ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Roadster and Coupe > General BMW Z4 Forum
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      12-07-2012, 05:56 PM   #1
beta
Lieutenant Colonel
28

 
Drives: 2006 M Roadster
Join Date: Mar 2011
Location: CA


Posts: 1,655
iTrader: (2)

Teaser: 3.91 Ring and Pinion shot peened and REM polished

Just got my 3.91 ring and pinion back today from being shot-peened then REM polished. Here are some teaser pictures. Hoping to get it installed after the holidays.



__________________
Appreciate 0
      12-07-2012, 06:53 PM   #2
johanness
Banned
23

 
Drives: 2008 Z4MC
Join Date: Aug 2010
Location: Seattle, Vancouver


Posts: 1,741
iTrader: (3)

Garage List
Sweet. Where'd u get it done?

Looking forward to your review, as I've been on the fence w/this for some time.
Appreciate 0
      12-07-2012, 07:28 PM   #3
papitosabe
Second Lieutenant
2

 
Drives: '06 Z4 Coupe
Join Date: Oct 2007
Location: Houston


Posts: 222
iTrader: (1)

I'm a complete newb, but why does shot-peen and polishing do for them?
Appreciate 0
      12-07-2012, 07:43 PM   #4
marinb
First Lieutenant
United_States
4

 
marinb's Avatar
 
Drives: 2009 X5 35d
Join Date: Jan 2011
Location: Cupertino, CA


Posts: 329
iTrader: (4)

What was the cost break down? I'm interested in the REM polish.
Appreciate 0
      12-07-2012, 08:43 PM   #5
Finnegan
Major General
United_States
80

 
Finnegan's Avatar
 
Drives: Sapphire Black/Black Z4Mc
Join Date: Oct 2008
Location: At the track..or wishing I were at the track


Posts: 6,487
iTrader: (18)

I just bought my 3.91 ring and pinon as well, and am getting them treated. (Thanks to Beta, who has been a great help with sourcing the gears, and with the treatment and associated legwork and research.) These are "before" shot peen and REM polishing.

I'm shooting for an install early next year (still need to ship for polishing and just got the ring and pinon).

Good description of the shot peen process here. The REM polishing/treatment creates a micro layer of treated material reduces friction (reduces wear and frictional losses). IIRC, the 4.1 gears from BMW are shot peened, while the 3.91 are not.

Beta will have the give the exact cost for the peen and REM. Should be somewhere about $125 based on my discussion with the company (range is lower and higher based on size of parts). Company is Weddle, near Santa Barbara.
Attached Images
 

Last edited by Finnegan; 12-09-2012 at 03:51 PM.
Appreciate 0
      12-07-2012, 10:13 PM   #6
mfanatic325
///M-fanatic
Taiwan
50

 
mfanatic325's Avatar
 
Drives: '07 Z4MC, '04 325Ci
Join Date: Oct 2007
Location: Cupertino, CA.


Posts: 3,684
iTrader: (20)

Garage List
Send a message via AIM to mfanatic325
You guys are gonna love it!
1st gear becomes practically useless however
And it'll take a tiny bit of getting used to throttle modulation for daily driving, as you'll be seeing more torque earlier on in the rev band; as well as twitchier in-gear acceleration/deceleration.
Overall though, gearing isn't a bad stepping stone to FI
__________________
VF570 S/C|TIAL BOV|SetRabCooler|Brembo GT 6/4|TE37s|NT05s|3.91 Gearing|TCK D/A|RPi Induction|SS Race Mufflers/X-pipe|JVT Headers|AS SSK|VibraTechnics Mounts|Sparco Pro2000/6pt.Harness|MS FloorMounts|SE Custom Harness Bar|Tekarbon Angels|M-Tech Pedals|OE Strut Bar|RE RSMs|8000K D2S|CDV DEL|CF Roof Wrap|MB Grills|UUC TrannyMounts/ClutchStop|V1 Mount|P3C Gauge
Appreciate 0
      12-07-2012, 10:27 PM   #7
Rick F.
Major
40

 
Rick F.'s Avatar
 
Drives: 2013 BMW 335i cabriolet
Join Date: Jun 2009
Location: Baltimore, MD


Posts: 1,136
iTrader: (0)

Beta,

Those are works of art, for sure!

Rick F.
Appreciate 0
      12-08-2012, 01:35 AM   #8
beta
Lieutenant Colonel
28

 
Drives: 2006 M Roadster
Join Date: Mar 2011
Location: CA


Posts: 1,655
iTrader: (2)

johaness, papitosabe: see finnegan's post. Thanks for chiming in.

marinb: I left my invoice at work with my gears. Everything with shipping was around 150, but I'll get the breakdown for you tomorrow if I remember (working on saturday bleh).

mfan: can't wait, power is addicting. Installing these should push out the temptation of FI another 6 months...

