Seeking difinitive reason to "redline"
 

I have been re-evaluating the whole issue of the rationale for redlining for some time. No one has really given a definitive cause/effect for redlining and I been on this forum for some time.

I bought a new 90 NA in '90. Did not know squat about rotaries and never pushed it even close to redline. I had to get a re-build at 238,000. Rear rotor compression lost.

Replaced that one at 315,000 with another '90 NA in 2001. Had 93,000 and after finding this forum, I began to redline once a week. Sold it recently at 115K and it was strong as a horse. Now have a '90 mint vert with only 2,100 on an Atkins re-build. I dare not redline.

So, I have had great-prolonged experience never redlining and unknown experience doing so.

Redlining with a good cooling system should only slightly increase the temp of the rotors surfaces and seals and therefore the carbon or oil residues on them. It will increase the frictional heat on moving parts however. Rubbing = heat = wear. Wear = bad/break.

If someone can explain how very brief momentary redlining and a minor increase in seal temps can possibly be a benefit I am certainly open to a defensible sound justification.

Search on the first page of this section for the other topic about redlining. it's explained pretty well in there.
Matt:)

Redlineing causes enough internal combustion temperatures, and turbulance to break free carbon into pieces small enough to exit the exhaust freely.

Not to mention 2nd gen n/as Need to have the Aux ports open up often enough to keep them from sticking. S5s need to be opened up often enough to keep the vdi from sticking.

Now... how much HOTTER do you think the seals get? The seals are well within specifications at redline. "Redline." The Actual redline is only trivial anyhow.

For example.

Remove the engine and throw it on a dyno bench. Remove the flywheel so you don't die.


Carb the engine to eliminate any and all fuel cuts.

When do you think the rotary will die? Its not going to be below 12k.

You weren't around when the two nebraskan punks fucked a 13b engine with lsot compression on one rotor were you.

That is the best video that I have ever seen that speaks millions of words for what a rotary can do at "redline."

I suggest you go find the video, and wonder in amazement how a engine that is half blown lasted 11 minutes at 8000+ rpm. ON ONE ROTOR. The only reason the engine dief after 11 minutes is because the punks decided to remove the radaitor cap and purposely overheat the engine.

Still worried about seal temperatures? It ran for about 4 minutes with no coolant at 8000+ rpm.




EDIT: And I redline every shift. If you can't handle redlining, sell your car to someone who can drive the car to its potential. A redlining rotary is a happy rotary... and driver. The rotary engine isn't built to shift at 4000 rpm.

redlinig is awsome, ya hear your gauges start to sing and ya know your good

everytime i shift at redline, it blows like shit out the back, i only did this once, and thats what it done, so i dont know if im going to do it any more, one redline in 3 months

Thats the carbon blowing out? Ne ways I never redline cuz my peak hp is at 6500 or so. Only 500 before :)

True, mods move the powerband around some though. And if you can see the smoke noteably, its not carbon.

A lil insight,

The RX-8 owner's manual states in black and white that prior to shutting down the engine rev it to redline. Dont quote me on the wording.

Performance cars are made for performance drivers. The rotary motor is a hi-rev motor made for high revs. If not driven as such the quality of the car itself will decline.

Keep those revs up.
Rabbit

I hear from alot of people that your suppose to redline your rotary at least once a day. I do it about twice for good measures.

Read your owners manual!!!!!! Or Down Load It.... It clearly states to REDLINE!

i have that video, he had a blown rotor but it would still run and it was at 8K and was still climbing, and the only reason it blew up was of course because the dousches took the radiator cap off. poor car. but still rotaries do need to be redlineed, i agree with the statements of increaseing engine temp to break carbon off and such

I think after we have all graduated for flaming the punks, we've accepted it, and now look at it as proof of the strength of a rotary. I think what they did was stupid-- they turned a few good housings to mush, but I think their actions have a posetive outcome-- its proof for us all. A couple housings had to die, but I learned something from it, and it raised the value of my 13b block by $.000001 by scarcity.

