coldfire

iTrader: (1)

I'm just wondering if anyone has done an ITB setup on a NA 13b that has seperate runners for the secondary/auxilary and primaries?
i am thinking of doing an ITB setup with a weber/IDA lower intake manifold, however the main runner is shared between the primary and secondary.
haven't found anyone making an individual runners LIM, so either the stock LIM or a custom one would have to be made, i am thinking...

also, if anyone HAS done individual runners like this, has anyone managed to setup a progressive throttle plate operation? an example would be like the stock NA intake manifold, that has the secondary throttle plates opening only over a certain throttle percentage.

thanks

R.P.M.

iTrader: (3)

Sounds like an interesting idea.....would you use smaller throttle bodies for the primary ports and larger ones for the staged secondairies?
Like if you look at a stock LIM, the primaries are obviously smaller than the secondaries.

coldfire

iTrader: (1)

that is a good point, i didn't think of that one!
it would make sense that you would require less air for the primaries, and thus a smaller throttle body...
maybe using a three throttle setup? i mean, it could be done if you had to make a custom intake manifold anyways.
like use 3 50mm IDA TBs, one for the primary runners, and the other two for the secondary runners...

on the other hand though i don't know how using the same size TB for both primary and secondary runners would behave. as long as you have enough flow, then technically it will perform fine. but then issues such as throttle response, and air velocity become a factor...

astrochild7

iTrader: (3)

use a setup off off the 1300cc kaw busa... 4 50mm I think.. I'm looking in that direction.. even has tps options.

coldfire

iTrader: (1)

yeah, motorcycle TBs is one option...but that still leaves the issue of the intake manifold?

i mean, i'm not exactly a master welder and i don't have a machine shop. i would imagine that type of custom work would be expensive...

KNONFS

iTrader: (14)

I think it was Guru Motorsports who has the setup for race cars, the injectors are placed right in front of the air horns!!

BlastinSideways12A

You could actually have a half-bridge that is optimally setup if you did this. Its a good idea if you have the fabricating skills or lots of cash.

coldfire

iTrader: (1)

i am planning on building a half bridge 6-port (well, actually a 2/3 bridge if you want to call it that), and the stock manifold just won't do if i want to get the most power out of it.

just looking for manifold options. interested to see if anyone has done an individual runner ITB setup.

coldfire

iTrader: (1)

wow, that right there tells you that they don't care about anything other than top-end race performance!
i can only imagine fuel atomization problems at low engine speeds with having injectors right at that position.

BLUE TII

iTrader: (9)

One nice thing about having each primary and 2ndary port SHARE a TB is that you can still get the "tournament effect" of the DEI system that Mazda designed into the stock manifolds to gain nearly 2psi boost.

This is when the positive pressure wave from the abrupt closing of one intake port is reflected back to the opposing port just before it closes to boost the manifold pressure and likewise the positive pressure wave from the intake port opening is reflected to the opposing port.

It is a positive pressure wave when the intake port opens and not negative as one might at 1st expect because for the 1st 32 deg of intake stroke duration before the intake port opens on stock port timing the expanding chamber is sucking in hot expanded exhaust gasses from the intake/exhaust overlap period that will cause reversion into the intake manifold when the port opens.

Once the exhaust system is properly scavenging on a race rotary at the proper rpm and when the ports/rotors are ported/sidecut to open sooner the intake port opening may revert to a negative pressure wave?!!

Anyways, check out the 360 hp RE Amemiya GT 3 rotor streetport. Each TB feeds a small plenum which branches to runners to each set of opposing ports. This enables the use of the "tournament effect". In a race engine with race powerband it is likely the primary and 2ndary ports are exactly the same port timing specs. This will strengthen the "tournament effect" at the RPM(s) the system is tuned for at the expense of low end power from smaller staged primary ports like stock system.

R.P.M.

iTrader: (3)

Yeah those guys at Guru are cool !!

Judge Ito

I got a set up on my Rx3 is kinda kool and is working very well.. custom intake and dual 55mm throttle body. 4 inline Rc engineering injectors.. cosmo side housings with a large bridgeport. 52% throttle on my haltech e6K the engine is bouncing off the rev limiter. It takes very little effort to rev into redline. I love it!! power up to date is 310 rwhp and 225 tq.. next time on the dyno I'll be looking to fine tune the fuel curve.. power goal is 350 rwhp N/A

coldfire

iTrader: (1)

BLUE TII, that is some pretty cool theory you are talking about. it makes sense what you are saying.
it is actually what i am wanting to do. like, what i said is that the weber style LIM has a TB for each rotor chamber (one primary and secondary). you are saying that having something that feeds ONE TB for each set of primary and secondary ports. is it still considered an ITB setup? i guess it is...
basically it would be what i am looking for...a staged throttle progression of the primary TB would be even better, since this car will see track use but i will also be driving it to work in traffic. i don't see how a staged system would sacrifice top end?


