ve just never seen anyone run 4 TBs on a rotary. so, in theory it should work. but I guess you never know till you try it..

Also, when you say injector flow, do you mean im terms of what would be the correct injector size?

diabolical1

iTrader: (3)

oops on me. i didn't realize that you were planning to split the twins from the motorcycle and use only one. in that case, yes, i completely agree with j9fd3s' advice in not using less than 48 mm.

i've seen a handful of 4 throat ITBs on rotaries, the most notable that comes to mind was a gentleman in England that built a Gen I Rx-7. i forget his username (i think it was Mike-???), but i think he had a thread here. not to mention, there were a handful of twin carbie setups available back in the day for 12A and older 13Bs.

by far, unless you plan on fabricating your own or want to track down one of the old twin manifolds, you'll have your car up and running much quicker if you go with a single setup.

Doc Holiday

iTrader: (2)

Ito had 4 ITBs on his RX3, and it made big power. partial pport setup.

DAveFC3sNA

iTrader: (11)

has anyone ever thought about using the Mustang 4.6L Supercharged Dual 65mm throttle body, (they range from 52-65mm or so) i have one of those and designing a flange for it now, i like it cause its fairly affordable with a tps sensor and cabled throttle controlled and has the throttle body coolent lines for winter so the throttle plates wont stick.

i think it would be a pretty decent affordable budget dual throttle body setup very similar to tweakit kit or Borla Twm kit for a decent price if you can weld and make your own adapter manifold

DarrenTRS

iTrader: (1)

First thing that comes to mind is dear god the off-idle and low end would suck simply because of how massive that throttle body is but there is one shop here in someones signature that does make that throttle body from a mustang to attache to a holley LIM if I recall correctly.

The 2 cheapest ITB setups I've found so far are the Jenvey 48mm [they make a range from like 44-50] DCOE style throttle body w/ 2 injector bungs. and then the Auto-nomics holley style 4 barrell with 4 injector bungs.

Descriptions and links of both can be found here:
https://www.rx7club.com/forum/showthread.php?t=945202

As far as size for a 2 bbl I wouldn't go lower than a 48 unless you are trying to make it 'more economical' which of course is blasphemous. but I've also seen 48 IDAs run on full bridges as well as 51s run on large streets, might just be a question more on WHERE you want that power and what type of intake i.e. long or short.

blindboxx2334

iTrader: (2)

that you have correct. all that low end would go out the roof.. i looked into the jenvey kit. Id be spending just about 400 bucks for the 50mm TBs alone. Not too bad. Im still curious to see what a 4 thoater would do though. although the manifold would be a little tougher, since the upper part of it would have to taper in on the upper mani and then taper back out. (i plan on doing an upper and lower intake mani). im still lookin into the jenvey ones though

j9fd3s

iTrader: (3)

yes! i think if pj used one, i know two people that used ford TB's on p ports. the truck ones are like 2x45 or something so its a little small, but 2x52 sounds great.

t-von

iTrader: (8)

I remember that engine! It was a full bridge semi PP with 4 ITB's. 1 TB for each runner with the PP Y'ing off the secondary ports. It put down over 330rwhp. That engine was a high strung beast! The thread may still be up on Nopistons!

t-von

iTrader: (8)

Actually too big of a TB wont effect your bottom end like you think, if you build your intake to have secondary control. The main problem with too big of Tbs is tip in. You get too much velocity to fast which makes it harder to regulate speed while cruising. The gas pedal becomes wayyy to touchy. I actually experimented in the past with TB's that were to big. I just made some restricter plates to reduce the opening diameter to whatever size I wanted (which greatly improved the drivabilty). The nice thing about this is you can make your Tb what ever size you want if your experimenting with a larger enough TB as a starting point. Remember, it's very easy to decrease an opening size but much harder to make them larger.

blindboxx2334

iTrader: (2)

ah, i see. well i learn more and more everyday. thank you sir.

peejay

I used a 4.9 truck throttle body. 2x40. Yes, it sucked...

I have driven a 1x45DCOE equipped car and didn't know it wasn't stock until I opened the hood. (That's two 45mm barrels)

The TWM 2x40DCOE (four 40mm barrels) is supposed to flow like a single 48 IDA. Haven't driven one.

I drove Alex's (Low Impedance) 6-port on an IDA style throttle, I'd like to say a 51mm, and it drove very sweetly, no big throttle kind of problems.

My next 4 port build has a pair of 2x48 throttle bodies ready for it. They're both from LT1 engines (eBay: $20-40 a pop) but L98 and other TPI should also be 48mm. They have a narrow bore spacing though, much smaller than the Ford, or DCOE or IDA for that matter.

1973rx3

This is my setup, just haven't gotten around to continue my project rx626 its going on a 4 port full bridge port using these idf style throttle bodies 2x(2x48mm):

[IMG][/IMG]

[IMG][/IMG]

The intake and throttle bodies I got here on RX7club from Japan2la.

dj55b

iTrader: (2)

i run 2 x 47mm and I've seen pretty good number and throttle response with those so far.

RacerJason

iTrader: (5)

Gorgeous setup!!! Does it appear that the Manifold was fabricated by an individual or are there any shop names or markings on it? If you ever want to *cough* part with it lemme know! That would be great on my REW bridgey

peejay

Won't bolt on or mate up with the ports - you'd need something REW-specific.

blindboxx2334

iTrader: (2)

good deal. got any more info on your setup? like numbers, injector size, and any porting done?

thanks to everyone else whos also helped out.. Im looking into making the jenvey ones fit on a manifold like the one a couple posts up, very clean! im thinkin either twin 48's or 50's

1973rx3

Yeah this will not bolt on to a REW. It's an Old school 4 port intake with no markings and IDF throttle bodies are TWM! And no it's not for sale I will be using setup in my RX626 build. You can follow the build in the Old School and other rotaries section of this forum. Japan2La (whom i got setup from) is a vendor on rx7club and might be able to find something to suite your car/build.

dj55b

iTrader: (2)

Injectors are 850cc semiens, and its a fairly big street port. Most of the info for that is here:

https://www.rx7club.com/showthread.p...ht=fuji+racing

Latest HP are here:

https://www.rx7club.com/showthread.p...highlight=dyno

Pushed 165 whp and 132ft-lb of torque ... and yes it is a 12A not a 13B. After changing my fuel pressure regulator which I later found out was bouncing around the fuel read outs, I believe its in the 170 whp now. and maybe closer to 135 torque.

R.P.M.

iTrader: (3)

BAM! Do it!

This setup is on a customers FC road race car, half bridge, S5 rotors, T2 irons. Hybusa TB's










And this is a long term project.....