Lighten factory flywheel or eBay flywheel
 

OK I know I am going to get flamed for this, but please try to hold back unless you are running eBay 1.8 lightened flywheel or lightened 1.8 flywheel.

I have a 949 sport 1.8 clutch kit ready to go on the car. The original plan has always been to use the factory flywheel after a resurface, but lately I am wondering if I need to try something lighter. I was considering something like this.
FX Forged Chromoly Flywheel 94 05 Mazda Miata MX 5 1 8L 2004 05 mazdaspeed Turbo | eBay

But after searching around about eBay flywheels I don't have a warm and fuzzy about it. Recent scope increase has burned up all funds and a $300 flywheel is not an option. I was wondering if anyone has tried to lighten the 1.8 flywheel by removing the huge lip on the back of the flywheel. This could shave a few pounds and cost me $80 with the resurface included, at my usual machine shop.

I have read some reports of additional vibration and noise with these lightened flywheels, is this a problem with all lightened flywheels?

So, has anyone tried to lighten a factory fly wheel or had good luck with the FX Grip force 1.8 clutch listed above?

Flame suit ON.

I strongly recommend getting a lightly used Fidanza/Exedy/FM/949/not eBay for $200-300.

Ebay is almost always going to be a risk. The fact is some claim to have good luck with parts on ebay, others have terrible luck, it seems to be just that: luck. You can take your chances and possibly be in for more money than you would have been if you just went the legit route first. Or you could be totally satisfied and have no issues.

As for lightening your stock flywheel, I know other cars that do it with great success, as long as it is balanced and not overdone I can't imagine it being a huge issue.

I've lightened a 1.6 with great success. Mine was free , so no way the extra $300 for a few pounds was worth it.

I Have a XTD flywheel bought from ebay since 2010 an not a single problem. Lots of racing miles on it without a single problem. Hope that helps.

Also have experience in one 1.8 lightened flywheel in one 2002 VVt without any problems. I think the reduction was about 1kg. Not really a big difference to be honest.

Completely removed the lip on my stock 1.8 for $30. No vibration or additional noise noted after installation.

I've had an ebay F1 racing 4130 flywheel in the WRX since the winter. It has yet to cut my feet off or do anything else disagreeable. Its pretty hard to screw up a steel flywheel.

Having seen a shitty flywheel explode (granted on a bap bap rotor at 9k+ rpm), I'm inclined to steer clear in a racing applications though the risk is probably low. I bought a decent second hand Racing Beat alloy FW off this forum a cpl of years ago and it has been awesome, cost $150 shipped I think. Would go this way again given the patience to wait for the right one here, or on some less awesome that dare not speak its name forum.

Noticeable difference with the lip removed? Final weight?

About to do the same.

1.6l clutch and junkyard flywheel is the poor way.

My factory flywheel weighed 15.3 after the machine shop took that lip off. I think he was being conservitive. Pobably could have taken that last .3 off without trying too hard. I forgot to get a before weight but I've read they're 18-19 lbs.
I didn't notice much difference but I would do it again for the $45 I paid to have it done.

You're not going to get a factory flywheel more than 3-4 pounds lighter than stock. My Fidanza flywheel is a full ten pounds lighter than stock and I would still go lighter if I could. If you have a couple hundred bucks already earmarked for a lightweight flywheel, there's no sense in dicking around with the stock one.

I don't have the cash laying around for a $300 flywheel. Luckily I am not slipping the clutch I have in the car right now so I might just wait a little while longer to install the 949 sport clutch, sell a few more parts and get the real thing.

Just shave the weight ring off. You're talking about $300 for 4-6lbs more, think about all the other things you could buy for that! Then think long and hard if you'd actually feel that difference, and/or care about it on a day to day basis.

I'm talking about $200, which is the going price for a used flywheel, for more than double the effect. And if OP is paying $80 for a resurface and machining, he's already nearly halfway there.

