Kenku

All righty, I'm mostly throwing this out there for information's sake. I'm designing something akin to an old prototype car... which I don't have the money to build now, and may not ever have the resources to build, even though I really want to. I'm saying that right up front though so I don't get a bunch of people looking at me like I'm a moron with no idea what I'm talking about or how much this stuff costs. I also full well know that this doesn't precisely fit into any SCCA class... except maybe A Sports Race.

That said, anyone have some thoughts on what would work reliably for long periods of time (again, sort of paralleling endurance racing cars) to make big power? My thoughts are ranging between something like a GT40R or Dee's R85 setup on a huge street port and high boost levels... or a peripheral port running lower boost but obviously more airflow. 600ish horse out of a 2-rotor is a target, 100 or 110 octane race gas is assumed and low end power or idling isn't an issue... but controllable power is. I'm sort of leaning towards the peripheral idea, but wanted some other opinions.

rx7tt95

I'd contact CLR Motorsports in Miami. The owner won the SCCA GT1 class with a three rotor n/a in 2003. He's currently building my engine. As a road racer, he'll understand what needs to be done to make the engine reliable on a road course for extended periods of time with no overheating. He has many neat ideas/tricks and he's an exceptional engine builder. Carlos is on the forum under GT1-20B. Contact him with a PM.

gfelber

Carlos is an exceptional engine builder, chassis tuner and knows turbos very well. He's not necessarily well versed re: some of the newer techology/products, but may be willing to embrace it if you can make a good case.

Just to be clear, he won the South FL region GT1 class, not SCCA national.

Gene

gfelber

Even with your caveat I have to interject. If you want to race the car competitively you'd better have a damn good idea about where the car is going to be classed before you build it. A turbocharged rotary prototype won't "precisely fit", or even remotely fit, into ANY SCCA national class. Some local SCCA regions (like here in the NW) do allow turbocharged second and third gens to compete, so there may be provisions among these regions for forced induction rotary prototypes. However, SCCA will not allow these cars to compete on a divisional or national level. Other organizations, such as NASA, may have a class for this type of car. Of course, any car you build may be obsolete or uncompetitive the following year due to rule changes. This has frustrated and bankrupted dozens of race teams throughout the years. For example, look at the 2005 Grand-Am GT and GA Cup rules.

If you’re building the car just for fun/lapping, then it’s a different story.

With regard to your second question, there might be a few Japanese tuners that have done this but AFAIK no one in the US has campaigned a 600 HP 2-rotor car- particulalry in endurance events. Brian Richards (of M2 fame) was probably the closest to this mark with somewhere north of 500 HP. At this level of power, there were tremendous difficulties with turbo longevity during longer races due to extreme EGTs. Even the newer turbos with exotic turbine wheels (incolnel, etc) would fail. That is not to say that it can’t be done, but likely to be extremely difficult as Mazda would have done it by now. There were several 3-rotor turbo cars raced throughout the years, but even those were making less HP than your target primarily due to reliability concerns and fuel economy).

You very well might be okay for races of shorter duration (< 30 min). I know of one person who has had exceptional longevity (and is very quick) running a 500 HP, T78 turbo’d third gen, but again this car is run for relatively short periods of time.

Jim Downing has designed, built and raced turbo’d three rotor prototype cars and he would be a good resource to contact, but you'd better have a well thought out goal in mind before you contact him. Give Carlos (CLR) a shout as well. He is very knowledgeable with respect to the longevity of turbocharged, road raced rotaries.

Gene

rx7tt95

Well he seems to be doing and experimenting with a few things I've never even seen, not that I've seen all :-) Yes, he is on the conservative side in regards to some issues but not on internal engine configurations and fixing certain problems like overheating. I think he's on the cutting edge with certain items and is right up there with Jim, Rick, Racing Beat, etc...There's a guy on this list who regularly road races his single turbo third gen with a big single and a front mount IC. His dyno can be seen in the dyno section (490hp on 93 pump with alcohol injection) and according to Carlos, with a better turbo would see a big jump in hp. Rob goes out for the 30-40 minute sessions several times per event with no overheating issues. Even with the front mount. From talking to Carlos, he's solved overheating issues associated with road racing three rotors and can perform the same modification on two rotor engines. I've attached an image I took of Rob's car at Sebring International. I've seen his car at two different track events this year with no issues/problems in terms of overheating or anything else for that matter. Carlos built his engine.

Kenku

Gene: Well, you're absolutely right... I don't know of any national level class it would be legal for in SCCA, nor would it fit in even FIA LMP without modification. The general concept is to make a rotary engined supercar (to my mind, that equates to a prototype registered in a county with no emissions) because I think there needs to be one. I'm almost completely sure that it would be legal for A Sports Race (though getting the monocoque homologated will be a bitch) but that's a regional only class that's used more or less as a catch-all for people with heavily built cars who want track time... or at least, that's how it looks from seeing the cars running in it locally. So yeah, it's more intended as a godawfully fast engineering excercise than a nationally competitive car; it might be easier (and maybe even cheaper) to buy an old GTP car, but that takes away part of the fun.

Endurance events are probably too much to expect; not many it would be eligible for anyway, come to think of it... though I wonder if a rotary would necessecarily be any more stressful on a turbine than anti-lag, which I'm pretty sure the MG-Lolas are running. I was more concerned with having to tune the motor to a fine enough edge at those numbers that it eats internals often, truth to tell.