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Discussion Starter #1
Anyone given thought about a lightweight flywheel for our cars?
I don't believe any company offers this yet and I wonder why? Seems like
an excellent way of increasing acceleration in 1st and 2nd gear. Is the
OEM version already as light as it can get?

Why are these not available?
 

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Anyone given thought about a lightweight flywheel for our cars?
I don't believe any company offers this yet and I wonder why? Seems like
an excellent way of increasing acceleration in 1st and 2nd gear. Is the
OEM version already as light as it can get?

Why are these not available?
Maybe it has to do with strength/weight trade-off issue. You want to be light while still maintain durability/strength. Just my $.02
 

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With all the posts you have today, your broke!:rofl::rofl::rofl:

Oooh . . . I'm funny!
Yeah, since Gustav has m5board for mobile, I will be able to post anywhere/anytime. Today is a tragic day, and it kind of flashback to me what I had to deal a year ago with similar tragic:crying::crying:.

But you always give me a laugh.
:biggrinbounce::jump::jump:
 

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Discussion Starter #5
Maybe it has to do with strength/weight trade-off issue. You want to be light while still maintain durability/strength. Just my $.02
Yeah, it's possible that there's not much room for improvement. I
found this thread:

http://www.m5board.com/vbulletin/showthread.php?t=110888

It's concerning the Dinan S3 flywheel. Last post seems to indicate that
it's actually heavier than stock. Not sure if that's true or not and
I'm not sure why they would put a heavier setup unless it has to do
with durability. Can anyone confirm this?
 

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Discussion Starter #6
BTW, the Porsche GT is lauded for it's lightweight flywheel. It's
possible to make a flywheel that handles the power. Perhaps it's
cost prohibitive though?
 

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BTW, the Porsche GT is lauded for it's lightweight flywheel. It's
possible to make a flywheel that handles the power. Perhaps it's
cost prohibitive though?
It doesn't really have a flywheel, as we normally think of flywheels, and even if you consider the ring gear & clutch assembly it's tiny.

http://www.zf.com/s/content/en/impo...k-kupplung/Keramik-Kupplung_fuer_Porsche.html

I honestly love lightweight flywheels. They make a great difference in the way the car feels, with the rev up and down. It does have its drawbacks though (easier to stall, less inertia for launch so higher possibility of bogging, tendancy for more drivetrain noise and vibration, etc).
 

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Anyone given thought about a lightweight flywheel for our cars?
I don't believe any company offers this yet and I wonder why? Seems like
an excellent way of increasing acceleration in 1st and 2nd gear. Is the
OEM version already as light as it can get?

Why are these not available?
I think a lightweight flywheel is a great idea. I had one on my E39 M5 and it was great. I must say it felt like a lost some low end punch with it though. Then I got the diff and felt the best of both worlds it felt like it wound up fast like a 2 stoke with the punch of a 4 stroke (referring to motorcycle of course.)

Now I have the diff so a lightweight flywheel would be a great option. I actually do not know if you loose any low end torque of if it just winds so much it quicker it decieves you into that feeling. Anyone know for sure?
 

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Discussion Starter #9
Thanks for the link!

I've been trying to read up on the downsides and many mention
the need for a tune to avoid stalls and the advantages of dual vs
single mass flywheels. Hopefully someone will come up with an
offering at some point.

As always, I'm looking for where to go next with mods. ouich
 

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Discussion Starter #10
I think a lightweight flywheel is a great idea. I had one on my E39 M5 and it was great. I must say it felt like a lost some low end punch with it though. Then I got the diff and felt the best of both worlds it felt like it wound up fast like a 2 stoke with the punch of a 4 stroke (referring to motorcycle of course.)

Now I have the diff so a lightweight flywheel would be a great option. I actually do not know if you loose any low end torque of if it just winds so much it quicker it decieves you into that feeling. Anyone know for sure?
+1, I like to hear some of the practical aspects. UUC has come good info
on their website in relation to the e39 M5:

http://www.uucmotorwerks.com/flywheel/m5_flywheel.pdf


<table border="0" cellpadding="5" cellspacing="0"><tbody><tr><td align="center">GEAR</td> <td align="center">M3 and 3-series "virtual"
weight lost:
</td> <td align="center">M5/Z8/540i "virtual"
weight lost:
</td> </tr> <tr> <td align="center">1st gear </td> <td align="center">346.5 lbs. </td> <td align="center">394.4 lbs.</td> </tr> <tr> <td align="center">2nd gear </td> <td align="center">133.15 lbs. </td> <td align="center">151.7 lbs.</td> </tr> <tr> <td align="center">3rd gear </td> <td align="center">68.9 lbs. </td> <td align="center">75.4 lbs.</td> </tr> <tr> <td align="center">4th gear </td> <td align="center">46.18 lbs. </td> <td align="center">48.5 lbs.</td> </tr> <tr> <td align="center">5th gear </td> <td align="center">36.15 lbs. </td> <td align="center">37.6 lbs.</td> </tr> <tr> <td align="center">6th gear </td> <td align="center">30.04 lbs. </td> <td align="center">31.0 lbs.</td> </tr> </tbody></table>
A general rule of thumb for weight loss equivalence to "gained" power is
approximately 10lbs/hp. That is for every 10lbs lost, the car gains the effective
performance increase of 1hp.


