Revving to redline, is it necessary???
 

To an earlier post, several advised that I follow the manual but a couple insisted that you must rev to redline "at least once a day", that failing to rev it to redline damages the "seals and apex and builds Carbon dioxide in the rotors". Is this really true? Why does it not say so in the manual?

I am not a racer and generally shift between 4 and 5000 rpms, have some 30K miles on my '09 RX8, and while I have hit 100-105 mph, I have never come close to redlining.

I am concerned about the advice to redline every day and what the real recommendations are as regards Revving. No flaming about why I bought an RX8 or some such nonsense. I had the RX7 in the 80's, another 94 RX-7 and now the 09'. I just enjoy the handling and the looks and want it to be trouble free.

for a long time people have always claimed that a redline a day keeps the carbon away but to be honest, I'm not sure I completely believe that anymore with everything I've seen here over the years.
I will say that you're missing out if not going a bit higher in the power band from time to time and that hitting redline will not cause any damage to the vehicle but I'd stop short of saying it's mandatory.

My opinion: It might help, it probably won't hurt in moderation, it's a lot of fun. :)

+1

I don't think it's mandatory, but you're totally missing out on the fun.

Your intake tract isn't even fully open until after 6k.

The redline once per day is a good rule of thumb to follow.

"Not reving" won't directly damage the seals, but carbon buildup in our engines is a recognized problem. If you spend lots of time under 5k rpm, then yes, you are probably building up excessive carbon needlessly. This carbon will start unseating the seals, causing uneven wear, and start clogging the secondary injector ports. Those ports don't open until 6,500rpm, and under heavy load (meaning lots of throttle input). Over time, this will shorten your engine's lifespan.

I know with my 8, if I spend too much time under 5k (usually in the winter with snow/ice on the roads), my engine starts running noticeably rougher. Taking it out for a good wankle spanking, standing on the throttle through 1st and 2nd gears at least, shifting at redline, the engine smooths right up. The high V/E of the high load high rpm high heat helps to burn off and keep carbon clear. Will it remove all carbon? Nope. But it definitely helps.

Don't be scared of redline. It is there for your transmission, not your engine. Over ~7k rpm there is lots of heat buildup. It's perfectly fine as long as you don't sit in that RPM range. Full power to redline, shift, maybe again a time or two, but let it cool off between and you are fine.


It's also where our power is made, and it puts a smile on my face.

If you have never done it, you are missing part of the joy of this car. :)

Short answer: Yes, redlining this engine is good for it. But not just sitting in neutral and revving the engine. It isn't about just the high revs, its about heat and pressure inside the chamber, so the engine has to have a high load. The best way for me (and a lot of others) to do this is a good 2nd gear pull getting onto the highway in the morning.

The only way this will hurt your engine is if you do it while the engine isn't up to temperature. Otherwise, yes it is good for engine health and longevity. It does exactly what they told you it did in the other thread.

Everyone has their opinions and I don't think anything is set in stone. Carbon does build up inside the engine, there is a fix to removing the carbon, don't personally know if it works, i just do it. I do it cause most rotary enthusiasts say to do it. I guess I would jump off a bridge too if everyone did it. I don't know if trouble free will be correct, as the 04-08 engines have been replaced left and right. I have replaced my engine and i think most of us have had to. The 09 have different modifications to try and alleviate the previous problems. I don't know everything specific just what I have read.

:rolleyes: Generalized statements like this are what perpetuates the notion that an rx8 doesn't last more than 30k/60k/100k whatever. Yes there are a lot of engine replacements out there, but it's no where close to "most of us" especially if you count all of the S1 cars. The majority of the problem cars were 04 and 05 4 port autos. You can even lump all of the pre MSP-16 flash cars in and still not have a majority. Post MSP-16 (all 06+) have had far less failures than the previous two years. Not to say there aren't any, but far less. A lot of people are on 3 or more engines due to shitty remans. FWIW i'm at 100k+ on my original late 04 build 05 engine and have no compression or issues otherwise.

