RoninS2k

Yes, it is. It's stated in the first line on their description on their website:
In case you didn't know 4140 is chromoly steel.
[/quote]

Thanks man, I did not know that 4140 meant chromoly . Looks like sos full setup it is

LeonV

If you would've stated that you don't recommend Aluminum because it could possibly have a shorter service life (although ans2k and Fadis2k have proven that they hold up great), it would've been a different story, although even that's debatable. However, this is not at all what you were originally arguing, hence why I said you've changed your argument as we've moved along.


Now, I've seen not one article, let alone physical evidence, posted by you. I would appreciate some raw data instead of just more conjecture. I've explained (very well, I thought ) why Junky's flywheel mishap is likely not due to it being warped.

I've laid out the evidence, corroborated by people that actually use the products. I've explained my reasoning as to prove my hypothesis, along with the aforementioned evidence. I don't know what more you want? I'm even willing to buy Junky's old flywheel to measure and test. This is pure scientific method!

You talk of a genuine possibility of it possibly hurting or killing someone, and that in particular I find ridiculous. There's no evidence backing up this opinion either. Technically any flywheel can hurt or kill someone. Is it going to happen? No, unless there is improper installation or manufacturing involved, e.g. bolts not tightened evenly, bolts not torqued enough, bolts over-torqued, surface not per-inspected for flatness or balance, etcetera.

If you want to retract your previous statements that infer that an Aluminum flywheel will explode into pieces from use, and that they warp from usage, then we're good. I haven't seen evidence that proves otherwise, unless I get Junky's flywheel and actually confirm the failure mode.

SpitfireS

Hmm... I was trying to bring some lightness into the conversation with my self straighting at high temp comment.
I know it is difficult to get your (funny?) point across on the internet as no-one could see my face when I replied.
And, I have to say, I forgot to add the "end-of-punchline-drum-smiley" a the end.
In fact, there IS no end of punch line drum smiley on this board, unfortunately.
Why there isn't
^This is a funny smiley though.

My thinking-out-loud-remark (this would be a nice smiley) about warped disks actually being warped was sincere though.
A truely warped disk would be noticable at 9k rpm for sure, and maybe make the car undrivable, not just be noticable during clutch engagement.
If you watch what happens when just one (1) sock is out of place in a washer during the 1400 rpm spin cylcle, I think a truely out of balance FW at 9k rpm would.... make the car hop like it was a Boys-On-Tha-Hood-Low-Rider with controlled hydraulics - and a big hydraulic pump in tha boot.

Why would a clutch assembly get much hotter in a race car?
Wouldn't a competent driver on a track actually have less clutch slippage as he/she would more carefully rev match and heel-toe (and what not) to take engine braking and/or no drive because of a slipping clutch out of the equation?
On a track you're on the throttle or on the brakes.. no?

Oh well.. I think I will just this conversation.
(no I won't.. I'm just typing this to use this funny smiley)



edit: some typo's

slipstream444

You're probably the only person on this string who didn't get the message - and you still just can't wrap your head around it. Just so we're clear, here's my original post on the subject:

"While aluminum is lightweight - it's prone to warpage, and billet aluminum is extremely weak when hot. A flywheel will get pretty hot. Aluminum does not deform elastically, and therefore will fail over time (micro-fractures) - it is cycled frequently as a flywheel. Additionally, any aluminum flywheel is typically 3-piece. The friction material has to be a steel alloy or iron and the ring gear typically is steel. Those are all dissimilar metals with different expansion characteristics. This is not optimal - especially attached to a high-revving motor.

Chromoly steel is significantly stronger than aluminum (almost twice as strong - depending on the specific alloy), is more rigid (a good thing for a flywheel), and much more durable than aluminum - while being relatively lightweight. It's probably the optimal performance flywheel material for a high revving engine."

This contention still stands. And everything I have posted has thoroughly backed up my original thesis, to include providing sources. It's obvious your reading comprehension is not up to par - it's like trying to communicate with my 14 month old.

You in fact have provided NO evidence to support anything you have posted, let alone provide a legitimate argument for your position in the first place. You have one person, and a person he knows, who allegedly have not had bad experiences with a billet aluminum flywheel. That's awesome for them, but it's far from scientific data.
It's not even a sample size that anyone could begin to draw a conclusion from - it's not "scientific" in any way, shape or form. Once again - if you're using the three experiences noted in the post and they account for the sample size - you still have a 33% failure rate over a loosely defined sample period. That is in no way scientific either (there's no control groups, no data to define the conditions in which the cars were operated... etc.). Nevertheless - you have hung your hat on two positive results while trying to discredit S2000Junky's experience. That's politics - not science. My previous comment framed around political behavior applies perfectly.

