I've seen some posts over on Edmunds claiming that it's necessary to drive a rotary at high RPMs in order to preserve engine life. For example:

http://townhall-talk.edmunds.com/WebX?14@165.mse7cboho6B.3@.ef17e71/340
http://townhall-talk.edmunds.com/WebX?14@8.kzlycKs4o7c.2@.ef17e6f/2

Can our resident rotary experts speak to this? I drive an AT, so if this is true I will have to make a point to drive in manual mode more frequently, as the auto mode shifts very early except when being driven fairly agressively.

its built to spin up. i make a point to try and redline at least once each drive, just to keep and gunk off the plugs and out of their little burrows :P

Great excuse to USE that wonderful motor. Just do it to be on the safe side. hehe

interesting...good to know.

BTY -- salesman told me its best to rev the engine up after you've stopped right before turning engine off so that it "clears" built up gas, etc. from the engine. anyone heard of this and would this be beneficial to longer life?

In regards to reving the engine before shutting it off, this is primarily used during short drives when the engine has not had enough time to warm up. Reving the cold engine before shutting it off will help against flooding.

I've heard the same thing about the engine liking to be revved high. I make a point of redlining it at least once a day. There's a nice spot after I turn onto the road I live on where I can usually run it to redline. My favorite part of my daily commute! :D

Honestly, officer. I was just trying to ensure engine longevity.

Honestly, officer. I was just trying to ensure engine longevity

Probably not one they have heard before:cool:

I have a tendency to bounce off the rev limiter when the stereo is too loud. Unless you're watching the tach, you have no indication you've reached 10K, the engine is so smooth.

The dealer told me to baby it for the first 600 miles and then to "drive it like you stole it".

Just got past 600 and this weekend is the first decent weather in weeks!

I just broke 600 myself this week. I can't wait for the weather tomorrow and Sunday :)

a redline a day keeps the mechanics away.

all this talk of redlining!!!!

Each km i'm almost at redline given a break in the traffic!

seeyas, all this talk has got me in the mood for a squirt.

a

BS or not, rotaries love to rev. Aside from fuel economy, I see no reason to keep the revs down when the motor is warm.

baller.

Do you understand why we use mineral based oils? or why the oil is burnt leaving carbon deposits in the housings and on the plugs/rotors ?

There is only 1 way out, hard driving.

not to sound dick, but i'd like to hear an arguement for not redlining...the fact it burns the gunk out is enough for me to floor it, but i'd like to hear the other side...if there is one.

I drive the car sanely during the week for fuel economy. But then i make sure to redline it on the weekends to keep the stuff out, is that often enough. I normally don't take it above 4k rpms on the week days. I am practicing my self restraint :)

Originally posted by Kas
baller.

Do you understand why we use mineral based oils? or why the oil is burnt leaving carbon deposits in the housings and on the plugs/rotors ?

There is only 1 way out, hard driving.

"We" don't use mineral based oils, perhaps you do.

The Baller

Originally posted by Rotarian_SC
I drive the car sanely during the week for fuel economy. But then i make sure to redline it on the weekends to keep the stuff out, is that often enough. I normally don't take it above 4k rpms on the week days. I am practicing my self restraint :)

Rotarian, you have much more self restraint than I. The weather's been nice lately and my last two tanks less than 14 mpg. Damn third gear is great at highway speeds.

I normally get over 20mi/gal

I believe that i will get like 325mi or so on this current tank if the milage keeps going the way it has

how the hell do you get 325 per tank?!

shit i cant beat 200 on the highway!

Originally posted by epitrochoid
i cant beat 200 on the highway!

wow, you need to get your thermo sensor checked out bad (one person had a non-CEL problem of the temp sensor failing and never sending a "warm" signal to the engine, thus running in cold-start mode constantly... sub 10mpg no matter how easy on the gas).

maybe a reflash would help.

i dont know my build date, but i bought my car in early febuary. shouldn't i have the flashed ECU?

I need to figure out a way to get mine flashed out here in germany..... Mazda dealers keep tellin me they cant :(

My car had stickers for what lookes like two flashes "in port" . Both of these stickers are on the hood.

