I want to use a set of S5 NA rotors in my next engine and i was curious if any one has machined the sides of their own rotors and then had them rebalenced? I read on here about 6 months ago a guy from NZ said he removed almost a 1/4 inch and then were balenced by drilling the bearing support. i wonder if they were S5 though. Any ways has any one bought a set of RB light wight rotors and could tell me how much they mahcined off the sides? Or does any one know aout how deep you can go. i know they say you can get a pound or a little more out of them.

CJG

 

That was me
No, they were early 13B rotors, so even though they were lightened that much, s4/5 rotors were still lighter.
I didn't do the machining, they were in an engine that I rebuilt, so I couldn't tell you how much you could take off before you made a hole or weakened the sides enough to cause other problems. Maybe send an email to Racing Beat and ask them.

Gary

 

if you wait a bit , look for a set of renisis rotors and parts, Option2 did a comparison, the weight of the rotors alone compared to an S5 rotor was over 380g lighter. if you replace the rotors, E shaft stationary gears with the renisis you save over 2kg from the S5 parts.. ( this months option2 )

 

I wonder how long it'll be before RB starts offering Renesis stuff to update our engines?

 

If I wanted to use renesis stuff can i use a set of machined converted renesis rotors on the old S5 gears and S5 shaft? Or do I have to converts to all renesis rotating assembly?

CJG

 

if ANY one knows what this would take, im sure our friends with the deep pockets would love to say they have some renisis sh*t under the hood......wonder when some one will be crazy enoughto try a renisis swap...who knows!

i met this guy with a 1G GSX that wanted to do somekind of honda 20B swap in it. It was so hard not to laugh if ya know what i mean... crazys, but we know that its always the crazy ones that achive the "imposible"

 

I heard rumors once again rumors from old timers that Jim Downing back in the day actaully had some custom casted rotors that were like 7.5 lb. but the gain was really not a whole lot. I don't think RX8's hp gain was from the lighter rotating set, I am sure it hleped but I just don't see that much more hp from lighter stuff. ( lets not forget actual RX8 owner dyno number is a lot lower than what Mazda is claiming.) I would love to get some RX8 rotors maily because of the 10 to1 ration and do a bridge port again. So what are the difference of the rotors? gear teeth and bearings are different sizes?

 

lighter rotors allow you to ligten the counter weights and reduce the rotational mass.. this allows you run a higher RPM with less moment loading. That's about the only gain I can see, ( faster revving engine too but too much of that requires you to heel and toe in a daily driving situation with is a pain. )

 

in Japan they have enisis parts alrady for sale, but from what my local parts counter guy says, Mazda north america s sweating a bit, they won't have ANY parts for the 8 until after X mas and probably won't have any engine parts redily available till well into next spring.. For NA buys the 10:1 compression is a nice option, I know I'll be picking up a set of rotors for my S5 na as soon as they become available..

 

it goes right in you just have to pay the $200each to get em

mike

 

The dealers here in Florida got a lot of the rx-8 parts in stock. One dealer sold four sets of rotors! I've already ordered and collected rx-rotors. I have a couple sets being milled for 3mm!
My cost on the rotors are around $250 each. I'm waiting on the counter weights though.
From what I've seen they are only 75 grams lower than the 89 to 93 rotors. Kinda strange considering with the extra oil scraper seal they would weigh the same as the 89 to 93 rotors. They are also casted a lot better than the older rotors. It's a lot more dense and there were no balancing marks seen. I'm also going to lighten a set to see what happens. A friend had them x-rayed and it seems very possible to have it done. What I don't believe Mazda spec's on was the compression. It's seems to be a lot higher than the quoted 10:1!

 

Hey crisspeed, so who are you having mill those? because i thought the stock renesis apex seals are "shorter" so no other seals interchange. And i also saw mazdatrix claiming that the stock renesis seals cant handle running over pp's? 250/rotor is really cheap compared to a new set of S5 rotors. about 200 bux cheaper actually. So do we know for sure that we will be able to use the renesis rotors? If so i will get me a set ASAP.

CJG

 

I went into the MAZDA service this evening and their computers show no parts in north america ??!.. this is stupid.. I see another rotary debacle comming on like it did for the FD.. mazda will pull the car in a few years becuse of north american service, or lack of..

your sure the rotors with seals and everything was $200/per ?? if so I'm buying some pronto and selling my S5's

 

The rotors alone are $250!
The side seals are around $14

 

Thats still not bad at all. Any more info on machining to use older apex seals?

CJG

 

You know, he could be talking about a B20B or B20Z CRV engine swap right?

GREG