Damn, you beat me to it, Ken. The engine still have to last 2 races BTW. The thing weight 90kg and make over 7-800hp @19000rmp. You wouldn't expect it to last too much longer.

As for high rpm kill engines, my old Honda H22 rev to 8500 all day long, with almost 10k mile on it. If it wasn't for bad luck (got the engine used with crap in the oil pan, found out the hard way), it'd still be running. Oh, and it has pistons going up and down.

 

Rotaries and high RPM go hand in hand. MUCH different than in a piston engine. If you shock the eccentric shaft (like drop from 5th gear to 2nd gear when aiming for 4th near redline) you might lose your seals, but other than the, the most limiting factor on a rotary engine is the flywheel, and where in the powerband it stops making power.

The rotors are actually only spinning at 1/3 the RPM you see on your tachometer -- if its showing 3000RPM, the rotors are turning at 1000RPM, due to the gearing. So if you decided to run at 9000RPM all day long, the rotors are actually only spinning at 3000RPM. While yes, the heat build up would suck, and it would REALLY tax your ignition system - nothing would *most likely* go wrong. Rotaries die, not because of design error, but because of operator error. Remember that.

 

this is the absolute truth, N/A rotaries will have a long long life (couple even hit 300,000).

In all honesty i'd bet my N/A renesis against some of today's most popular engines to see which one last the longest, even the VQ's of nissan and the KA's in the honda's.

 

Whoa, is this really true? That is interesting. Any reason why they show 3 times the rpm on the tachometer? Is that to make rpm more comparable to piston engines?

Anyway, I think if you go for 6-port renesis engine with 2 oil coolers (manual or 06+ auto), car will last much longer. I have 04 auto and I had the engine replaced around 30k.

 

rpm has nothing to do with internal engine movements. Otherwise diesel and gas piston engines would also be different. RPM is the measurement of the output shaft - in the rotary's case, the eccentric shaft.

 

rpm shows speed of eccentric shaft so it does match up to speed of a piston engine crankshaft

 

Recall 4206F has nothing to do with heat. Catalytic converters do not cause loss of engine compression. The recall was issued to reprogram a few PCM parameters. The update modified the oil injection system. It also leaned out the fuel system on cold starts in an attempt to reduce carbon build up inside the engine.

It's probably to early to determine the Renesis' life span. There are many variables that effect the life of these engines. One of them being driving habits. You can't drive these cars like an old lady. They need to be revved. This is one of the reasons that you'll find the majority of flood rotary engines in the RX8's are attached to an auto transmission. People with manual transmission tend to drive a little harder. As far as heat goes, I haven't seen that being a problem. Early on in 2004 there was an issue with coolant leaking from between the engine housings but that was fixed with a production update.

On the other hand, last week alone my dealer order 3 engines for RX8's. One was replaced today, I was working on replacing another one today, and we've got one more to do. The thing that is killing these engines is carbon build up. That has been the major cause of compression loss. Mazda is currently investigating a fix but it may be some time still.

Brendan

 

^^^ A fix to the carbon problems? Find a way to include "must redline daily" in the owners manual WITHOUT people using that as a way of blowing up there engines on purpose and expecting a new one, or using that as an excuse in court for why they were speeding.


That or, get rid of all the automatic's. But, that will never happen..

 

It'd be pretty funny if all it took to remedy the engine replacements was a prescription from the dealers (or NA Mazda) for a bottle of BG44K or SI-1 every 5000 miles coupled with an order of mandatory WOT at least once a day. For legal reasons they'd pay the price if they told owners to redline 3rd gear unfortunately. Another example that, once again, bureaucracy rules over common sense in this country.

 

hmmm.. interesting... so I guess what I'm getting from all the reading is that by reving the engine it possibly increases it's life expectancy....

 

Maybe not necessarily increases so much as it "maximizes" it.

 

RX26B...you're not far off from the current thinking. Mazda has been experimenting with a chemical to decarbon these engines with some good results; it's stronger than BG44K, etc.... They are seeing engines with below normal compression readings that "come back to life" after the decarbon procedure.

Brendan

 

I think the chemical you are thinking of is...carburetor cleaner, or WATER.

Letting either of these get vacuum into your engine will cause it to clean itself, like a steam cleaning.

The carburetor cleaner is not recommended, however, as it removes oil and leaves behind a residue which makes the oil unable to lubricate. Simply letting a gallon of water get sucked into your engine (not all at once) and holding the gas pedal down enough to keep the engine from stalling, will clean out almost all the carbon in your engine.

Of the engines I've seen post-tear down with this procedure done, ALL of them have been spit-shine clean on the inside. They looked brand new.

 

Add another to the "previous RX owners club"! I had an '88 RX-7 GXL that had 125K on it when I traded it in!

 

The RX8 is my first foray into a rotary engine in a car.

I have had lots of experience with wankle engines in model aircraft. The only engines I didn't have a bi-monthly tear-down on were the wankles... they just ran.

I realize the comparison is thin at best, but it gave me a bit more confidence when I decided to buy my 8.

 

Yeah, of all engines used in competition platforms, the rotary engine is by far the most reliable. You don't hear, these days, of pro-drag cars running an entire season, if not multiple seasons, on ONE engine. Clutches, transmissions, they all blow -- but most rotary engines do not.

 

LOL - that was great

 

Gearing has nothing to due with rotor speed inside the engine. The rotors turn at 1/3 the speed of the eccentric shaft due to the rotors "stroke" (if comparing to a piston engine) or length or travel during a combustion cycle.


But reguarding e-shaft speed: In a convetional V8 engine, the pistons are only moving at 1/4 the crankshaft speed (where RPM readings from from), you but can't exactly compare piston rpm to rotary engine like apples to apples because rotars move in an orbital contunious movement (rotational), whereas pistons move up and down, stopping and starting 4 times during a complete power cycle, and their movement isn't rotational like a rotor is.

 

I found out today I need a new engine. Just turned 44,000 miles on the car, started experiencing some power loss and got a CEL. They checked the cat, which was good and then did the compression/vacuum test, which failed.

 

You got past the recall test with a bad engine?

 

...

 

You are confusing RPM & velocity .....

 

Good idea, yet i thought that if we told Mazda Techs that we experience an issue during redline, our warranty may come into question or 'abuse' may be brought up? Perhaps if worded, "I redlined to clear carbon and experienced ____ issue." Would allow dealers to work on issues that arrise during WOT?

Laters!
Edgardo

 

unless you complained about issues prior to the recall, all they do is check the cat and spark plugs.

 

Heres just a thought that goes back to all the talk about heat for anyone who might be confused.

When you heat something up, especially metals it expands. When it cools, it contracts. In an engine, which is typically made of metal, it heats up and then cools down. This is called a cycle. Every metal has different characteristics that relate to these cycles. Steel is effected way less then say aluminum. If designed correctly (and typically many years of research and development like the renesis engine does that), these cycles should not be the determining factor in the life of the engine. Some people believe these cycles will cause an engine made out of aluminum to fail sooner then an engine made from steel, but like I said before, if designed correctly, aluminum can work too. The other debate would be does the metal heat up enough to cause enough expansion to even cause concern, and this is all part of the design. That is why engineers spend many hours and many dollars to develop new technology.