Could be an incredibly stupid question, but in an effort to assure a smooth break-in and conserve gas mileage, I've been keeping the rev's pretty low. The engine's so smooth, though, it's hard to tell how low is too low. I've always heard that lugging a piston engine is a bad thing. How careful to be with a rotary...?

 

Not sure what you mean by "lugging." Can you elaborate?

 

I think high and constant revs is the only thing you need to aviod

 

I thinking lugging should be avoided as well. Sure it's possible to lug a rotary. I would keep the revs up near at least 2k, and below 4k (but even occasionally going to 5 or 6k won't really hurt).

 

The main problem with lugging an engine is related to oil pressure. In 99.9% of piston engines (and 100% of rotary engines), the oil pump is driven by the crankshaft. At idle, the oil pump is turning slowly, and the oil pressure is not very high - maybe 15 - 20 psi. That's OK for an engine under no load at low rpm, but definitely not adequate for an engine under heavy load. At high rpm, the oil pump might be generating an oil pressure of 50-60 psi, which is plenty to prevent any damage or untoward wear even at full throttle/full load.

However, lugging an engine is defined as running it at heavy load/large throttle openings at low rpm. The problem is that the oil pressure will be too low at lower rpms to prevent loss of the oil film on the bearing and contact surfaces, resulting in metal-to-metal contact and rapid wear. This can happen in a rotary engine as well.

Personally, I avoid driving at less than ~1800 rpm in a piston engined car in any gear other than 1st, and I do the same with my RX-8. If the revs drop to under 2000 rpm, it's time for a downshift!

Regards,
Gordon

 

Shoot. You guys have a mechanical background that the rest of us yearn for... Thanks for 'splainin to me.

 

Yes. anything under 6,000 Rpm is very bad for a rotory engine.

Zoom Zoom !

 

6? try 9? :p it is only safe to change when you hear the 'ding'

JK!

 

Lugging an engine isn't a good thing, pistons or no.

 

You can definitely lug a rotary. I can feel the engine lugging if I keep it below 2k rpm. 2000 seems to be the magic number to cruise above...in fact the moment I gas it hard enough to get over 2000, the engine note instantly changes and just jumps to life.

 

Lugging is also very hard on the manual transmission's input shaft bearing, and turns into a very expensive fix if you wear out the bearing. Since the 8's manual transmission is borrowed from the lighter Miata, I'd agree that lugging an 8 is a bad idea.

 

Try this experiment. Put your ten speed bike on the highest gear and try riding really slow. Not the easiest on your legs is it? Now imagine your engine going through that. I knew a guy who destroyed his engine cuz he tried to drive it up a steep hill in 5th (not an 8 thank goodness) so I definately wouldnt recommend it.

 

any engine can be lugged!! avoid if at all possible as it will destroy any engine
too much load for the engine to handle - give it more gas or a lower gear

 

My '91 N/A RX-7 starts bucking below 2k RPM if it's not accelerating, then again I don't have any auxiliary port sleeves....

Anwho, just think that next time your cruizing @ 1500 rpm your rotors are going a measly 500 rpm. (Look at your watch and tap your desk twice per second, you should be getting 120 beats per minute, then tap four times for each time you are tapping the desk at 120 bpm (it's easier with two hands). You should be getting ~480 beats per minute... so think everytime you tap is a rotor completing one revolution -- yeah, they're going THAT SLOW!)

 

Oooh, I didn't realize this was so bad. I just learned stick and still do this sometimes. Don't stall, don't grind, don't burn the clutch, don't lug. Boy, so fussy!

 

lugging the motor is probably the worst thing for any engine. High revs aren't as hard on the motor because they only last a few seconds. When you are rowing through the gears.

 

You know, people on here are always saying that the rotary "likes" to be revved high. But in reality, is this really true? Won't this just succeed in shortening its lifespan? I just got over break in and have been doing redline runs in first gear when I can, but I can't help but feel guilty about hurting my baby somehow. I've never really had the heart to run it around like a madman, as some folks here have been doing, like "never shifting before 5k".

 

There is a thread regarding this subject on the RX7club.com... check it....

http://www.rx7club.com/showthread.php?t=349451

 

I drive between 3-5k when driving normally... I am getting better mileage than most people and the car stays responsive in that range should something unexpected occur.

Tooling everywhere at 3 doesn't use any more fuel than wallowing round everywhere at 2, contrary to what you might expect.

Performance driving requires staying over 6!

For those fed up of shuffling, consider:

You don't have to use every gear. For instance, using an on-ramp, boot it through 1 and 2 and then drop straight into 5th when up to traffic speed.

The advanced drivers here (UK) teach IPSGA...

Information
Position
Speed
Gear
Accelerate

where Speed refers to "am I going the right speed" not "change speed now"

In other words, select the correct gear FIRST and THEN sort your manouevre out. So to use a freeway example again, I often change down from 6th to 4th and -then- move onto the offramp.

In town I just pick 2nd or 3rd and stay in it.