It's actually quite clear you have no idea what "scientific" actually means, and purchasing S2000Junky's flywheel to "take a look at it" also falls in the category of "not science" as well. Looking at it won't show you anything you would understand. You can poke, prod, check it for runout or warpage and there is still no conclusion you could draw other than the state it's in - unserviceable. You might want to look up what the scientific method actually is.
The bottom line is you couldn't afford to have the flywheel properly analyzed.

One of my specialties in the military is aviation safety, and I specialize in analyzing components recovered from aviation mishaps to determine the cause of the mishap. This includes analysis of material component failures - the how and why things fail. I am thoroughly versed in understanding the failure modes in different materials - to include chromoly steel and aluminum - which is why I stand by my contention that billet aluminum is far from the ideal material for any component that gets cycled (to include heat cycling) in the way a flywheel is cycled.
Chromoly steel is in fact an ideal material for a street and track driven automotive flywheel (as long as it's not too thin) - which goes right back to my original point (see above or go back to my first post).

Aluminum is possibly suitable for racing applications when the part is either going to be pulled and inspected frequently, or is thrown away.

I have never inferred that an aluminum flywheel will "explode" - that would be your imagination. I have stated they can come apart (high RPM failure). Fidanza states in their owners manuals that you should run a scatter shield in high performance (not limited to racing) applications. I think this speaks for itself.

From Laskey Racing's website (http://www.laskeyracing.com/shop/harmonics.htm):
"Personal experience...We abuse the drive train launching at 8000 rpm and shifting over 10,000 rpm. The aluminum under the flywheel bolts started to eat away and the flywheel started to vibrate back and forth. When it came completely loose it sent a shock thru the crank so strong that it snapped the key holding the harmonic balancer in place. The balancer spun on the crank, put the crank fired ignition out of time and shut the motor off. When pulling everything apart, we found that the shock wave had actually also bent the crank to the point where it was unusable again. This proved to me the useful purpose of a harmonic balancer. We run steel flywheels now, BTW.

This is from a highly reputable racing company, that has been building some of the fastest Hondas for years. It reflects many of the points I've made with regard to aluminum flywheels (and it highlights the importance of the equipment on the other side of the crankshaft - the harmonic balancer). An aluminum flywheel simply can't take the rapid cycling from rapid thrust load impulses and harmonic shock that a steel flywheel can. The aluminum in this flywheel started to deform and then rapidly and catastrophically failed - a failure that destroyed the engine. The final note punctuates my point - they only run steel flywheels following that experience.

__________________________________________________ __________________________________________________ _______________________________

Here's some reading with regard to aluminum flywheels - it took me only a few seconds to find a couple examples, and I'm sure I could find something specific to the S2000 if I had the time to search:
http://www.ducatimonsterforum.org/in...?topic=49683.0
http://forums.evolutionm.net/evo-eng...l-failure.html
http://forums.evolutionm.net/evo-eng...el-review.html

There are a number of other failure modes in some BMWs running aluminum flywheels where dowel pins are let loose due to the expansion of the aluminum under stress and heat. I didn't copy the website, but you can google it. Nevertheless, this goes right back to my "dissimilar metal" point - as in the ring gear failure in the Evolution noted above. There were also a number of posts relating to ring gear failure in 3000GTs/Stealths running Fidanza flywheels.

In fact - ACT specifically annotates warping and ring gear failures with aluminum flywheels as a reason to go with their Chromoly steel flywheels. An interesting fact, considering they used to manufacture aluminum flywheels as well. http://www2.advancedclutch.com/produ...flywheels.aspx

Every manufacturer of aluminum flywheels that I have reviewed (specifically when I was shopping for a flywheel) recommend a scatter shield for "high performance" or "high RPM" applications - which was more than enough for me to steer clear of them. It's fair to note scatter shields are required for most higher level sanctioned racing - regardless of the flywheel material.

Of course there's also the the sound advice of companies that have been in the business of either selling, racing or manufacturing flywheels as well. This would include experts in the industry such as Laskey Racing (noted above) and King Motorsports.

Based on your previous track record Leon... I doubt you will either read all of this, let alone understand it. I could tell you the sky is blue and provide all the scientific evidence in the world to prove it - and you would still say it's green. Anyway, good luck with your aluminum flywheel.

slipstream444

Unfortunately you couldn't see my laughing at your previous post - I knew what you were doing.

LeonV

Thanks Spitfire... at this point it's just

I honestly don't have the time for this anymore, I have a flight to catch. If we're putting in personal credentials in here, I'm a mechanical engineer. I study and work with this stuff, e.g. failure modes, automotive engineering, tool-building, machine work, etc. I have access to extremely precise measuring and analysis tools. I'm not some hokey backyard mechanic telling wives-tales.

