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7.5 Fidanza Flywheel?

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Old Oct 19, 2006 | 05:49 PM
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Default 7.5 Fidanza Flywheel?

What you guys think if I go that light on the flywheel..what are my advantages/dis advantages..Thanks
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Old Oct 19, 2006 | 05:59 PM
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Default Re: 7.5 Fidanza Flywheel? (IntegR)

https://honda-tech.com/zerothread?id=1770590


I had one before and I have one again
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Old Oct 19, 2006 | 06:07 PM
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Default Re: 7.5 Fidanza Flywheel? (43!)

Thanks 7.5 it is!!!
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Old Oct 19, 2006 | 10:07 PM
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Default Re: 7.5 Fidanza Flywheel? (IntegR)

Love it.

No dissadvantages, only advantages.
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Old Oct 19, 2006 | 11:02 PM
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Default Re: 7.5 Fidanza Flywheel? (92TypeR)

what he said^^^
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Old Oct 19, 2006 | 11:39 PM
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Default Re: 7.5 Fidanza Flywheel? (GRAVEDIGGER)

thinking about getting a lighter flywheel myself now! haha. sounds excellent.
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Old Oct 20, 2006 | 06:55 AM
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I'm going to have to say no. 7.5lbs is way too light for a stock motor. You're adding way too much stress on the tranny.

somewhere around 9-10lbs for a stock motor is where you should be.
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Old Oct 20, 2006 | 07:06 AM
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Default Re: (98 ITR)

And you got that info from where???

Let me guess a shop told you that so u'd buy one of the MORE EXPENSIVE flywheels. I have been driving with this flywheel for over a year and haven't had a problem. My tranny is completely fine. And yes I have opened it and there is nothing abnormal. So please don't generalize a specific situation as pure truth.
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Old Oct 20, 2006 | 08:37 AM
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Default Re: (98 ITR)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 ITR &raquo;</TD></TR><TR><TD CLASS="quote">I'm going to have to say no. 7.5lbs is way too light for a stock motor. You're adding way too much stress on the tranny.

somewhere around 9-10lbs for a stock motor is where you should be.</TD></TR></TABLE>

Damn, I read that and immediately felt dumb and dumber....

true story.

The next time you tell us a fable like this, at least explain to us how it stresses the transmission too much.....

Or at least cite the insidious source so we may flame them to a firey crisp....
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Old Oct 20, 2006 | 11:25 AM
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Default Re: (P1_Variable)

They blew the towers up with lightweight flywheels, didn't you know?
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Old Oct 20, 2006 | 11:27 AM
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Default Re: (Dr Pooface)

yeah, the problem was that the flywheels were TOO light, and that caused undue stress on the towers.
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Old Oct 20, 2006 | 11:44 AM
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Default Re: (jetydosa)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr Pooface &raquo;</TD></TR><TR><TD CLASS="quote">They blew the towers up with lightweight flywheels, didn't you know?</TD></TR></TABLE>


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jetydosa &raquo;</TD></TR><TR><TD CLASS="quote">yeah, the problem was that the flywheels were TOO light, and that caused undue stress on the towers.</TD></TR></TABLE>

distasteful humor

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Old Oct 20, 2006 | 12:08 PM
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Default Re: (KayOs)

i've had mine in for 6 months now. no problems and i absolutely love it
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Old Oct 20, 2006 | 12:15 PM
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Guys, this is common sense. Too light of a flywheel reduces rotational inertia in a stock tranny (with a stock motor) that has been balanced to a specific spec (especially ones that take weight off the outer rim of the wheel rather than the center) which in turn kills your torque at the top of the RPM range. That is fact.

Too light a flywheel will also create dramatic drops in RPMs during downshifting which can sometimes create notchy shifting and increase the chance of driver error during shifting. This is fact.

Extremely Lightweight flywheels are often constructed of metals or alloys that are very brittle to keep structural integrity due to less material used in construction. These metals can crack under load. This is fact.

This is what I meant about added stress.

