Spinning to 9K
 

I have heard that this can be done with a relatively stock rotary. What do you have to do to achieve this? Getting rid of fuel cut, pre-mixing?

there is no power there you don't need to go that high unless your heavily modded.

lots of porting, removed fc, increased fuel delivery, newish transmission to shift that high on a constant basis.

here is a link that will answer your questions

https://www.rx7club.com/showthread.p...&highlight=rpm

At 9000 RPM the stock motor has long since fallen off. No need to wrap that high, unless you enjoy buying new motors.

The link you gave me said that power falls off after 11, all I wanted to do was rev to 9, why did some people tell me 9 was impractical. Sounds totally doable to me.

Stock, power drops off for an N/A around 7K actually :)

i believe for safety you should consider either fd stationary gears or hardened s4/s5 gears along with oil mods (FD oil pressure reg atleast)

way to bring that thread back from the dead ;)

I was the one that said the power drops off at 11k. That's on a bridge port. Do you understand the basics behind porting a rotary?

To answer your question: You can certainly rev to 9000 rpm on a 'relatively stock' rotary motor, but there is no power there for 'relatively stock' cars.

To rev much higher than that, one would need to have the rotors milled so they do not come into contact with the rotor housings. there will always be people who claim they rev their stock-engined car to XXXXX RPM, but you can't do it reliably, and you can't do it for very long, with a stock motor.

Here are some of the issues you need to address:
water pump cavitation
rotors contacting rotor housing
actually having power past ~8000rpm

For 9000rpm you may want to think about a clutch scatter shield. If you value your feet and ankles, that is. However, i do not know if it is necessary. Something to consider.

also oil mods and stationary gears, as blink mentioned.

transmission has been mentioned before.

there are a lot of different issues. i have to go now, though. i'll check on this thread later tonight.

victor

On a nicely modded TII you can create power all the way up to 8-9k rpm on a stock motor. Will shorten the lifespan big time to be revving that high though on a stock motor.

i thought stock turbo drops off around 7k so what's the point if you're power band isn't there.

Yeah a stock turbo would. But if you got a TII with full exhaust, intake, upgraded turbo, fuel mods, and piggyback or standalone then your car should pull hard into some high rpm.

Crap, you will never need to wind a stock turbo that high, it's pointless and will generate slower ET's- the turbo is too much of an intake restriction.
NOw, when my car was a tightly tuned NA, I shifted at 9K on the dot, that was with a nice free flowing intake and exhaust, as well as a nice big street port, and substanial leaning out with the S-AFC. Jumped my torque curve up quite a bit. (In RPM,)

Posted by Rotary Racer
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Ok I think it has been a while since some one has posted a question like this so I will chime in and see what I can add to the mix.

From my experience and from talking to a lot of the seasoned professionals in the rotary field I would say the magic # on a stock block would be 8,500 RPM. After this point you are taking your chances for a few things (if not all of them) to go wrong. Now some people will argue that the stock S5 internals will rev much higher and I know they will. Case and point, when Todd had his RX-2 (I think it was an RX-2 correct me if I am wrong) we all saw it on the dyno out rev the computer up hear 10ish or so. But I would not feel comfortable doing this every day.

Getting away from the internal modifications that it takes to make sure the motor can spin that high, we have to look at power and air flow efficiency. On a stock block car there is no need to spin the motor that high just due to the simple fact that the motor can no longer suck in the % of air flow it will need to make adequate power. So to make the motor breath up at that RPM range you will be looking at a very large and aggressive port, with just as much fuel (if not more) to compensate. This will do two things, one it will take away the streetability and longevity of the motor (not to mention the gas mileage). Two your low end will suffer greatly and your power band will not start for at least 4-6k. Cars that are ported and meant to be at this constant high RPM are generally racecars that do not care about gas mileage, stop and go traffic, and are more than likely sponsored and rebuilding a motor is not a large financial deal to them.

Now that we have the air and fuel into the motor the next group we have to think about are compression, explosion, and expulsion of the air and fuel. The apex seals I feel are greatly over looked when people broach this subject. Your standard 3 piece steel apex seal does not seal/make good compression at these upper RPM’s thus making it one of the many weak points to address. Now on the other hand a Carbon or Ceramic apex seal is a good mate for a motor that wants to have adequate compression/seal at those RPM’s. But like everything else they have there down side. These apex seals do not make good compression down low so again your power will be limited to about 5.5k and above.

Next on our list of things to modify are the rotors them self’s. These units need to have at least two procedures done to them before I would even thing about attempting this. First they need to be clearance so they do not come in contact with the rotor housings. Second the rotor gears need to be machined for snap rings so they do not “walk” out of the rotor and touch the side hosing.

This is starting to get longer than I thought it was going to, so I will try to sum up the rest. Your stationary gears are going to need to be hardened so they gears do not warp/flex under those loads. Your bearings and oil system will have to be modified to make sure you have adequate oil flow so metal-to-metal contact does not occur. The rotating assembly (Front counter weight, rear counterweight, rotors, flywheel, e-shaft) are going to need to be balanced so there are no vibrations. Said before you are going to need a clutch that has been approved for those RPM’s and a scatter shield so in case it blows so you can still walk away from the crash. Oil and water-cooling is going to be an issue as well. These excessive high revs are going to generate a lot of heat. You are going to need a good oil cooler and radiator. The water pump is going to need to be addressed due to the capitation it will most likely be doing.

This is all I can think of now at the time. Rotor on!!

- Dana

Sorry all did not see that RarestRX was logged in on my CPU.

- Dana

Haha. I thought it was weird that the post started with out

Yo,

:D

Yo,


Dana, quit postwhoring on my handle!!

*snicker*

Oh, and check out how far I got on Aliens vs. Predators. You're gonna sh*t when you see where you start off.

Kevin
1989 GTUs "Warm that pulse rifle up..."