# My Review on the 13.4 lb UUC Lightweight Flywheel



## JawKnee (Dec 20, 2001)

http://forum.e46fanatics.com/showthread.php?s=&threadid=20643


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## nate (Dec 24, 2001)

Ever find out what ratios the Hi-op LSD is?


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## blackdawg (Jan 4, 2002)

*minor points:*

the advantage of the lightweight flywheel is from standstill to redline and its effect is greatest in first and second gear (in apparent weight reduction to rotational mass on the driveline).

where most of the power is lost is from cruising speed and then trying to accelerate, i.e. 4th gear ont eh highway and then try to go from 80mph to 100mph. the inertia is less here and most noticeably down compared to the OEM flywheel.

i think the concepts you state in your review are slightly reversed to what they should be/how they should be stated. this i only know because i also employed a LTW in my former car and read up on its benefits as well. european car did a wonderful set of dynos on this as well as a great layman's explanation of the benefits.

just to clarify your points.

and also: since this is the summer: there is a lot of chatter on idle when the A/C is on.......nothing major to complain about, though.


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## JawKnee (Dec 20, 2001)

*Re: minor points:*



blackdawg said:


> *the advantage of the lightweight flywheel is from standstill to redline and its effect is greatest in first and second gear (in apparent weight reduction to rotational mass on the driveline).
> 
> where most of the power is lost is from cruising speed and then trying to accelerate, i.e. 4th gear ont eh highway and then try to go from 80mph to 100mph. the inertia is less here and most noticeably down compared to the OEM flywheel.
> 
> ...


Hmm, so you don't agree with me that there is or should be a loss of low-end torque which would hurt off the line accelerations with the lighter the flywheel the greater the impact? I personally don't feel the loss of torque but I really don't feel the gain if I'm climbing through 1st. However, if I cruise at 3k in 1st and then go WOT I can feel it.

Correct me if I am wrong but drag-racing vehicles depend on a near-stock-weight or heavier flywheel to store the necessary amount of energy for an explosive launch. Since the launch is the most critical aspect of a drag race, most racers cannot afford to give up launch quality by using a lightened flywheel to pick up a slight improvement in acceleration... :dunno:


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## JawKnee (Dec 20, 2001)

Per a european car article that reviewed a lightweight flywheel...
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"But, another noticeable difference was the loss of some low-end torque. The car seemed to rev more quickly but not until higher up in the rev range. Off the line, the car wouldn't pull like it used to when I dumped the clutch at 3500 rpm. The inertia generated from the heavier stock flywheel couldn't be reproduced with this lightweight unit for an out-of-the-hole launch. "
_


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## JawKnee (Dec 20, 2001)

nate328Ci said:


> *Ever find out what ratios the Hi-op LSD is? *


No!  They've been horrible at calling me back so I've given up for a while until I find a 3.38 first


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## blackdawg (Jan 4, 2002)

*on the loss of torque.*

yep.

on the inertia, which is where you are mainly wrong:

most of the intertia is the benefit from the spooling from idle to redline. going from steady speed to WOT is where you will feel the loss in power the most.

that was my main point. the loss of torque seemed negligible to me.

that car was also a different beast, first off, it wasn't an e46, it was an e36/8 and it was supercharged. i have no idea how a LTW feels on an e46. my guess is that everything helps an e46.

i feel like i'm in a coffin or sensory deprivation chamber when i drive my wife's e46.


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