Damn - I'm getting all excited inside. The MS flywheel will indeed be my 1st major mod.

Keep the impressions coming cortc.

 

I agree. It was my second mod, after the Borla. What a difference in feel!

 

About the stock flywheel--Besides the cost, I wonder if maybe they weren't overcompensating in an attempt to keep the rotary from stalling, and the flooding problems that go with that. (Side note: I was moving my car after washing it last weekend, and wanted to warm it up before putting it in the garage. So I gave it a series of revs up to 8k or so...I was really surprised at how slow the throttle response was even under ZERO load...)

Another question--around here, everyone who gets a lightweight flywheel is amazed. With other cars, it doesn't seem that way...like if you made a list of the 10 most popular engine mods, "lighter flywheel" would hardly be mentioned. Does the rotary benefit disproportionally from a lighter flywheel, compared to piston motors?

I guess maybe a flywheel is a smaller portion of the reciprocating mass on a piston motor, because you've got a crank, rods, and pistons that have to be replaced with lighter units too(?). Whereas on a rotary, you just have a couple of rotors and a small eccentric shaft.

 

From what I understand, an aluminum flywheel costs a few times more than the standard iron unit, and makes the engine a little *too* rev-happy (accel and decel) which makes the car harder to drive. Also, lighter (and sometimes thinner) materials supposedly have more of a chance of explosion at high revs, risking the chance of your legs getting sawed off by shrapnel spinning at 5000rpm.

But those are just urban legends.

Have you tried starting in first on an steep incline yet?

 

actually a lighter flywhell will help prevent flywheel explosion if properly designed. It's lighter weight which is more concentrated twards the center dramatically reduced the centrifugal force on a stock flywheel.

 

The main reason is that the energy stored in the flywheel (i.e. robbed from the wheels) goes up by a factor of RPM squared.

This means that the same flywheel on a car with 9000 RPM redline vs. a 6500 RPM redline engine will be wasting about twice the power (9000*9000 = 2*6500*6500). Thus every pound saved is twice as important on our RX-8 versus standard engines.

About a year ago I was really surprised to read that the RX-8 used the same diameter clutch/fywheel as the RX-7. With less torque than the RX-7 it really doesn't need a clutch/flywheel that large. (After FI mods, that additional size is going to come in handy however.)

It also appears that our 6-speed is the same design or based on the design of the Mazda EDIT: MX-5 6-speed. I think they forgot or didn't want to spend the developement time to redesign a few components for our high reving engines.

-Mr. Wigggles

 

Yes, stopped on a very steep incline/ramp in the parking garage at the office and no problem...

 

so when can i come down and install mine? :P

 

Mr Wiggles,

Slight correction. The Mazda 6 is a 5-speed Manual Transmission. Its also mounted sideways (as opposed to front/back) as the Mazda 6 is designed as a FWD or AWD platform.

Just from glancing at the Rx8 tranny photos of the flywheel install...I'd say the 8's transmission is roughly 3-4x the size of the 6's.

 

crossbow,

I meant the MX-5, but I don't know how accurate that information is.

The lineage of the RX-8's 6 speed is supposed to be derived from another Mazda car. If someone has more info please share.

-Mr. Wigggles

 

cortc a ? for you

is the ring gear on the std fly wheel removable or is it one piece?

 

The ring gear is built into the stock and Mazdaspeed flywheel... The counter weight is built into the stock and a separate piece on the Mazdaspeed... Usually you only see separate ring gears on aluminum flywheels do to the fact the gears really need to be steel as the aluminum teeth are not very durable; so hence two pieces...

 

cortc-

Please let me know exactly how long the install took you. my dealer claims the job is at least 5 hours. i'm highly skeptical of this estimate and feel $560 labor is a rip off.

-breezy

 

breezy_rx8: The install took 3.5 hours, but it was my and the techs first time with an RX8 and we took our time, and there were a few interuptions... It should have taken 2.5 hours or about U$250.00, that is the most I would pay a shop for installing it...

 

Hey cortc, Any special tools required to do the install? I think I am going to get the srmotorsport's aluminum flywheel. It is a little cheaper and a little lighter. But I have not quite decided on that one or the mazdaspeed one.

 

You will need a clutch alignment tool, flywheel socket and to get the stock flywheel off a puller... A lift, transmission stand and some one to give you a hand...

 

Thanks a lot for the info, can't wait to get this mod done.

 

My local MazdaSpeed dealer today told me that the Mazda manual indicates 7 HOURS as the tech time for installing the MS Flywheel $75/hr = $525 labor. Retail on the Fly is $620 = $1,145 total -- they were going to "cut" me a deal for $1,025 installed.

I am going to talk with them some more -- I think $800 to $850 max installed price -- given that the install is really 2.5 to 3 hours.

 

My local Mazda dealer quoted me $350.00 install this week. I think I might bite.

 

anyone know how long a flywheel should theoretically last on a flywheel? Sorry for the ignorant question.

Thanks guys.

 

Depends on the driver. Most cars get away with never having to do any type of flywheel servicing. In the event your clutch fails or wears down, and you continue to drive it until the bare disc grinds into the flywheel, then your flywheel could be toast.

 

If I remember correctly the manual says 4.9 hours, if they told you it took longer they are not being honest go to another dealership... A good tech can do it 2.5 hours easy...

 

What is the part number of the counterweight? I cannot quite make it out. I would like to check if it is the stock AT counterweight or not. We have done some testing and found that there is a difference in balance on the automatic counterweight and manual flywheel. Japan says they are the same, but they are wrong! This corresponds to a difference in the front counterweights as well. If you ever do a search for Mazda part numbers, you will find that the numbers are different from auto to manual. We tested them on a special balance arbor and sure enough, they are different. Mazdaspeed has helped us out with test parts and we have forwarded the information to them. If you have the stock AT counterweight and you think it's smooth, think how much better it will be with the right counterweight.

Note: Once the counterweight is installed, the aftermarket flywheel is the same part as the early Turbo RX7.

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ACTman,

With the following choices:

MT = N3Z1-11-D6X
AT = N3Z2-11-D6X

From the second pic, the 4th letter looks like more like a 2 than a 1.

That would make at least two people who have installed the Mazdaspeed flywheel with the auto counterweight with no problems.

-Mr. Wigggles

 

What are you talking about?? The part numbers you are listing are FRONT counterweights, not rear counterweights. Of course there is no rear counterweight for the manual. The counterbalance is incorporated in the stock flywheel. The part number for the stock RX8 automatic counterweight is N3Z2-11-52X.