ITR flywheel on Gen2 GSR (BEWARE! Specs and Math Inside)

INFORMATION G2IC Archives
1

So Check this info out. ARCHIVETHIS cause it took me weeks to get it all together for my fellow GEN2ers.

*1992 Gen2 B17A (GS-R) STOCK Flywheel: 19 lbs. 0 oz. (19.0 lbs.)
*98 B18C5 Type-R (ITR) Stock Flywheel: 15 lbs. 8 oz. (15.5 lbs.)

If you want the Kilos, do the math on your own. Soooo is it worth grabbing the ITR? Let’s do the math.

[SIZE=3][B]Here are the facts:

Dave Coleman’s term… taken from SCC

Effective weight =
1/ 2 * (FWweight)((FWradius) * (GearRatio) * (FinalGearRatio
)/TireRadius)^2[/B][/SIZE]

For example 92-93 GS-R
[SIZE=1](Same for all B Series engines, Gen2)[/SIZE]

gear ratio
1 3.307
2 2.105
3 1.458
4 1.107
5 0.875
F 4.400

GS-R FW weight = about 19lbs
Type-R FW weight = about 15.5llbs
tire radius for stock rims(Michelin 195/60R14 85V) = 10.8"
FW radius = about 5.625"

effective weight for GS-R in 1st gear
=0.5*(19)((5.6253.307*4.4)/10.8)^2
=545.63 round to 546

Effective weight for GS-R with Type-R FW in 1st gear
=0.5*(19)((5.6253.307*4.4)/10.8)^2
=445.11 round to 445

Therefore… 546-445 = about 101 lbs

With the Type-R flywheel, 92-93 GS-R engine is able to spin faster with 101bs in savings in first (1st) gear thanks to the YS-1 tranny’s shorter gearing!!!

[SIZE=1]For example 94 GS-R

gear ratio
1 3.230
2 1.900
3 1.360
4 1.034
5 0.787
F 4.400

GS-R FW weight = about 19lbs
Type-R FW weight = about 15.5llbs
tire radius for stock rims(195/50VR15) = 11.3"
FW radius = about 5.625"

effective weight for 94 GS-R in 1st gear
= 1/2(19lbs)((5.625"3.2304.400)/11.3")^2
=475.475

effective weight for 94 GS-R with Type-R FW in 1st gear
= 1/2(15.5lbs)((5.625"3.2304.400)/11.3")^2
=391.373
[/SIZE]

[SIZE=3]HOPE THIS HELPS YOUR CHOICE![/SIZE]

2

101 lbs! wow
other than the fast revs cars dont seems to be any faster with a lighter flywheel in my experience. :stuck_out_tongue:

3

math hurts my head, but the itr flywheel is good in my opinion. not too heavy, not too light. :cool:

4

Originally posted by cspeed
math hurts my head
Ditto. Just for clarification the '94+ GSR uses a 195/55R15 tire (not 195/50).

5

Originally posted by LeftCorner
Ditto. Just for clarification the '94+ GSR uses a 195/55R15 tire (not 195/50).

Unless, of course, you change the tires… The beauty is that now you have a formula to work with. Change the formula values for the 195/55’s and then you have the data!

–jay

6

Originally posted by Jay
Unless, of course, you change the tires… The beauty is that now you have a formula to work with. Change the formula values for the 195/55’s and then you have the data!
Right, but if you change the tires the gear ratio is going to change as well. There needs to be a formula for that change then it can be plugged in for the original gear ratio to get the effective weight in any given gear. Did that make sense?? Please correct me if there’s a flaw in my thinking, as math isn’t really my strong point.

7

Here’s the thing… the size of the wheel doesn’t change the ratios in this formula, as the rations are taken from the transmission itself and the tire radius changes with each different tire size. Review the formula below and you’ll see what I mean.

1/ 2 * (FWweight)((FWradius) * (GearRatio) * (FinalGearRatio)) / TireRadius)^2

If you are still missing it, try using actual figures and you’ll see that the result differs if you change the tire size.

–jay

8

Man your really trying to push this mod to be popular :stuck_out_tongue:
Sounds like your really proud of your itr flywheel, what have you noticed since swapping it in?

9

Nah, just trying to pass along the knowledge. People buy mods and crap with NO IDEA what they do. I’m trying to help fellow G2er’s be informed. I posted questions and never got any answers so I finally did the research on my own. Now you get the fruits of my labor.

An informed consumer…

You know the saying.

Besides… If I want to get something and I ask, I hope someone else would be as willing to share the knowledge.

–jay