A stock B18C5 does not require a 7.5lbs flywheel. You're killing the top end of a motor that only has top end, and majorly increasing the chances of failure. A 9-10lbs flywheel would be better suited for this application.
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Old Oct 20, 2006 | 12:27 PM
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Here is an article concerning this issue. It's applied to a bike, not a car, but the same principles are there.

http://www.ducati.net/faq.cfm?id=44

Light weight flywheels - What do you think?
submitted by Larry Kelly, Alex Ortner

The following is Larry Kelly's excellent response to the question below. I think it's the best explanation of the pros and cons of this often questioned "upgrade". Following Larry's opinion is Alex Ortner's opposite opinion, also worth posting because as with many modifications you can do to your Ducati, there's more than one opinion:

On May 3, 2004, at 9:15 AM, DUEVALVDUC@aol.com wrote:

&gt; I understood you to say that your were opting &gt; for the slipper clutch over a lightened flywheel. Is this an either/or &gt; proposition? I understand the benefits of the slipper, but isn't there &gt; still something &gt; to be gained by lightening up the rotating mass of the engine?

Larry's reply:

A lightened flywheel is one modification to a street bike that will have more negative than positive effects. I left mine stock. Here’s why.

Why You Have a Flywheel

An engine makes the least torque at idle and low rpm, especially when cold (when there are more misfires.) So when you release your clutch a little too fast, the engine torque is too small to overcome the bike's inertia, and it stalls. If you have a flywheel, the stored momentum augments the engine's torque allowing you to use a lower rpm starting-off. Without a flywheel you'd need a higher idle speed, or constantly need to start-off at a higher rpm in order to raise the engine torque output enough to avoid stalling the engine.

As you ride at lower rpm in traffic, you are constantly changing between acceleration and deceleration. Engine torque levels are still fairly low at these speeds, so slack in the drive train needs to be smoothed-out with a flywheel. Otherwise, on-off throttle transitions have a jerky effect, giving a less comfortable ride and causing you to use smaller throttle inputs (which is not always easy to do.)

At higher speeds a flywheel slows the rate at which an engine rpm changes, so cracking the throttle open or closed results in a smoother transition in torque being applied to the drive train and tires. Again, without a flywheel more careful throttle transitions are needed. The key to faster track times is reduced wheel spin so a light flywheel works against you by making it more difficult to modulate wheel spin, even though it helps lap times by producing more acceleration in the straights.

So in effect, a flywheel slows an engine's ability to change rpm producing drive train smoothness and drivability. It also reduces the engine's ability to match it's rpm with the drive train's rpm making it more difficult to downshift without producing wheel-hop.

And, when you miss a shift you’ll be glad you have one.

Lightweight Flywheel - Pros and Cons

The weight of the stock flywheel is selected by Ducati test riders to provide an overall balance between performance and smooth drive train behavior.

When you remove weight from the flywheel (and to a lesser degree, from the clutch) the effect on the engine’s ability to more quickly spin-up is indistinguishable from increasing your engine’s torque (and consequently horsepower) output.

But only in neutral. In any other gear, there’s little benefit at all.

Obviously, your bike’s ability to accelerate faster through the gears is enhanced by reducing the overall weight of the bike as well as the inertia of rotating components. The crankshaft, pistons and connecting rods, transmission gears, drive chain and sprockets, wheels and tires, clutch and flywheel are all candidates.

However, the overall weight of the bike and rider completely overwhelms any reduction of rotational inertia produced by a lighter flywheel. A two pound lighter flywheel on a 600 pound bike-plus-rider will accelerate only 0.3% faster. F=ma.

Of course every 0.3% helps a racebike. When you reduce weight you’ll get faster acceleration, and faster lap times - IF - you can modulate your wheel spin driving out of corners. Factory racebikes make so much power, for example, that transmitting the power to the road effectively becomes the limiting factor - so heavier flywheels actually become a benefit. Fear the high-side.

The ability of an engine with a lightened flywheel to SPIN-UP more quickly is often pointed-to as a benefit when you bang a downshift and wheel hop is reduced. In this situation, it can be said you have LESS ENGINE BRAKING. However, if your riding “style” makes this an issue, a slipper clutch may be a better alternative than a lightened flywheel; at least that’s what the factory racers think. A lightened flywheel is like a poor man’s slipper clutch in this situation.

