It all depends on the modifications to the engine.The limit with steel seals,and stock stasionary gears would be 8500.It doesnt make sense to rev it that high if its not making power anymore though!

I normally shift @ 8000 and when pushing hard ; 9-9500.I still have to install a scatter shield ,havent gotten round to it yet,thats why i try to keep the revs down a bit.

 

Scatter shields are a great idea in any case.
You plan on making power they are a must for survival.
Even if only for piece of mind it is mutch better than killing your best mate or girlfriend or even yourself.....
ESPECIALLY if you going to be going to 10000 RPM on a daily basis...

 

I go a bit past 7k regularly for brief moments, and I do not take it above 8400 as I have been told that it will start to bend gears and or warp the eccentric shaft. I've had no problems and my engine runs really strong for its age and having 290k kms on it

 

i normally shift at 3500-4K on a daily basis (daily driver)

 

The stock 3mm apex seals start chattering at 6200rpm. This accelerates seal wear and especially housing wear.

The seals tend to shatter at 8500.

So, on an engine with stock seals, don't go over 8500 if you want the engine to live, and don't hold revs over 6200 if you want it to live long. If you want more revs you need different seals (2mm or carbon-aluminum)

Other factors:

With the stock pullies, the water pump starts cavitating (creates vapor pockets behind the blades, and flow drops dramatically) aorund 6200-6800. Another reason not to hold revs up that high for long periods.

The rotor gears can start to walk after 8500. Rotor gears coming loose does bad things to the inside of the engine as they try to force against the side housings.

The stationary gears see exponentially higher loads on the teeth starting at 8000. After 8500 you run the risk of pounding out the teeth, causing the kind of internal mayhem you could imagine would happen.

The eccentric shaft whips and turns into an S shape as you rev the engine higher. At some point (9000ish?) it physically contacts bearing surfaces. That's why race engines run such higher clearance.

 

cant you get a different pully for the cavitation?

 

Yep, but different pullies didn't come stock.

 

How long do you want it to last? Everything must be just right to live at 7G for high end shifts. Be smart. Whats it worth to rip it out - like any other engine? Where is your power curve anyway?

 

Is there anything that can be done to prevent this?

I'm suprised at this fact because the redline is 7k and I would've thought that everything below that is safe and sane. Guess I was wrong?

Does this mean I should not hit redline in every gear? Every time I drive?

 

You'll just be accelerating wear.

The engine is safe to 8500 as-is, however longevity goes down as RPM goes up. Same as any other engine. RPM = Ruins People's Motors.

Really there's no point to holding revs that high anyway... peak HP (in a stock engine) is 6000rpm. Stock engines make only noise above 6500.

Note that, with only a Pacesetter exhaust and a fuel pump upgrade, I was getting my best 1/4 mi times shifting at 7700-7500-through in 3rd. I think the tach might be off. The Pacesetter is garbage, it has a big restriction in it, in theory the engine should be laying down and dying at 6k.

 

My SE with Mindtrain headers/exhaust pulls hard past 7k. I never shift any higher than 7200; I think it's pointless anyway. Daily drivers aren't race cars either. If you guys have the unbeatable urge to rev to 9k, either port your motor and upgrade your seals or buy an S2000 (although I'd prefer you ported your motor ).

Zac

 

RX8 goes up to 9k, with out any problems. I dont know of any changes mazda made to the motor adressing the problems that PJ mentioned. I guess we'll see how long the 8's motors are gonna last. I exoect em to last well past 250K however.

 

A lot of the things were addressed starting with Series 5. I think S5 and I know FD have hardened stationary gears, and the 2mm apex seals seem to handle the revs sorta okay. Mazda did start adding three additional rotor gear roll pins somewhere in the timeline, dunno if that is a "fix" or a crutch.

Word is though that apex seal wear goes up drastically past 8k... granted with a 9k redline you won't see much time past 8k, but the problem is still there.

The RX-8 engine will probably last 120-150k or so on average, depending on how it's driven. (like 60k for the low end and 200-250k for the high end)

 

I have to say I'm nothing but disappointed by this whole read. I thought my rotary was just as good in reliabilty as them piston bangers, especially with the new RENESIS motor.

Anyways, assuming somebody has a high powerband (ported motor), is there anything you can do to "fix" the seal problem other than perhaps using S5/FD rotors or stuff like RB hardened stationary gears??

The low of 60k on a RENESIS shocked me to go look for the warranty info on MazdaUSA.com. Here is what I found.
Do you think seal failure is "normal wear" and thus not covered? =0

This was taken straight off Mazda's site. here

 

Yep, there's heaps of things you can do starting with carbon apex-seals.

You can also clearance the rotors by machining the sides to provide more clearance between the rotor and side plates. Some people also clearance the rotor tips.

Then there's a modifcation called "circlipping" which involves machining the rotor to accept a circlip which stops the rotor gear from walking at high rpm.

If you're really serious you can get two-piece eccentric shafts and centre plate bearings from Guru. In the end it comes down to how much money you wanna spend.

 

Everywhere I've read in technical articles, and from racing beat, Hayes, History of the Rx-7, they have all given the Hp reading maxed out 100Hp-115Hp @7000 rpm, peak torque @4000rpm. Even when racing beat dyno'd thier Dellorto and header exhaust it made peak HP @6800rpm, and that is a restrictive intake past 6800rpm. After driving many 1st gens, they all pulled hard to 7k, and then you can feel power loss shortly after. Where did you find out about power loss after 6k? I would like to see a dyno graph, or a source that I could see?

This is also very new to me, I've never heard of that. Most sources have always said after 8,500 is when the stock seals chatter. Race car builders of the stock class It7 and Pro-7 say the same. Not to say your wrong, but do you have any proof of this? Where did you learn this from, you definitly have had lots of posts, and know alot.

 

You know how you can tell when you have over reved it ?
....B A N G !!!!

Plus a large shell out of cash to the local ROTARY mechanic. . .
Cheers Nick, goes like a dream now !!!

 

The seals *shatter* at 8500. The chattering that causes them to shatter begins at only 6200.

One of the reasons why the engines had 2mm seals starting with the FC. The engine was tuned to make power higher up in the rev range and the 2mm seals don't have as much of a problem as the 3mm do.

I have never heard of the RX-7 12A engines making peak power at 7000. Everything I have ever seen says 6000, and they feel like it.

BANG indeed... actually it's more like a hiccup

 

Well, time will tell with how long the renesis will last. It has re designed apex seals as well. So I really do think mazda did everything they could to make the motor last. They have to, especially with the bad rep the FD got. I persoonally am expecting at least 200K.

 

Peejay, where did you get this information?? I also have never seen a dynograph for an rx7 that peak power is made at 6000, always at 7000. Where is your data and sources?
By the way this is SHM21284, he mustve left it logged in and i cant seem to delete this post so i can reply under my name...

 

Mazda's stated power and torque figures have always been 100hp at 6000, 105lb-ft at 4000, for the 1st-gen 12A.

 

i must have a bad memory then

 

it isn't worth going over 7k in a stock port, damage issues aside. they make peak power around 6k.

 

The renesis has many advantages for long life, but a MAJOR one is the computer controlled oil injectors. An rx-8 has a fuel cutoff at 9500 rpms, and does so from completely redesigned side seals, apex seals, and lighter rotors. This decreases the forces on the eccentric shaft. Their are always exceptions, but a well maintained 8 should last as long as any new car. Some japanese tuners are using the motors to 13k with no internal mods.

 

I shift when the car beeps at me... so redline that ****!