Wow, 325mi per tank.. I can't believe you are going for that.
I am around 250 when the low fuel indicator lights up.
I thought this was normal for all the "slow" drivers like myself ;)

no reasons to redline, and modern oils, injection and ignition systems do not create deposit. Redlining just wears out the renesis quicker.

No reason *not* to redline. Rotaries love to rev, and NA rotaries are built to last.

Don't cheat yourself and miss the entire point of the engine. Run it hard through the gears as often as you can! Why did you buy this car in the first place?

/Gets 11-12mpg and doesn't care.

nobody says you have to redline. in fact, if you didn't redline, you'll definitly prolong the engine longevity. but considering that the rotary engines are designed to be high reving engines, and the fact that most car owners these days dont own the same car for 10+ years..... if you dont redline, your engine/car might last you 10+ years. but for the rest of us who will probably sell/trade in the car around 5 years, i see no point of saving the engine for anything. rather than redlinining, i'd say that constant stop-and-go traffice is worse for your engine and you probably do that anyway everyday.
redline it. do it hard and do it often. you didn't buy a 238hp car do drive it like a civic.

Originally posted by RX8Bliss
nobody says you have to redline. in fact, if you didn't redline, you'll definitly prolong the engine longevity. but considering that the rotary engines are designed to be high reving engines, and the fact that most car owners these days dont own the same car for 10+ years..... if you dont redline, your engine/car might last you 10+ years. but for the rest of us who will probably sell/trade in the car around 5 years, i see no point of saving the engine for anything. rather than redlinining, i'd say that constant stop-and-go traffice is worse for your engine and you probably do that anyway everyday.
redline it. do it hard and do it often. you didn't buy a 238hp car do drive it like a civic.

although i dont agree with it entirely, it does make a good point.

While reving an engine will create wear, rotaries are less prone to wear from high rpm running than a typical piston engine. They are extremely prone to wear from the torque of lugging an engine though.

Typical ideas of engine wear do not apply to rotaries since they inject oil into the combustion chamber and the seals are fully lubricated on both sides. A piston engine is designed to not allow oil into the combustion chamber and the rings actually act as scrapers to clean the cylinder walls durring normal operation, hence they do not get lubricated on both sides.
The seals in use in rotary engines are also self lubricating to an extent.

So don't drive the engine at high load low RPM, and rev the snot out of it. :)

phink, just stop with the shadetree rumor garbage, ok?? the internet is cluttered with this stuff enough as it is.

Originally posted by wakeech
phink, just stop with the shadetree rumor garbage, ok?? the internet is cluttered with this stuff enough as it is.

Which part of his post did you not like?

It was all pretty factual.

Originally posted by wakeech
phink, just stop with the shadetree rumor garbage, ok?? the internet is cluttered with this stuff enough as it is.

Exactly what was garbage about my post?

If you can find any scientific proof that anything I said was wrong then I will by all means retract my statements. But you won't so you might want to think before you type next time.

And of course there is the point that the rotors are only spinning at 1/3 of the speed of the shaft which I did not see anyone point out.

I think we should all be very careful about redlining....
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The traffic ticket for redlining in 4th or 5th could be really bad.
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F U N getting to redline...... but B A D paying the bill....

Just redline in 2nd, never got a ticket for that.

I am all for revving the engine but won't the engine become hotter if you rev it more and that would in turn produce more stress on the engine and especially on the exhuast system?

Originally posted by rxphink
Exactly what was garbage about my post?

If you can find any scientific proof that anything I said was wrong then I will by all means retract my statements. But you won't so you might want to think before you type next time.

shadetree rumour stuff: rotaries are magically less prone to running wear, and are magically more prone to "lugging" wear. (instead of proof disproving you, how about proof proving your claims??)

piston rings are somehow less lubricated, and only on one side no less (which is just plainly wrong).

Proof is easy if you have ever taken apart a rotary engine that has been driven at low RPM for most of it's life. You will find telltale chatter marks from the seals on the rotor housings.

