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Opinions Lightweight Flywheels for the 2.2 F2T MX6 or Probe?

3K views 57 replies 13 participants last post by  imagoonmx6 
#1 ·
I need a new clutch, I am looking at the ACT's. I will need to get the flywheel resurfaced, but the thought crossed my mind of swapping out the flywheel for a lightweight like Fidanza. Anyone who has a Fidanza, or equivalent, what do you think of it? and if possible, do you have any dyno sheets of before and after install?

In general, I am wondering if the lightweight flywheels are worth the money that they cost? I would rather not start a "In Theory" discussion. I would like to have good hard facts from people who OWN a lightweight flywheel, and it is INSTALLED on an MX6 or Probe, specifically the F2T.
 
#2 ·
not on my car, but on Sigmafours that i have been in many a time. the car feels more like a race car. the engine is a hell of alot more responsive. when you touch the pedal, the engine just comes right up to 3-4K with what seems to be no effort at all.
 
#4 ·
one of the things I was worried about was over revving due to the lightened flywheel, I'm sure it would be pretty easy to do if you didnt pay attention ie: lined up at the track with a big bad V8 that you know you can smoke, that has been smoking everyone allnight. That situation could easily turn to nervous, overanxious, I really want to get a good launch and good run and smoke this Mustang Cobra...and all of a sudden.....REDLINE:eek:

depending on the condition of your motor, that could be a whole new headache, granted you wouldnt/shouldnt/probably couldnt smoke a Cobra without a decent rebuild and a good amount of mods, and probably shouldnt try but, ya know how that goes :lol:

so where have you found good lightweight flywheels? I know about the Fidanza and have heard of a few more, what kinds have you guys heard of for the MX6 and Probe? what kind of dollars are we talking? and where did you buy them?
 
G
#5 ·
Don't believe the rubbish from SCC. Lightened flywheels do not CREATE any power.

A lightened flywheel is a two edged sword. Yes, it does allow you to rev the motor up faster due to the lightened rotational mass, but....

The flywheel is used to help keep the engine balance and momentum. By lightening it, your throwing your entire crank off balance which could very likely cause bearing problems in the end run.

Also, Your engine speed will fall faster as well, and thats not usualy desired.
 
#6 ·
FlySwat said:
The flywheel is used to help keep the engine balance and momentum. By lightening it, your throwing your entire crank off balance which could very likely cause bearing problems in the end run.

Also, Your engine speed will fall faster as well, and thats not usualy desired.
The flywheel is balanced separately from the crank, so changing the weight of the flywheel shouldn't matter unless it is not balanced. You can say that it wouldn't absorb vibration as well, but that's the harmonic dampner's job anyway.

Also depending on what you're doing, having the RPMs drop quickly could help, especially if you have problems rev-matching on turns or when up-shifting.

to keep on topic, SPEC clutches makes an Al flywheel for less than $400. They even sell ligthened clutch assemblies. i'm going to be going ot them for my next clutch, and basically being a guinea pig for some of these things (good value or cheap crap, only experience can decide). they're at www.specclutch.com . Lemme know what you decide on, Damian, since I'm in the same situation but you might be doing this before I do.
 
#7 ·
if you can afford to buy one then buy it. i payed $345 shipped from www.rr-racing.com for mine. you can definetly notice a difference. in first gear when i hit full boost the tach needle would climb so fast i could barley see it. but it does have some down sides. nothing major to me. like since its lighter there is less momentum of course. so you have to use the clutch differently. it takes a little getting used to. i killed it the first couple of times. as for the revs dropping faster. yes they do, but whenever i raced at the track i would shift so fast they didnt have a chance to fall. plus i noticed with the zombie chip, after i would depress the clutch the revs would continue to go up slightly. lightweight flywheels wont make your car super fast. i would say it changes the way it feels. i like the way it feels.
 
#8 ·
SixSick6 said:
have any dyno sheets of before and after install?
Butt dyno only. For an extended conversation on this topic (with the odd hint about why a dyno plot will not show any improvement) read this thread.
 