Rick: thanks!
__________________
Appreciate 0
      12-08-2012, 08:17 AM   #9
inTgr8r
Major General
Canada
112

 
inTgr8r's Avatar
 
Drives: 07 M Coupe
Join Date: Mar 2006
Location: Toronto


Posts: 8,069
iTrader: (7)

Subscribed

I did a quaiffe plus R&P change on a G35 and it was a huge improvement
This has been on my list for a long time now for the M Coupe.

What was the deciding factor for going this route rather than doing the exchange thing with someone like diffs-online?

Looking forward to the results, need all the info I can get
__________________
Alpinweiss '07 M Coupe •DKF Section1•RPi GT exhaust•Fabspeed Headers•Autosolutions SSK•APR splitter•Tekarbon headlights•StrongStrut STB•H&R COs + ARBs•Poly FCAB/RTAB•Volk Racing G2•Direzza ZII•Stoptech BBK•Vibra-Tech mtr mounts•
Appreciate 0
      12-08-2012, 09:01 AM   #10
Gt4
Captain
Canada
7

 
Gt4's Avatar
 
Drives: E36/8 Z3MC / E90 M3
Join Date: Jan 2012
Location: Montreal


Posts: 625
iTrader: (4)

I had a 3.91 with 2-way Carbonetics LSD installed on my car this summer.

The shorter gear ratio compare to OEM 3.62 was a nice upgrade but the LSD was too agressive for me.

I recently installed a 4.10 pinion/ring in my OEM diff with the M-Variable LSD. I love it! It's so rev-happy compare to the 3.91. Even with my ESS VT-445, the 4.10 is a great match. I can't wait to try it next summer on the track.



I still don't understand why people choose a 3.91 over a 4.10???

Especially when NA
Appreciate 0
      12-08-2012, 09:13 AM   #11
inTgr8r
Major General
Canada
112

 
inTgr8r's Avatar
 
Drives: 07 M Coupe
Join Date: Mar 2006
Location: Toronto


Posts: 8,069
iTrader: (7)

^ that is my dilemma
You are the 1st person I know that has had both and can offer a real world comparison.


Everyone that has the 3.91 says they're great & the best way to go.
....those with the 4.10 say the same damn thing.
__________________
Alpinweiss '07 M Coupe •DKF Section1•RPi GT exhaust•Fabspeed Headers•Autosolutions SSK•APR splitter•Tekarbon headlights•StrongStrut STB•H&R COs + ARBs•Poly FCAB/RTAB•Volk Racing G2•Direzza ZII•Stoptech BBK•Vibra-Tech mtr mounts•
Appreciate 0
      12-08-2012, 09:47 AM   #12
Caddyshk
M = Midlife Crisis
Canada
21

 
Caddyshk's Avatar
 
Drives: 2006 Z4MC Interlagos
Join Date: May 2007
Location: Oak Ridges, Ontario, Canada


Posts: 1,917
iTrader: (0)

Quote:
Originally Posted by inTgr8r View Post
^ that is my dilemma
You are the 1st person I know that has had both and can offer a real world comparison.


Everyone that has the 3.91 says they're great & the best way to go.
....those with the 4.10 say the same damn thing.
Either way; you'll need 5th gear on the Andretti straight which makes a smooth entry into 8 a little more difficult. Added higher revs however should allow for staying in 3rd through 5b and the Moss corner
__________________
2006 Z4MC - #LL93158
SuperSprint Race Cans, RE X Pipe, Fabspeed Headers, OE STB, AS Shifter, Dave Z Modified CDV, Ground Control Coil Overs, Stoptech lines, Hawk DTC Pads, RE Clutch Stop, RE Transmission Mounts, Vibra-Technics Engine Mounts, ZHP Shift Knob, LeatherZ M Shift Boot, Tekarbon Rear Spoiler, CF Grills, Advan RS DGM
Appreciate 0
      12-08-2012, 10:02 AM   #13
Dammmittt
My favorite sign.
South Korea
65

 
Dammmittt's Avatar
 
Drives: 2007 M Coupe
Join Date: Dec 2006
Location: Der Autobahnen


Posts: 4,332
iTrader: (0)

I think you just need to balance acceleration and top speed...for driving in the states I think you'd go with acceleration over top speed...but I could be wrong....
__________________


07 ///M Coupe (Premium Package) Black Saphire Ext. Imola Red Int.

