Lightened Flywheel on a track/road car....
 

About to put in a 6 speed driveline in to my car. May as well do the clutch while I am there.

My question is, is a lightened flywheel worth the money for a track day / toy car (with a little DD use)....

Previous rotaries etc made driving a bit of a pain at lights and so on, stall easier, harder to get off the line....is it a similar deal with the MX5 and a turbo....

why are you putting is a 6 speed?

5 speed is a little whiney and as I increase boost want to have a strong gearbox.....should I not?

and the flywheel..? :)

Its not as bad as a rotary as far as stalling, etc. obviously the lighter you go, the more driveability issues come up. My miata has a super light billet alum. Flywheel and the only issue I have is when driving really slow in a parking lot, or bumper to bumper traffic, it bucks like a rodeo bull. I just give it gas and coast to prevent that. If you bought an act streetlight or other brand lightened steel flywheel you wouldn't have any issues.

I love my aluminum flywheel, swapped it in when I put in the 6 speed as well. Only issue is resonance gear noise.

I'm running a 13.5lb wheel. Lighter than stock, but heavy enough for any average driver / valet / girlfriend / parents to get in and drive your car if they need to without even noticing it. This is for a daily driver, no track duty, with maybe 3 autocross events / good year.

Learn to drive it and they are fantastic... not that comfy driving clutch and it'll annoy you at parking lot/bumper to bumper speeds.

I loved my 9lb ACT...

Yes it is worth it.

Kill yourself.


I have owned a stock, 9lb, and 949's twin disc flywheel.

Stock is sluggish as crap.

9lbs was a lot of fun in regular daily driving.

Twin disc. Not recommended for daily.

um what? you talking to me?

as for the 6 speed I don't know about them at all, however I've read some posts that claim they are not as reliable and or they have inferior "feel" versus the 5 speed. I've not done the research, Ive just seen posts when trying to find other info. another option could be to do a final drive ratio change but I don't know what you are really going for.

they are more reliable in the sense that they can handle a lot more power than the 5 speed.

They don't feel as good, and the gearing kinda sucks.

Reliability? 5 speeds are generally considered reliable up to 200-220hp. Not enough 6-speeds have actually failed to be able to determine their upper limits, and those 6-speeds which have failed have done so on the race track at extremely high temperatures. The best guesses are that the 6-speeds are reliable beyond 450hp.

Feel? It's not that big of a deal, but the 5-speeds do feel more precise. I sometimes fumble 6th or reverse, and I don't exactly use those gears competitively.

Gearing? There's a fix for that, it starts with a "3" and ends in a "636" - fortunately, both the "3" and the "636" were made by Mazda.

Thanks guys. Better start saving....

Fooger, you got me, what the hell are you talking about.... :) DIff ratio..?

I got the Flyin' Miata 10.3lb flywheel with their level 1 (318lb-ft) clutch for my 5 speed. Bought it to prepare for putting a turbo on hopefully later this year. Clutch pedal feel is very similar to stock. It is ever so slightly easier to stall if you're used to being stingy with the throttle from a standing start, but it's easy to adjust. It does make a noticeable difference in how freely the engine revs, and I'd swear it adds a couple ponies on the butt dyno in the lower gears on my stock engine. Overall I'm happy with it.

Okay fooger, a succesfull search reveals Cheers.

props

To add to what Track said about their superior strength, keep in mind they don't change your ratios either. Don't think of it as a 5spd plus another gear, it's more like 1,2,3,3.5,4,5. or something similar.

Urgh. 5 speed can break under stock power. I will break mine in my daily miata. Trust me. I am gonna treat my car real good.

My 6-speed is awful, Jeff's is great; the Mazadaspeed metal bushings help a lot. Sometimes mine won't go into 5th; like the shifter won't engage or slide the fork. My sister's is like this in reverse. Aisin can mouth my dirt-pipe. However, after a few months, it won't bother you anymore.

The 6-speed with the 3.63 is the way these cars should have come from the factory, everything is better aside from the shifter feel.

yea definitely, I think for reliability if i was at 200wtq, I wouldn't even complain one bit.

Its interesting you say they are hit or miss...is it a fluid or age thing or seemingly random?

I think the hit-and-miss probably has a lot to do with how they were treated - though I've heard the motorcraft oil makes a huge difference - I put motorcraft in mine a couple times when I was having problems with the engine seal and installing/uninstalling crap. Got sick of replacing the expensive oil and put cheap stuff in it - whaddaya know, i fixed the unrelated problem as soon as I did that, I still have ---- oil in the tranny.

Do you mean the good oil made it feel crap and the cheap oil made it feel alright?

If so I mentioned on another thread about my motocross bikes having the same problem. Took years to figure out...

The "expensive" gear box oil motul do was horrendous, missed shifts, slip out of gear etc (you don't want any of that when you are approaching an 80' jump at speed).

Going to the "cheap" motul gearbox oil made it feel great....someone (here i think) said something about the oil being to slippery and the gears/syncros not engaging properly....YMMV.

If I had Fooger right...? (otherwise that weas a needless ramble :) )

Nah, I never actually got to play with it with good oil in it - unrelated problem was the rear oil pan seal - that I eventually fixed - but emptied the tranny a couple of times trying to figure out the problem, and ended up dumping all of the expensive motorcraft oil and didn't want to buy any more of it at the risk of losing it too - ---- gets expensive at $20/quart. I'd use the motorcraft stuff now if I didn't have to go out, empty the tranny, remove the shifter and associated interior parts, and refill it. Apparently the motorcraft does magic things to these 6-speeds.

I don't hold a lot of hope for my new 6 speed by the way....


The owner watched the tide come in and drown his car that hada relatively soft landing in to the dry sand but couldn't recover the car as the tow track couldn't come in to the closed road until the event had finished.

Gutted.

just gotta hope the output seal held up and the pressure relief vent was clogged... hope you had the chance to watch them drain the tranny immediately afterwards.

It' sort of coming free (ish) with the new 86 rear complete subframe/diff/brakes etc, so I might be lucky, might not...My companies mechanic and the transmission place up the road say to run it and see how it goes and I think that is just what i'll do.

Not to mention a few oil flushes along the way....

I just did a 6 speed swap and installed eBay XTD "stage 1" clutch kit and lightweight flywheel. Drivability on street did not really suffer at all. The only thing that is a little more difficult is heel/toe'ing through gears since RPM's drop faster but even that can be cured by practice.

Cool, thanks guys.

Ended up buying a set of wheels while I was at the wreckers. very poor now.

Clutch and flywheel may have to hold out a bit longer :facepalm:

Might have issues with the 6 speed as well, I can't turn the input shaft by hand even in neutral. might have to pull it apart after all.

Anyone done this before? any gotcha's?

( I have worked with Motorcycle, cassette style gearboxes before but never a car one....)

haha label EVERYTHING, and take lots and lots of pictures. I suggest you look at some transmission diagrams too.

Turn the driveshaft instead of input shaft. Also, when you are installing the 6 speed - tilt your motor by putting a jack under the crank. It will make mating engine and transmission MUCH easier if the motor is tilted back slightly.