nittoracer753

okay, since the rotary engine is a rotor that spins...can it revv to forever? cuz piston engines' seal fails, but what bout rotaries? or does the rotor just blow up?

mxd

iTrader: (1)

idk the specifics.
The limiting factors are linked to centrifugal forces causing the eccentric shaft to warp or bend under the force of the rotors weight spinning pulling and pushing on it, which leads the rotor to contact the irons or the alum housing.

People use light weight rotors (then machined lighter) heavy apex seals and springs, high speed bearings, large ports, and other modifications to intake and exhaust velocity and masses. I know I missed somethings required, but that is the idea.

phoenix7

I would say redline. I say this because you're not making any power past redline unless you're ported. As far as safely? when it comes to the motor itself, I don't know. But the clutch and flywheel become leg-slicing shrapnel at/past 11K rpms.

Sideways7

iTrader: (7)

Actually, they can blow if taken past 8.5k. If you rev any higher much at all you need a tranny scatter sheild.
As far as a stock motor, you can probably take it to 8.5-9k safely, but it won't make power there. There have been properly built motors (read: mega money) taken past 11k.

Don49

iTrader: (3)

My engine builder says 9,000 is a safe redline for my street port E Production SCCA 2nd gen motor. I have run it to 10,000 in 5th gear and when the motor was taken apart to repair an unrelated problem .everything still looked perfect. I use Redline 50w synthetic racing oil, have 125# oil pressure and see water temp of 200 with oil temp in the 210 range. I guess what I'm saying is that a properly prepared , balanced motor should live to 9,000 all day long.

BrettLinton7

iTrader: (33)

so revving an S4 na to 8K won't warp or snap the e shaft? lol

Evil Aviator

The rotors don't spin in a perfect circle, but rather an oval type shape that does induce some side loading. This makes the rotary engine less rev resistant than an engine that does rotate in a perfect circle, such as a turbine engine. Also, rotors weigh over 11 lbs vs. about 18 oz for a piston, which makes the rotary engine more difficult to balance than it would seem by simply looking at an engine diagram. The clearance between various engine parts also plays a role in operating rpm. Additionally, the fuel injection system, lubrication system, cooling system, and accessory drive systems have their own rpm limitations. At a certain point, even the airflow entering the engine would have a limit due to friction and compressibility issues. Even a turbine engine has a rev limit.

Also, FYI, the tachometer reads the eccentric shaft speed, which is 3 times faster than the rotor speed due to the 3:1 reduction ratio of the Wankel engine.

More info here:
http://www.rotaryengineillustrated.com/RE101.html

nitronatefc

iTrader: (2)

I'm pretty sure you can rev as high as your wallet allows for Don't S4 stationary gears run the risk of disintergrating over 8500 rpm or somethinglike that? Redline totally depnds on your build, which since you are asking we all assume is stock. Rev the **** out of it man. Then you can tell us the answer...

TehMonkay

iTrader: (-1)

i thought the rev limiter was set at 8500?

10000rpm in 5th gear in an NA with a 4.1 rear end is 250mph.

Do you have the 5.1:1 rear end and a TII trans? That's 178MPH.

You should look up how a rotary engine works, the triangle doesn't just spin, it moves eccentrically.

musicman3x

There was a video of a shop that took a stock na, I think, and reved it up to a high rpm, 9k+, untill the bumper lit on fire. It lasted a good amout of time. I can't find the video though.

Ballin_is_a_Habit

yea they just redlined the **** out of it, for 6 minutes before they swap the engine, i dont know why they had to trash this one though i could use it

here it is they claim 15k? im not sure whats goin on here

http://videos.streetfire.net/video/6...ef855ba56e.htm

demontwig

Damn

RotaMan99

15K....BS FLAG.

Anything over 8000 is unreliable for a stock motor. You can build them to withstand high rpms, such as 9500-10K, but you are talking $$$$$

Spectator

iTrader: (1)

Worst video ever. And the guy even states that the rear rotor has zero compression. Bullshit. I can clearly make out the sound of a fine working engine.

RotaMan99

^ I heard the same. I had a blown engine once and it did NOT rev up that quick or sound like that at all.

Sideways7

iTrader: (7)

There is a video somewhere where a guy had a blown engine and he took bets on how long it would last when floored in neutral. It really was a blown engine, though. I think it lasted 7 or 8 minutes before the oil control rings finally disintegrated and the motor died.

phoenix7

it lasted 9 minutes WITH NO RADIATOR CAP. So I'm sure they would have been there much longer if it had a full radiator, oil and the cap.

Spectator

iTrader: (1)

Yea, I think it was a white vert right? Stupid dumb ***** burned the car.

Don49

iTrader: (3)

Teh Monkey,
10k rpm with a 5.12 rear, mazda comp trans (.85 overdrive in 5th) 23" diameter tires= approximately 144mph. This was at Beaver Run near Pittsburgh. At Pocono with the 4.8 rear I saw 9.4k in 5th on the front straight. The formula is mph= rpm x diameter over final drive ratio x 336 - do the math!

AUGieDogie

iTrader: (4)

Well if you are using the stock ecu you won't get to 10k! They have limiters in them to prevent you from killing the motor and mangling your self. I know some guys race them and red at about 10 but they have scatter sheilds in case the clutch blows it wount take out a leg.

as far as your piston ideas, some formula 1 V8s red line at 20,000 rpm! I dont know of any rotory tested that high. I bet is someone wanted to though are little engines could do it. Just takes money.

Raid3n

i remember seeing a shop in ontario i think that had a 20b with a 16k redline i think it was...14 or 16k something like that

SaabGuy

I used to pit crew for a fellow racing a heavily modified 12a motor stacked into a completely custom tube frame with a 3rd gen body. Car raced in GT3 class by David Pettigrew in case anyone wants to look it all up.

For one of our races we were allowed to change our maximum rpm because we did not have ideal gearing, by tht ebook. I personally bumped up the rev limiter from 10,800 rpm to 11,200.

The 12a engine was NA carb fed full bridge port with a range of about 250hp +/-. Lightened and hardened everything we could: Basically the motor cost was about ten thousand every time a rebuild was needed, which sometimes went 2-4 seasons.

ziig

iTrader: (1)

well i ran 10000 rpm all year ..then my last race for the year we pullld the rev limiter and i ran 11000 in 33 degreee celcius heat....and the engine was fine when we did our yearly rebuild......this was a na PP with stock shaft and rotors..no lightnening..or major balancing work............my stock 6 port will peg the dash rpm guage..lol

GarageAlchemist

what did the 787B rev to?

SpeedOfLife

iTrader: (16)

I suspect it would be a different beast having four rotors instead of two (I would guess it could rev a little higher than a two rotor, but I could be wrong, a much longer eccentric shaft probably complicates things). Not to mention megabucks probably went into the motor.