BigTone

I think it was explained in my first post.

Simply put: less wight=higher redline

This isnt a new concept. It has been talked about fairly often. When a newbie comes in and askes why his S5 na has a higher redline people tell him it is because his rotors are lighter.

Why can the rx-8 spin to 9k, it has even lighter rotors then the S5. It all has to with weight and the lack of it. The lighter you can make a rotor the easier it will be able to rev higher. However it can not make it too light(or take away to much material) because then you would start risking the structural integrity of the rotor.

bindeezel

Say what?

http://www.mazdatrix.com/faq/rotorwgt.htm

1987RX7guy

iTrader: (3)

I didn't argue that I just wanted some confirmation from other people on the forum. I didn't want to assume too much on my own without support from other members. But the fact is I wasn't asking about price or how to get lightened rotors. I have the RB catalog and have read a lot of the stuff on it. I know the rotors they sell cost both left and right nuts.


Santiago

MrBob 86

I posted that, but I have no idea how I got under Bindeezel's user name.

BigTone

True

However,

It really would not have mattered becasue one would not be able to get much more power changing the redline in the S5 with the stock turbo.

BigTone

Thats for sure

MrBob 86

It matters because S4 NA rotors and S5 TII rotors are not the same.

BigTone

Yes they are not the same. However, adding another 1000k to the redline would not matter on a stock application. The stock engine/turbos would not benefit anything from the additional rpms.

andrew lohaus

caugh, caugh, called by a new meber.
id have to say this is the first time you've been off that ive seen.
a commendable record

well you are always way more accurate than me so i geuss i cant give you too much of a hard time.

1987RX7guy

iTrader: (3)

He's been wrong a couple times before. But he still right like 99.5% of the time. So I think thats ok.


One other time he was wrong was in the gph of the stock fuel pump.


Santiago

andrew lohaus

lol. yeah icemark's the man i can forgive him on this one.
i geuss thats why hes a moderator. he accutaly cares about the accuracy of his statements.

MrBob 86

Actually it was caught by me. Do to a forum **** up I was logged in as someone else.

domesttuner

Well, if you increase the size of the apex seals, wouldn't that allow the engine to have a higher redline? Or would you have to increase the side seals as well?

MrBob 86

No. I think that the rule of thumb is that heavier apex seals dont seal as well at high rpm, therefore you would in effect be lowering the redline. Sort of. Ever seen those carbon apex seals? They are lighter than steal apex seals. They put those in high revving engines because they seal better at high rpm.

Basically the "redline" of a rotary engine is determined by the rpm at which the e-shaft flexes enough to allow the rotors to make contact the the side housings. But there are other factors that must be consider as well, such as the stationary gears, bearing clearances, boost pressure (e-shaft flex), and so one.

domesttuner

Yeah, I figured that out when I looked at Mazdatrix.com to prove a point to a drunk ASE mechanic that rotaries are better than his 305 chevy. The carbon seals had a statement that said the same thing you did - sealed well at high speed, sucked at idle or low rpm.

domesttuner

He also said that up until 5 years ago, you couldn't have them rebuilt. He has had a tee many martoonies.

andrew lohaus

the size of the seal has nothing to do with redline, just like piston rings dont effect redline. its always an issue of how much mechanical strain you are putting putting on a component with respect to its strength.

so the stronger and lighter the driveline is the higher the redline before it breaks.

domesttuner

True. I'm just now getting into the mechanical part of 7's, i've still got a lot to learn.

andrew lohaus

yeah thats cool man. i didnt know anything except that they had rotors when i got mine. but thats kinda the fun of it.