question... just graduated from college in december and am planning on buying my first car around the start of '03. anyway, the rx-8 is on the top of my list of cars that include the passat, the new saab 9-3 and others. i've been trying to investigate about rotary engines and how reliable they are and how they fair versus normal engines. i know that mazda has been testing this renesis engine for a while now but just wanted some more info from all you rotary heads out there. since this is my first car, i want something a little flashy and reliable/to last for quite sometime as well. do you guys think the rx8 will be a keeper for some time.

thanks in advance

 

Well, I think you're about to get flamed on this thread!

Basically there has been a lot of discussion on the "first car" topic,... While I believe that dispite the reliability problems in the past, mazda has been VERY carefull to address them with this car and it will be reliable.... the conclusion has been that this is NOT "first car" material since it will undoubtedly take some experience etc. to drive safely.

Any 250+ Bhp RWD car is going to be a handful, and you should probably get somthing a little more forgiving for the first year at least.

 

Blue, he didn't say it would be the first car he's ever driven much, just the first car he's going to buy himself.

To answer your question... There are at least two main differences between the RX-8 and the other cars you're looking at. One is, of course, the RX-8's rotary engine. Rotaries, when normally aspirated and taken care of, can last a *very* long time. It is not, however, an engine that you can abuse (not keeping the oil topped, etc.) and expect to forgive you, as I understand things. Most of the maintenance problems you hear about are, from what I've heard, due to people not taking care of the engine, or in the turbo-charged versions, which tended to have heat problems.

The other main difference between the RX-8 and the cars you mention is that the RX-8 is a rear-wheel drive car. The Passat is available as a manual only in the front-wheen drive versions, not the all-wheel drive versions. The Saab is front-wheel drive only, and the high powered ones (9-3 Viggen, in the past) have been criticized for torque steer pretty severely. I will, however, admit to liking the current 9-3 and the Passat. The new 9-3 though... losing the hatchback just makes it to vanilla for me. Most enthusiasts prefer rear-wheel drive (or AWD for the rally-car fans) to front-wheel drive.

Most of us here are waiting for the RX-8, but if you're looking at spending about $30k, which is what it appears, other cars you might as well at least consider are the Acura TL type S and CL type S, and the new Infiniti G35. Acrua has a great reputation for reliability and several people here have raved about the TL-S. The Infiniti has been very well-reviewed, too, and the engine in it has been around a long time and has most of the bugs worked out of it, too.

 

Yeah... I wasn't flaming thou, just observing what has been said before.

 

dankgummy,
To echo PatrickB's post, the 1st & 2nd generation RX-7 motors (13Bs and 12As) were quite reliable and lasted a long time. However a rotory power vehicle is not something to bring into Firestone or Sears for service (I learned the hard way on that a long time ago).

My 85 RX-7 (12A engine) ran 135,000 miles with only one problem, I let it over-heat (fault radiator at 120,000 miles). However when I had it repaired (and modified) they had to open up the engine. The rotor chamber was almost smooth as silk. If I remember correctly, Pettit Racing did the work in Ft. Lauderdale, FL. Most of the time they recommend sand blasting/refinishing the rotor chamber but mine was flawless. The apex seals were replaced, the inner & outer seals replaced and I was in business.

The moral of this story, with regular oil changes (I always used 20w-50) at 3K miles, keeping the car motor tuned by a knowledgeable rotary mechanic, and keeping the cooling system in good running condition, you'll get 200,000 miles out of a rotary engine. Last I heard (around 99) my old baby had 280,000 miles on it and was losing some compression (time for new apex seals).

Okay, I've rambled on enough.....

 

If you do a quick research on rotaries, you will probably think they are unreliable. That's partially because the newest and most popular rotaries are turbocharged. Turbocharged engines just don't last as long as n/a (goes for all types of engines). For instance 2nd gen ('86-91) RX-7 Turbos like mine will only last around 120-140k miles vs the n/a will last 200k miles pretty easily. I can't remember exactly, but 3rd gen RX-7s (TT) tend to only last 100k miles or less. (not really out of line given their performance, you wouldn't complain if you owned the 911 turbo that the 3rd gen nuked on the track when it first came out)

A big advantage to rotaries is that they can be driven hard and will last like you drove them nicely. The forumula is baby them on maintanence, beat on them when you drive them! Rotaries can be more reliable in the sense that there is a lot fewer things to go wrong. The only purely core engine problem you will hear of, is when the seals go.

Note: Rotaries are more suseptable to poor maintanance than piston engines. You can make a n/a rotary pop very early if you treat it poorly. Rotaries are also much less resistant to overheating.

