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Dedicated Lemons/Chumpcar Thread

Old 03-27-15, 10:40 AM
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Then it's a perfect LeChumpWRL car. Patch the floors, tie the spreader plates to the sills and you'll be golden.
The NA trans is made of glass, you'll end up using all 3 of the spares you have. Unless of course you can convince your teammates to count to 2 alligators while they make that 2->3 shift at 8k RPM as they try to outdrag that E30 off the corner. I got tired of swapping trans' and put miata trans guts in and haven't looked back. Replace with new every cooling hose that's needed and bypass all those that aren't needed. Plumb into the cooling system an oil pressure idiot light switch from a 65 Impala (or whatever) and wire it to an LED trailer clearance light on the dash. Once the car comes to temp the light goes off. Instruct drivers to stop immediately if it ever comes on. As someone pointed out once you overheat, the first tool you grab is the engine hoist. While I haven't messed with any of the BMW stuff, I've found these things are the easiest to make handle and easiest to drive fast. Keep it cool and you'll have hours of fun.
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Old 03-30-15, 04:04 PM
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Was anyone at VIR last weekend?
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Old 05-04-15, 04:33 PM
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Well the test race at gingerman was both good and bad.
The car was fairly sorted handling and braking wise. It should now that is has three new calipers and all new rotors and pads.
We were running a top ten setup if we could run a two hour stint.


Bad news is we ran low on oil twice and and then blew the motor. =[
It made over 100 laps in the race plus 5 or so 20 minute test sessions.

Anyways it looked good! Cant wait to rebuild and dominate at the 24 in Joliet!!!









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Old 05-05-15, 10:35 AM
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Did the exact same thing to ours at Thunderhill last year. In the process of re-installing a rebuilt one. As part of that process, I've put in a Rotary Aviation OMP bypass along with an old snowmobile oil tank to hold 2 stroke oil. It seems like we're fighting oil consumption when the thing is WOT alot. I'm sure everyone will chime in to just premix but that's a risky proposition for us. We've got 4 cars and only one is rotary. Making sure it's only premix going into the RX7 only is not something that's easy to police once you go past the first stop unless you have someone whose sole job is to pit manage. Well, we all drive so we don't have that. Anyway, I feel your pain.

I'm curious about your splitter. How/where is is mounted? How far under the car does it go? What's it made of?
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Old 05-07-15, 08:00 PM
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Yeah its my fault as the warning buzzer was going off and i thought it was my coolant level sensor bypass acting weird. Turns out it was the oil level buzzer. We have no idiot lights and that again is my fault. Lesson learned.

The splitter came off our Trans Am cars where i work. We replace them all the time so i pulled it out of the trash for myself.
Its made of signboard. Basically a 3/16" sheet if plastic sandwiched by aluminum foil.

It 80" wide by 24" and we mounted it by welding washers horizontally off the front tow hooks. Then putting a long bolt down throught the washer to the splitter.
The front is just held in by little l brackets inside the front of the fenders.
Plus the front splitter braces.
It goes just behind the bottom of the radiator to seal it as the undertray.

Its a good setup. We ran cool as hell the whole weekend.
I also fabbed an airbox in front if the radiotor so air has no option but going throught the radiator and oil cooler. Designed off the trans am cars as well.

And the brake ducting hose is shop ac plastic hose but it wokted awesome! No signs of melting at all

Last edited by Customisbetter; 05-07-15 at 08:05 PM.
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Old 06-10-15, 08:58 AM
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1st rebuild!

Hey guys, I have never posted in the rx7club lemons/chump section before but here I am!

Anyway, been racing lemons on the east coast for the last 3 years and then we did some chump last year as well. The car is a 84 gsl-se, it was painted like a snail initialy "es-car-go" and now is just mazda blue and white.

Long story short as a lot of you have described we had been mysteriously losing coolant for awhile. Not too bad, but we had to watch our temps. Finally in NH the coolant seal gave up the ghost and we were just shooting water and exhaust out the radiator. (I will also admit we ran the car for 2 days like this, stopping every 30 minutes to let the motor de-spike it's temp and refill the radiator)

Through all this the motor has always pulled strong though, which is reassuring. It is also totally stock.

With that background: Any suggestions for a first time rotary rebuild? Specifically as it pertains to crapcan endurance racing. It is the stock s2 13b that came in the car. The motor is currently out and in my garage. It comes apart this weekend.

Note: we do plan on porting it. Was going to do a basic street port to keep things reasonable and so we don't have to rev it out toooo much.

Also note: We are not/can not blow major dough on this rebuild.