Conversely, a heavier flywheel will provide more protection for the engine being over-revved in a ham-fisted downshift.

The ability of an engine with a lightened flywheel to SPIN-DOWN more quickly is often pointed-to as a benefit if you want the revs to die as fast as possible when you lift the throttle for a corner. In this situation, it can be said you have MORE ENGINE BRAKING. Under normal street riding conditions we tend to prefer less engine braking so we tolerate a less efficient situation where the motor then has to work harder to put more momentum into the flywheel. When racing, you don’t care about storing momentum, you just want to get around the track as fast as possible.

This enhanced ability of the engine to spin-up and spin-down also makes it less critical to match engine and drive train rpm for smoother shifts.

So, the purpose of the flywheel is to store momentum, reduce vibration and smooth out the loads transmitted to the drive train. It takes energy to first store this momentum, so if the flywheel is lighter it takes less energy and it accelerates up to speed faster. There is an opposite effect when you lift off the throttle and momentum is given up, so the revs drop slower for a heavier flywheel.

Because the engine will spin-up more quickly with a lighter flywheel, when you loose traction, modulating the throttle (especially in the rain) will be more difficult. Especially if your throttle position sensor, idle and CO are not adjusted properly. A light flywheel seem to exacerbate a poorly tuned fuel injection system. If you make 100 horsepower it’s less of a issue. Make 130 hp and it will matter a whole lot more.

The amount of weight removed from the flywheel and inner hub is proportional to this effect, although if you remove most of the weight from the outer rim area, the effect is stronger. Different after-market manufacturers of flywheels offer different weights and geometry. If lightweight is good, ultra-lightweight is better - just doesn’t apply here. Too light a flywheel can make the bike a handful to ride so a two pound flywheel for the street seems to be a good compromise to preserve some ride-ability.

A cold engine runs rough until there’s enough heat to vaporize the fuel, so until then, a lighter flywheel will be less effective in preventing stalls, especially pulling away from a uphill stop. You’ll need to rev the engine a little higher to compensate and you may find it’s a little ornery when running at light loads (3,500 rpm) in the lower gears around town. Often, your idle speed will need to be raised to around 1,300 rpm to help minimize stalling.

Lightweight Wheels Instead

Lightweight wheels don't have the stalling and drivability drawbacks of a lighter flywheel. Also, since the wheels have a much greater rotational inertia than a flywheel, weight reduction here results in a much greater improvement in acceleration (and braking) with an added benefit of reduced gyroscopic forces for improved handling. Lighter front rotors have a similar benefit. There’s even a significant difference in tire weights between brands to consider.
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Old Oct 20, 2006 | 12:32 PM
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Default Re: (98 ITR)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 ITR &raquo;</TD></TR><TR><TD CLASS="quote">Guys, this is common sense. Too light of a flywheel reduces rotational inertia in a stock tranny (with a stock motor) that has been balanced to a specific spec (especially ones that take weight off the outer rim of the wheel rather than the center) which in turn kills your torque at the top of the RPM range. That is fact.</TD></TR></TABLE>

No, it's not. Whatever source you got this from is simply incorrect.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 ITR &raquo;</TD></TR><TR><TD CLASS="quote">Too light a flywheel will also create dramatic drops in RPMs during downshifting which can sometimes create notchy shifting and increase the chance of driver error during shifting. This is fact.</TD></TR></TABLE>

No, it's not, and "dramatic" is an exaggeration. Competent drivers should not have any problem with such a light flywheel, and as you can see by the responses in this thread, many individuals prefer them.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 ITR &raquo;</TD></TR><TR><TD CLASS="quote">Extremely Lightweight flywheels are often constructed of metals or alloys that are very brittle to keep structural integrity due to less material used in construction. These metals can crack under load. This is fact.</TD></TR></TABLE>

