I just bought an RX8 and I have a couple of questions regarding the rotary engine.

1. Is redlininig OK for the engine?
2. what is the warm up and cool down requirements?

I've heard that rotary engines like to be driven hard and that I should not be afraid of the redline. It's been said that running the engine hard several times a month is even better for the long term health of the engine. Is this true?

The salesman told me that the engine should be warmed and cooled for 5 minutes. I've since been told that this is not necessary. I now unerstand that keeping the RPM below 3000 until the engine is at normal operating temperature is all that is required. Also, I now understand that the cool down for a rotary is not different from any other type of engine. Is this true?

Any thoughts on these points and any other helpful advice on the proper care of my rotary engine would be appreciated.

Stan

Stan

 

Stan,

Redlining any engine frequently places demands on the entire drivetrain that would not otherwise occur. It can be argued that the design of the rotary engine lessens those effects, but it doesn't eliminate them. Furthermore, effects on the rest of the drivetrain (including transmission, tires, etc.) must be considered, as well.

There is, of course, antecdotal evidence of vehicles that are regularly redlined that run for hundreds of thousands of miles; just as there are stories about "babied" engines that fail at 50K miles. Having said that, however, there is no "free lunch" in this area. Regularly redlining your vehicle will probably cost you whether it's an RX-8 or any other car.

The best advice I've seen specific to breaking in the RX-8 is found on the Racing Beat website. As far as "cooling down," a broken-in engine is concerned, there's no reason to be overly careful if the car is driven normally. And if redlining your engine is routine, you're probably not going to save much by cooling it off; you've already paid the price.

None of this is good news for those who want to abuse the hell out of their cars without paying the price. And that's why I'd never buy a high performance automobile from someone who bought it so they could redline it.

 

Your response makes sense. Redlining aside, is it true that a rotary engine likes to be driven hard (maybe just not that hard)?

The owners manual says that you should be in 6th gear by 45 mph. This seems overly conservative to me.

I've always owned sports cars and have never abused them. I'm just trying to establish generally acceptable driving habits to maintain a healthy rotary engine.

 

The shift points in the owners manual are for fuel economy and longevity. Hard to say what the longevity differences will be if you don't follow the manual, but the fuel economy issues are well documented on this forum.

If you shift at the points listed in the manual you might as well go out and buy a Geo Metro because you will be accelerating like a three cylinder economy car.

With a 9k redline shifting at 6 or 7 or even 8k is no big deal. Personally, I rarely ever shift under 4k.

I have also never warmed up the car, but mine is always in a garage. I have always subscribed to the it's better to warm it up with easy driving (shifting at 3k) than sitting idling and burning fuel for no reason.

As far as cool down, if you go right from hard driving to shut down the radiator fans will run-on to protect the engine.

The only special treatments you want to keep in mind is the cold start/cold shut down procedure and until you have a handle on the oil consumption, check the oil every other fill-up.

 

Also, make sure your oil is religiously clean and changed at the correct frequencies.

 

My rule for redlining is... Hear the buzzer once a day.

 

I don't know if that is really true. Sure the fans will cool the coolant in the radiator, but it won't circulate the coolant and it won't help the oil coolers.

That being said, I don't think cool-down is an issue for 99% of driving scenarios. However, if you've been running you car really hard (at the track or some serious back-road romping) it would probably be better to cool down the car for a bit than just shutting it off when your done.

A few miles of low rpm crusing around 50 mph would probably be nice to run some cold air through and cool down all engine components at a steady rate. Rarely will you see race cars come right into the pits and park after a race... but of course we're talking serious extremes here and they don't even have radiator fans...

On the safe side, its probably a good idea to cool down after hard driving, but I doubt it would cause any problems if you didn't unless something was defective anyway.

 

As long as the coolant is hot, the thermostat is open and good old convection will keep circulating the coolant. Same goes for the oil.

I have owned heavily turbocharged, air cooled motorcycles that never had any trouble at all. At least the Renisys has coolant and a radiator (and fans) to help it cool off after running.

 

running it hard a couple times a week at least will help clean out any carbon build-up. carbon build up can be the cause of many issues including misfires.

 

Good point! My how much we forget since highschool physics class. I would still probably do at least a cool down lap after a track day because i'm a better safe than sorry type. But I definately agree with u beachdog, convection makes perfect sense.

 

My rule is hear the buzzer at least once a trip, several times per day.

 

Might be ok for the manual tranny since it's built to handle the 9000 RPM redline. But I do wonder if constant redlining on the AT might be worse for its tranny, considering the 4 speed tranny seems to be just an afterthought toss in by Mazda to rush an AT RX-8 out the door. I do redline runs about once a day myself in my AT, and I always wonder if my tranny might just die a little sooner than normal because of the fact that it's just not that great of a tranny to begin with.