Here's a manifold I came up with over the weekend. I'm actually supposed to be working on the auxiliary ports, but the barrel throttles were fun to draw. The proportions of the engine are messed up, but it gives you some idea of what it should look like.







what do you guys think?

 

looks good...i dont know much about intakes but what effects will it have being that the there is two tbs instead of one and the pipes are seperated?

 

ITB's? Interesting. I think I've seen someone that sells a TB velocity stack combo. Back on topic. Nice drawing/ idea. I wonder if anyone will ever design a variable length intake runner system like the one used on the 787B.

 

Nice- ITBs. I like that design- Im assuming you would need a standalone with a setup like that though.

 

I plan to run something similar on my FC. I'll be using off-the-shelf parts, though. DCOE upper manifold with a slightly modified stock lower intake manifold, and I'll utilize a pair of TWM 48mm throttle bodies. I'll let you guys know how it works out in about 4 or 5 months, hopefully I can break 200rwhp N/A with a mild streetport.

 

http://www.rotaryshack.com/Products/...sp?intView=100 i bet if you ask these guys they will probably make it for you.

 

thanks for the feed back guys. actually i have a guy locally making it for me for free. no telling when ill get it started tho. i have to get him the materials to machine and build. as for the ecu, i have a friend whose running something similiar and hes actually using the stock ecu. its not exactly efficient but he wasnt left with enough cash to megasquirt it. Ill probably design a penelum(air volumizer) to put around the trumpets. 13turbofc, basically you get a shorter length for the intake to pull air in. if you look at the stock manifold it curves under itself and is rather long. i designed it with 2 separate pipes for each rotor to have its own intake. just seemed logical.

 

There is a reason the stock intake manifold is that long, low end torque. Its what makes the car somewhat decent for the street.

With a shorter IM the power band is shifted up. The bad thing about this is that with the stock ECU, you cannot take full advantage of it. Not to mention the heavy S4 rotors and stock ports will limit how high you can rev.

The plenum should be placed after the throttle for maximum driveability at part throttle.

 

That's some nice work! But it's not exactly new. Take a look at the Renesis intake...

You're going to want some kind of air volume after the throttle bodies. It will help tremendously with throttle response.

 

thanks alot. i know its not a new design but i was really just wanting to design something with acad(i get bored easily). then i really started to think about it. I forgot to add the air volume but it is in my next design. this one is taking forever but when it is ill post it.

 

If I might make a suggesting: Throttle the secondary/aux ports together and the primarys together. If you throttle them with each other you wont get any high pressure wave benefit at any point. If you throttle the secondarys and primaries seperately then at least at some point in the mix the high pressure wave from the intake port closing will reach the chamber at the same time that the other intake port is opening, causing the same effect as the VDI.... If you did that I would stack them on top of each other, or stagger vertically so that the runners are the same length to the barrel.

If you are doing this on a turbo its not nearly as important. Otherwise it looks good. You could probably source TB's from an Honda RC51 or Ducati sport bike.

BC

 

Oh, and if you can get your friend to make a few of those LIMs you could EASILY sell a few of them on this board for a few bucks.

I would buy one.

BC

 

Everything except the barrel throttles is easily available from RB and TWM. The plenum takes some work. Another Ludwig Motorsports product.

 

Is that alternator rusty as hell or am I seeing things?

 

Good work! I just love seeing custom intake systems being designed and worked on. However that design will not work well on a rotary. A larger plenum will help. However running the P-S into a 2-1 setup with an equal size runner is too restrictive. It is also keeping the same length to all runners. When developing a custom one you can gain much benefit from varying the lengths based on size and low end velocity to gain some more tq. Run the secondary runner shorter then the P. Remember your secondary runner tends to draw more air as people port the secondary larger and on 6pt motors they are supplying two feed ports. I would also run the TB setup P’s-ITB and S’s-TB and stage the plates. This will allow for much greater tuning.

This is the most important aspect of the motor. Unfortunately the hardest to tune. Remember as the RPMS rise the pressure waves change and the reverb into the intake is also changed. Account the amount of volume needed for the trailing bounce of the reverb to be picked up on the scavenging timing and volume of the ports. Your high point of the velocity pulse will carry a high pressure zone and the trailing will carry a low pressure zone. When you get the reverb these will colloid and stall your intake. This is where runner bounce comes from, more prominent on NA engines. Things as bends and actuators are used to counter it.

 

I talked to some one that says that this design pops motors. Well can we see the inside design.

 

You can even get roller throttles comercially. Here's a pic of some webber flanged ones.

http://www.flyinmiata.com/projects/c...flip.php?x=674

Also on this page you can see another option for the intake manifold.

http://www.yawpower.com/dec2004.html

 

If you're gonna go and make a custom manifold with ITBs, why not just put the secondary injectors on the lower half of the manifold, closer to the ports (basically spraying right into them)? Seems like it would work better...

 

I've heard they run best with these manifolds and a standone . . .

 

i agree with the statement made before. the primary and secondary ports really shouldnt be on the same TB. Look at any factory EFI manifold for the rotary. the secondary and primary ports are seperated hense the three plate TB design. Helps driveability a ton too.

 

If going custom with the TB's and manifolds you want to place the injectors as FAR away from the ports as possible, because it leaves more time for better fuel atomisation.

 

Fuel atomization is at its best when the spray velocity as reached its max end point. Any time after that is soly fuel collection time.

 

that and wont moving the injectors back cause a delay between the time when its injected and the time when its actaully in the combustion chamber?

 

^ Yes generaly you would have to run the injector duty more to compinsate the fuel collection. Closer is bettor to a point. This is where the direct port injection theory comes from.

 

This is basically what he told me. The guy also has a pretty nicc FC as works at a shop.