Judge Ito, that sounds like a pretty crazy car! really makes me want to do a crazy 4-port NA like that (seems that follows quite a few peoples way of thinking...). for some reason i am thinking that the 6-port will provide better low-end than a 4-port setup...also i am going with a half and not full bridge.
not too sure what power i expect to come out of this. i'd be happy with stock TII HP actually. anything after that, as long as it is reliable for track use i am happy

coldfire

iTrader: (1)

i've been thinking about it some more, and i have come up with an idea that may actually work decent:

- TII throttle body
- NA dynamic chamber
- custom intermediate manifold, straight down to...
- S4 NA LIM

this setup would retain the stock progressive throttle and seperate runners for primary and secondary ports, and it also reduces the stock runner length significantly (this is basically turning the stock setup 180 degrees around).

the hardest part of this setup is making the intermediate manifold...also the secondary injectors will have to be custom setup somewhere in this manifold, or elsewhere...

BLUE TII

iTrader: (9)

Hmm, I have found the 3rd generation UIM on '89 TII LIM works well for dynamic effect. The 3rd gen UIM 2ndaries are connected like a horse shoe at the TB so the dynamic waves get good tournament effect. Mated to the '89 TII LIM it doesn't have the flow imbalance the 3rd gen LIM does.

The 2ndaries don't have much plenum, but the primaries do have an inline plenum. With the stock progressive throttle opening it shouldn't hurt your low end much.

I don't think the runner lengths aren't going to be short enough for much of a late closing port though. You could shorten the 3rd gen UIM up to ~6" I think between the TB and the bend into the LIM because it is so straight.

On my set-up I was seeing boost in the manifold runners before I added my turbo (dynamic effect) and even when I added the turbo I could still see the pressure spikes on the data logs from dynamic effect if I measured MAP at the runners instead of TB.

For good dynamic effect polish the runners, matchport them and pin them for a perfect fit. The smooth interior will help the pressure waves travel without losing strength.

coldfire

iTrader: (1)

hmm, some intersting info there.

i'm just wondering though if a 4-port LIM is a good idea on a 6-port motor? it seems that port matching to fit might not give great flow...

BLUE TII

iTrader: (9)

Indeed I was thinking 4 port motor.

GtoRx7

iTrader: (5)

hmmm

coldfire

iTrader: (1)

yes, interesting

coldfire

iTrader: (1)

lol,

anyways, i think the bane of this is using a 6-port in the first place. makes it even more convinving to build a 4-port motor instead...anyways, let us stay on track here, heh.

another option would be to mate the stock TII UIM with the NA LIM...looks like maybe just a spacer? but who knows if that is an easier and better solution than other options...

guess this has turned from "ITB setups" to "let us ghetto make a setup out of stock parts", lol!

but really only person in this thread that has mentioned using a ITB setup was Ito, and i think his motor and setup is a lot different than what i am planning for...

GtoRx7

iTrader: (5)

It is very interesting that you made this much power. What type of dyno was this on? And do you have a copy of that run I can look at? I dyno'd 310rwhp and 216 Ft-lbs on a first crappy dyno run on a mustang dyno. Now it is 345 rwhp and that is on a 3-rotor and not a 13B, so how are you getting this power and torque on a 2 rotor again? 220 rwhtq is around 285 at the motor, which is 100 more than I have ever heard of on any 13b. So let me know your secret, please.

AHhhhh, I found your dirty secret, nitrous is the main way your previous setups ran, so I assume this one is no exception, so its not N/A w/ nos.

Smilodon

Ach der lieber. So, if 220 rwtorque means 285 at der motor, then that would mean there is 65 free hp to pick up by reducing the parasitic losses of the powertrain.

Interesting indeed.

coldfire

iTrader: (1)

swapping manifolds isn't that big of a deal, so maybe next summer i can set aside some extra cash, and then do various dyno runs with different manifold setups...see how each compares and where the strengths of each one lie. if not for other peoples interests, than at least for my own curiousity...

t-von

iTrader: (8)

I was thinking that too. I never thought a side port could make as much power as a PP.

Judge Ito

dyno is a Dynojet.. I have a copy and better yet I have the dyno runs on video. Soon I'll have my friend host the video. I don't know how to post the video.
My N/A set up is working really well. I'm almost sure I could make 380 to 395 rwhp all motor no nitrous if I change my rotors to renesis rotors, 10.0 to 1 compression and change my fuel to methanol. but I am not looking to maximize my all motor potential right now.

My Rx3 Sp is on a mission to break the rotary nitrous non-turbo challenge! Yes my car has nitrous, not 1 stage but 2 stages of nitrous. I'm looking to make over 500rwhp with my first stage of nitrous and a little over 600rwhp when my second stage kicks in.

My bridgeport engine is making more power then most full peripheral ports I have seen in the dyno. I was looking into exploring my N/A potential after my nitrous challenge. maybe run in the nhra all motor class.

fastest rotary nitrous car is a mazda miata called"Kamikaze" running 8.2@158mph.. thats my goal right now!!!