Well, I'm not sure if this has been covered in another thread yet or not, as the only threads I searched for were the ones involving overheats (I was trying to find an overheat related to mass RPM...).

I should be able to nab a spot in the engine lab tomarrow to bring my RX-7 in finally, and hopefully in a few weeks, I'll be able to drop the $200 to get the seal kit in, as well as getting an aggressive streetport template, and while the negine is apart I'll do that to...

But that's not what I want to ask. What I'd like to ask is what can I do to unlock a higher redline? I would like to be able to run my engine (when the thing is rebuilt) up to 12,000RPM, just so that I can get that screaming exhaust noise, as well as unlocking the rotaries ability for torque as the RPM increases (or so I've heard).

I noted something in one of the threads about Carbon Apex Seals? Do they have those for the 12A engine? And how good will that hold up under a high boost pressure?

I also noted that MazdaSpeed (I think) has rotors with snap-rings to hold the inner gear to the rotor under high RPM. They stated that this unlocks the issue with seperation at 8500RPM.

I understand the issues of heat, and I've been trying to come up with ways to increase the cooling through the engine, including using sub-radiators and additional venting through the sheet metal. I'll probably also be looking into one of those cool looking vented hoods I've seen else-thread.

Anyone found a new peak for their RPM? How high have you gotten it, and what problems do you find at the high-range? Any advice would help, and hopefully as money slowly trickles in, I'll be able to arrange for my project car to live again, and hopefully eat Honda's.

 

Oh, I forgot to put down what my vehicle is! She's a 1983 FB, the tag was lost long ago (unknown specific model). 12A engine, A/C, with a Thermal Reactor (oddly enough). I got her hellaciously beat up, and I'm going over trying to get her back up to snuff, and better.

 

12000 RPM is gonna be useless. To get above 8000, you're gonna need carbon apex seals. To get about 9000-10000 youre gonna need hardened stationary gears and/or rotor clearancing...

At about 8000 RPM, the apex seals begin to skip and "chatter" against the rotor housings, tearing up the chromium coating, and eventually nicking the aluminium...

At 9-10K RPM, the eccentric shaft may flex and the rotor may contact the rotor housing... Kiss that engine goodbye. You also may deform the rotor gear or stationary gear.

A street port will probably peak out around 7500 RPM for HP anyway.

You can do all this if you REALLY wanna, but you're not gonna get peak power at 12000 RPM wiht a street port (Or any port I believe.) Plus Carbon Apex seals dont do well at low RPMs so it won't be able to be street driven.

The mods above are done to Bridge, Monster, and prehipheral port engines that don't idle below 2-3K rpm and are for race ONLY.

 

Without porting its mostly pointless to rev beyond 7500. and thats only after you have modded the intake and exhaust systems to their max.

 

plus many people have told me that if you want to run 10k+ rpms you will wanna invest is a scatter shield for the trans/clutch otherwise WHEN something in there breaks you could be saying goodbye right foot

 

what's a good shift point for a stock 12A engine........7000?

 

Pretty much on every car I've driven, I acceletrate till I feel the pull of the engine let up... That'd be the peak of the power curve.

Shift above that point, keep it near the top of the power curve...

 

The rotary is going to scream way before 12k!

Also, rotaries are unique for NOT having the torque increase. It is pretty much stable the whole RPM band. This is what I've heard anyhow. EX: Torque peak in GSL-SE (133lb/ft) is @ 2750 rpm and pretty steady all the way to redline (7k). Of course, this also has to do with intake runne length. YRMV I suppose.

HTH

 

Yeah... Just run her open header, or hell, open exhaust ports! You'll hear it scream from idle for about 2 or 3 seconds before you're deaf.

 

i've been told carbon apex seals are not recommended for boost applications...

 

Thats true. They are too brittle. One hiccup, one detonation event and they will shatter.

 

ok in my 12a BP i quite easily go past the 8000 on the tacho. I dont have carbon seals, i dont have hardened stationary gears, i dont have a scatter shield. I recently pulled the engine apart after a good 15000km from rebuild.... no sign of wear what-so-ever, just a bit of carbon on the rotors. The housings were just like when i put them in (2nd hand) and the end plates looked just like when i got them machined.

now i dont hit the 8000+ constantly, but usually a coupla times a day. i think that maybe for a race engine.. yeah go the whole shebang, but for a daily.. a good port, a free exhaust and a lightened flywheel will see you there easy. 12000 might b a bit high but 9000 or 10000 is easy to reach.

-James

P.S. Before the flamage starts, i am looking into a scatter shield, i dont care if the engine goes bang, but i do want some legs if it does :P

 

Now I'm no expert Or genius, but with the right mods you can hold an 11k RPM for a little under 8 secs. I know this beacuse My uncle's done it with his racing Rx-7. Though I've never seen it done on a 12A. Go with the carbons man they help get you to a higher redline

 

Looking for Carbon Apex seals, as well as pricing how much it would cost to get new steel seals, I noticed that they have /ceramic/ apex seals for a 12A engine... anyone know of this is some sort of uber legendary apex seal with the abilities of both steal and carbon, or what?

I would like to run a turbo, so unfortunately I can't go Carbon.

Also, the ceramic seals are 650 a pop. A bit expensive for them to be useless. So I'm curious if they will help at all.

 

Look around in the tech and performance sections. Youll find out all about the different seals and what they can handle.

 

I some how made the discovery that the 84s and 85s tach will only go to 8K, the engine will keep reving but the needle stops at 8K.

Anyway, NO you do not need carbon apex seals to go past 8k.......... Arent any of you guys thinking about the rx8 for a second? It has a redline from the factory of 9K. And that thing does not come with carbon apex seals. Not having any periperal ports helps though. Makes sealing easier.