#10 ·
so getting back to Flyswat's idea of throwing off balance, what do you think about the lightweight crank pulley? performanceprobe.com sells one for $105 and it stays the stock size but is made of aluminum and weighs a little less.So what do you think about this scenario: stock flywheel & lightweight crank pulley? lightweight flywheel & stock crank pulley? lightweight flywheel & lightweight crank pulley, I'm more interested in ideas on the latter, I plan on getting my motor rebuilt, but if I am going to be adding things like flywheels and crank pulleys (basically things that are a PITA to do) I'd prefer to do it all in the same time frame, not all at ONCE...because it's dumb to do a ton of mods at once, you never know which ones work and which ones didnt do a damn thing. But I'd prefer to do all of the PITA mods in the same time frame:shrug:
 
#11 · (Edited)
the harmonic dampener is the only thing designed to absorb vibration. As long as the Flywheel and pulley are balanced by themselves, you should have no problems. The crank, fly, and pulley are balanced separately then assembled, not balanced together. See where I'm going? Save some pounds, go light-weight. Sleepcounter even brought up that it would lessen the stress on the bearings because of the reduced side-loads or some such compared to the heavier flywheel.
 
G
#12 ·
HotRodMex said:
The flywheel is balanced separately from the crank, so changing the weight of the flywheel shouldn't matter unless it is not balanced. You can say that it wouldn't absorb vibration as well, but that's the harmonic dampner's job anyway.

Also depending on what you're doing, having the RPMs drop quickly could help, especially if you have problems rev-matching on turns or when up-shifting.

to keep on topic, SPEC clutches makes an Al flywheel for less than $400. They even sell ligthened clutch assemblies. i'm going to be going ot them for my next clutch, and basically being a guinea pig for some of these things (good value or cheap crap, only experience can decide). they're at www.specclutch.com . Lemme know what you decide on, Damian, since I'm in the same situation but you might be doing this before I do.
Quite right, my apologies for the missinfo.

Whatever happened to a763811 anyway? I miss the arguments. :(
 
#14 ·
If the flywheel itself is balanced (which it is) that is all you would have to worry about in terms of bottom end balancing.
 
#15 ·
HotRodMex said:
(good value or cheap crap, only experience can decide). they're at www.specclutch.com . .
there cheap crap, i bought one for my tiburon at kore motorsports like two years ago, and from the begining once it got hot, it slipped, i actually have had to pull over and sit and let it cool off just so it would ingauge, customer service pretty much told me to screw myself, spend the cash, buy a dxd clutch.
 
#17 ·
crusty said:
Oh, I do so much hope this thread turns into something like that.;)
Need more engineers for cannon fodder. You Oz guys familiar with the term schadenfreude?

HotRodMex said:
The crank, fly, and pulley are balanced separately then assembled, not balanced together.
If you understand tolerance stack-up, you'll know that they should be balanced together. I guess it depends whether you're one of those guys for whom "good enough" is good enough.

HotRodMex said:
Sleepcounter even brought up that it would lessen the stress on the bearings because of the reduced side-loads or some such compared to the heavier flywheel.
Torsional crank loads, actually. Rod bearings would be (theoretically, at least) better off. That being said, how often do you read hereabouts about people encountering rod bearing problems. Not often enough IMHO to justify a US$300-400 investment.

FlySwat said:
my apologies for the missinfo.
You sure you're not an engineer?:D

FlySwat said:
Whatever happened to a763811 anyway?
You mean he wasn't an alias of yours? Well I'll be!

SixSick6 said:
so by balancing, you mean having a shop somehow install it so it is trued? doesnt seem like there is much to balance besides a couple bolts, how could a shop install it different than anyone else?
Dynamic balancing eliminates vibration which can arise out of tolerance stack-up. Why do you balance a turbo when the wheel's been off?

drsjr1980 said:
If the flywheel itself is balanced (which it is) that is all you would have to worry about in terms of bottom end balancing.
If "good enough" is good enough for you, that's true. Not the way I'd do it, though.

If only there were a decal.....
 
#19 ·
SleepCounter said:
Need more engineers for cannon fodder. You Oz guys familiar with the term schadenfreude?.
Isn't that a bit like apple strudel?

Last time I had an engine (datsun L20) "built" at a machine shop they balanced the crank and flywheel as one unit. I don't know how it was actually balanced though, I've always thought small surface drillings to drop weight from a particular area but I'm probably way off the money.
 
#20 ·
SixSick6 said:
so how is the flywheel itself balanced?
Holes drilled (usually on the outside diameter alongside the starter ring gear) on the heavy side.