I just missed out on a ACT 9.4lb used FW this morning. After additional research I am leaning back to just using the factory FW. I run MS2 and need my AC for summers in the south. I already do not have the best idle and halfing the FW weight will not make my DD experience any more fun. I am just going to chicken out and run the full weight factory FW. Sure the quicker response and snappier heel-toes would be great, but it is not like I am having issues right now. Kinda wish I did the 1.6 clutch instead now, I have a factory 1.6 laying in a box.

Oh, well.

Why are you opting out of shaving a few pounds off the OEM? I have the same concerns as you, not wanting it too light and went with a lightened and balanced unit. I think you'd be happy and still have plenty of $$$ in pocket after dropping the weight to like 15 or something. The steel vs aluminum is also less chattery I've heard.

I have the "F1" chromo ebay flywheel (10 lbs), works great. Like Failure said, I too would go lighter if I could. It's no night and day difference, even at 10 lbs. Wouldn't waste my time lightening the stock flywheel for the minimal weight savings.

-Ryan

The extra mass probably helps when the a/c cycles.

So, who has MS1/2 control and still runs AC and then used a lightweight flywheel? This is not a track only car and I need my AC in the South!

I probably would still go for the shaved flywheel. I am in the middle of adding sequential injection, sequential COP and AC input to the MS so I can bump idle up when AC kicks on. If I can get he idle cycling stable with AC on, I might go back to a full light FW.

DIYPNP here. Fidanza flywheel, working a/c. It's not a problem. Idle bumps to 1000rpms when A/C is on. GSlender code.

I have stock ECU but 10# FM Steel FW and A/C. You just have to learn how to drive two totally different cars. With A/C and without. :P

Planning on swapping to NB A/C components with a Sanden 505 compressor, though, so that should change.

Does the nb compressor run smoother?

The Sanden 505 isn't the NB compressor. It's a smaller unit that uses less power to turn. I'm also going to load it full of envirosafe Propane/Isobutane blend refrigerant, which works at lower pressures than R-12 or R-134a.

I'm going to use an NB condenser and evaporator, as both are parallel flow designs which are the highest efficiency for the most cooling, compared to the NA's serpentine condenser and tube and fin evaporator.

The goal is ice cold A/C that plays well with my super light flywheel. Throttle tip in varies a lot between no A/C and A/C on, and is worse when the A/C compressor suddenly kicks back on.

So which model Sanden 505 compressor has the mounting holes and dimensions like the Miata NB compressor?

There isn't one. You need to fab up some brackets.

I ended up getting a FX Racing Chromoly 11.7lb forged 4140 flywheel. After doing a lot of searching I found several good reviews. Some minor issues with pressure plate bolts not matching the factory bolts, but other than the usual "its ebaycrap, dont use it" no major issues that I could find. I did look for a descent used Fidanza, FM or 949 wheel with no luck.

This one looks very well made. Hopefully I will find some time to install this with the 949 sport clutch soon! I will report back once I get this on the road.

https://www.miataturbo.net/attachmen...1&d=1408642000

https://www.miataturbo.net/attachmen...1&d=1408642000

https://www.miataturbo.net/attachmen...1&d=1408642000

That's the one I've had since ~2009. I've found it to have no flaws.
Yes, the PP bolts are the same size as stock but a different thread pitch.

M8-1.25 x 20mm works

I finally got the flywheel and 949 Sport Organic Sprung clutch installed this past weekend. The flywheel went in fine and the supplied M8 bolts worked. The combination works very well so far. I will have to wait until I get at least a basic breakin period done before checking for any performance gains due to the lighter flywheel. I have noticed a quicker response when heel toe'ing and a slight (tolerable) increase in drivetrain noise when downshifting and engine braking. I believe the added noise is just part of going to a lighter FW and has nothing to do with it being an "ebay FW".

I really like the 949 Sport clutch so far. The pedal is only a little heavier, the only time I could really tell is when I got in my wife's stock 97 right after driving my 91. It has a great engagement feel and allows you to control the clutch much better than other racing on/off clutches I have driven in the past. I can't speak to it's torque capacity yet, but I should be way below the 260 ft/lb limit with my MSM turbo (only 190 ft/lb on virtual dyno). It is a great clutch that I would recommend for any sub 250 ft/lb setup.