Badmofo, I certainly wish I had the opportunity to read the second generation Owner's Manual you are refering to. The three second gens I have owned all came with the manual and I must have simply overlooked that part you refer to. Section 3-23 specifically warnes about red zone operation. If Mazda actually recommends redlining I am sure they would recommend a frequency and duration. Since I could not find it Section 6 Maintenance they must have forgotten to put in in the Maintenance Schedule.

Would you be kind enough to please tell us what page you found this recommendation or better yet quote it directly. I am sure there are lots us out here who will benefit from your wisdom and experience.

I just recently had the auto to mt swap done but I have still have the auto tac with the 7k redline? With the mt is the redline the same or higher? Probably a stupid question but wanted to ask anyway.

Yep, with my mods, my powerband is now closer to an S5's. It doesnt lose power until about 7500+ RPM, so pretty much rev limiter. I used to redline it several times whenever I drove it, but i dont anymore. Its got an exhaust leak before the presilencer, so it will set off car alarms for blocks if I actually redline it. Now I just do it getting one the highway and such.

i rarely redline. so i guess i should start doing so?

I'm sorta glad you revived my post. Most of the reply threads have been emotional support lacking a "definitive" fact based explanation of the benefit of redlining. Bzah, you can obviously "start doing so" but only Kenteth offered a reason which was based on increased "internal combustion temperatures, and turbulance". But I am not certain I buy that arguement. Combustian temperatures will not increase. At a constant spark, 87 octane will burn at a constant temperature. Increasing the number of burns per unit of time does not change that fact.

I do not see how increased turbulence, which will increase principally at the ports, with an increase in RPM's will be sufficient to blow away carbon on seal sides and bottoms let alone surfaces.

I am not enjoying being a doubting Thomas but neither do I want to be a blind follower of an unproven speculation or myth. An good example of ignorance believed can be found in Badmofo3000's response above.

I started this post by saying my new '90 lasted 238,000 and was not redlined once. That is a fact. I'd love to see a fact that justifies redlining.

We have exciting sports cars with rev happy engines. To NOT redline is absurd. Forget for a second of whether or not it's good for the engine. This isn't a diesel engine, it's a rotary. Shift at redline. That's where the power is. Go fast. This car was meant to do that. If you're worried about "wearing out the engine faster" then don't even drive the damn thing. Whether it's idling or redlining it's going to kick the bucket sooner or later so you might as well put it to use. A car going 238,000 miles and not hitting redline once is the most boring thing I've ever heard. But whatever. To each his own...

when i asked ppl told me it wasn't as important to bring the engine to redline as it was to simply drive it aggressively and keep it at high rpms on a often enough basis.

if you drive it hard and see weird wispy stuff blowing out your back, keep at it until it stops. well, as long as the smoke isn't cloudy white or blue... :P

It's not as stressful as you think...
If the engine *could* redline up to 9,000RPM, the rotors are only spinning at 3,000RPM.

The eccentric shaft is the only thing spinning at actual tach RPM.

At 6,000RPM indicated, the rotors are only spinning at a leisurely 2,000RPM. :)

Basically, it blows off the carbon on the rotor faces.


-Ted

After skimming through this thread, I didn't see any reference to to oil injectors.

A WOT pull to the red line opens the MOP to lube the apex seals.

This is especially true or the S5's

Also it gives the secondary fuel injectors a brief full duty run to keep them clean.

If you're not going to redline, at least take it over 5000 RPM on a semi-regular basis.

My car was originally owned by a woman who apparently didn't drive it hard. My 6th ports (S4) were completely seized up, and one of the actuators was so badly frozen that I couldn't even free it up with a hammer. It obviously was not opened up for a long time. I suspect the S5 VDI system is the same - use it or lose it. The RX-8 cycles all the various actuators when the key is turned on to prevent them from freezing up in the same way.

When I tore it down, the rotors were caked with carbon. I'm sure part of this was the stock oil injection system, but it wasn't pretty, either way.