Trouble is, it may not register on your crank the way it did on the balancing machine at the factory. Probably won't be that far off, but when the weight is that far from the crank centerline, it doesn't take much.

Same reason you match mark your pressure plate when you take it off your flywheel or match mark your flywheel when you take it off your crank. So that it can get back on the way it was.

You DO match mark your pressure plate when you take it off, don't you??:rolleyes:
 
#21 ·
well that is something that I need to do anyways, I need a new clutch and while I'm at it, why not get a lightened flywheel and do it all in one shot. I'm still not understanding the whole balancing idea, if a lightweight flywheel comes to your house made of aluminum and is a perfect circle, and is made by the company, wouldnt one think that the flyhweel is balanced ALLREADY? Whats the need to DRILL MORE HOLES? have you looked at any of the sites that offer lightweight flyhweels? are we on the same page? I'm at a loss for where I would even get that done, at a transmission shop? Do you have any idea of the cost?
 
#22 ·
SleepCounter said:
If you understand tolerance stack-up, you'll know that they should be balanced together. I guess it depends whether you're one of those guys for whom "good enough" is good enough.
I do understand that they should be balanced together but I also realize that taking the engine completely apart is not a weekend undertaking for everyone. I would love to be able to build up my engine, balanced and blueprinted to the last nut and bolt. But, in the real world, with my engine seing no more than 5500 rpm on occasion and my tires spining faster and less accurately balanced, why it should be a huge deal? Plus, exactly what type of tolerances are we talking about from the factory. I would trust a custom made CNC'd piece versus a stock cast piece that just had to work, wouldn't you (provided we trust the aftermarket manufacturer here).

SleepCounter said:
Torsional crank loads, actually. Rod bearings would be (theoretically, at least) better off. That being said, how often do you read hereabouts about people encountering rod bearing problems. Not often enough IMHO to justify a US$300-400 investment.
I don't think that alone justfies the investment either. but I guess that if you think "good enough" is "just good enough," right?:D

SleepCounter said:
Dynamic balancing eliminates vibration which can arise out of tolerance stack-up. Why do you balance a turbo when the wheel's been off?
Now, wouldn't comparing something that spins at 175,000 rpm be just a little different than something that spins at, say, 3000-6000 rpm? especially when 1 gram is a much higher weight percentage of a compressor wheel than a crank shaft.

SleepCounter said:
If "good enough" is good enough for you, that's true. Not the way I'd do it, though.
well then where's your Al fly so you can make those rod bearings last 546,378 miles?:D

SleepCounter said:
If only there were a decal.....
I got a friend with a vinyl cutter that can make you a decal, Sleep.

Cheers, boss. All in good fun:tup:
 
#23 ·
SleepCounter said:

You DO match mark your pressure plate when you take it off, don't you??:rolleyes:
but what about when u put a new clutch in? u cant really just hope its about the same, so then it would be unbalenced. not trying to flame, but just doesnt make since to me, different clutch's are heavier then others, so then wouldnt it be unbalenced?
 
#24 ·
yeah all of that about balancing doesnt make sense to me either. I'm not trying to make torque and hp monster capable of taking out a Hyabussa from a roll. I'm talking about my daily driver that I would like to get rebuilt and in good enough condition to take off the road completely and use as a weekend track runner, not the pages of Import Tuner. Sure in theory all of it being done absolutely correct would be WONDERFUL, but who has that kind of money and has those type of contacts? Surely guys with vinyl decals have that stuff done, but then again they are sponsored, see Sleep, those stickers are good for something@- j/j :lol:
 
#25 ·
I suppose what I think is, ideally you'd replace the flywheel at a time to coinside with an engine build and get the crank & fly balanced.....IDEALLY. "Ideally" doesn't always happen though, but at least you know the optimal way to install a flywheel.

That's the way I did mine (L20 , not F2t) I was having the engine bored and built & at the same time the machine shop reccommended a lighter flywheel & crank balance. The 2 other guys I know with light flys also had them fitted with a rebuild.


Any shortcut you take has a puddle.
 
#26 ·
obviously, but how would you go about getting it done with the engine still in the car? I would like to get it done together, rebuild, flywheel, crank pulley, clutch. But more importantly I need a clutch as we speak, so if I were to go the route of doing all of that without a rebuild, would it be worth it, is what I'm trying to find out?
 
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