And as for piston rings, what would you say their purpose is then? Piston rings are there to keep combustion in the combustion chamber and to scrape oil away as the piston moves.

What oil lubrication do piston rings have on the combustion chamber side?

You claim I'm plainly wrong but offer no explination why.


Originally posted by wakeech
shadetree rumour stuff: rotaries are magically less prone to running wear, and are magically more prone to "lugging" wear. (instead of proof disproving you, how about proof proving your claims??)

piston rings are somehow less lubricated, and only on one side no less (which is just plainly wrong).

could you desbrice lugging a little more in detail? do you mean like flooring it in 6th gear when you're at like 45mph?

if i do that in my car, it makes a very low frequency sound, so i don't do it on a regular basis.

as a side note, what minimum speed do you cruise at in 6th?

"Lugging" is wide open throttle (or nearly so) at RPMs below 2700 or less, especially in 4th or above.
I will cruise at 35 MPH in 6th if I have no throttle needs.
I'll do the same in 3rd if I need to get in an out of traffic.
Let your ears and the seat of your pants be your guide - put some tape over the tach and pay attention. The car will let you know what it needs and what you need.

Also won't the higher revvs wear out the stationary gear much quicker?

Originally posted by wakeech

piston rings are somehow less lubricated, and only on one side no less (which is just plainly wrong).

Unless the design of pistons has changed radically since I last took a motor apart the top rings are designed specifically to keep the gases in the combustion chamber (compression rings).

The bottom one (the oil control ring) is of a different design and its job is to both help distribute the oil around the cylinder wall, and also to control how much oil is spread around.

Inevitably (as the oil is introduced below the compression rings), there is more oil below the piston than above - as rxphink suggests. How do you see it differently???

Also, he does not suggest that there is anything magical about the properties of the rotary engine. He just says that the different designs have different outcomes. What he said sounds reasonable to me.

Back to the original topic:

To thrash or not to thrash?

If you read the "running in" instructions for the RX8 you'll see cautions involving not lugging the engine and not running at the same revs for extended periods. Even the suggestion that you should not over-rev only says:

"Avoid driving constantly at full throttle or high engine RPM (over 7,000rpm)". Note that is says don't do it constantly - not don't do it at all.

From what I've read about rotaries, (and from 45 years general experience of owning and working on cars), my style is to drive on the high side of moderate without constantly going the full hog of thrashing the crap out of the thing. Thrashing done in enthusiastic bursts. :)

Grannying around, babying the motor, and generally lugging the engine is not a good idea with rotaries. However, no piece of machinery really responds well to being constantly thrashed to the limit.

But, hell, it's only a car - just a piece of machinery - and it's all fixable. So I say drive it in whatever way gives the owner the most fun, most satisfaction, or best suits the style they feel comfortable with. :D :D

Originally posted by BVD
"Avoid driving constantly at full throttle or high engine RPM (over 7,000rpm)". Note that is says don't do it constantly - not don't do it at all.



There is a part you left out
It says to avoid constantly revving beyond 7k rpms FOR THE FIRST 600MI to add to the future performance and longevity of the car.

Originally posted by wakeech
piston rings are somehow less lubricated, and only on one side no less (which is just plainly wrong).

Wakeech has only driven cars that smoked a lot and changed their own oil a puff at a time.
Of course his compression ring is lubed on both sides.:p

Originally posted by epitrochoid
could you desbrice lugging a little more in detail? do you mean like flooring it in 6th gear when you're at like 45mph?

if i do that in my car, it makes a very low frequency sound, so i don't do it on a regular basis.

as a side note, what minimum speed do you cruise at in 6th?

Exactly, I was going to type an example but I was a bit to quick on the trigger myself.

So, if you rev your engine to 1500 RPM and hold it, the engine will be smoth and perfectly happy to keep doing it.

