Rx7carl

Well peejay isint that one of the reasons that rotaries have inherently good ve?

Rotortuner

If your going to use this for the street, or just because its your first one, i would kinda recomend just using a regular weber ida or mabe a 51. I dont think for you it is really worth spending all the extra money to go with the berg. The bergs dont give you all that much more hp for the amount of money they cost. I think there are other things that would give you more pwr for the $. IMO.

CJG

Kenku

You know... that's really a pretty good point, especially given my financial situation. Plus, I suppose there's not much to keep me from getting a bigger carby later on if the '48 proves to be insufficient. But what I've seen places the pport at the upper limits of what a 48IDA can flow; or am I mistaken there?

coldy13

My neighbor used to be part of a race team, 12a PPort making 280hp on a Weber 48. They could have gotten over 300hp if they switched to a 51, but they stuck with the 48 since they had hours of tuning in it, and they were running plenty fast already . I think the 48 will be good for your engine.

Scalliwag

The good thing is that a Webber 48 is fairly common. You can pick one up on Ebay or somewhere and use it for a year or however long you want to and if you change to something else later on you can sell it for as much or more than you paid for it.
It will get you going even though you may not get the full potential of the motor but if you play it right you will not lose money on it once you do have the money or find a good deal on a 51.
Just make sure if you get a used on Ebay that the seller has a very good feedback rating and don't get anything that the seller does not know it works.
When someone says they found something in a box of parts and they don't know anything about it, it better be really cheap. That's my 2 cents.

Kenku

Yeah; actually there's a guy around here who killed the 12A bridgeport he had attached to his IDA, so I might have to see what he wants now that he's decided to go with a TurboII swap.

Metallic_rock

Ok, I was thinking of doing something slightly different-

1st, street port the 4 port 13b.

2nd, I was thinking of doing that p-port, but only with a 1 inch hole, thus reducing apex seal bend. I would end up setting it up with the stock intake manifold (from an older 4 port 13b)

I would then make an adapter so that I could run a tube from the one inch hole to a corresponding hole in the intake manifold.

I was also kicking around the idea of setting up an actuator so that it could be used as a 6th port and set it up to open at a certain rpm.

comments? Suggestions?

Scalliwag

I don't like RPM actuated ports. While it beats the stock 6 port setup it is still more trouble than it is worth. Even a mechanically controlled "butterfly" or even "slide" valve setup non-primary ports is more appealing to me.
I like semi-peripheral but absolutely love peripheral ports
I hate NOS but if I was ever to play with it I would build a pport and then plumb it into cover plates on the primary and secondary ports. Mainly because it would look cool as hell

Metallic_rock

Re-thinking my thoughts here... I don't think it would actually be necessary to use an actuator with a carb because you already have the butterflies on the carb. All you should have to do is increase the mixture. Right?

Scalliwag

Providing everything is plumbed through the same intake it is limited to the carb you are using as to how much air can flow through it. The more air the more fuel you need.
The mixture you need remains the same regardless of the volume. How much control you have on richening or leaning comes into play too.
A carb is easier to setup because the air/fuel is pretty much figured for you by the metering system and the jets.
But if you hook a wideband to it and don't like what you see at various ranges there is only so much you can do.
With an injector setup and a haltech or comparable unit you can make it so that the fuel map is perfect throughout the throttle range.
There are variables but that is the concept in a nutshell. When you start talking about runner lengths, sizes, all has a very profound effect on torque and hp, but this is mixture.

Metallic_rock

hmm... wonder about doing that with EFI and a Haltech... that would make it expensive, but probably well worth it. I'll check into it.

Thanks for the comments!!! I'll update you on what I decide to do.

Can you see any problems with using a carb?

Scalliwag

what carb? What is the car going to be used for?

85rotarypower

Scalliwag: How much would you charge for a set of 12a PP housings?? How streetable are the housings?