Regarding combustion temperatures, more combustion cycles per second *will* heat the engine internals up. There coolant and oil aren't infinite heatsinks, nor can they pull an infinite amount of heat away. The metal will absorb more heat at high RPM operation because more fuel is being burned per second, and as a result more thermal energy is being transfered in. The combustion temperature may not change, but the temperature of the combustion chamber will (and if the combustion chamber were already running at the same temperature as the combustion, it would be liquid). The proof of this is simple - take your car out and run it at high RPM for a few minutes - the coolant temperature will rise.

The point about the rotors spinning slowly is also very valid - the e-shaft is whipping around, but the internals really aren't being pushed that hard. The engine is also very happy at high RPM - some engines make it known that they're not amused by being run at 6000 RPM, the rotary just sits there. I've not seen the video being tossed around (link?), but I know that in some tests the rotary engines have been pushed beyond 15,000 RPM without failure.

So, if you're not going to redline it, at least push it high enough that the 6th ports and VDI (if they're still even working) get cycled.

-=Russ=-

werd

So you shift at 6500? I would think you would want to keep the peak power centered when you shift. Its not like after peak power you lose all power...it goes down fairly gradually. It is more effective to shift later to keep the peak power centered and take advantage of a higher average power between shifts. If peek power is 6500 and your most used gear shift (2-3?) drops about 1000rpm per shift, then 7000 would be ideal for shifting, imo.

What's the difference in redlining and driving around at 3000 for the whole life... Ever heard of centrifugal force? What's going to get something off a rotor face better, high g loads or low g loads?

Syonyk, I agree with your comments about a heat sink and "heat the engine internals up" I admitted that in my initial thread comments. But would you agree that the increase is momentary (less than a parsec? LOL) unless you keep it at redline several seconds?

For what it's worth, I have pushed all 3 '90s. It (they) frequently visits 5 - 6 K especially downshifting around turns/corners. So, they were not babied they actually seemed to enjoy themselves a lot.

i've had two rx-7s. one '83 gsl with the 12a and a '84 gsl-se with the 13b.

both of which i redlined repeatedly, every time i drove 'em. i sold the '83 with 181k mi on it after daily driving it for 40k mi. the gsl-se died at 215k mi due to coolant seal failure.

no problems with the apex seals at all.

Well, I think the general idea behind "redlining it" isn't to just blip it to 7000+ for half a second, but to actually drive it hard for a while up above 5000.

Interestingly, my "babied for most of it's life" '7 chewed up the rear rotor at 120k miles. People who drive them hard seem to end up with some of the most insane engine life...

-=Russ=-

just to keep the fire going......could the engine failure be caused by carbon buildup?.....

Absolutely. A carbond chunk large enough could break off and make a nice mess inside.

The lower redline on the tach of the auto is for the protection of the auto tranny. After you swap to a 5-speed you can safely rev it to well beyond 8K. It seems a little weird since the buzzer starts howling at you so soon, but just keep your foot down and watch it climb past 8K. If that bothers you too much, you could swap out the cluster for a manual one. I kept my auto cluster and I don't mind listening to the buzzer when I "super-redline" it's kinda fun when a passanger thinks you are about to rip your engine apart by going "so far into the red". Also I like how the little red R comes on when I throw it in reverse:)

ok..im not asking COULD IT....im asking WAS IT....meaning did u take the engine apart and see....

personally.....i think that extra layer of carbon increases my compression ratio

Kevin Landers should post. He's ripped apart every kind of conditioned engine and probably has some valuable insight to add to this.

I personally rev it up all the time. I have a TII with 130,000 miles with good compression if that means anything. I think the best reason we have for redlining the engine is the life of people's cars that have treated them so. People that drive their rx7's hard generally have high miles before they need a rebuild. Its a odity and it may not make sense, but such is the essense of the car and even moreso, the engine that powers it.

http://photos.sevarg.net/russ/albums...0007.sized.jpg

Those were my rotors (one on the left is obviously the one that blew).

I don't know how bad they are in terms of other rotors, but in scraping the carbon off, there was a good thick layer in some areas. Likely more than enough to do some damage if it fell off.

This was an engine with 120k miles and the 6th ports totally seized up - it obviously never saw high RPMs.

Anyone have pictures of rotors of similar mileage (or higher) engines driven hard?

