Lightened Flywheel with Supercharger?

[FormerDatsun510Man]

Back when I was at BRP we used to not recommend lightened flywheels because on the Hotsides we would have idle dip that would only become worse with a lightened flywheel. However, times change :biggrin: . Specifically, the PC Pro seems to have my Miata running so well, I am thinking perhaps I could now run a lightened flywheel.... even with the air/air intercooler. I have my sights on this one at Flyin' Miata:

http://www.flyinmiata.com/index.php?deptid=4531&parentid=0&stocknumber=08-26500%20%2013.45

I like the fact that is steel, which I think is safer to go with for the high heat environment and for resurfacing in the future. Anyway, I am curious to hear from any supercharged people out there running lightened flywheels. What's your take on it? Would you do it again?

Bill

[Tom @ Fast Forward]

I looked at that flywheel. It would be a good compromise from stock (~18) and the light (~9) flywheels. However, I have the 9# Fidanza in my 99 and I hate it. I do more street driving than track and the light flywheel is a real pain. Even worse when I had the ACT HD as it was more on/off than the ACT XT. On the track, they are OK as you don't do any starts from a dead stop. Remember, the flywheel has ONE job in life. To help the car get moving from a dead stop without stalling the engine.

You just have to weigh your stop and go driving with your track time.

The other consideration is that a supercharged engine has no problem blipping an engine with a stock flywheel that is in neutral or the clutch is disengaged. Light flywheels were really intended for the stock Miata and track use. The next time my transmission comes out, the Fidanza is history and the stock flywheel is going back in.

Then the Fidanza will be in the "Free to good home" section. :)



Back when I was at BRP we used to not recommend lightened flywheels because on the Hotsides we would have idle dip that would only become worse with a lightened flywheel. However, times change :biggrin: . Specifically, the PC Pro seems to have my Miata running so well, I am thinking perhaps I could now run a lightened flywheel.... even with the air/air intercooler. I have my sights on this one at Flyin' Miata:

http://www.flyinmiata.com/index.php?deptid=4531&parentid=0&stocknumber=08-26500%20%2013.45

I like the fact that is steel, which I think is safer to go with for the high heat environment and for resurfacing in the future. Anyway, I am curious to hear from any supercharged people out there running lightened flywheels. What's your take on it? Would you do it again?

Bill

[99mx5]

I asked this question in the past and was told by several people at the auto-x that lighter flywheels will also kill torque when coming out of turns.

[Mark]

I'm running an ACT HD clutch with their 9.5lb flywheel. These went in the car about 6 weeks before I did the SC install so I don't have too much to compare it too. I can say that at least under my left foot, this setup felt pretty close to stock. I didn't have to adjust my driving style at all to keep engagement steady and smooth. I've not had any issues with idle droop. :)

[Tom @ Fast Forward]

I think that is true for turbos and stock Miatas but I don't think it matters with a supercharger. Especially a coldside. :)

I asked this question in the past and was told by several people at the auto-x that lighter flywheels will also kill torque when coming out of turns.

[Toby Weir-Jones]

Interesting. I was planning to recycle my 1.6 lightweight flywheel from the race car, my ACT HD PP, and a slightly uprated 1.6 disc. I like the immediacy of rev movement, makes me focus on shifting better.

When not under load (i.e. blipping for downshifts, bypass open) wouldn't the parasitic load from the supercharger slow things down compared to stock?

twj

[Tom @ Fast Forward]

When you blip the throttle sharply, it will close the bypass momentarily and shoot a blip of torque to compensate. :)

[Toby Weir-Jones]

Gotcha. I still think I'm going to go with the 1.6 parts, I guess I'm too much of a purist but I have this nice expensive flywheel sitting here doing nothing...

I did convince myself not to use the 4-puck unsprung copper clutch disc from the race car though. It actually wasn't that bad to get the car rolling but there weren't a lot of hill starts to worry about...

twj

[scrapman]

I'm a former BRP hotside user and do have a lightened (9lb) flywheel. Living in Pennsylvania I get to use it on hills quite a bit. Took about 1 hour to get used to the difference from the stock flywheel but is no problem otherwise. No idle dip and fine with the a/c on or off. Seat of the pants feel is that I get to redline quicker. I'm using the old PC for fueling (the ELF didn't work) so I get a little lean tip in and that makes it hard to judge the real effect. Would I do it again? Probably not, but the clutch and PP had to be done so while in there, I just did it. Hindsite, no ELF, no light flywheel, add in wide band and either PC Pro or Megasquirt.

[da_blue]

Hi Bill,

I am Yanick from the crazy Montreal guys, how are you ?

I have an ACT HDSS clutch and a ACT Streetlite flywheel siting in the garage waiting to be installed. I didn't want to go super light so I think this flywheel will give me a little more zip while preserving drivability. That will be installed this winter along with all the other mods that are waiting for me to get them done like Innovate wideband and most likely a PC-Pro to replace gremlinsful ELF. I am also seriously thinking adding a Thompson relocation kit since my oil changes have been a pain since I installed my coldside.

Enjoy !!!

[FormerDatsun510Man]

Hi Yanuck! Not to cause too much thread drift :), but the PC Pro on my car has proven to be a great solution. Much better than either the ELF or the original Powercard. After the last revision I would say it drives better than any of the engine managements setups I have either used myself or tuned on customer cars in the past, including the SDS standalone.

I've decided to also go with the ACT HD clutch, still a little bit on the fence about a lightened flywheel, but I am currently thinking of just resurfacing my stock flywheel and being done with it :).

Bill

[stratosteve]

"last revision" ????

do tell

[99mx5]

Bill is probably talking about that PC-Pro software update that Tom mentioned if I'm not mistaken.