hey im new to the wankel i have some questions


Asked by Apr 07, 2009 at 12:44 PM about the Mazda RX-7

Question type: Car Customization

Hey ive been podering the idea about the Rx-7 for a long time. proforably the 93 and up body but people frown upon the idea of this vehicle everytime from a tuner aspect.

I was wondering if anyone of you have experienced tuning this beast of a motor and what the pros and cons are?

what are the best aftermarket parts for it?

and is it really that hard to work on a rotary engine?

oh and also how easy are the parts to come by?


9 Answers


she's a bitch, I own a 93, a complete love hate relationship, and if you do something wrong, you're gonna end up having to rebuild the motor. She responds really well to meth/water injection as it really cools everything down, the best part about a rotary is it's ability to flow so much air. the best aftermarket parts are a good meth/water injection kit and a standalone ecu, preferably an Apexi power fuel controller (PFC) or a Haltech (SP?). after that it's all about what's in your budget, but quality parts are what you want and things can get pricey, but there is a LARGE aftermarket for these cars.


nice thanks for your advice. what are some common problems with them?


I can not recommend the rx-7 to anyone I liked and i have a hard time telling people I hate to get one too. The sites listed are about the best. Expect to pay $2500 for rebuild kits every so many years under normal use. Under extreme tuner conditions you are going to pay through the nose not for the parts and kits but for just the regular maintenance. Apex seals are the killer, expect to pay $900+ and having your engine pulled ever so often with break downs and rebuilds. Also if your photo is anything like the temperature where you live, the rotary has a subzero starting unit that can be tricky for people that have never seen anything like it before. Another problem with the rotary is the lead in and lead out spark plug rotations and expect to foul out plugs with a vapor lock every so often as well which will run you $12 and a headache if your car happens to stall out. If you can get past all that and still have your heart set on one. Go for it, could be the best mechanical toy you have ever had and you'll be in good company of other rx/fc fans. If anything you will end up learning a lot about cars and how cool the rotary is. But if that is not your thing then I would suggest looking at a Z car. Find a 300z or a Supra(sled), or even trick out an econo-box crx. Will save you the headaches and heartbreak that the rx-7 will give you.


I own a 1979 and have had many friends with Rex's over the years, the best advice I can give about the rotary engine is change the oil often, when the apex seals go out you've basically destroyed half your engine. In my case for reliability Im going to swap a GM v8 into mine, the power/cost ratio is much much better after the swap, tons of information as its quite popular, and quite a bit of aftermarket such as new engine cradles custom drive shafts etc. The rotary is great if youve got alot of mechanical knowledge and alot of money if you want to make it fast. I prefer the V8 swap for simplicity, economy, performance and reliability. This is my opinion there are alot of heated debates over this so you can take it or leave it.


As a foot note to my post about the V8 swap, dont listen to anyone who says it destroys the handling. Hundreds of guys have weighed the car before and after the swap and are damn near dead on 50/50 ratio afterward.


From a thread on https://www.rx7club.com """"The LS1 T56 88 TII that I have registers 2785# on the Longacre scales. The engines are heavier than a 13b (LS1 T56 completely dressed and with driveshaft is approx 535#) but the supporting hardware of the rotary makes up the difference. And yes my car has power steering, but it doesnt have AC which is usually dead weight on most FCs because it doesnt work anymore. All in all it made the car do everything much better than the rotary engine.""""" This site has alot of info and backyard engineering done by alot of people on the merits and challenges of V8 rx7's: http://www.v8rx7forum.com/ And finally the difference in cost: USED Rotary 1.3l two rotor turbo JDM spec 1200 incl manual trans and ecu !!205HP!! - http://www.bestofjdm.com/COMPLETE-PACKAGE-JDM-ENGINE-13B-TURBO-86-91-p/jdmmazda7.htm NEW V8 Crate motor 355ci no trans, no ecu required !!360hp!! -http://www.jegs.com/i/Blueprint+Engines/138/BP3555CTC/10002/-1 The difference is like apples and oranges, the turbo rotary is used but comes with a transmission, ecu and wires and stock is rated at 205hp(much less if your non turbo). As far as I can tell youll never get a waranty or a guarantee of HP when you buy a used JDM engine. The V8 is covered by a 30 month 50000 mile warranty, all new components, balanced, blueprinted ready to roll right out of the box. Just pick one of a dozen transmissions that fit. To make a more realistic comparison here is a three rotor twin turbo JDM engine (http://www.bestofjdm.com/JDM-ENGINE-20B-TWIN-TURBO-93-p/jdmmazda5.htm) which makes 280hp but does not include a trans and does come with ecu and wires (also much much heavier than a v8). To upgrade the performance of each you could add nitrous oxide and that will be a wash between the two, one could argue the v8 could run nitrous with out rebuilds longer but thats my opinion. Bigger turbos for the three rotor will cost alot (guessing around 5-6k) and will bring you to about 500hp in the 20b. A roots style supercharger for the v8 will run between 2-4k and will bring power up around 550 or so. The parts are cheaper and easier to find for the v8 vs the rotary. The problem is the cost curve is alot steeper for the rotary than the v8.. the faster you want to go the more expensive it gets. I could go on and on, obviously Im biased towards the v8 conversion its tried and true parts are alot cheaper etc...


just remember everything you do wrong will cost you a new engine, so don't do anything wrong. 93 Rx7 is a great car, stock 255 hp, but the fuel system is max out in stock form, so any upgrade you do, you have to do it with a fuel pump. When the car is new people put exhaust, air filter and down pipe, those upgrade are great when you got a WRX or EVO, but once the RX7 owner put those on the car, they blown their engine. Also wire tired all the vacuum hose when you take the engin out, or you could go V8, nothing is better with a 450hp on pump gas.


From my previous posts you may think I dislike the rotary, not so. The rotary is a great and unique engine if you can afford to learn about it. The BIGGEST problem I see with the rotary motor is its version of piston rings - the apex seals. Basically when your apex seals go out youve got a 95% chance that you destroy an entire rotor housing because the peices will get tossed around while the rotor spins causing much havoc. Also people who dont change the oil often enough ALWAYS have problems. The Wankel requires oil changes like clockwork, the Wankel requires oil changes like clockwork, the wankel requires oil changes like clockwork, the wankel requires oil changes.... you get the point. Multiply the urgency for consistent oil changes by 1000 if you own a turbocharged model. And here is a great visual representation of how the wankel works: http://auto.howstuffworks.com/rotary-engine4.htm


I had the original RX-7 and loved every minute I owned it.....but....you MUST CHANGE THE OIL!!!!! A lot!

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