 

Well I personally do treat my cars very well.. regular maintenance, synthetic oil changes, etc. I do most of the minor mechanical work myself. What if any "special" attention will this motor require? I'm used to just doing regular maintenance on my Honda's.. fluids, filters etc.. valve adjustments, not with the rotary
I definitely baby my car and definitely beat on it at the track! :D

 

Quick_lude,
It's really the oil and watching the engine temp. I always used 20W-50 in my first gen. I let the car over-heat and thus we had to replace the inner seal of the rotor chamber. Well that's when I saw the pay-off of the religious oil changes with high quality oil. The chamber was flawless. At 120k miles the apex seals really didn't need to be replaced (although we did it anyway).

Another issue, however minor, is the exhaust. Because the rotary engine produces so much more heat, you just need to ensure the exhaust system flows well.

Then there is detonation. This will kill a rotary engine. It's very important to keep the engine tuned and use the correct fuel grade. This is especially crucial with the FDs (93+).

Lastly, some RX-7 owners (especially FD owners) claim there is a start up procedure to ensure oil is not sitting in the pan when you crank her up. As with any car (especially with a turbo) you need to let the car cool down properly.

It's not that a rotary requires more maintenance or is less reliable, it's that a rotary motor is a high performance engine and should be treated as such.

I hope this helps.

-Mike

 

What are the special cool down procedures that a rotary requires?

 

With a turbo, you should allow the car to idle for at least 2 minutes after driving. More time is recommended if you've just been driving hard.

I'm not exactly sure what happens but allowing the to car to idle will allow for circulation of the oil thus more effecient cooling of the turbos. Any FDs out there, please explain this better because I certainly can't.

A popular aftermarket accessory that does this for you is a turbo timer.

-Mike

 

Turbochargers(and rotaries for that matter) generate tremendous heat. Shutting down the engine before the turbos slow and cool down to idle temps can boil or "coke" the oil in the shaft bearings into a sludge. There's different opinions of how long you should let the engine idle on the RX-7 TT, because the non-sequential turbos are also water-cooled and don't operate as hot as "oil-cool-only" systems. The RX-7 needs lots of cooling air, and idling too long brings the temps way up. They also heat-soak after shutdown, where the underhood temperatures actually INCREASE after engine shutoff. Guaranteed to heat up a closed garage. Sometimes you can hear coolant boil in the turbo cooling lines and hoses if there is any air in the system. Many people do the "fan mod" to manually turn on the radiator cooling fans a few minutes before shutdown. Babying the gas and popping the hood as you approach your parking spot aids in cooling the car.

 

While some turbo rotary engines, especially the modified ones, require a little more than normal care and feeding, the normally aspirated rotaries of days gone by actually proved to be very reliable engines, which didn't require any more maintenance or attention than other engines (I had an '86 NA RX7 for five years as my only car, and I paid no special attention to it). From what they've mentioned about the gains in the Renesis engine, I would expect it to be even more reliable than past rotaries, so I personally expect this car to last me for as long, if not longer than my RX7.

---jps

 

I'm a 2nd gen TII owner with 145,700 miles. Will probably be 175,000 by the time the RX-8 comes out

My only real problem is a leaky injector that I've been too scared to fix (afraid all of the wiring will crumble), so I just use a fuel cutoff switch for starting and shutting off the engine.

 

From what I have read Mazda has really taken the Reliabilty thing very seriously, they made major modifications to make it freer breathing, made it Natuarlly Aspirated and coated the engine with Ceramics. This engine is much more resistent to heat than the old engines thus much of the reliablilty problems are gone. This engine is going to be Mazda's bread'n; butter for few years. I think more work was put into that engine and its exhaust and intakes system than anyother part of the car. If you look at the other post about no tranny til 2005 you can see that they engineered the engine past thier ability to build a auto tranny for it. I can't wait to open that car up at full throtle on a smooth long road.........:p

 

With your 'ludes 4, you could change your oil every 10,000 miles and it would last. A rotary would not last long in this situation. Most people do not follow the oil changing schedule with thier cars.

When Mazda was developing the 3rd gen RX-7 engine (13B-REW), they performed one test where they held the engine at 8000rpm for 6 months and it was still running. Another osscilated between 7000 and 8000. :D Granted this probably wasn't under load.

 

true, a loaded engine would place far greater pressure on the seals, but it was a test for oil, right?? the temp would be very close to the same, wouldn't it?? and thus, wouldn't it not matter the load on the components, but only the tempurature of the oil and how quickly it was being mushed around and circulated?? just wondering...

 

It was done as an overall test of reliability. I'm not positive, but I don't think the temps would be the same as underload. More gas = more explosions.

 

Well the exhaust ports are on the side now so apex seals should last longer without having to move over that port . I can see this engine easily lasting over 250,000 miles.