First gen man

iTrader: (24)

Here's a pic of the rotors.
http://i18.photobucket.com/albums/b1...r/SANY0200.jpg

I used to have a C and a D weight rotor in my engine. I popped it and trashed the C weight. I got my hands on another C weight through the forums and I was sent the rotor on the right side in the picture as a S-5 j-spec turbo rotor.
The compression pockets have a different outline though. My original rotor (left) and my old C weight rotor I trashed have the rounded corners and smooth waves in the bath tub.
This new rotor is squared though. It seems like I have seen this before but I'm not sure and I am double checking.
The weights for the rotors are 9.562 for the rotor on the left (D weight) and 9.774 for the one on the right (C).


help?

Jet-Lee

iTrader: (1)

Kind of on topic, but along with explanation of the compression pockets, could someone explain the differing uses of different weight rotors and how to know which I have?

Sorry OP, just lookin for additional info, that could prolly help others out as well, and it's pretty in-line with your topic.

First gen man

iTrader: (24)

http://www.mazdatrix.com/faq/rotorwgt.htm
That identifies all the rotors and weights.

The heavier the rotor the worse.. for lots of reasons.. But people deal with it sometimes for the particular compression ratio they want.

The rotors also have minor different weights in each model. Mazda marks these weights on the rotors with letter (A though D I believe) and always uses matching set from the same letter in an engine stock.
Word on the street is "C" can be used with everything and this is all Mazda sells if you purchase a brand new rotor. I am not sure on this though. Seem's like the weight didn't matter as much as they thought or something. Maybe sheer lazyness. maybe a lie.. Someone help me out on that.

farberio

iTrader: (7)

Both of those pockets are machined finished?

Looks like your JDM may be an FD rotor. It may be the camera but it looks like the profile of the upper part of the pocket is different from the lower part of the pocket. If they are in fact different, that seems weird to me.

beefhole

iTrader: (29)

Weights can be mixed as long as they are within 2 letters of eachother. Obviously, they have to be of the same series and engine type. You wouldn't want to mix a 9.7NA with an 8.5TII rotor.

farberio

iTrader: (7)

Weight matters very much, mismatched rotors will have bad vibration. This can lead to bad rotor/stat gear bearings or low compression.

First gen man

iTrader: (24)

Ya I know that, but I heard things like the same weight letter rotors can vary pretty heavily in grams, so I believe mazda said screw it and now only sends out "C" weights..
This is just what i have figure on some one telling me that mazda only sells C weights now..
Also my engine when I cracked it had a D and a C weight. It was very smooth. That is alot of my backing for this argument.

Yes they're both machined. Both of them are JDM and the rounded pocket is what was in my S-5 j-spec, but it had been rebuilt before I cracked it.
I also am pretty sure that FD and S-5 are also exactly the same. Not 100% though.

farberio

iTrader: (7)

More then likely that is due to Mazda having better casting processes for the rotors, so that rotors come out as C's instead of different letters.

S5 and S6 are different, different pocket shape and S6 has the hardened apex seal grooves.

diabolical1

iTrader: (3)

as stated by farberio, they probably have a better, more consistent casting process by now. however, the reason they chose C as the stocked replacement is more than likely because C is smack dab in the middle of the range of weights they used in production, which would put it within 2 letters of any other weight code. think of it as the rotary equivalent of Type O blood ....

First gen man

iTrader: (24)

Ya that's kinda what I mean they figured out the weights didn't matter as much. Like even though you can mix rotor 2 letters apart, mazda didn't do it stock. and they finally said the weight didnt matter as much so they gave in to the 2 letters apart thing.

So can anyone tell me if I had a set of FD rotors in my engine or what?

farberio

iTrader: (7)

S5 TII
http://www.auctiva.com/hostedimages/...0,0,0&format=0

FD
http://cgi.ebay.com/ebaymotors/Mazda...item35a7777721

First gen man

iTrader: (24)

So the boxier older looking rotor is for and FD?
and the smooth rounded pocket is for the turbo FC?

Then I have received an FD rotor when I wanted an FC turbo...

First gen man

iTrader: (24)

Can anyone confirm what I asked above?

farberio

iTrader: (7)

Right = S6
Left = S5

First gen man

iTrader: (24)

So the S6/FD rotor does look older and shitty to most? And the S-5/FC Turbo rotor has the cooler and more advanced looking shape?

Sorry, I know this sounds redundant but it confuses me.. I'm a little scared people will answer with that guys post with the links to the rotors. I'm just trying to triple check.

I also know things that work better aren't always prettier. To say maybe square bathtubs work better than the non-symmetrical design. Again just triple checking.

farberio

iTrader: (7)

Stop thinking, it is what it is. You have zero data or evidence to suggest or back up what your saying. Clearly Mazda went to the FD design after the FC, I highly doubt they did it to go backwards in technology.

