StewC625

Actually what's causing that issue is not high RPMs but driveline shock - if you redline, then shift hard to get the rear wheel spin "chirp" on the 1-2 shift, it's quite a shock to the driveline and that puts side pressure on that bearing/seal.

Redline, but then don't shift so hard and let the revs fall to the right match before taking out the clutch.

Redlines do no harm to this car. The good they do, is theoretical at best. But I'm more than happy to redline it a couple of times daily!

I think the biggest thing it does is make you like the car more - it firmly attaches my grin every time I do it ...

Rx8urZ

i love owning this car bacause i can just leave it in a low gear like 2nd and drive around wherever and at whatever rpm it still wont hurt the car and when i have poeple riding with me they always say " man your gonna blow your motor if you keep driving like that" that just makes me smile because i know this car just begs to be driven even harder

zoom3x

would it be okay if you just redline while it's on neutral?? sorry just got my 8 today very excited

SayNoToPistons

iTrader: (8)

Wow...


YESSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSsssssssss sssssssg dgdaga omagoomgadgdag after it warms up from a short drive...

Spinning Sushi

iTrader: (21)

That's just a waste of gas.

Speedy400

Any theory on how throttle position while approaching redline daily, affects carbon buildup? In other words, does a slow build up to 8-9K work as well as a 1/2 or WOT acceleration to redline?

Mysql brings up an interesting point that only 7K is good enough to accomplish carbon cleaning. Any basis to this?

Another question is how the once a day redline affects gas mileage. According to my Scangauge, it doesn't mean all that much. Gas mileage seems to be mostly determined by how spirited and heavy footed the driving was for most of the day compared to a one time WOT carbon cleaning.

Renesis07

iTrader: (1)

wait, stew, so chirping my wheels from 1st to 2nd has given me all these problems??? I mean im clueless, I dont do it alot, but when Im getting on it I redline 1st then shift quick to second, not an abusive power shift, just an aggressive shift usually resulting in a chirp

DeViLbOi

iTrader: (1)

Yea...definitely out of your *** on this one. In order for you to blow out the carbon you need to open the third set of ports on the engine. This happens at the 7K RPM range. At 4K you barely just opened the second set so you aren't helping at all.

agcutie03

Why stop at redline? I try to do that AND hit triple digits everyday. It never gets old!

DeViLbOi

iTrader: (1)

Because unless you own a race track that gets very expensive.

mysql101

the real question is what in high rpm cleans the engine. Is it the spinning of the components? Is it the air flow? The amount of fuel and the resulting explosion?

Because at 4k I have more of two of these than a NA car, and at 7k unless its the spinning force, I have 1/3rd more

DeViLbOi

iTrader: (1)

my understanding from one of the other threads was that when the last set of ports open the carbon gets blown off. if you don't redline the carbon builds up on the port and eventually it fails to open properly.

StewC625

Yup - sure does! This is my third Mazda rotary car (albiet the first one in 20 years) having had 1981 and 1984 RX-7s (1st gen) cars prior to this. Not saying there's anything comparable but ... those two cars (when I was much younger and drove much harder) had constant problems with this. I'm much nicer to this car than I ever was those cars.

Basically, what happens when you do that hard shift is what's called "driveline wind up" - it's the same thing that causes axle hop too. Easiest way to imagine it is that the car is trying to pop a wheelie when you slam all that power through the driveline. Since this isn't a bike weighing only 500 lbs with rider, and since the driveline isn't rigidly attached to the overall structure of the car, but is instead suspended under the frame, the hard slam of power (and by the way this also occurs if you dump the clutch at any revs over about 2500 from a standing start) causes the pinion in the differential to "climb down" the ring gear, thus rotating the front of the differential upwards - the pinion is the gear on the end of the driveshaft, and the ring gear is the big round gear in the diff that is at a 90 degree angle to the pinion (making it parallel to the rear wheels). That causes the entire differential to rotate it's front upwards - the amount is quite stunning if you've ever seen this on a high speed camera - as much as an inch or more of rotation - until the restriction of the suspension snaps it back into place and instead causes the wheels to spin.

That rotation of the differential takes it out of line with the rest of the driveline and puts side load on everything in the drivetrain - the output sleeve bearing/seal in the tranny, the u-joints, the input sleeve bearing/seal in the diff, etc. And that load causes those seals to fail.

So, ease up on the hard shifts and that should make stuff last longer.

Sorry for the long-winded answer, but figured you were interested in understanding the phenomenon at play.

BTW, as I said before, axle hop is also causes by driveline wind up - this is caused because the friction between the wheels and the pavement is more than the driveline windup - so in axle hop, the driveline rotates upwards, the suspension catches it, the wheels literally hop off the ground to correct things, and the driveline snaps DOWNWARDS this time as everything over-rotates, the wheels come back down and the cycle starts again. Axle hop is absolute HELL on your driveline.

Stew

Uncivilizedracer

Hence gettting tickets - lesson learned

zerobio

Someone here said redline but try to avoid hitting the fuel cut-off. Is that really important? I usually don't hit the fuel cutoff but it's pretty close and sometimes I do. Is that really bad? How to avoid it? It's a murky territory up there.

DeViLbOi

iTrader: (1)

Good question. I was wondering the same thing. How much different is hitting the fuel cut off as to just hopping off the gas? Is it because the fuel ports open and close a lot while you bounce up against it, or is there something else involved in the fuel cutoff? Something tells me Stew or MM will know for sure.

champi0n

iTrader: (1)

A rotary engine is perfectly fine to redline and even drive at redline. A piston engine I'd never do it.

jmsinclair

wow I just learned a lot from this thread.

1. Don't pop your clutch
2. Burn Carbon above 7K (the third fuel port opens and causes this)
3. Don't shift at high revs, let the revs drop to a lower value (less stress on trans)


Great info, now to try it!

Spin9k

If you rev to 9K you'll be at what is it? 45, 65, 90 mph in 1st, 2nd, 3rd - and hey! you gota shift at high revs cause that's where you are - right? So what is meant is that as you shift **deliberately and smoothly, but quickly** your revs come down auto magically cause you lift your go pedal briefly, which matches the rev perfectly for your next higher gear. But wait for the revs to drop? Your speed would drop too. No way!

Bester

Use the clutch??? Lift off the gas??? whats that?

j/k. I dont power/speed shift this car. That's only for straight line runs. When in the twisties its all about smoothness.

mdw1000

Guess that means if you have a 4-port you only really need to rev to 4K, because I believe the secondary port opens somewhere around 3750 rpm. But what fun would that be?

enforcer

I've just picked up on the discussion on carbon buildup, so a 7K> acceleration (to redline) is what we should be doing on a adhoc basis.

I appreciate Mazda will never recommend this course of action, and there seems to be a strong case here.....but is there evidence it will improve the performance or engine life long term?

raphy3

Mazda doesn't recommend we redline it? I have some literature in my glove box that states otherwise, in fact. It's called a driver's guide, provided by mazda, and it encourages you to rev it up to redline.
As far as someone else mentioning having just learned to not pop (drop) the clutch... of course that's not good for the tranny... that's true for any car....

DeViLbOi

iTrader: (1)

Other than the injector not getting clogged shut? newp

motorups

Now I'm confused....
one only needs to get to 3750 rpm to open the 4-port and if so does this figure hold ture for both a manual and automatic?