Help me understand - why is an OEM clutch not a good idea for ~260whp/290wtq

[FPerron]

Lightweight flywheels suck.

 

No, No. You're supposed to say "I've heard bad things about lightweight flywheels.":lol:

 

In point of fact, they take a small amount of finess to get used to, but then they improve throttle response.

[LosAngelesLGT]

You are supposed to say

 

"...but then they improve throttle response while destroying off the line feel.";)

[FPerron]

Google is your friend. Look up "finess."

[derp]

spelling isn't your friend, though.

[FPerron]

:redface:I didn't look it up.

[BAC5.2]

No, No. You're supposed to say "I've heard bad things about lightweight flywheels.":lol:

 

In point of fact, they take a small amount of finess to get used to, but then they improve throttle response.

 

No. They suck. They hurt launching, and there is no notable change in response when in gear.

 

If you want the car to free-rev more quickly so you feel like you have a race car, go for it.

[FPerron]

I do have a race car - but not the kind you "launch."

[BAC5.2]

You have a Legacy that you race, not a race car.

[derp]

it's okay, we still love you. capitalization isn't my friend.

[iNVAR]

BAC, you didn't find that a LWFW helps with quicker rev matching on downshifts?

 

Just asking, I've never tried a LWFW.

[FPerron]

You seem to know what you're talking about so now I'll slink quietly away. Time to get to work, anyway. (in response to BAC5.2, of course)

[BAC5.2]

BAC, you didn't find that a LWFW helps with quicker rev matching on downshifts?

 

Just asking, I've never tried a LWFW.

 

No. Not enough to give up ease of launching.

[iNVAR]

Hrm. It's supposed to improve acceleration also though? From reading a few sites, the numbers/calculations vary, and obviously depend on the car, but it seems to be universally agreed that in lower gears, the reduction in mass at the flywheel translates to an equivalent car weight reduction of anywhere between 70-300 lbs, depending on who you ask about which car and how much lighter the flywheel can get. That doesn't seem too bad...

[iNVAR]

omg this is an awesomely funny read

http://chicaneculture.com/2010/05/basics-flywheel/

[praedet]

The only HP a lightweight flywheel can give you, is some of the hp you lost due to the drivetrain. Maybe 4-10 hp at most in our cars...

 

You will notice lighter wheels and tires first. For rev matching though, it works well...

[iNVAR]

People say that the acceleration improvement isn't dyno measurable, so it's not a matter of picking up HP...

[BAC5.2]

Hrm. It's supposed to improve acceleration also though? From reading a few sites, the numbers/calculations vary, and obviously depend on the car, but it seems to be universally agreed that in lower gears, the reduction in mass at the flywheel translates to an equivalent car weight reduction of anywhere between 70-300 lbs, depending on who you ask about which car and how much lighter the flywheel can get. That doesn't seem too bad...

 

In cars that have 40lb+ stock flywheels, there is a big reduction in rotational inertia to be lost, especially at high RPM.

 

Our stock flyhweels aren't THAT heavy, and dropping 7-9lb is really only a marginal decrease.

 

You'll never be able to defeat the built-in rev-hang, so even rev drops will be limited. In a street car, the benefits of a LWFW would be largely negligible, and not worth the trade off for degraded launch performance (not just a drag launch, but even leaving a stop sign or going up a steep hill in traffic).

 

True story:

 

My best 60' with a LWFW in my old first gen Legacy was around a 1.90. Swapped to a stock flywheel with the same clutch and no other changes, and I could crack 1.60's all day long.

[iNVAR]

Okay, thanks for the explanation. I'm not looking to go LWFW or anything, just curious.

[JoeFromPA]

I don't like LWFW personally just from the perspective of harmonics and driving happiness. So little potential for gain for so much potential for annoyance in a daily driver who I don't track or race.

[Max Capacity]

I think you know my opinion of the (POS) OEM clutch.

 

I would also not do a LWFW again.