over rev?
 

is it posible to over rev on our cars? last night i was testing my intake in the freeway and i gunned it.........while shifting to 4th i dropped the clutch too early and the RPM needle bounced off the rev limiter 2 times...and my battry..power steering. tire sensor. and check engime lights lit up for a second.......and then went back down to normal........now to the point..........was that bad? lol

nah, even in neutral the rev limiter will have kicked as you noticed, so no damage at all. the lights probably just came on as a result of the rev limiter, or the ecu getting confused!

supposidly the renesis will happily rev up to 12K and more, but 9K was chosen as the power drops off above 9.5K and the life of the engine would be reduce.

anyway the rev limiter is there to stop any possible damage. its been lowered i the M flash also, so previously you could rev higher.

according to the canscan utility the rev counter reads 2-300 high anyway, and the rev limiter actually kicks in at about 9100

Rev Beeping is fun!!!!!!!!

when you go over the rev limit, your engine will cut off, and you will slow down :)

Don't get over confident about rev limiters.

They don't act like a brake on the eccentric shaft. They just cut fuel and/or ignition. If you do something like miss an upshift at 9000rpm the momentum of the engine will continue to accelerate the rpms while the engine is off loaded.

Also, you can force the engine way past 9k on a badly executed downshift.

Overrevving the rotary might not be quite as bad as overrevving a piston engine but it's not something to make a habit of.

I bounced off the limiter twice when I was first getting used to the car (after break-in of course). Both times I thought I was in 3rd when I was actually in 2nd. Punkassed engine is just too smooth for me to tell the difference at the time. I won't hurt if you make a mistake, but like BeachDiggetyDog said, you won't want to make a habit of it.

So is this to keep the MT/T from going boom?

its fine.. spent the day at Lagun at the rev limit.. :)

this is the beauty of a rotary...enjoy it, we all do (if you want change the seals ;) and some other stuff and you can be like Mazda's rotarty race car...zoom zoom beyond 12000rpms)

So does the M flash really lower the redline? This is something I have never heard before. I am still at L.

You can't do damage if you accelerate while in gear or in nuetral, it will cut the fuel. But, somebody correct me if I'm wrong on this, if you accidentally downshift from 5th to 2nd you could go past redline and possibly cause damage.

when all the lights came on that was a stall... happened to me with a new intake between shifts.

an evo was messing with me in the freeway when this happend. the funny thing is.....i got him on top end, i was kinda suprised...he was just behind though...my car revs up to 9700+ no cut off with an M flash, i do it all the time...

Maybe the UK M flash and US M flash are different then - given that in general the engine characteristics as subtly different anyway (we only get 231PS)

As stated earlier, the important thing to remember is that the rev limiter will only cut the gas flow; downshift incorrectly and it's all over for your engine as there's no way any rev limiter can prevent a mechanical overrev with a manual tranny (only an SMG or auto tranny can by physically refusing to do a downshift if it would cause an overrev...)

Spark....
 

The rev limiter actually cuts ignition, if it cut gas it could create a lean/detonating mixture right at the rev limit - bad news!

S

aw c'mon, the stealth pounds of torque ensure that detonation of such a small charge of energy wouldn't break the apex seals.

No, even if you're accelerating hard, the very micro-second that ignition is cut, the acceleration of the engine will stop, and rpms will not increase further. That's basic physics - inertia and momentum apply to speed (or rotational speed), but as soon as a force to change that speed is removed, then the rate of change in speed drops to zero, and then normal frictional forces still work to decay that speed. For accelerating, the rev limiter will absolutely prevent an over-rev.

You're absolutely correct, though, that a mechanical screwup like on an unintentional downshift (when you meant to upshift) can easily force the engine past redline. It might not kill your engine for one time, but it's still a very bad thing to do! ;)

Regards,
Gordon

Gord, on the former, I will defer to your knowledge on the subject. However this is also going to be dependent on the action of the rev limiter. On a previous car that I owned, the rev limiter didn't completely cut the ignition, it randomly cut ignition to various cylinders. If you were determined to overrev, ie missed a powershift, didn't take your foot off the gas, that system would allow it.