Best Website EVER!
Appreciate 0
      12-08-2012, 11:16 AM   #14
inTgr8r
Major General
Canada
112

 
inTgr8r's Avatar
 
Drives: 07 M Coupe
Join Date: Mar 2006
Location: Toronto


Posts: 8,069
iTrader: (7)

Quote:
Originally Posted by Caddyshk View Post
Either way; you'll need 5th gear on the Andretti straight which makes a smooth entry into 8 a little more difficult. Added higher revs however should allow for staying in 3rd through 5b and the Moss corner
I think your absolutely right about the 5 complex
....I wonder where you'd hit the shift point on the Andretti straight, it would suck if it was just before the crest.

--------------

To do this mod I'm not sure who I'd trust to do the job right

When doing the ring & pinion change, are you guys changing Bearings, Seats / Gaskets, Crush Collar etc?

& what kind of deals/pricing are you finding out there.
__________________
Alpinweiss '07 M Coupe •DKF Section1•RPi GT exhaust•Fabspeed Headers•Autosolutions SSK•APR splitter•Tekarbon headlights•StrongStrut STB•H&R COs + ARBs•Poly FCAB/RTAB•Volk Racing G2•Direzza ZII•Stoptech BBK•Vibra-Tech mtr mounts•

Last edited by inTgr8r; 12-08-2012 at 11:57 AM.
Appreciate 0
      12-08-2012, 01:43 PM   #15
Finnegan
Major General
United_States
80

 
Finnegan's Avatar
 
Drives: Sapphire Black/Black Z4Mc
Join Date: Oct 2008
Location: At the track..or wishing I were at the track


Posts: 6,487
iTrader: (18)

Quote:
Originally Posted by Gtfour View Post
I had a 3.91 with 2-way Carbonetics LSD installed on my car this summer.

The shorter gear ratio compare to OEM 3.62 was a nice upgrade but the LSD was too agressive for me.

I recently installed a 4.10 pinion/ring in my OEM diff with the M-Variable LSD. I love it! It's so rev-happy compare to the 3.91. Even with my ESS VT-445, the 4.10 is a great match. I can't wait to try it next summer on the track.

I still don't understand why people choose a 3.91 over a 4.10???

Especially when NA
Hmmm....Should I have gone with the 4.10?

If I'm doing this correctly, and assuming stock sized tires:

3.62 -> 3.91 = 8%
3.62 -> 3.91 = 13.25%

3.62 -> 3.91 8% with 265/35 tires (2.81%) = 10.81%
3.62 -> 3.91 8% with 265/35 tires (2.81%) = 16%

I went with 3.91 because FI is a future enhancement I plan at some point; and my rear tires are 265/35, which already gives me close to 3% more wheel torque.

But my math assumptions could be off--but FI is in the future. Like Caddy, I figured off speeds (current and factoring in future improvements in times) and didn't like the shift points req'd for my local track with the 4.1 (ran numbers with and without tire factors).

I went the R&P direction because there's a good local shop (off road / diffs only) that will do the work for under 200. They did a great job on my friend's E46 M3. R&P was 545 shipped (Bobby Rahal BMW). Those costs, plus additional parts, fluid, REM and polish, and install are a better deal than an entire diff swap. Plus I know my diff's history...

Last edited by Finnegan; 12-09-2012 at 05:36 PM.
Appreciate 0
      12-08-2012, 01:58 PM   #16
Caddyshk
M = Midlife Crisis
Canada
21

 
Caddyshk's Avatar
 
Drives: 2006 Z4MC Interlagos
Join Date: May 2007
Location: Oak Ridges, Ontario, Canada


Posts: 1,917
iTrader: (0)

Quote:
Originally Posted by inTgr8r View Post
I think your absolutely right about the 5 complex
....I wonder where you'd hit the shift point on the Andretti straight, it would suck if it was just before the crest.

--------------

To do this mod I'm not sure who I'd trust to do the job right

When doing the ring & pinion change, are you guys changing Bearings, Seats / Gaskets, Crush Collar etc?

& what kind of deals/pricing are you finding out there.
I start bouncing the rev limiter now just before the crest...
__________________
2006 Z4MC - #LL93158
SuperSprint Race Cans, RE X Pipe, Fabspeed Headers, OE STB, AS Shifter, Dave Z Modified CDV, Ground Control Coil Overs, Stoptech lines, Hawk DTC Pads, RE Clutch Stop, RE Transmission Mounts, Vibra-Technics Engine Mounts, ZHP Shift Knob, LeatherZ M Shift Boot, Tekarbon Rear Spoiler, CF Grills, Advan RS DGM
Appreciate 0
      12-08-2012, 02:58 PM   #17
mfanatic325
///M-fanatic
Taiwan
50

 
mfanatic325's Avatar
 
Drives: '07 Z4MC, '04 325Ci
Join Date: Oct 2007
Location: Cupertino, CA.


