12A stand alone for 250 HP
 

I am working on a SCCA sports racer engine program. Rules limit the rotary to a 12A Bridgeport with a rather small 48 weber with 34MM veturis. - OR - 12A streetport with open induction.

I am pondering a 12a with a massive street port, custom intake manifolds, large injectors and stand-alone EMS. I wonder if you could see 250 HP with this setup. It should lend to better fuel economy, which relates to carrying less fuel on board. As well as better drivability and less heat buildup.

What do you guys think? Manifold stuff would be no problem. Been there done that.

-billy

Bump

I have seen dyno results from an EP motor(street port) that made 240hp. this was a 13b but it has to run a very restricted intake and throttle body(stock 86-91 RX7). I think with some time on an engine dyno experimenting with intakes and exhaust systems you could see those numbers. it wouldn't last long and would have to be reved to the moon. what kind of budget are you prepared to spend?

I dont want to give racing secrets away...
 

Theres a guy at my work who races a 3rd gen with a 12a. Sounds like he has the exact same limitations you do. He runs in Nationals GT3. Does that sound familiar?

He is running 12a bridge ported. This season will be his first time with EFI on the car. He is going with Motec equipment. All of the fuel injection stuff will be done by Marron, www.injector.com.

My correction. The guy I work with WAS allowed a 48 webber with a 38 venturi, bridgeported. Streetported hes allowed 40 venturi with a lighter car in general.

NOW hes going with Motec EFI and is allowed a 38 venturi on Bridgeported. His car dynos at your target 250hp on the old system. Hes still building the efi.

This is the engine program in a two car team. The cars have been in engineering for close to a year now. We started manufacturing in mid March. There will be close to 200 hours in engineering when the cars are ready for the 2004 season, hopefully in late August.

Two engines will be dyno tested and track tested before the 2004 season in tandem. The Bridgeport option and the streetport/EFI setup. We currently have the Bridgeport and Drummond will build the streetport. We will develop the intake and fuel system from scratch.

I am also working on a single rotor 12A for a lower displacement class. We would then test carb verses EFI on the single rotor.

-billy

Interesting... Im not into this hardcore racing stuff as you are, but it sounds like you have a lot more resources and manpower than my friend here at work. Do you have a sponsor?

I am pretty sure the engine I was referring to was built by Drummond or maybe a past employee of his. with some time and experimentation the EFI motor should be able to outperform the carb(all things equal). not sure if the carb venturi size matches well with the throttle body size. sounds like a great project. pressurized airboxes and ram air might overcome some of the intake restrictions. let us all know how the cars perform. Do you have any info or pics on the chassis and body?

The body stuff is just concept sketches so far. This link is to a early rendering from the CAD assembly file. It is about 4 months old. The chassis has changed dramatically since then and the rear suspension is completed now. I have not rendered a new one in a while, it takes a long time since it has 200+ parts in the assembly.

http://home.attbi.com/~bwaits/main.jpg

-billy

any particular reason for the front engine layout?

Originally the customer requested the design to use the engine and trans he already had. 12A and Miata 6 speed. His budget did not allow for the 8 to 10K gearbox for a rear engine. After running some numbers I found that the polar moment from the motor where it is was not that far off as most people would think. I spoke with some of the engineers here at work about the Panoz LMP and decided I like the idea. There are many GT2 and GT3 tub cars out there that the owners do not have the money for a competitive tube chassis. The original goal may have changed from 1 or two cars to a "customer kit" that would allow them to use their small bore GT engine in a new competitive chassis and class. We will see after testing and development.


-billy

so this is a kind of multi use chassis? GT's and CSR's? front engine can be usable, especially in this type of racing. I was just curious. I am a great fan of tube chassis cars and would love to replace my RX7 with a tube chassis race car. what type or design or front suspension are you using? and what CAD software are you using?

The front suspension is unequal length wishbones with pushrod to a bell crank inboard shock setup. There is a slight amount of anti dive built in.

I do all my design in SolidWorks. I have heard of problems with Solidworks and large, many part assemblies - But I have yet to have any problems. It generates prints from the solid models easily. If you have a part change it will automatically update the drawings as well.


-billy

Unfortunately my engineering training was in the stone age before computer CAD and simulation programs were available, so I am trying to learn and gain some experience on these systems. can this program also show the camber and bump curves on the suspension and calculate spring and damping rates for differing wheel speeds? I would like to simulate an existing suspension system I have and be able to use the basic geometry on another car. thanks for any suggestions

No, it has does not deal with the geometry. The latest version does have built in FEA, I hear. You would need to find suspension software to do what you want to do. Try this link, under software.

http://www.gmecca.com/byorc/

-billy

bwaits-We are providing 12A Bridgeported race engines for some CSR teams. These engines feature drysump oil system, Electomotive HPX crank trigger ignition, and develop 235-250 hp depending upon induction, exhaust etc. We have been using the Weber style 48mm carb made by Gene Berg. SCCA allows EFI only on Streetported engines and our experience is that the EFI/Streetport combination will not be competitive.
For details on one of our projects-www.diasio.com
This is a CSR legal car with a Hewland 6-speed sequential gearbox. FYI a future version of this car will have a Streetported, fuel injected & turbocharged 13B with an Electromotive TEC3 engine management system for customers that plan to compete in NASA or just want a faster track event car. It may be able to run it in the new Formula S class as well.

Bryan Smith
Rotorsports Racing Inc.