A couple of the major changes for the S2 engine are a different water pump, different OMP and control for it, and a 3rd oil injector in each place.

So what I said was pretty much correct and also he has a different setup than what I was describing, and it doesn't pretain to him. And alot of them were auto's, mine was not and I know several that were 6 port manuals. And the 100,000 extended engine warranty wasn't for autos it was for all rx8. just saying. I was 100k+ on my first engine as well. Also depends on how well you take care of preventative maintenance on the car. There are several cars out there with 100k+ miles, I don't think it will hit 200k on an engine like other cars out there have.

and you're completely missing my point.

1. Several people that you know does not equal most rx8's.
2. I was not saying it was all auto's. I was just clearing up the general misconception you are spreading by saying most people are on their second engine. I pointed out the 04-05 autos to show that they were the majority of the early replacements, not all of the S1 cars. Again, 06+ have had far fewer replacement engines than 04-05 regardless of transmission.

You have however, proved that you just regurgitate what you've read and don't actually take the time to understand what you're reading or the concept presented. This is how mis-information keeps getting spread throughout the forum.

The AUTO's had the issue of the owners driving in DRIVE. That kept the rpm's down low. A lot of Automatics died and early death due to carbon build up.
Remember that your injecting oil into the combustion chamber. If it's not burned away it becomes sludge then carbon around the seals. Causing sticking of the side seals/apex. Resulting in low compression, lack of power, stalling and hard starts.

It depends what you mean by redline. IIRC, It's be noted by people such as Eric Meyer and others that there is really no benefit revving over 8500RPM. You don't get anymore power beyond that point and typically that is where damage to the engine can occur.

In the SARX group we have seen the progression of failures extend from mainly 04's to 05's, 06', and recently one 07', all of which were well maintained by rotary enthusiasts so I think the flash may have had something to do with it but it was a band aide at best because as the mileage increases in the later models, the failures are increasing as well. One of local guys in a dealer tech who even did the swap in his own RX-8 and from what he has told me the replacements in Series I Rx-8's has not slowed down.

There are also different modes of failure but from my experience (on my 4th engine in my 07/2003 build RX-8 MT) I can say that a redline a day will not save a Renny from failure. But if you own a MT RX-8 I don't see how can not redline it at least once a day.

Just like putting your seatbelt on every time you get behind the wheel won't stop someone from crossing the double yellow and hitting you head on.


But you put it on anyway right? :)

Makes the curves more fun.

If you don't mind me asking, which I'm sure someone will anyway, what were the causes of those engine failures?

From what I've heard, the redlining helps clean carbon out. So if it was a different failure, such as lack of lubrication somewhere, well, you get where I'm going with this. Besides, I'm just curious as to what went wrong with them.

And the '07 is the newest one to run into problems there?

Pretty much, in order for an engine to last, you have to NOT have one of these going on:

- Insufficient oil injection leading to apex and/or side seal wear (oil injectors or OMP lines clogging)
- Insufficient cooling leading to oil viscosity breakdown, and/or oil ring failure and/or coolant seal failure and/or warped/deformed/cracked block
- Insufficient decarb leading to apex seal wearing unevenly
- Insufficient seal tolerances on reman engine
- Insufficient fuel delivery (pump, starvation, etc...) leading to a lean spike that destroys seals
- Excessive exhaust port temperatures leading to side seal spring deformation
- Insufficient intake filtering leading to particle ingestion and damage
- Insufficient gasoline octane leading to detonation
- A Mazda tech incorrectly diagnosing a blown engine (some "failures" were likely just ignition failing)
- Ingesting water causing the pressure to crack the block
- Attempting to force too much air into the engine from a compressor (FI)
- Having an incorrect engine tune resulting in a lean spike
- Clogged cat leading to excessive exhaust pressure and localized heat spikes
- Having a transmission failure lead to an e-shaft crack (presumably, two S2 that I've heard about)
- Insufficient oil remaining in the block
- Insufficient coolant remaining in the block



...I think I'm still forgetting some.


It's actually not really a bigger list than a piston engine's possible failure points. Smaller actually. It's just that some of those are problems from the factory, where piston engines have basically all of those solved.

