E=MC2????

[JackD]

They are to loud and give the starter a head ache.

See,even Glen likes them.

[dick elliott]

Somethings wrong here! If a rotary is such a ringer, why is there only two(2) rotary records, that are 20 and 28 years old? Could it be that the factor is wrong. If SCCA has got it right at two(2) times, maby its time for a change.

The records I mentioned in an earlier post are slightly in error. I spoke to Steve Shotrosky who owns most of the records. I found out from Steve that only the E reocrds were set with his rotary. The F class records were done with a water cooled V6 Mazda piston engine.

Sorry for the misleading post.

DW

[NArias3]

They are to loud and give the starter a head ache.

...and don't have any pistons! Boo

Just kidding, guys. Ever since pitting next to Terry Hoard's "Samurai Warrior" years ago, I've been intrigued by the inner-workings of Rotarys. Still baffled by their function.

Nick 3rd.

[Dr Goggles]

...the mercurial Dave Partridge runs a 13B Rx7 in the DLRA with a Megaphone that looks like a gas gun that they scare birds off crops with.....it gives the starter and anyone else within MILES a headache ...everytime he shuts it down he gets a round of applause....it sounds BAD!!!!!...it's in E.....I'm not sure if that's Evil , Ennoying or Excruciating

[Rex Schimmer]

Dr. Goggles,
When we ran the RX7 in GTU with our fuel injection set up we would run 10% nitro , just to get a little more off the corner torque (10% would move the max torque up to around 185 lbs_ft) well when the car would go into a slow corner we would pump raw fuel into the exhaust and it would light as soon as the throttle was picked up and we would get a 10-12 foot blast of flame out of the big megaphone! Nobody would follow us into a corner close the dam thing would take the paint off their hood!! Damn those were fun times!! The only guy that knew that we were running some "pop" was Jim Busby, an old drag racer.

Rex

[Dynoroom]

I am a big fan of the rotary as I was involved with 3 different race teams back in the early 80s that raced them in the IMSA GTU class. At that time there was a big protest by the recip guys that the rotary had an unfair advantage and made more hp than the 2.5 liter Datsuns and Porsches. Well I can tell you I spent many hours on making special parts and testing on the dyno and we never made more than 305 hp on a 12A with periferal ports. This was done with an engine that we built just for development work and it was built using "race tested" parts, ie. OLD. and used a mechanical fuel injection system that had a pair of 50mm slide valve throttles and a Kugelfisher injector from a BMW 4 cylinder race car. We tried lots of things, including 2 stroke style expansion chambers and every kind of port configuration you could think of and found that the standard Mazda race parts were the best. The engine like to be well broken in as they got more hours they ran better. We also found out that they liked to run lots of oil temp. Running the oil at 275 deg f was good for about 10-15 hp over running at 175 F. We never saw much more than 160-165 ft-lb of torque, we got 175 ft-lb once by making the injector stacks about 15 inches long. This got us thinking about making the intake lenght variable but the development money was gone by then. Mazda did this with their GTP cars.

The rotary had two real advantages in my mind, 1. They were "anvil" reliable. We would run 24 hour races with a 9500 rpm limit and 12 hour races at 10,000 and sprint races at anything it would take to win! 2. The rotary has a very low moment of inertia for the rotating parts, which means that they rev really fast. Add a two plate 6 inch dia clutch and a spidered flywheel and a good gear box and they would beat anything out of a corner.

If SCTA would go to a 2 times factor instead of the present 3 times sweep volume factor I would build my future lakester with a rotary in a heart beat! You can rebuild one in a couple of hours and again you just about can't break them.

Rex

What did you say Rex? Hello...hello... Rex you there...

I musta spent my time at the IMSA races to close to Cunninghams weed wackers.
See ya later cause I'll never hear ya.

[Rex Schimmer]

The first RX7 that I worked on was the 79 car of Bob Bergstrom and I think it was in 1979, and at that time IMSA did not require mufflers and the Mazda competition exhaust was two 1-3/4 stainless pipes coming from the engine and merging into a big megaphone and man it was LOUD!! So bad that in 80 IMSA required mufflers and Mazda came out with a real nice stainless steel unit that cut the sound but had a very minimal affect on the power.

I will bet that the noise level without the muffler was 125-130 db. I know my hearing was damaged by these things.

HUH! what was that you said!!!

Rex

[JackD]

There is a back motored dragster hooked to an auto trans that runs the Sport Compact series for cheap.
He runs outboard style exhaust stacks and I can still hear them.
The Street Race kids like them because they make a lot of noise and you can really rev them because they(the kids or the car) can't shift very well anyway.

[Bob Drury]

Nick, I remember Terry Hoards Mazda well.  No matter if you were in the pits, or the bleachers, that car was louder than any Fuel car of the day!  The S.O.B. was also plenty fast, even if it was anoying to the ears........

[Dr Goggles]

....and it's not just the volume it's the unsettling ( or lack of) rhythm that really makes your hair stand on end