I have the ports and the turbo to extend my power output to 8K+ although I may be limited by the FD's upper/lower manifold. The lower portion is ported.

I'm using Cosmo RE 2 rotor plates/housings (ported everything) but stock Mazda oiling system and bearings. Can I safely raise my rpm limit to 8500 or even 9K or are the bearings/oiling system the limiting factor? I've been getting contradictory information on this and I'd like to set the record straight. It's been my belief that Mazda "race" bearings would be needed (possibly have deeper "channels" to hold more oil) and clearancing. I have the clearancing part done. Thanks in advance.
Michel

 

FYI Using Atkins 2mm 2 piece seals and solid end seals.

 

I'm no expert, but I think you'll be fine at 9k. Clearancing is the main issue, but you have that covered. The manifold isn't really an issue, plenty of people are making tons of power with stock manifolds.

 

I don't think it's going to be that easy...I've heard that the oiling system has some sort of shortcoming but I don't know what that is nor how to fix it. Anyone?

 

judge ito told me as long as its a mazda matched unit you can goto 10k rpm safely. mine see's its 10.5K rev limit quite often

 

What gear are you revving to 10,500 rpms in? Does your dyno sheet reflect this?

 

Dude I wouldnt even take my full house J-port to 10.5K!! Hope you enjoy your motor cos it aint gonna last...oh and when it blows post up pics of your raped side plates.

FD owners should know better.

 

Vosko just likes to break ****.

That is his way, let him do it.

 

I'm tempted to call Bullshit. Vosko, when I'm back in NJ I'd love to go for a ride in your FD and enjoy it's insane drivetrain-destroying power

 

You should probably underdrive your water pump pulley. At that kind of rpm the impeller won't really pump it will just kind of swish the water around.

If it were mine I'd also go with a higher pressure oil pump.

 

Have the GReddy underdrive pulley. Switched to Royal Purple 20W-50 and my pressure is waaay up there now. Almost 120psi at a redline of 8K rpm. Big difference from the Royal Purple 10W-40 which after 1000 miles, was almost water-like.

 

Hmmm....

I do know that Mazda uses a alphabet coding system for their rotors (A - E). I'm assuming that it is based on the standard deviation of weight for each rotor, meaning, the perfect weight rotor would be a "C", but that is just a guess.

I wonder if this type of coding, pertains to the eccentric shafts as well?

The reason I know this is because it is in one of my Japanese magazines. Unfortunately, I don't remember much from my one of year Japanese class,...back in 1992!!!!

Hey Vosko, see if Judge Ito can confirm my assumptions...

I gotta bring my magazine over to the guys from Signal. See if they can translate it.

 

If you plan on running above 8K often, you need the clearanced rotors, MFR bearings which have .0005 more clearance and a .050 deeper oil groove, hardened stationary gears, a balanced rotating assembly, and if it were a perfect world, lighter apex seals would be nice too. If you only want to run it to 8500 once in a while. I think you're fine. I do it.

 

Yeah just once in a while, I may discover that my powerband falls off before 8500 after I get it on the dyno. We'll see. We actually had to pull the motor out due to a coolant leak (caused by overzealous porting on my part!). Bearings looked brand new after 3K+ miles.

 

How much clearance between end plates and the sides of rotors?

B

 

when he gets back from vacay i will ask him

 

THE REV LIMIT. all depend on ur port. most street port make their power between 4000-7500. BP some time to 8000+ . and PP is much highter some time u can see 10000+. but the higher u got the short life u will get from ur engine . EVEN 4 rotors LE MAN RACE car's red line are 8000. if u want to know go get a RB catalog it explain pretty good.

 

10500K is krazy.....that's more of a story than my ferrari story....

 

i had a friend that had a 280Z with a L28 N/A and he reved to 11000. It blew up the clutch one time and cut his legs up really bad....


I wouldn't go above 8500 with-out a scatter-shield.

 

I used to rev the secondary bridge to 10.5 in 1st and 10 in in the rest of the gears. This was with no special clearancing and stock bearings. After teardown of the motor there were no signs of damage from over rev. No rotors tagging end plates, no abnormal bearing wear. I think this was more of a problem with FC and older motors because of the old style bearings and the lower oil pressure.

 

I just tore down my Cosmo motor after I discovered it was burning coolant due to me hitting a porous spot in the front primary runner. Wasn't a hole per se, but it did allow coolant to enter the combustion chamber. Anyway, the engine has seen 8500rpm a few times in it's 3K lifetime. Upon teardown, the rear e-shaft journal had a small, probably and inch in length score (discolored due to heat and rough edge) along the back side edge as it melds into the e-shaft tail. Not very big but it did scrape a ring on the outside of the bearing a few thousanths in thickness exposing the copper. The rear rotor didn't come off the shaft easily either. Bearings did not spin and looked like new everywhere else. For the life of me, I can't think what would hit that portion of the e-shaft. There's nothing there for it to hit and cause that kind of damage (to the best of my knowledge). Any ideas? I'll try to get some pics this weekend.

 

Rotor clearancing is a good idea

 

Nocab72's car!

 

I supose it depends on the Power you are puting out as well, if i was building a high RPM/Power motor i would be looking for a 2pc Crank and center bearing and a set of Ceramic 2mm's.

There are ways round it (Clearance rotors etc) but this is the best way of doing it i feel, but it depends on your Buget.

But i like to be on the Side of over engineering.

Chris

 

104 is bad LOL

Probably ok though, I heard the PFC and the Knock sensor dont play nice sometimes. Or just could be loose