Jaguar_MBA

I am researching light weight flywheels and I am surprised at how little of a weight reduction the MS one is:

http://www.mazdausa.com/MusaWeb/spee...rLineCode=RX8#

The MS one weighs 6.92 Kilos, 1 Kilo = 2.205 lbs ~= 15.2586 lbs. Racing Beats reports the weight of the stock flywheel is 16.8 lbs. So MS "light weight flywheel only weighs 1.54lbs less then Stock? That seems as if it is hardly worth $620.00? No wonder some people complain that a light weight flywheel is not a rewarding HP mod.

The Racing Beat light weight flywheel is 12lbs ~ 4.8Lbs lighter.....$455...not sure if that is enough of a weight reduction either for me.

Lastly, I looked at the SR Motorsport one: It weighs 9.75lbs ~7.05lb (using the guidance that the OEM one is 16.8lbs) reduction off of the crank and it is for sale at $429.00 + 18 hardware install kit + $139 for counter weight. = $586

Also SR Motorsports reports the stock flywheel weight as :20-28 lbs? Racing beats shows it as 16.8lbs? Why such a disconnect between the two companies?

http://www.srmotorsport.com/RX8_Clutch_Flywheels.html

shelleys_man_06

Well, you don't want to have too light of a flywheel. Otherwise, you're going to lose some street-ability. On the other side of the coin, you're freeing up more power your flywheel is otherwise absorbing. Remember the mechanical energy balance?

philodox

I have the SR Motorsports Flywheel installed in my 8. I love it. I have had no issues with drivability around town. Most of the weight of the SR fly is in the center of the wheel, where is should be. I noticed the discrepency between the stock weight and what SR reports, I weighed my stock flywheel after I changed it out and it weighed in at 17.5lbs (flywheel and bolts). The SR Motorsports flywheel weighed in at 12.5lbs (flywheel, counterweight, and bolts). Even though there is only a 5lb difference between the two, it is very noticable. The car is much easier to rev, and goes through the power band much faster after 5k RPM. Hope that helps. I attached pics of the SR fly and the Stock flywheel for comparison.

Jaguar_MBA

This makes me wonder if the "racing beats" weight includes all the bolts, counterweight and flywheel also? Thus making it lighter then the SR one, for less $$$....ceteris paribus

Also Phil, how is that SRMotorsports Intake? Does it make the car louder?

Relentless

I believe the weight of the MS flywheel includes the counterweight. The actual MS flywheel itself I think is something like 10.6 lbs? I'm sure SR Motorsports calculation of the stock flywheel also includes the counterweight.

philodox

I cannot attest to the performance or weights of the Racing Beat flywheel. You may want to send them an email or phone call to ask about that.

The SRMotorsports Intake is very nice. Sounds great. Though, no noticible improvment to power which is pretty much the same with everyones intake right now from what I hear from my car club. Mazda did a good job designing their stock box, though it's very quiet. However, I have hooked up a CANScan tool to read the intake temp. The intake temp with the SR intake fluctuates around 100deg F. Which is about 10-15deg F cooler than the stock air box. I took that reading with the car fully warmed up (had a 3 hour drive before I took the reading) at idle when the air would be at it's hottest. Take that for what it's worth. At my car clubs next meet I'll hook up my CANScane to some other 8's that have different aftermarket intakes. A few people have K&N and RotaryExtremes intake. I'll post results in a different thread when that happens. If you have any other questions about it let me know.

philodox

The stock flywheel has a built in counterweight in the outside of the flywheel. Look at the picture of the stock fly. SR Motorsports must have a bad scale or weighed a different flywheel other than the RX-8's stock one. Notice the outer lip is much thicker on one side showing the poor design of the built in counterweight. Weight found further away from the center of any spinning surface is very inefficient.

Jaguar_MBA

I asked them asking them what parts are included in the 12lb weight calculation.

Jaguar_MBA

I received two replies from Racing Beats, both from Jim Langer.

1st: JLanger@racingbeat.com wrote:

I just went out to the parts shelf and pulled the components out of the box and recorded the weights on our digital UPS shipping scale. I recorded the following:

RB Aluminum Flywheel: 8.00 lbs
Hardware kit (nuts & bolts): .60 lbs
RX-8 counterweight: 3.55 lbs

Total: 12.15 lbs

We have found this flywheel to be a very "streetable" unit, if you want a lighter flywheel than this, it is certainly a subjective issue. It is interesting to note that Mazda first offered flywheels that weight 30lbs on the early 74-80 applications, then reduced them to the 22-24 lb range in the '80's, and now they have reduced it to the sub-20 lb range.


2nd: note from Jim Langer:
Ok... Jim Mederer just confirmed the weighs of the two stock flywheels for the RX-8.

Auto - 19.3 lbs
Manual - 16.82

We having working with Mazda for several years, and after the Protege MP3 and Mazdaspeed projects we came away with a much better understanding of how and why they operate. Mazda is guided by a set of engineering standards that must be adhered to during the design and development of a project. These standards ensure the these products meet safety, emissions, reliability standards, etc...

For this reason, it doesn't surprise me that that MS flywheel is relatively "mild" as compared to other aftermarket offerings. (I am not sure why, but Mazda uses the same pricing philosophy as the Disney company and major league sports and establishes sky-high pricing!!!! Trust me, Mazda is making some REALLY good margins on their products.)

It seems that our weights are accurate, and are very close to the 17.5 claim by PHILODOX. Besides, his measurement includes the bolts, which can account for the extra 1/2 pound. As for SR's claim..... I don't know, give him a call and ask.

RACING BEATS seems to be a world class operation in service !!

Fanman

Jim Langer & Jim Mederer are first class people. I'm am glad that most of my parts are Racing Beat. They sell high quality parts. This is interesting. I suppose a lot of it is about transferring the weight more to the middle, than major lightening of the flywheel. If the wheel is too light you risk driveability & durability.

shaunv74

Please do a search on the forum for flywheel conversations. There's a lot of info. already out here that will help answer your questions and concerns.

epitrochoid

its not just about the weight, but about the lesser moment of force...the MS wheel keeps the weight close to the e-shaft

swoope

iTrader: (5)

yes, but this is all in one. keep it going.

beers

Jaguar_MBA

.....exactly why I started this thread after doing my searchs. It always means more when it comes from a 3rd party.

Well last night I bought the Racing Beat Flywheel due to: 1) Racing Beat's good reputation 2) Having a lighter flyhweel setup then SR~MS 3) The cost was also in the correct range and to 4) Philodox/Racing Beat for their weight measurements........ :D
Not to leave SR motorsports out of the upgrades for my 8, so I bought their Power Pulley set.