OK, well when I get my engine rebuilt I will be using S5 rotors, along with a large streetport. Also a aluminum flywheel and upgraded clutch if you care Anyway, Im sure that I will be making power much higher than I am now with my stock port S4, and Im thinking that I will be revving to close to 9000rpm or so after my rebuild (will dyno just to see exactly, just speculating now). Anyway, my question is , is there anything different in the S4 engine (beside rotors) that would make it unsafe to rev that high? I know even a stock S5 N/A it would be no big deal, so I wouldnt think that it would be for me either when I use the S5 rotors.

 

The flywheel could break apart, maybe. Its rumored thats more like 10000ish rpm though.

 

What about the bearings? I don't know what the stock
bearings can handle in a S4 or if there is any difference
in the S5 bearings. How much of an issue would that
be?

mothership
87 N/A

 

most aftermarket clutches and flywheels say not to go above 12,000 but i wouldnt go above 10K fo fear of loosing my legs as the flywheel comes threw the floor board

and i just get nervious taking mine to 7500 now

 

I believe most clutches and flywheels specify to not exceed 10,500rpm. I wouldnt be going near that high, Im thinking ~8500 somewhere, is where my power will peak, and start to drop off. Im just wondering if there are any Diff in the S4 housings or bearings or anything that may cause problems with those high of revs?

 

 

Unless you've got

a) high-pressure oil pressure regulator
b) well-clearanced bearings
c) chamfered rotors
d) hardened stationary gears
e) light (S5+) rotors
f) comp apex seal springs
g) at least some balancing work

I wouldn't take your motor over 8500 RPM. There's a reason Mazda put the redline where it is, and why Mazdacomp has plastered "hardened stationary gears are necessary for high-RPM (over 8500) operation" all over their website and catalogs.

Brandon

 

Thanks, thats what I wanted to know. I dont "want" to rev that high (ok, I kinda do ) But am assuming thats around the point where my power will be peaking with the S5 rotors and large streetport.

 

s5's peaked at 7500, so with a big streetport it would probably be pretty high. I would probably never take my car over 8500 though, even if I had hardened stationaries and apex seals that could handle it.