Are there any companies or individuals that makes intake manifolds for 13BT?

Seems like the IM is the biggest bottle neck for 2nd gen 13BTs, especially the S4.

Jay Kim

 

Aside from what Mazdatrix and some other various companies (racing beat) offer, I don't know of any. You should have a custom one fabbed out of aluminum tubing!

 

The biggest bottleneck for the engine are the ports. Intake is not really an issue.

There are many NA aftermarket intakes in the form of carb (don't go there) based kits, and the IDA style dual throttle body intake. Many of then are suitable for race only.

 

In my experience a intake manifold with carb (and I asumme even more with a stand alone system) WILL yield more power than a full exhaust system on NA's.

BTW - Jay Tech also "used" to make AWESOME manifolds, etc.

 

What do you have to back that up?

 

http://12.232.38.41/WebSite/Products...sp?intView=100

 

why do you hate carbs so much?have you had bed experience or something?

 

There are plenty of people that make aftermarket intake manifolds the 13bt motors but you need to look to the land down under (Australia). I can probably dig up some pics with some links if you are really interested.

 

EXPERIENCE!

you can drive them on the street, but cold starts and such become a pain, amongst other little details.

If you're really concerned with the intake manifold sizing. Then port it out, or get it extrude honed.

 

I love those aftermarket fuel injection throttle body designs. You can pick up manifold/throttle body sets off of EBay for like $500. That is where I am getting mine from. They are Australian folks.

 

I was not referring to carbs. I will never have a carbed car. I was referring to Aaron Cakes statement that the ports are the restriction on a n/a, instead of the intake manifold. Thats simply ignorant. Its an overgeneral conclusion that leaves so many other variables its not even funny. He is assuming the ONLY thing preventing 6 port motors from makign power is the ports. If that was the case, you would see very large gains from porting, but very little from everything else, including exhaust, intake, etc. Thats totally opposite of how it actually is.

 

I am 100% sure that you know that is not that easy!

 

If you could get your hands on a 13B-RE intake manifold, you'd never have to worry about it being a bottleneck again.

 

What I mean is that before you start looking at replacing a (very well designed) intake manifold, you should look at porting the engine so you can actually benefit from the intake swap. Sure, changing the intake on a stock port car will obviously result in some power gain, but without the porting, it will be less then optimal (and thus, for the price and PITA factor, probably not worth it).

For the record, I don't hate carbs. I just believe that fuel injection has so many advantages over carb setups that I wouldn't even consider swapping "backwards" from EFI to carb. Even mechanical fuel injection (ie. Bosch K Jetronic) is superior in many ways.

 

For those who missed it, the question was about manifolds for the 13BT, not the 6-port NA.

Nobody makes complete custom intake manifolds. What the Aussies often do is assemble one using a Weber manifold, an IDA throttle body and a custom-made barrel plenum.

There's no reason why anyone couldn't do that without buying from Australia. The only custom part is the plenum.

And to back up Aaron, I've seen 500hp FC 13BT's using the stock manifold and TB bolted to a ported engine.

 

I've known about the carb'd setups for a while, but I would like this to be a step forward for my 7 not a step backward. I mean that in both performance, gas mileage and technology.

What makes RX-7 so much more complicated than, let's say....a Honda Prelude or Acura GSR intake manifold with dual runner lengths and aux ports, just like 6-port n/a?

Is there a reason why a simple, well-thought-out, sheet metal, log style manifold won't work on rotaries?

Jay Kim

 

The reason no-one makes then has got nothing to do with the fact that it's a rotary, it's simply that the demand is not there for mass-production like there is with Honda manifolds.

There's no reason you can't make your own, but remember that inlet manifold design is not as simple as it looks. It's quite easy to go backwards in performance if you stuff it up.

 

K, that was the answer that I was looking for. I figured because of the lack of demand.

Another question...are the bolt patterns the same for the intake manifolds for 13BT and 13B-REW?

Jay Kim

 

http://www.rotorworx.com.au/perfor_manifolds.html

 

$750 for a IM? Wow that's expensive.

Are there any other companies that are proven to make power down there in AU? And maybe a little cheaper?

Jay Kim

 

Check out E-Bay, there is a group os Aussies that sell a complete intake manifold/fuel injection throttle body kit for about $500 buy-it-now. They also have all sorts of accessories for the project too, but thise most certainly requires a standalone ECU.

You may sacrifice a little in drivability though. you are talking about 2 throttle plates that feed all four ports at the same time, it will not be progressive like a carb that has primaries and secondaries(although this effect is really only drastic on 6 port engines).

 

Doesn't work. The runner angles on the FD LIM don't match the ports of the FC engine. You can (with a bit of work) bolt an FD UIM to a S5 LIM. The S4 doesn't work very well. You won't see huge gains from this unless you're already making a lot of power.

Just like the stock TB you mean...

 

If I were to have a product similar to the one by RotorX and sell it for $300-400 would there be enough interest?

Of course that's only if these RotorX things prove their worthiness on a flow bench.

I wonder if RotorX had them flowtested and even better, sonic tested.

Jay Kim

 

I think the testing is what is holding alot of people back. Sure I could go into my garage and fabricate a log style plenum and make it look really cool. But will it flow properly, let alone as good or better than a stock manifold.

Once you've made this manifold, who is going to flow test it. By the time all the testing and dyno time has been done, you have to selli t for 700 just to cover all the research costs.

 

I'd rather they prove their worthiness on the engine than on a flowbench. That's what counts. They have a fairly good reputation in Oz, so their 30rwkW (40rwhp) claim shouldn't be ignored, although that would apply to a modified engine, not a stock one.

BTW, that plenum is A$745, or US$514. Loose the chrome and it's probably cheaper.