Now do the exact same thing while in 6th gear. You will notice that there is a rather rough vibration and as you put it a low frequency rumble. This is the engine resisting the load put on it. In a condition such as this what you are hearing are the seals dragging against the rotor housings as they bind up trying to fight the load put on the engine. This chattering can cause little pock marks on the rotor housing which will over time cause more damage and lower compresion. These little pock marks turn the face of the housing into a very rough surface and will "sand" down the seals reducing compression.

I normally keep the revs at ~4000 in 6th.

Originally posted by BVD
"Avoid driving constantly at full throttle or high engine RPM (over 7,000rpm)". Note that is says don't do it constantly - not don't do it at all.



There is a part you left out
It says to avoid constantly revving beyond 7k rpms FOR THE FIRST 600MI to add to the future performance and longevity of the car.

I also want to re-point out to everyone what murix said, the rotors only turn at 1/3 the speed of the shaft.

Right now I have only heard evidence that too much high revving causes engine wear, but doing it occasionally is good cause it cleans out anything that might be forming in there. I have also heard evidence that lugging is not good. What evidence is there that a lot of high revving is good, if only revving it high occasionally (8500 three times a week?) will clean the plugs and all the deposits out.

Originally posted by rxphink
Proof is easy if you have ever taken apart a rotary engine that has been driven at low RPM for most of it's life. You will find telltale chatter marks from the seals on the rotor housings.

And as for piston rings, what would you say their purpose is then? Piston rings are there to keep combustion in the combustion chamber and to scrape oil away as the piston moves.

What oil lubrication do piston rings have on the combustion chamber side?

You claim I'm plainly wrong but offer no explination why.

ohhhhhhkay. chatter marks??? that'll kill an engine within a few hundred miles, best case senerio. that was a specific problem that they had to solve before Mazda even produced a rotary engine commercially (from all that publicised history). seals are so light and pliant that i've never heard of anyone ever getting chatter marks, they'd break before they score the housing that bad.

ring seals seal the combustion chamber, protecting the sump. the higher the pressure in the combustion chamber, the tighter they seal (just like any other gas seal, and analogous to the apex and side oil seals in the wankel). the rings also do scrape off a lot of oil, but slide on a film of it which is consumed during the combustion phase, and replaced during the exhaution phase. they are very well lubricated, on both "sides".

...ah, i left my computer in the middle of the post for a few hours...

he says "one side", indicating the sump side. there is no lubrication on the sump side, the oil is obviously needed only between the ring and the block, to seal the combustion chamber. i dont' know where you are all geting this "both sides" bullshit.

The only evidence I can offer that high reving isn't that big of a deal are the many housings that I have seen with well over 100K miles and are still within spec and can and have been used again.

Wear will take place, but you can pretty much safely assume that it won't matter in the lifetime of your car as long as you do regular maintenance.

Originally posted by Rotarian_SC
Right now I have only heard evidence that too much high revving causes engine wear, but doing it occasionally is good cause it cleans out anything that might be forming in there. I have also heard evidence that lugging is not good. What evidence is there that a lot of high revving is good, if only revving it high occasionally (8500 three times a week?) will clean the plugs and all the deposits out.

But don't you have to look at more than the housing. How about the stationary gear, which is mainly what helps determine the redline of a rotary (besides ignition timing). Revving it high causes wear and that is how it sets the redline, so it seems that if you revved high a lot and redlined it a bit the stationary gear would go.

I've never seen a stationary gear out of spec, and you should always replace the bearings when rebuilding the motor.
For a staionary gear to be out of spec I would expect the engine to have been run without oil or have become unbalanced in some way. If either of these things happen you've got a lot more problems than hte gear. Plus the gear is only a few hundred $, and cheaper still if you join Mazdacomp(Mazdaspeed USA).

The rotors and housings are the most expensive part of a rebuild and hopefully they will never have to be replaced. :)

If the stationary gear got out of spec though cause "you made it a point to redline it each trip" then wouldn't that also cause other damage to the engine if the gears wouldn't mesh right, like destroying the seals/leaving chatter marks? Well it is good that there you have never seen a stationary gear out, that means that it is promising that mazda tends more towards the ignition timing to set the redline. I heard that was part of what set the redline in the 8. The rotor was spinning so fast that no more power could be made without advanced ignition timing.

