RX-7 - good track car?
 

You may remember a while back my wife was deciding between a Boxter and a 964. The idea was to have a car that would be both a good daily car and a good DE car.

Well, that all changed. She decided to keep her car as the daily driver, and to get a track car for the track.

Next month, she'll change her mind again. :D


Anyway, the question at hand today is regarding the first gen, series 1 RX-7 (SA22C). I have found one that is prepped to the limit of SCCA's ITA/IT7 class. And it is at decent price.

Are there any RX drivers on the board that can give me an informed opinion about the durability, etc?

Thanks.

What kind of track driving do you want to do?

Are you only interested in DE's or do you want to race?

I know a little bit about RX-7's.

Nah, they're horrible, just as that Jim Cesiro (hope I spelled that right) guy. J/K

I'm sure Jim will be along any minute with a plethora of info for you.

Like I said, any minute now. :D

LOL!!


This guy is a friend of mine and drives car #63. It runs in the ITS class. This car is a front runner and has run the same engine for 8 years now. It has never been open and he races full seasons throughout the southeast. He is fighting for second in this pic.
http://i6.photobucket.com/albums/y21...3/DSC_0044.jpg


These are faster than a IT7 or ITA car but both will provide you with a good reliable car that will need little work. Of course I would prefer to have one built instead of buying someone elses car. The initial outlay will be more but the long term expenses would be much less.

I prefer the 2nd gen cars over the first due to the IRS on the second gens. The 1st gens as you probably know have solid rear axles. They handle amazingly well, but, a well setup second gen is just amazing.

I hop this helps.

As mentioned, the car is primarily for my wife. She wants to participate in DE events.

My interest is that it is a fairly inexpensive way for her to have her own racecar. And if she finds that she doesn't like racing, it should be fairly easily to unload without too much of a loss (tire walls permitting).

She has never done any type of racing.
This is an entry level item for her.

I thought the Wankel engines were considerably less efficient than "conventional" piston type engines. . .

It sounds like you have a good plan. Great little cars not to fast in a stright line but they handle great. Good well balanced car to learn in.

How so?

A fist gen has a 1.1 lter engine cranking out 125HP in a car that is about 1800-2200 lbs.

They can have the piss revved out of them for many years before they need to be rebuilt. Where as a piston engine will need a yearly refresh after a season of abuse.

They do drink a lot of gas. She will probably see 10MPG on the track in a 1st gen. My Turbo which is a 1.3 liter gets 5MPG on the track. It eats a lot of gas though, and makes a lot of power.

And oil, I have heard.

I'm talking about Carnot Efficiency. . . I think a good piston engine runs on the order of 20-25% and a Wankel running in the 15-ish % range. . .

Of course the power output is only one piece of the puzzle, but I was just curious. I've always been fascinated by the rotary engines in those RX-7s (wanna-be 944s! :D :D :D ).

The power-to-weight ratios are very good, despite the fact they're less efficient with their chemical-energy-to-kinetic-energy conversions though.

They actually burn oil on purpose. They have oilers that inject oil into the Rotor housings in order to keep the Apex Seals lubricated.

Which did not work good BTW - I actually mix 2 cycle premix in my gas, about 4 oz. per 10 gallons for the street and 8 oz. per 10 gallons on the track. This is for a turbo though. My friend with his ITS car does not even premix.



Jeff- You lost me dude. I am no engineer. I just play with cars. All I know is that I have a 1.3 liter engine with a mild turbo on it, (T04e) and it puts down 400 to the wheels. It did this problem free for 3 years until my dumb ass overheated it.

I know that the non-turbo RX-7 back in the day put out power comparable to engines 3 times its size and was classed accordingly in Drag Race events.

My RX-7 with its 1.3 liter engine was classed in ASP in Autocross when I first started (Now its in BP) that class had modded Vipers and Vettes.

BP has very light big engine Vettes in it. These little engine put out a lot of power.

How a rotary works.
http://www.youtube.com/watch?v=oGrD7FTFLJc

Honestly, for a cheap, reliable track car, nothing much beats a Miata.

While I am a fan of rotarys, they do have poor thermodynamic efficiency due to the crescent-shaped combustion chamber, compared to the ball of flame in a conventional piston engine. The flame front pushes directly onto the piston dome, whereas the flame front in a rotary has to push to rotor sideways (to oversimplify).

Lotsa power when you spin them up fast, but it takes a lot of gas to do it.

The Wankel motor is, from what I've heard, extremely hearty - maybe even more so than the flat-six. There's a reason the new RX-8 can safely rev, in the consumer's hands, to 9,000 RPM.

Jim - what is your opinion of the RX-8? I've seen some reports that on the race track, with light modifications, they've pretty much wiped clean a lot of the competition.

If you're thinking about RX7s, why not consider a 944?

Price.
The 944 would cost more to purchase and considerably more to maintain and repair.

Amen,
plust the IT/7 cars are very obnoxious. Very, Very loud. If this is for your wife, she probably won't like that.

Get a miata...I drove a spec-miata to get my SCCA license and it was a blast...as much or more fun than my 911 race car.
Very well balanced.

I was at a Rotary only AX and my friend let me toss around his bone stock RX-8 with worn out street tires. This was right after getting out of my car with slicks.

I was blown away at how well it turned. Yes it was down on power but it could rail.

Speedsource is doing quite well with the 8's racing they are having lots of success.

I agree a unmuffled cat free rotary is just plain rude. My car with its turbo muffles a lot of that obnoxious sound. My car has a deeper sound than a NA a lot of the tinny sound is not there.

If she is only doing DE's though there is no need for a full on racing exhaust. She could even put on a stock exhaust complete with the cat and it will be very quiet. She might loose 10-15 HP.

I still contend a Rotary is a good choice. Maintenance requires you to change the Spark Plugs, Fuel Filter, Air Cleaner, and oil. Thats it. Then engines are hearty and will last a really long time without a rebuild. My friend racing for 8 years without opening the engine is typical.

I like Miata's too but I am unaware if the engines hold up to the abuse long term.

Also if she misses a shift or hit a wrong gear a rotary will usually hold together from the abuse.