I'm tired of banging my head against this wall. Enjoy your steel flywheel and I'll enjoy my Aluminum one.

ans2k

just my two cents, again. it is very unfortunate for those people to have those kinds of problems with their fidanza flywheel. fidanza even admitted that 5 out of every 1000 fail. that number may just be for the evo flywheel and different for our cars. My parents and i run a small restaurant and we have hundreds of customers everyday. many people come and go, we have repeating customers and we have occasional customers that tell us that our food is the best they have ever eaten. but on our online reviews, we have people complain who just complain.

where i am getting at is that fidanza will make thousands of flywheels and a handful of them will fail, no doubt. but you will rarely see the reviews for the ones that have held up perfectly. just like my family's restaurant, if we had nothing but complaints, we wouldn't be in business for so long and we have been in business for 16-17 years out of the 27 years we have step foot in america.

take it for what it is worth, from a engineering stand point, yes an Al flywheel is more likely to fail than a steel flywheel. but mine and my friend's has lasted pretty well for the punishment we have done to them. i most likely will not go with a fidanza flywheel on my next set up. just as such i wont go with an ACT clutch disc again. but mine worked for the last 3 years or so and 40K miles and it still works now.

also, just throwing this out there. more jokingly, so no one get offended by this. the op asked what would be ok for street use. im pretty sure the fidanza is decent enough for street use. but yes steel would be better. its just like if i asked " what would be a good gun to use for house defense?" a glock 19 9mm would be fine with 16 or 18 shots, but a 50 cal anti-tank rifle would be better.

slipstream444

I understand what you're saying - and in most cases an aluminum flywheel on a street-driven S2000 "shouldn't" fail and would be fine. The caveat for this is in the company's caveat, in that they tell you to run a scatter shield in high performance and high RPM applications. A stock S2000 is not necessarily "high performance" with ~239 BHP, but it is definitely high RPM - any car that revs past 8,000 RPM is a high RPM application. Additionally, if it's a street driven car – there’s really not a significantly measurable benefit to running a lightened flywheel in the first place - especially considering the expense to complete the entire mod (pulling transmission, clutch...). Therefore it comes down to a simple cost/benefit analysis, but failure risk should be incorporated in that process.

Your analogy with your family business is very effective (the family business should be a point of great pride - it's part of the American Dream!).
The point I differ with you is in what you would define as a failure.
When considering reviews, you should consider the source - and a complaining customer that complains for the sake of complaining is not a failure on the part of the business.
Now consider this, if a customer received food poisoning or was somehow injured through negligence on the part of the company - now that's a failure. The difference here is in the severity of the “failure”. In the case of a failed flywheel, it is more than an inconvenience or something that person would dislike out of personal taste - it's a mechanical failure that will not only cause damage to the car, it has the potential to injure and kill in extreme instances.

The failure rate that was claimed by Fidanza, 5 out of 1000 (1 in 200), is one half of one percent - and at first look doesn't seem statistically significant - until you consider the potential consequences of those failures.
To put this in perspective: if gun manufactures accepted that 1 out of every 200 guns they produced would fail - we'd have a lot of dead or maimed gun owners out there, and a ton of litigation that would ultimately destroy the gun company. In reality, gun manufacturers give more than their due diligence through extensive testing, extreme levels of quality control, and process analysis to ensure failures do not happen. It only takes one material failure to essentially ruin a manufacturer or company.
This type of consequence goes beyond annoyance, inconvenience or preference. Another analogy would be comparing a legal infraction such as jay walking to the criminal acts of reckless endangerment, 2nd degree battery or manslaughter. When the consequences of an action (or omission of an action) include the potential for property damage, personal injury and death - the incidence of 1 in 200 is simply unacceptable - and that's based on THEIR numbers (the ones they want to give out).
Companies that design and build items that carry the potential for property damage, injury or death tend to typically tie several legal disclaimers to the use of their products and are heavily insured (ladder manufacturers for instance) and/or build their product such that the failure rate of those products are better than 1 in 100,000 (typically much better).
A lower failure rate helps cover the potential cost of a liability lawsuit - they would have sold enough product by that time to cover the cost of potential litigation. This is also why a number of manufacturers (ACT for instance) have moved to chromoly steel for the manufacture of flywheels - the potential for failure and litigation is significantly lower. Aluminum is much cheaper to manufacture and machine - and the profit margin potential is obviously much higher. High profit and high risk typically walk hand-in-hand. It's the liability that will get you in the end - and it only takes one major lawsuit to sink a company these days.
I hope this makes sense.

Nevertheless, I wish you and your family the greatest of continued success with your restaurant!

w00t692

leonv, do you argue just to argue? Because at this point, it's just getting ridiculous. Aluminum flywheels are dumb for the same reason aluminum brake rotors were dumb.

The end.

SgtB

Next time you're sitting in your S look at where your legs are in relation to the flywheel. Do you want to be in that car at 9k when one of those 5/1000 faults occurs? What about with a loved on in the passenger seat? You just turn a steel flywheel down and slap it back in. No rivets or any other failure point. One big simple chunk of steel, The prolite weighs 8.6 pounds, how much lighter do you need?