Second Gen Mazda rx-7 Crap Can racing

Potentially interested in a race perapred Second Gen Mazda rx-7 for Crap Can racing. There seems to be a big gap between Team Sahlens the pro team, who I think is running a Rotary engine, teams that swap to V-6 or V-8, and the non-pro teams that run a Rotary. My question is can a rotary be reliable, fast, and do a 2 hour stint? Are they cheap to maintain, other then the $1k plus rotary seal? V-6 and V-8 are nice, but is the expense and reliability sacrificed? Plus your putting it in a "$500/500 point car" that can run in maybe 2-3 series (CHUMPCAR, AER, & WRL), 1 competitively.

yes

Chump I would be surprised you can get the point values for the swap cheap enough? Rotary's AFAIK are usually fine if well cared for in the bridgeport etc variety its when people go farther/add boost etc they seem to start blowing up?

There is at least one built car for sale on racingjunk

https://www.racingjunk.com/24-Hours-of-LeMons-Cars-for-Sale/182899802/1986-Mazda-Rx7-Racecar-Lucky-Dog-Racing-ChumpCar-Le.html?page=2&categoryId=4520&offset=12&from=category

There's a reason every sanctioning body has outright banned or severely handicapped the rotary engine:  they thrive on hard use and high rpm, so long as their requirements for fuel and cooling are being met.   It's a superior design. 

Well, I feel I am uniquely able to answer this....

We have 3 wins and 4 podiums overall in chump and lemons with a carbed 12a rotary in a first gen.

We have 3 wins with a stock 13b in a second gen.  Too many podiums to count....

We have 2 podiums including a 2nd with the same second gen now running a gm 3400.

Rotaries are stupid reliable when left stock.  Gearing is great!  They are a little outclassed unless you open the engine up and run a standalone.  Then, the sky is the limit.  Reliability goes down and fuel use goes up.  Still probably more reliable than any other engine in crapcan.  More thirsty too.

The v6 is more fuel efficient and makes 85 more lbft of torque.  About 30 more wheel hp too.

Do it.  If ya wanna swap engines after missing wins by a lap or two, let me know and I'll tell you how to make or swap for more hp.

Suspension is the key for these cars.

They are VERY fun to drive!

Wow great information.

I think a lot of the cars we run in spec7 can be run in LeMons.

To answer the op' s question... a second gen is reliable, quick, and can go 2 hours.

Team sahlens cars have a crazy amount of dialing in over the years.  They put down 187 up at Daytona 2 or e years ago supposedly on a stock intake, computer, and fuel injectors.

Now, they run haltech stand alone computers and some other fancy stuff.

Plus, they have some very good drivers!

All that being said, I believe they only beat us once....

The only time we beat the second gen RX7's we race against in Chump is when they break their transmission.

Fact or Fiction, you should add 16 ounces of castor oil per gallon to the rotary engine

Ummm, both?

I forget the ratio, but we just used regular old engine oil and removed the oil metering pump.

I think it is significantly less than 16 oz per gallon.  More like 1 oz per gallon.  I'll Google later and get you an exact answer.

Ours was a rally car, but met the requirements for crapcan racing as well- we mixed 1 oz per gallon of 2-stroke oil into the fuel.  It handled very well, had great brakes, and ran a whole rally with effectively no air filter, which did terrible things to the engine but didn't actually stop it from getting us to the finish line.  We only retired it because the chassis was disintegrating from metal fatigue after 30+ rallies.

Did you sell that rx7 yet? That would make a great ice racer and donate the used rally car engines too for their last hurrah lol.

In reply to fidelity101 :

I sold it and it subsequently changed hands like 3 times- I think it's in NY now.

-shameless plug-

I have a good FC starting point for sale, if you're looking for one :). It has Booooost, but that can be fixed pretty easily since it has a megasquirt.

-/shameless plug-

1988RedT2 said:

There's a reason every sanctioning body has outright banned or severely handicapped the rotary engine:  they thrive on hard use and high rpm, so long as their requirements for fuel and cooling are being met.   It's a superior design. 

People might think you're trolling, but strictly for racing use...this is not wrong. Rotaries work best when being run hard at all times. While they have some fast-wearing parts, they also have many less "lunchables" than a piston engine.

Do make sure the engine is burning extra oil along with its gas. A common RX8 mod is to remove the stock oil injection system and install a separate (remote tank) system so the engine isn't feeding on its lubrication oil, which is good for both combustion cleanliness and avoiding oil starvation.

Oh yea, we also ran a turbo rx7 at 2 races.  We did hurt the engine through water loss and overheating.  Put it top 5 at Watkins glen.

It was fun as crap until that happened!

In reply to GameboyRMH :

What, me troll?!

You must have confused me with someone else.

What kind of power does a NA FC make with your basic exhaust/intake mods and some porting? What can you safely repeatedly spin them up to?

Unless you upgrade the stationary gear, best not to exceed stock redline.

Stock S4 was 146 HP, S5 was 160.  So that's where you're starting. 

Jaynen said:

What kind of power does a NA FC make with your basic exhaust/intake mods and some porting? What can you safely repeatedly spin them up to?

We had intake, exhaust, no accessories except water pump and alternator.  Stock computer.

We put down 146 hp at the wheels.

They stop making power (with stock tune) fairly quickly above 6800 rpm (according to my dyno charts).  You can spin them all day long to the redline.

However, over-rev on downshifts can bring them up pretty high if you make a mistake.  I have accidentally got the wrong gear and saw the tach try to get to 8K+ with no ill effects.

I was auto crossing my RX-2 once and missed the first to second shift, the revs went to 8k+. The engine had a slight ticking noise after that wasn't there before. What could it be I wondered? I found out a week later driving home. Broke a tooth on the rear stationary gear. Ruined the rear rotor housing and side housings. 

While on the subject, if you're ever overhauling, switch to a Rx-8 stationary gear..

They're a much harder gear from the factory.  From what I've read (a few years ago), the Rx-8 gears should support up to 11k RPM.  Of course, you'll run out of stock porting & intake long before then.  The 4-ports (turbo) housings flow better at the high range and can of course be ported better on top of it, so setting a red line of ~9500 should be fine as long as you have the tuning and fuel to support it.