stock flywheel vs lightened stock flywheel weight (and sensors)
01-12-2005, 08:18 PM
#1
Burning Brakes
Thread Starter
stock flywheel vs lightened stock flywheel weight (and sensors)
hi all,
what is the weight of the stock flywheel? i see figures being thrown around that are as low as 14 and as high as 19!
how much weight can reasonably be taken off? i'm asking b/c i've had a local machine shop lighten my flywheel for me and they've taken it down to about 5kg (around 11lb i think). but i see people running around with like 8lb lightened flywheels. the shop says then can take out another kilo or so, but then they have to bust out the CNC mill or something and the $$$ goes up significantly.
i assume they've left all the sensors in place, but common wisdom seems to be that you can get rid of the two forward (engine-facing) sensors, and leave just the rear one. does that mean they can grind this entire area off as well?
what is the weight of the stock flywheel? i see figures being thrown around that are as low as 14 and as high as 19!
how much weight can reasonably be taken off? i'm asking b/c i've had a local machine shop lighten my flywheel for me and they've taken it down to about 5kg (around 11lb i think). but i see people running around with like 8lb lightened flywheels. the shop says then can take out another kilo or so, but then they have to bust out the CNC mill or something and the $$$ goes up significantly.
i assume they've left all the sensors in place, but common wisdom seems to be that you can get rid of the two forward (engine-facing) sensors, and leave just the rear one. does that mean they can grind this entire area off as well?
01-12-2005, 08:24 PM
#2
Three Wheelin'
Join Date: Jun 2001
Location: San Jose, CA
Posts: 1,598
Likes: 0
Received 0 Likes
on
0 Posts
You can remove the one sensor that was needed for the factory test port. This is not used by anybody that I know of.....does the dealer use this? I doubt it. Mine was shaved and they shaved all the way down removing this pin. The two pins that were left were for the reference sensor and speed sensor...both are necessary on the 951. I beleive mine was lowered around 6lbs from stock according to the mechanic. The 8lb flywheel you are referring to is probably the aluminum ones that folks pay $300 for. The weight removed from mine made a big difference and I would not wanted an more removed because of the sudden drop in rpm which makes matching revs a little different. You will also notice that getting off the line quick is a bit tougher.
01-12-2005, 08:28 PM
#3
Burning Brakes
Thread Starter
i already suck at getting off the line, not an issue 
.
hum...but i've read everywhere that only one of the sensors is necessary! eg the fidanza only comes with one sensor! maybe it's a MY thing? can't be though, i don't see different fidanzas for different MY.
the 8lb flywheels are definitely stock lightened - NZ951 has one, and so does mwc951.
.hum...but i've read everywhere that only one of the sensors is necessary! eg the fidanza only comes with one sensor! maybe it's a MY thing? can't be though, i don't see different fidanzas for different MY.
the 8lb flywheels are definitely stock lightened - NZ951 has one, and so does mwc951.
01-12-2005, 09:10 PM
#4
Racer
Join Date: Aug 2003
Location: Oslo, Norway
Posts: 445
Likes: 0
Received 0 Likes
on
0 Posts
The factory test port uses the 2 pin at the original FlyW that are 8cm away from each other, that are at the exact same position when rotating the FlyW. (nearest the engine) Those you dont need!
Then the last and single pin at the FlyW is needed for the reference sensor.(mostly)
The speed sensor is taken its signal from "tannkransen" in norwegian. Where the starter push the Pressure Plate to start the car.
My Spec Alu FlyW is only about 2.8kg weight! The OEM FlyW is 6.8kg!! Huge difference! Havent got the chance to test it yet, hope it`ll be ok...
I think I got this pin stuff right, I`m a bit tired right now
Then the last and single pin at the FlyW is needed for the reference sensor.(mostly)
The speed sensor is taken its signal from "tannkransen" in norwegian. Where the starter push the Pressure Plate to start the car.
My Spec Alu FlyW is only about 2.8kg weight! The OEM FlyW is 6.8kg!! Huge difference! Havent got the chance to test it yet, hope it`ll be ok...
I think I got this pin stuff right, I`m a bit tired right now
01-12-2005, 09:16 PM
#6
Addict
Rennlist Member
Rennlist Member
You've got the pick up for the reference sensor left, the speed sensor picks up the signal off the starter ring gear teeth. Most people do cut off enough to eliminate the factory diagnostic pick up sensor. The stock flywheel is around 16 IIRC, it's been a while. I got one down to 11.4 then the next one we got to 10.2 but that was thin in a couple of places.
Trending Topics
01-12-2005, 09:44 PM
#9
Burning Brakes
Thread Starter
sigh my brain hurts...so the upshot of all that is that...we can remove the two sensors that rotate in a single plane with each other (the engine-side) sensors? sorry, i'm a little tired 
.
oh...and where do sfr, ph, lindsey etc grind the remaining 3-4lbs from?
.oh...and where do sfr, ph, lindsey etc grind the remaining 3-4lbs from?
01-13-2005, 12:09 AM
#13
Race Director
Originally Posted by Driv200mph
What does a complete lightened clutch cost.....with all the pieces needed to make a complete clutch upgrade for racing. Any range????? Andy.
KEP Light weight PP $600 (stage 1 or 2), lighten the stock fly (no more than $200), and your choice of disks, maybe a cup sachs version...
01-13-2005, 12:48 AM
#14
Burning Brakes
Thread Starter
hum...i don't doubt the figures, 'cos my machine shop says they can get it down to that weight. just it's expensive . i was hoping there might be a cheaper/easier way that wouldn't involve breaking out the CNC mill.
. i was hoping there might be a cheaper/easier way that wouldn't involve breaking out the CNC mill.