Any experiences and advise appreciated!
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Old 06-10-15, 11:06 AM
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This is one area where you are probably going to get a very wide range of opinions. Some people will say you need new housings, irons, all hard seals, etc. Some (like me), try to do it in the most crapcanlike method possible and reuse everything possible to keep the bucks down. I'm currently going through a backup engine that all I did was assemble from my best used parts except for new soft seals. Why am I going through it again if it's a fresh rebuild? It doesn't make enough compression to start on the starter but push starts and runs fine otherwise. I cheaped out too much.

So here's my recommendation. Buy the Rotary Aviation rebuild DVD. Buy some porting templates (can be found used in the buy/sell forum, I bought used Pineapple ones). Look at your housings. If the chrome isn't flaking off the edges (too badly) and the area around the exhaust port isn't too jacked up, I'd probably use them again. If not, you can find good used ones on the forums here. I just bought a set of newly Goopied housings off craigslist for a good price. Buy 2 good carbide porting bits and 4 flapper wheel polishing bits that will fit inside the ports. Put tape around the face of the ports because you will skip the bit off the face of the iron at some point. Everyone does at first and so far I've been able to polish my whoopsies to smooth them out with no problems. Port your irons. Now take them to have them checked out and resurfaced by a shop that knows how to do it. At that point you'll find out whether or not you can reuse them. If so, great. If not, you got in a practice porting run and you'll have to find some other ones. I've got irons ready to go off the forum, ready to go off craigslist and cores or rebuilt off craigslist (reminds me that we've blown up a fair number of motors in 6 years of LeChump). Dunno if they work in an S2 but a S4/5 T2 middle iron is essentially preported for us NA guys. Buy one of those gallon cans of carb cleaner. Find some tupperware just big enough for a rotor to sit in. Let it marinade in the carb cleaner overnight and then flip and another overnight soak on the other side. All the built up crap on the rotor will come off with a brass wire brush (harbor freight). There is a Racing Beat mod that involves replacing the stock ball bearing oil jet setup in the eccentric shaft with a weber carb jet. Google it and do it. Buy a harbor freight micrometer and check your side seals. Same with the hard oil and corner seals. They probably are within spec.

Next is the hard part. Buying parts. I typically buy the Atkins kit A (or Rotary Aviation equivalent) and the Rotary Aviation classic apex seals and springs. Bearings are usually fine unless it got run out of oil at some point. The bearings will show copper at the point they are joined but shouldn't show copper or scratches elsewhere. I typically clean the crap out of the insides of the motor but don't bother with the outside (don't want to look too cheaty, Judge Phil knows how much a rebuild kit costs). Setting the end play is important in these things so make sure you can beg/borrow/steal a dial indicator setup. When they resurface the irons, the engine gets a little skinnier which changes the end play so you can't always expect to put the same spacers back in and be stylin.

So to recap, your shopping list should include a kit that includes all the soft seals and gaskets ( i think the RA set doesnt include the pan but can't remember). New Apex seals. Resurface the irons. You can scrimp everywhere else. I've bought used side seals off the forum here. Something to remember, most rebuild opinions are based on making a motor that will last 100,000 miles. While it's a sad thought, your 3-4x a year racecar won't get that far so rebuilding to last 10-20,000 miles is more realistic. That's why new housings, irons, etc are not an absolute must. I would guess that you should be able to pull this off for $700-$1,000.
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Old 06-11-15, 11:30 AM
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Thanks cheseroo! I think you actually responded with similar detail to a lemons forum post I made on the same topic

Well, I'm doing the tear down this weekend, so expect pics of the rotors and housing and irons to guage re-usability
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Old 06-14-15, 08:51 PM
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You guys have no idea how badly I want to throw together a rotary powered LeMons car, I picked up a 12A a while ago with the intentions of it going in our foxbody Mustang for that exact purpose, but alas those plans fell through.

Awesome to see other people doing it though!
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Old 06-15-15, 10:06 AM
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My motor spun the front rotor bearing in spectacular fashion due to no oil. Lol

Front and center irons toast. Front rotor has every seal welded to it. Eccentric shaft could be saved with machining but why when a replacement is so cheap.
Just got two rotors, e shaft and two irons for under $350 delivered. I expect to pay another 1300-1500 on the rebuild kit and bearings. These motors last way longer than the v8s but the cost of rebuilds is much larger those piston competitors.
Excited to get my beast back up and running for some track days this year. Not sure if i can get to a lemons race due to my work schedule. However i work on a trans am race team witg a trailer so maybe i could being it to a test day.
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Old 09-28-17, 02:48 PM
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double post