-=Russ=-

I'd like to support that through personal experience. I bought my first RX in '88 new from a Mazda dealer in Phoenix.
I drove it hard for several years - I'm either standin' on the gas or standin' on the brake. And, yes I heard the redline buzzer regularly. (I'll digress a bit: I *was* scared one time when I stood on it around a corner, hit redline plus a bunch and with the warning buzzer howling, suddenly all the warning lights came on at once and stayed on. turned out I ran it so fast that the alternator belt exploded)

I retired it at 180,000 miles in Dallas when a moron blew through a light and ripped the front end off. Otherwise, it was still going strong. Started every time, used a reasonable amount of gas - never failed or let me down. The only maintainence I did outside the usual was to replace brake pads and rotors several times - for obvious reasons.

After the wreck, I replaced my car with an RX TII with 75,000 miles. I continued my habit of driving the piss out of it, have just passed 185,000 and it still runs like new. Starts every time and outruns any other car I've owned except my original RX.

I've done a few things beyond basic maintainence, but haven't torn into the engine beyond removing the UIM and other stuff on top to replace old rubber and the MOP lines. Oh, and I replaced the spark plugs - first time since I've had it.

My experience says that regular redline in no way shortens the life of the engine.

- k -

i really dont think there is a "concrete" answer to this question! yes, rotarys were designed to be "rev happy".. but ive read most years owners manuals, and have never heard them say to rev it to redline! the rx8's owners manual on the other hand does say this! i happen to drive the crap out of mine, and she loves every minute of it! i would agree to drive it hard enough to open up the 6-ports so they dont sieze.... and carbon build up does happen, but i dont think it has to be redlined to remove it!! id say, onece a week, give it a good workout through the gears (maybe while getting on the freeway).. take it to like 6000-6500... and you should be good!

I say once a day take it to 8500. In all the gears. Even reverse :)

First off, I very VERY rarely LOL.













This made me LOL ;-)

I hope you finished your break in period!
Then you can rev all you want!:D

I just hit 1k miles on my reman. I took out the plugs and there was alot of carbon build up on them not revving over 4k rpm. This is reason enough for me to redline my car every day once it is fully broken in.

yeah i redline the shit out of my car. when i got it, it had carbon all over the plugs. but after a couple of months of working on it and not letting it go, and then driving the piss out of her, i find no more carbon.

I have the 9k vid for 11 minutes, Also didn't mazda test the rotary engine @ 28,000 rpms for like 4 days straight un-weighted or something like that, and they just gave up because it wouldn't blow?

158k on my engine, nothing went wrong with it but it ran unusually great... except for some heat troubles because of the radiator sucking.

But I decided it was a good time to rebuild it, I want a daily driver, not something that might blow up at any minute and require new irons and a rotors...

And the first owner of the car that had it for like 10 years kept VERY good service records of when he took it in for servicing... which isn't very much like a good mechanical person.. so sure enough, I don't think that owner used the throttle at all...

I drove it for about a month... and I drive hard, redlining at least once if not five or six times a day. ;) I also ran it couple of times... which is like 3 minutes straight of keeping the revs always above 5k and either full braking or full acceleration up through the redline... so the buildup that WAS on there was REALLY on there.

--Gary

Actually, I do believe the RX8 manual recommends revving to 3K RPM just prior to shutting the car off, not to redline.

edit: and I'm really doubting the 28,000 RPM bit... That'd be pushing beyond the abilities of the ignition system I'd think.

so... im safe revving to 8k when i want to scare people? (87SE)

rev limiter at ~7600RPMs

I don't think he meant with fuel.. I think he meant they hooked it up to a machine that spun it that fast... that's probably what the "no load" meant... I know there is a difference between "no load" and "no ignition" but I also highly doubt a LOT of the systems on the engine functioning at 28k. If they were to do that just to see if it could mechanically turn that fast, I'd be interested in seeing it heh.

--Gary

i'd like to see a clutch that wouldn't explode into pieces at 28,000 rpm.

I'd be more worried about the flywheel...

that's gonna be giving out around 15k.... at 28k it would be like someone set off a shrapnel bomb. ;)

--Gary