And those are failure methods I've seen mentioned, discussed, or reported over the years that I've been on here.

Since you can't prevent all of them, it's pretty much a dice game on doing what you can to mitigate the rest and hope they don't bite you anyway.



I know, I paint a grim picture. If someone doesn't want to stomach that, then maybe they should move on to something they can.

To be honest I never really bought the "redline a day" mainly because my mind is saying "exactly how much does the chamber temp increase during a redline in first or 2nd gear which is generally a short time". I mean, I have heard 2 theories, one that the increased temps causes whatever garbage is between the seals from hardening, and second that the redline is supposed to stress the seals to make sure that they dont get stuck from poop that is in the seal valleys. Instead what I like to do is every few days or so I will drive the car with longer shifting times. Especially getting on the highway riding 3rd gear towards 6-6.5 as well as subsequent gears until i reach my maintain speed.

Who knows if that is really making that much of a difference, but I can only assume that the sustained higher rpms should increase combustion chamber temperatures just as much, if not a bit more than quick peak to peak redlines, while keeping the rpm's at a more tolerable level.

does it affect my gas mileage, you bet ... do i care, not really, after all...i am driving an 8.

When I bought the car, there was a little Mazda pamphlet in the glove box that said, among other things, the "Renesis loves to rev," or something to that effect. I think that was Mazda's way of saying rev it high and often.

I believe the S2s come with a rev limiter from factory. So technically, the idea of not revving up when the engine is cool is probably more of an issue with the S1 cars.

/\
That is the answer to the issue.

Also confirmed by some pics floating around the web showing how nasty some of those early auto engines looked inside:SHOCKED:

I have a feeling you don't mean quite what you actually wrote :)



The cold rev limiter on the S2 exists on the S1 as well. Just the S1 is a single lower rev limiter at 5.5k until water temp exceeds about 60F (I believe, though it's guessing. I know it's REALLY low), and there is no visual indicator. Just a sudden solid wall you weren't expecting. :suspect:

The S2 cold rev limiter is 2 stage, and has a visual cue in the form of two lights that add additional length to the red band on the tach, and turn off at each of the two trigger points that release that particular lower rev limit.

LOL!!!

I was under the impression that you couldn't rev past those red lights with the S2s even if you wanted to. I test drove a few S2s when I was shopping for a car, but I always waited for the cars to be fully warmed before pushing them anyway.

So, I don't really know!!! Maybe somebody with an S2 can clarify.

Wrong, when your cruising for a long period of time your cooling system establishes equilibrium at some temperature. Since you cannot increase this cooling any more but you can increase friction and therefor heat you can and will see higher temperatures at higher rpm's.

You are correct. They are actual hard rev limits. Just there is 1 on the S1s, a 2 stage with visual on the S2. You hit that and it feels just like you are hitting the 9k limit. It's pretty ... sudden.

I've tapped it a time or two (or more), light load, not WOT, just not really paying attention to upshifting from first when my mind is wandering in the middle of winter and <10F temps. The S1's falls away so fast though, that even turning it on, pulling out, practically idling down to the stop sign ~200 feet away, making the right, drifting another 3 streets to that stop sign means it's gone, even in the middle of winter.

Yes and no. I have gone over the interior red band but I've also felt the car stop me from going to 9k+ when cold.

It's not something I'd want to test just something I've noticed from time to time.

I'm a 100% believer in redlining, my engine will always run smoother after a very hard long drive threw some back roads early in the morning. I don't think a red line here and there really helps, but a few good long pulls back to back repetitively does. I mostly drive in stop-n-go traffic, so when ever the opportunity arises I normally take it. Besides, it's fun!

When I had a comp test done before my engine replacement they did a decarb to try and bring the numbers up. The numbers didn't move.
I redline a few times when I drive it.

If you speak to alot of shops that rebuild motors, they will tell you that alot of the ones that fail due to carbon build up are the ones that are babied. It doesn't even matter man, you didn't buy a rotary to drive it like you have no balls did you?