Well the rotor meshes with the stationary gear and remember it only moves @ 1/3 the speed of the eccentric shaft. The shaft has a bearing between it and the gear so wear there shouldn't be a problem either.

,

Pretty much every time I drive the car, I red-line every shift. 5300 miles so far.

I'll keep you guys updated on repairs.

OBTW, 12.2 mpg is best I've gotten so far,

I'm with ya Doug!

Originally posted by Maniac
.... I will cruise at 35 MPH in 6th if I have no throttle needs...

MazdaManiac,

Wow, that's only 1750 RPM ....... and no lugging? Can you or anyone else please describe to me what lugging a rotary feels/sounds like?

What is the RPM below which lugging would start occuring (while cruising at constant speed, not accelerating)?

Thanks,
rx8cited

Originally posted by rx8cited
MazdaManiac,

Wow, that's only 1750 RPM ....... and no lugging? Can you or anyone else please describe to me what lugging a rotary feels/sounds like? What the RPM below which lugging would start occuring (while cruising at constant speed, not accelerating)?

Thanks,
rx8cited

No lugging, because there is no demand for power.
I'm talking about gliding down Rockville Pike in mild traffic that is moving at the limit.
The second I need to move, I go back to 4th or 3rd.

IMHO we should listen to the engine to get our hints:

1) When it's cold, it sounds rattly, so don't stress it
2) Once warm it has this wonderfully linear torque curve ... It feels like the pressures on the engine are linear from 3500 revs to 9500 revs. I for one think that's fine and using the whole rev range doesn't feel or sound like the car is complaining.
3) The car doesn't sound smooth sub 3000 revs, so I'm sure it's complaining.
4) There are bits of the car (secondary and tertiary ports I think they are called) that only come into action at higher revs. If they are not exercised then I am sure they won't work properly when you need them.

Just a few thoughts.

I feel my car feels smooth even at 2500 rpm.

The mileage thread that I started in the Discussion forum might be able to determine this. If it's lugging, wouldn't gas mileage go down? We can determine the "point of diminishing returns" in the manner that I suggest in my mileage thread.

You all are probably tired of my observations, being piston-based and Italian and all, but I can't resist:

- there's no quicker way to make an Italian perfomance engine ill than to drive it easy. The term 'Italian tune-up' is common in Alfa and Ferrari service circles and generally means 'drive the car HARD like the owner probably doesn't'.

- performance cars are designed to deliver performance. Our 8's are billed as such and should be employed as such -- the engineers presumably designed them that way (coil packs, possibly, aside.) Long-term, I doubt you're doing the car or yoursefl any favors by lugging it around town. Time will tell.

- I cannot fathom how anyone can keep the revs on this engine under 5K during regular driving after warm-up, much less under 4. The operating parameters of the engine are 1K to 9K RPM...'normal' driving should entail regular 5-6K shifts, with 7+ added for enjoyment and preventive maintenance

- My experience thus far (7100 mi.) indicates the car doesn't like to be driven in the 'diesel range' (1k - 3k) if any changes in velocity are involved -- climbing or descending hills, accelerating or decelerating on flat terrain. There's an element of lash in the drivetrain under 2.5K which just doesn't feel right and can't be healthy.

- The relatively low torque coupled with the high-rev HP, just screams 'high-rev engine.' My only other Mazda (and only previous new car) was a 1988 323 GTX, a piston engine, true, but with DOHC 1.6L, 4 valves per cyl and turbo...the car didn't like to be lugged (I called it 'bogged'.) It drove like new at 70K when family changes made it inappropriate. The only problem ever encountered was when I cooked the spark plug wires being a smartass: I installed Bosch Platinum plugs hoping for some gain -- they leaked where the ceramic met the metal and wrecked the long ends on the wires.

With the 'sweet spot' so high on Mazda engines -- both pistoned and rotored -- isn't it obvious they're designed to GO? If RPMs scare you, get a 'Vette...you'll probably get better gas mileage to boot as GM is highly concerned about fleet fuel economy.