I have two styles of engine that I can build within the class rules I am working with.

1) 12A Bridgeport / 48 MM Carb with 36 MM Veturis
2) 12A Street Port / Induction Rule Open (Non Turbo)

Lets see what we can come up with and get the most HP out of these motors. Races would be 20 laps on a 2.5 mile course. Weight, including fuel, need to be bare minimum. Consider both engines are built identical internally with all race parts as needed. Exhaust is some what limited to size.

Pros, Cons, 2 Cents, Hard Facts and Hearsay are welcomed.

 

I take it your planning on running a GT3 first gen? I'd go with the 12a bridge. You will make more power easier. And for racing you don't need to worry about the idle or anything like that. Because you will be in high rpm's anyways.

 

Number one.

 

Bridge-port all the way... though outright power will be somewhat limited by the small venturies. Also, what are the exact rules regarding exhaust? As you probably know a bridge-port needs a very free-flowing exhaust to work properly.

Those things aside, the bridge-port has a higher, fatter power band and shouldn't chew much more fuel than a street-port as they have better BSFC under load.

 

Great info so far guys.

As far as the exhaust, REVHED, There are no rules minus a suitable muffler to pass track DB checks. I am limited only by the size of the car.

We have touched a little on where I was heading with this thread. Take into the fact that I am limited to a 36MM Veturis with Bridge and the Street Port could have any size. I am curious myself about the HP potential of a Bridge with such a small restrictor verses a Street Port with open induction rules. Or even, a Street Port with fuel injection that may make just the same HP with 3 gallons less used for an event. That could be 18 pounds I could leave behind at the start and first half of the race. You see where I am heading.
I guess it all comes down to how much air each of the different port jobs flow and is the 48/36 carb limiting that.



Any body got some good HP numbers of a Bridge with a 48/36 configuration?

 

I have a bridgey on ebay... go buy it!!!



Search 12a on http://www.ebaymotors.com

 

Call Rodger Mandeville. This guy has raced rotarys since the early 70s! You can get alot out of a 36mm with some good tunning.(864-582-0038) He is in Spartenburg, SC. All he does is build RX race cars....no street cars.

Just think about the NASCAR guys who are getting 600hp or what ever it is through 4 holes the size of quarters!!!

 

If it's a track car only, and your rules allow it, try thinking about a peripheral port.

You'll really smoke the competition then.

 

What series and class are you running the car in people including my self could probaly help you out a bit more.

 

79+80_rx-7 , I have a Bridgport.

Directfreak, Only the motors listed above would be allowed.

Mr. ImportGuy , The class is "C" Sports Racer within the SCCA. Engine rules for the rotary are basically GT rules.

 

Ok well I would still do the bridge. You will get the most power and it will be nice and high reving. Oh and I know of a bridge port 12a that complies with a 75db sound limit so you will be fine.

 

hmmm, i didnt see the brigeport car on there, but i did see my car as the spokesmodel for the CP racing strut tower bar!

 

Making a bridge-port quiet is easy. Getting it to still make decent power is the hard part.

 

My point exactly. I have some major limitations with the carb rule and the length of the car (Exhaust length). I am not saying that the SP would or could make more power - I am just not one to simply ignore the possibility and blindly run the same engine as others.

Anyone with some dyno results of Bridgports with primary length changes, over all length changes and carb bore changes.



defprun , - What?