With that in mind, the effective performance increase expressed in gained power can
be expected to be the same as the "virtual" weight lost due to the flywheel in each
gear divided by 10:



<center> <table border="0" cellpadding="5" cellspacing="0"> <tbody><tr> <td align="center">GEAR</td> <td align="center">M3 and 3-series "virtual"
performance gain:
</td> <td align="center">M5/Z8/540i "virtual"
performance gain:
</td> </tr> <tr> <td align="center">1st gear </td> <td align="center">34.6 hp</td> <td align="center">39.4 hp</td> </tr> <tr> <td align="center">2nd gear </td> <td align="center">13.3 hp</td> <td align="center">15.2 hp</td> </tr> <tr> <td align="center">3rd gear </td> <td align="center">6.9 hp </td> <td align="center">7.5 hp</td> </tr> <tr> <td align="center">4th gear </td> <td align="center">4.6 hp</td> <td align="center">4.9 hp</td> </tr> <tr> <td align="center">5th gear </td> <td align="center">3.6 hp</td> <td align="center">3.8 hp</td> </tr> <tr> <td align="center">6th gear </td> <td align="center">3 hp. </td> <td align="center">3.1 hp</td> </tr> </tbody></table> </center>​
 

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the m5 already revs pretty quickly...haha...but It could be cool
 

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It doesn't change the gear ratios. It works by making the rotating mass of the drivetrain lighter.
My bad. My apologies for the 'bonehead' questions, but just intuitively speaking, with less resistance from a lower rotational mass, wouldn't the engine attain higher revs in a shorter period of time? I'm obviously missing a key element in this physics question, but I just don't know what it is.
 

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My bad. My apologies for the 'bonehead' questions, but just intuitively speaking, with less resistance from a lower rotational mass, wouldn't the engine attain higher revs in a shorter period of time? I'm obviously missing a key element in this physics question, but I just don't know what it is.
Yes, it would reach redline faster. The effect would be similar to going with lighter wheels and tires. Lb per lb, weight loss at the flywheel tends to make a bit bigger difference than elsewhere.
 

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Discussion Starter #17
Please correct me if I'm wrong but it's effectively reducing the
mass the engine sees after the point of the flywheel. You would
still be traveling the same distance spatially. You would just get
there faster due to the virtual lightening of the car (assuming no
wheel spin of course). As the numbers from UUC suggest, it can be
as much as losing reducing the weight by 400lbs.
 

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Well, since you accelerate to the end of 1st gear slightly faster, you should travel a slightly shorter distance before the shift to second. However, the difference wouldn't be very large, I think.

Honestly, I think that though that 10 lbs per hp rule of thumb is used a lot, it's not very accurate in all situations.

For instance, let's take a look at two very basic examples:

1. Car 1 weighs 3000 lbs and has 100 hp. It's effectively 30 lbs per hp. If you lose 100 lbs, you're at 29 lbs per hp. So, the 100 lb loss is equivalent to putting your hp to 103.4. Each 10 lb loss is only like gaining 0.34 hp instead of 1 hp.

2. Car 2 weighs 2000 lbs and has 400 hp. It's effectively 5 lbs per hp. If you lose 100 lbs, you're at 4.75 lbs per hp. That 100 lb loss put you at an effective 421 hp. So each 10 lb loss "gained" you 2.1 hp.

10 lbs per hp rule of thumb assumes a car starts out at about 10 lbs per hp, which very few cars are. Heck, the stock M5 is 500 hp and 4012 lbs, so it starts out at 8 lbs per hp.
 

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My bad. My apologies for the 'bonehead' questions, but just intuitively speaking, with less resistance from a lower rotational mass, wouldn't the engine attain higher revs in a shorter period of time? I'm obviously missing a key element in this physics question, but I just don't know what it is.
This is what I would think also.

But I went to SC and all were know for is football players receiving homes for their parents. Certainly not an education!:nono: At least we don't steal handicapped placards and give them to their football players (UCLA)hiha

Totally jacked that thread up! Anyway, what about Boner's comment?
:cheers:

Doh!! missed this page!ouich
 

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Discussion Starter #20
I think a lightweight flywheel is a great idea. I had one on my E39 M5 and it was great. I must say it felt like a lost some low end punch with it though. Then I got the diff and felt the best of both worlds it felt like it wound up fast like a 2 stoke with the punch of a 4 stroke (referring to motorcycle of course.)

Now I have the diff so a lightweight flywheel would be a great option. I actually do not know if you loose any low end torque of if it just winds so much it quicker it decieves you into that feeling. Anyone know for sure?
Hey Brad. Found this article concerning torque loss and lightweight
flywheels:

http://www.uucmotorwerks.com/flywheel/there_is_no_torque_loss.htm
 
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