No, it's not. Would you kindly share your source regarding the material composition, toughness, and structural integrity of the most popular lightweight flywheels versus the stock piece? Obviously you must have researched this to be confident in making such a statement, and I'm sure many members would be very interested in knowing the various properties of each model.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 ITR &raquo;</TD></TR><TR><TD CLASS="quote">A stock B18C5 does not require a 7.5lbs flywheel. You're killing the top end of a motor that only has top end, and majorly increasing the chances of failure. A 9-10lbs flywheel would be better suited for this application. </TD></TR></TABLE>

True, it doesn't require one. Obviously, the stock unit works fine or the engine wouldn't run. Again, perhaps you can provide an explanation as to how a lightweight flywheel "kills the top end" and "increases the chances of failure"?
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Old Oct 20, 2006 | 12:37 PM
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Default Re: (98 ITR)

have you actually driven a car with both 9lb and 7.5 flywheels?

This is a perfect example of taking somebody's advice and developing it into mind numbing analysis paralysis....that you can lead yourself to believe it is going to be detrimental to an otherwise stock 18C5.

Taking all things into consideration. I have dynoed my car with the stock flywheel, Spoon flywheel (it was about 9lbs - so "perfect by your standards and apparently ducati's as well) and my CM 8lb'er.

It was really weird, but the torque curve dropped at the same place.

What's truly odd is that some of us are looking for that quick rise in revs, as well as quick decel that is commonplace on bikes that you like to cite so much.

I think some of us call this "response."

I'm not trying to sass you with this... but I hope you have a ducati yourself.

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Old Oct 20, 2006 | 01:25 PM
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Well, I've supplied at least one source explaining my situation because appearently my word wasn't enough. Where are yours? I will, in the next few hours source probably a dozen more saying the same thing. I know the article I posted was to do with a bike, but it's the same technology.

Go to google and type in "flywheel too light" and research. I'm not the only one who thinks this.

I'm not trying to sass anyone either, actually I'd love to be proven dead wrong. I'm not by any means an internet whiner. I'll admit when I'm wrong and learn something from it. But you guys haven't sourced anything to move me off my standpoint.


Modified by 98 ITR at 4:32 PM 10/20/2006
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Old Oct 20, 2006 | 01:52 PM
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Anyway do you have ac , is this a daily driver?
If so it is too light. If no ac go for it.
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Old Oct 20, 2006 | 02:03 PM
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Default Re: (01usjdmr)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 01usjdmr &raquo;</TD></TR><TR><TD CLASS="quote">Anyway do you have ac , is this a daily driver?
If so it is too light. If no ac go for it.</TD></TR></TABLE>

Huh?
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Old Oct 20, 2006 | 02:09 PM
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ac= air conditioner, instead of people arguing why not try answering his first post.
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Old Oct 20, 2006 | 02:13 PM
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Default Re: (01usjdmr)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 01usjdmr &raquo;</TD></TR><TR><TD CLASS="quote">ac= air conditioner, instead of people arguing why not try answering his first post.</TD></TR></TABLE>

because honda-tech wouldn't be honda-tech without arguing
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Old Oct 20, 2006 | 02:20 PM
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That is true,^^^^ I have had several flywheels. I currently have a Toda and I wish I got a heavier one. My car is a daily driver and we use our ac alot here in Florida. It is too light, when coming to a stop with the air conditioner on the rpms drop so fast it stalls the car. Other than that, it is fine. Basically, too light is bad for drivability.
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Old Oct 20, 2006 | 02:30 PM
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Default Re: (01usjdmr)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 01usjdmr &raquo;</TD></TR><TR><TD CLASS="quote">ac= air conditioner, instead of people arguing why not try answering his first post.</TD></TR></TABLE>

I understand what AC means. What I don't understand is why you suggest that if he has air conditioning, he shouldn't get the Fidanza. And the original question has already been answered.
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Old Oct 20, 2006 | 02:40 PM
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Default Re: (Padawan)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr Pooface &raquo;</TD></TR><TR><TD CLASS="quote">Beware of people who tell you a lighter flywheel makes you lose torque. They are idiots, and they are everywhere.</TD></TR></TABLE>

That has signature material written all over it
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