Scalliwag

For me to bore a hole, make a tube, and press fit it in would be $150.00 per housing plus shipping both ways. To have them sealed (Devcon) would be an additional $30 each)
Streetable is a relative term What I plan on doing with mine is making chokes that will reduce the flow to make it more streetable. The chokes can be removed for a day at the track and the fuel map changed to match the setup. That's really easy with a Microtech with a dash unit.
With a carb setup this would not be a very smooth transition.

Rotortuner

how much hp has the housings made? I know you have ken using them, has he ever went and dynoed?

CJG

Scalliwag

Ken dyno's at RP fairly often when he makes changes. Last time we talked about it I think he was at 315 or 330. I just can't remember which. It's alot for an NA.

85rotarypower

Is there still enough torque in the bottom end to drive the car everyday?? Or would I have to add the something to reduce the air flow when I am on the street. I kind of like the idea of having a slow car at the start, but with a large boost in power at higher RPM's. One more question, when will max power come in??

Kenku

At the crank or wheels, out of curiousity? I heard mention of those numbers before, and found myself wondering how people are doing compared to, say, what Mazda managed with the R26B.

Oh, on a side note, I saw one of those about a month back. Got to talk to Jim Downing and his engine builder when the ALMS race was at Road America. Quite cool; they say they haven't had to rebuild it since 10 years ago.

peejay

My guess is it is an engine dyno.

The R26B was not designed for max power output. It was designed for max efficiency.

Scalliwag

All that is controlled by manifold and header design. The length and diameter of intake runners and the diameter of the exhaust and the point the header tubes merge have a drastic effect on everything you mentioned.
There are a lot of variables to be considered and changed depending on the application. Striking a balance between street and strip depends on the individual and which they will lean more towards.
You will take away from one to add to the other.
I like both a lot but I don't mind twisting a wrench between the two.
My roadster will have a modular intake system with a 51mm slide throttle body (that is 51 X 2) For street driving the intake runners will be choke to around 40mm is what I am thinking right now. That is subject to change after I see how it works obviously.
The manifold for street wraps around and the throttle body will sit like the side draft manifolds they sell at Racicing Beat.
Since road racing a T-Bucket would look pretty stupid I only throw this out as an option for someone that was going to road race. That would be to leave the setup the same and play with larger chokes until you find what gets you the torque range you want.
My second setup would be ***** to the wall straight line. I would pull the wrap around off and put a short 45 degree manifold which leaves the throttle body sitting kind of like a down draft. This would not a any chokes.

Think of my modular intake system as kind of a Lego set of different tubes, chokes, 45's, 90's, 180's etc. with a madman (Scalli) putting them together in all sorts of scenerios.
Since the Microtech dash unit holds up to 3 different maps that can be loaded on the fly I will be like a little kid in a candy store

If you look at some of the pics early in this thread you will see a couple of pics with some of the modular intake pieces I have made for the pports.
Each piece has a male and a female end with o-rings to seal and allen head set screws to secure. Once a manifold is made all you have to do is pull the throttle body and fuel rail to the side, loosen some set screws, pop the manifold off and another on, connect the throttle body and fuel rail back, change the map and go.
Or at least I really really hope so Winter is near so the project is just around the corner.
To me this is the best way to balance between street and strip but I concede that it is not for everyone.

Rotortuner

It should be FWHP. Thats pretty good pwr for sticking with the circle ports. Do you know what kind of apex seals he is running? Or any other info your allowed to divulge on the engine?

CJG

Rotortuner

boy there are all kinds of people posting in like the the last 5 minutes.

Scalliwag

Good question. I forgot RP has both now. I assumed it was the chassis dyno but I'm not sure. The numbers sound much more like an engine dyno.

Rotortuner

Ya i dont see any way that it could be RWHP. Mabe he is on the chasis dyno and closly estimating the FWHP?

CJG

Scalliwag

Hell I'll just have to ask him