Japan2LA

iTrader: (256)

Best advise in this thread...

Tons of misinformation here..

The very minor different bathtub shape (the corners) will not affect anything.

Both rotors are 13B turbo, 9lbs, 9.00:1 compression ratio, and are with in spec (based on letter weight code) to be used as a pair...

There is ZERO issue with running them as a pair..

Stop the madness and misinformation...

First gen man

iTrader: (24)

You don't need evidence to suggest what I'm saying. You can suggest anything for any reason. I do not have evidence to back it up though. Just trying to stir up some thinking.
Also didn't say they did it to go backwards in technology. It just appears that way to me. I also stated though it appears that way to me, it could be better, worse, or exactly the same. There's no proof for any of it. I'm just throwing it out there.
I will be for sure to say, I won't be using the two rotors together. Different is different. Got enough problems trying to get the front and rear rotors perform the same. Don't need to add this to the mix.

First gen man

iTrader: (24)

Now the "no evidence or data to suggest something" guy should be getting on to you.

You have no evidence or data what so ever to say there is ZERO issue running clearly two different bathtub shapes.

Jimmy2222

iTrader: (3)

I'm sure people have done it before unknowingly, besides, Japan is right. The factors that contribute to mis-matched rotors are the weight and compression ratio and lettering, the inlet design probably would affect the way the fuel burns or something on combustion phase but I HIGHLY doubt it would have any notable side effects at all. But hey, if you really think it's a problem and want to dick around with getting a new rotor of the same weight/model, go for it, it's your car.

First gen man

iTrader: (24)

Right. Jimmy, your pretty spot on, but still everyone trys to claim there the same without ever measuring the actually notable side effects of the different bathtub.
I just don't think mazda would have made the change if the difference so minute it didn't matter what so ever.

farberio

iTrader: (7)

I know someone who is running one S5 and one S6 rotor. No problems to date.

And your choice of method in trying to 'stir up some thought' .... sucks. Probably because you need to learn a whole lot more about the rotary before you can start to ask some deeper questions.

First gen man

iTrader: (24)

I think you need to give alot deeper sampling rate on people before you try and make a judgment on there intelligence.
Anyways you started your argument on your lack of ability to even understand how I word things.

My question before your reply was, is the general idea that the FD bathtub generally looks like an older design. Then I followed with I know that things that get more advanced sometimes doesn't mean it's going to look fancier. Which is true.

Your reply was.. stop thinking, you have no data or evidence to back any of this up..

I didn't even say anything. Just simply asking if the general consensus was the maybe, or maybe not more advance FD rotor looked older to most.

farberio

iTrader: (7)

No, I don't need a larger sample set. Let me break down this forum.

User "First gen man" receives an oddly shaped rotor and:
1. Instead of doing his own research, asks the forum.
2. Gets asked about rotor weights
3. Responds by spreading disinformation saying Mazda uses equal weight letters in their builds and then accuses Mazda of lying about the importance of the weight stamp. Clearly answering a question without the true and full understanding of the rotor weight system.
4. Gets told that he may have an FD rotor and that rotor weights can be used within 2 letters of each other.
5. Says that he had a C and D that runs smooth, saying this is why he believes the weight code doesn't matter. Further proving his lack of knowledge and ignoring beefhole's post.
6. Says FD and S5 are exactly the same, again chooses not to research.
7. Is told by diabolical1 about why Mazda produces weight C rotors only
8. Again says that mazda didn't mix rotor weights stock, still believing in falsehoods, while also saying that Mazda gave up about the weight thing. As if it magically stopped being a problem.
9. Is supplied pictures of FD and S5 TII FC rotors
10. States that older looking is FD and smooth rounded pocket is FC. Asks for confirmation.
11. Is told specifically what his rotors are in one post.
12. Asks if the the S6 rotor looks older and shitty to most, which is an opinion, so who can speak for the entire forum. And asks that the S5 TII has a cooler and more advanced looking shape? Making it clear he believes the S5 TII is more advanced. Wants to triple check his rotors are what he has seen pictures o them to be, and after being told specifically what his rotors are based on his picture.
13. Is told to stop thinking about it, he has what he has.
14. Says he doesn't need evidence to suggest anything. (Good news for conspiracy theorists everywhere) Says their no evidence for the combustion shapes, seemingly ignoring that Mazda probably has documentation on it somewhere. Says will not run the rotors together.
15. Is told that running the rotors together will have no serious consequences.
16. Says that Mazda wouldn't make a change like that for such a minute change, showing clear lack of knowledge in how the auto industry works.

First gen man

iTrader: (24)

haha w/e.. drop it I got what I needed we're beating a dead cat.. Sure I can come off as ignorant as I see fit to get answers I want. Don't judge any ones intelligence based on what they say is my point. May sound funny, but wait till someone plays stupid to get the best of you.