cjcjag

I've got an '09 RX-8 R3, my first rotary. I'm enjoying the car immensely, but I'm also trying to understand more about this unique powerplant.

I've read many posters in this forum and other rotary forums advocate the benefits of taking the car to the red line at least once a day to "clean out" the engine. I'm no engineer but I think I can understand basic engineering concepts. So, I'm wondering if someone can explain the engineering theory that would explain how high RPMs "clean" the engine.

If the advice is correct, I can think of only three possibilities as to what might be happening: 1) high RPMs produce more heat and the increased heat helps clean out combustion deposits; 2) high RPMs somehow increase the friction of the apex seals on the wall of the combustion chamber; or 3) high RPM's result in a cleaner burn of the air/fuel/oil mixture (which might reduce new deposits but I can't see how it would "clean" old deposits).

Can someone provide me an engineering explanation to support the advice "drive it at the red line at least once a day to clean out the engine"?

kersh4w

iTrader: (3)

higher pressure forces built up carbon off the chamber walls.

schnipster

as well black lining shows dust more...lol lmfao sorry guys

laythor

and redlining the engine at least once a day is good for the owner's ears and heart

twelch

I thought I read somewhere that a redline (or close to it) ensures that the ports that don't open until 6500 and 7200 get a workout.

t

tubingchamp

iTrader: (3)

Yeah, there's a port that opens up over 7500RPM.. Without that port opening, carbon builds up and can glue it shut, causing engine failure eventually.

cjkim

it's not just redlining.. redlining in neutral will do zilch.
you need load

CyberPitz

It's been said for years that redlining the rotary helps to get rid of carbon deposits...

There are both sides to the argument who believe it works or doesn't. I'm the person who doesn't believe it because I've seen plenty of 13B's with a lot of carbon at low miles that I know are beaten on...but that's OK. These engines were made to rev high, so why NOT do it?

It feels oh so good, and gives you a euphoric feeling.

risky business

when you redline, the little tiny unicorns inside your engine get really excited and start to jump up and down, with there horns chiping away at the carbon buildup... thus cleaning your engine.... dont listen to the others, they know nothing of the mystical creatures.

tsxmidship

at redline the velocity of the exhaust gas is at its maximum, helping 'blow' out the carbon

Optical TDI

iTrader: (2)

Will we get a CEL if ports fail to open?

kersh4w

iTrader: (3)

lets go to candy mountain!

elysium19

iTrader: (1)

Candy mountain Charlie!!!!!! Candy MOOOOUUUUUUUUNNNTTTIIIIIINNNN!!!!!!!

Flashwing

I think much of the redlining suggestions have had their roots in OMP output. Up until the release of the accessport, OMP volumes were dependant on Mazda's upgraded PCM flashes. While the new flashes are said to increase OMP output, I think with many of the 2004 and 2005 models we were seeing those who would redline the motor having longer lasting engines.

No doubt people were getting proper oiling in the upper RPM bands that they were not getting with lower RPMs. More aggressive driving means more oil injection into the motor.

This is why it's important for RX8 owners to look into the accessport even if you're not concerned about performance gains. OMP increases, fan speed changes and some other tweaks will help the car run better and your motor last longer. Sure, $700 is a lot of money but that's a downpayment on a new motor should you not get one under warranty.

I still believe in not babying these motors. Drive these cars hard as that's what they were designed for.

tubingchamp

iTrader: (3)

That's something I'm not sure of. Most likely there will be detonation in that RPM range since the port doesn't open, but detonation doesn't always cause a CEL. I've never had issues with redlining my car, I love to do it Maybe someone could elaborate the symptoms when your port fails to open?

Flashwing

Yes, as far as I know there will be a CEL if the ports are not able to open.

I know as a fellow rotary owner got a CEL when there was a stuck open port on his renesis.

Brettus

iTrader: (2)

almost - the port you mean is the one that opens at 6250 rpm (the aux. port)
the one that opens at 7250 just balances the harmonics between the two rotors .

Nubo

Probably the most important carbon problem would be having the apex seals stuck in their slots. As they wear down, the spring wouldn't be strong enough to compensate, and you would lose compression. The faster the engine turns, the more centripetal force (sorry physics guys, I always seem to mix up centripetal and centrifugal so I'll apologize).... the more centripetal force is applied to the apex seals, forcing them outward. Redline will maximize this force. By "exercising" the apex seals in this way you may prevent an incipient "stuck seal" problem from becoming permanent. Move it or lose it.

And of course, the increased gas velocities and rapid temperature changes may help loosen Carbon deposits in general.

DOMINION

Realy? cuz when I had my AT put it in park hit the gas i seen a big *** cloud of black smoke come out

cjkim

Your secondary and tertiary ports won't even open without WOT. and it's impossible to sustain WOT at high rpms for longer than a split second without load.
I would think you need load + sustained high rpm + WOT to be in full effect. Maybe i'm wrong though

04RX8man

yeah first there are ports that need a "workout" so they don't get jammed with carbon and will not open..

Also running the car hard so it heats up will get that carbon stuck on the rotor and housing to loosen and the exhaust gases will push it out... And I believe that it has to do with some of the oiling of the engine also the harder it is ran the more oil/lube it gets and hopefully getting the engine to last longer(of course premixing helps with this...off topic i highly reccommend premixing started a couple months ago and love it

DOMINION

+1 on the premixing. K class is over kids lol

DMRH

I hope you have been told its "Very important" to warm the engine properly before driving off.

Think of it as part of the cars character.

REgards

CyberPitz

I've never let the engine warm up before driving off. I do as the manual states, let it idle for around 5-10 seconds, then take off. I've never had any sort of a problem with that. That's why they say to not drive too hard above 4k RPMs....the car is meant to be driven, not be some random and quirky thing you can't drive half the time.

DMRH

Another 1st time buyer heading straight to the warranty dispute centre......