Last edited by Vash Stampede; 09-28-17 at 02:49 PM. Reason: double post
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Old 09-28-17, 02:49 PM
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Other then team Shalen's has anybody else has success running the Rx-7's, not just finishing but winning? with the Original motor in it.
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Old 10-02-17, 11:26 AM
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Originally Posted by Vash Stampede View Post
Other then team Shalen's has anybody else has success running the Rx-7's, not just finishing but winning? with the Original motor in it.
Original drivetrain? Don't think it's possible. Only somewhat recent overall winner I can remember is the RX7 that won BFE twice in a row with the last one happening 3? years ago but that CO race seems to have a high number of hoopties and a low number of fast cars. The NA trans won't take the beating, they go about 1.5 races before 3rd gear synchro gives out. You need to do the Miata trans conversion. A stock S5 making 160hp isn't enough oomph to compete against the 3 series BMW nor do they have the torque to navigate heavy traffic like other cars. Once you start porting them and doing stuff like that, the fuel consumption gets near V8 levels. The best we have done is been as high as 7th late on Sunday (before wheel bearing failed) in these hugely competitive west coast races. It seems like the Rotary Rooter car has finished top 5 before but the top of the field out here is full of 3 series BMWs and Miatas. A group of experienced near pro level endurance racers could put one up near the top but would need everything to go perfectly their way to get there. I don't see amateurs winning a west coast race in a stock RX7 ever. We just ran a race last weekend in my teammates E46 that is about 5 secs a lap faster than our RX7 and it was a huge struggle to get into the top 10 (out of 135). I'm currently getting ready to swap a Duratec V6 into our RX7 because it weighs the same, a stock one makes as much HP as our ported one and the stock torque is 50pts higher than a ported RX7's.

Having said all that, a stock RX7 with all new cooling hoses and all efforts made to keep it cool will run reliably for many races on end. I haven't raced a 1st gen but our 2nd gen handles fantastic with only cut stock springs and used aftermarket swaybars front and rear. A set of Mustang GT wheels gets you 17" tires and Hawk brake pads will last you several races. That's like $300 of parts to make the car handle and stop pretty much as good as anything else out there. Sure you can certainly spend more money on stuff but the gains from there become incremental. A bigger rear swaybar does make it easier to spin out in the beginning but once you get used to it you can make all kinds of overdriving mistakes and the car is very, very predictable. Everyone who gets in it just loves driving it. Where you get into trouble is when you start adding performance to the engine without spending cubic dollars. Then your reliability goes to hell, you stop finishing races and spending more money fixing blown up engines.

If you haven't run LeMons before regardless of experience, you won't win right away. First you need to make the car reliable. Then you need to not only figure out how to race but to race with the weird techniques LeMons requires (passing 3 wide in corners without slowing yourself down much nor screwing over the other 2 guys at the same time). You also need to be able to be making the same lap times at hour 2 or 3 of your stint as you did 30 minutes from start of stint. Plus doing all that without putting 2 wheels off or PUY or anything that gets you a black flag. Your stops also need to be organized so you don't give away 5 laps to all your competition each time you come in. The pointy end of the field is very tough to break into. But the rest of the field might even be more fun because there is no pressure to do well but just go fast and have fun. If I come across as negative, that's not my intent. I'm just being pragmatic. We have been having a ball doing LeMons and Lucky Dog (Chump has been mixed but they dumped the guy causing most of the problems) and I highly recommend it.

Last edited by cheseroo; 10-02-17 at 11:27 AM. Reason: spelling
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Old 10-03-17, 08:27 AM
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I run Chumpcar now with a pretty much stock E30. The more races that I run the more I see that it needs the E36 engine swap, like pretty much everybody else has done.
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Old 10-03-17, 10:26 AM
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Or maybe a Slant 6 from a Dodge Dart?
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Old 10-04-17, 11:51 AM
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Originally Posted by Customisbetter View Post
Or maybe a Slant 6 from a Dodge Dart?
As much as I like the Leaning Tower of Power, it's nice to get into a faster car once in a while. Plus the /6 is a bit blow-uppy. I've won 5 or 6 IOEs with some pretty slow and unreliable cars (ToyoHog, Renault/Dacia R10,Sunbeam Imp,etc) so it's nice to stretch your legs from time to time. I'm ok with the Duratec swap. I already bought a whole Lincoln LS so I have most everything I need.
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Old 08-27-18, 01:33 PM
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Originally Posted by Vash Stampede View Post
Other then team Shalen's has anybody else has success running the Rx-7's, not just finishing but winning? with the Original motor in it.
Just to update this...

We won many races with our stock 13B powered S4. (We are also the team that Cheseroo mentioned when we won the BFE GP 3 x back to back with a 12A powered 1st gen). We won Lime rock 2 years ago (and the year before).

Last year we swapped to a GM 3400 engine. Thsi didn't provide much of a HP bump, but the torque is incredible and really helps go through traffic quicker.

If I was going to build an RX7 cheap car racer, I would probably start with a swap. Better fuel mileage and easier passing due to torque!
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