Posts: 3,684
iTrader: (20)

Garage List
Send a message via AIM to mfanatic325
I also plan on FI in the future, but I got 3.91 primarily because I came across a decent deal for a set of ring & pinion and also had access to a good diff rebuilder for an acceptable labor price.
__________________
VF570 S/C|TIAL BOV|SetRabCooler|Brembo GT 6/4|TE37s|NT05s|3.91 Gearing|TCK D/A|RPi Induction|SS Race Mufflers/X-pipe|JVT Headers|AS SSK|VibraTechnics Mounts|Sparco Pro2000/6pt.Harness|MS FloorMounts|SE Custom Harness Bar|Tekarbon Angels|M-Tech Pedals|OE Strut Bar|RE RSMs|8000K D2S|CDV DEL|CF Roof Wrap|MB Grills|UUC TrannyMounts/ClutchStop|V1 Mount|P3C Gauge
Appreciate 0
      12-08-2012, 06:15 PM   #18
beta
Lieutenant Colonel
28

 
Drives: 2006 M Roadster
Join Date: Mar 2011
Location: CA


Posts: 1,655
iTrader: (2)

inTgr8r: as finnegan said: price and history. My diff only has 25k miles, I know its full history. About the price, buying new R&P from bmw motorsport, shot peen + rem + installation is going to be in the neighborhood of 1k. Way cheaper than diff swapping.

As for 3.91 vs 4.10. I went the conservative route because my build is about the ultimate roadster, so I try to balance creature comforts, mileage, performance, etc.

Dammmittt: top speed should not be affected by 4.10. With 4.10 gears in 6th @ 8k rpm you'd be going a theoretical 175mph. There's a discussion here that goes into it, but that should be as fast as the car can go without FI.

marinb: REM was $95. Might be able to get it a bit cheaper if you say we referred you, I'm sure Weddle will appreciate the repeat business.
__________________

Last edited by beta; 12-08-2012 at 06:25 PM.
Appreciate 0
      12-08-2012, 07:26 PM   #19
marinb
First Lieutenant
United_States
4

 
marinb's Avatar
 
Drives: 2009 X5 35d
Join Date: Jan 2011
Location: Cupertino, CA


Posts: 329
iTrader: (4)

Thanks Beta. I'll give them a call.
Appreciate 0
      12-09-2012, 01:21 AM   #20
Dammmittt
My favorite sign.
South Korea
65

 
Dammmittt's Avatar
 
Drives: 2007 M Coupe
Join Date: Dec 2006
Location: Der Autobahnen


Posts: 4,332
iTrader: (0)

Thanks, I couldn't remember that far back
__________________


07 ///M Coupe (Premium Package) Black Saphire Ext. Imola Red Int.

Best Website EVER!
Appreciate 0
      12-09-2012, 09:08 AM   #21
Krypptic
First Lieutenant
3

 
Drives: Z4 M Coupe, 981 S
Join Date: Jan 2011
Location: SFL


Posts: 309
iTrader: (2)

Quote:
Originally Posted by beta View Post
inTgr8r: as finnegan said: price and history. My diff only has 25k miles, I know its full history. About the price, buying new R&P from bmw motorsport, shot peen + rem + installation is going to be in the neighborhood of 1k. Way cheaper than diff swapping.
A few questions:

What do you mean buying the R&P from bmw Motorsport? Dealership?

How much did they charge for the R&P?

How much for installation?

I only ask because every where I looked just the R&P where a 1k, and you are saying soup to nuts for 1k. Not doubting, but if that's true I am definitely making this my next project.
Appreciate 0
      12-09-2012, 09:46 AM   #22
inTgr8r
Major General
Canada
112

 
inTgr8r's Avatar
 
Drives: 07 M Coupe
Join Date: Mar 2006
Location: Toronto


Posts: 8,069
iTrader: (7)

^ I'm having a little trouble following the math as well.....

I can get an R&P for about $600 (probably Timken)
REM $195
Bearing,shim, crush etc... $200

Rebuild labour..... $6-800

That doesnt include Shot pean

I don't see how you get even close to $1k.
__________________
Alpinweiss '07 M Coupe •DKF Section1•RPi GT exhaust•Fabspeed Headers•Autosolutions SSK•APR splitter•Tekarbon headlights•StrongStrut STB•H&R COs + ARBs•Poly FCAB/RTAB•Volk Racing G2•Direzza ZII•Stoptech BBK•Vibra-Tech mtr mounts•
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 04:30 PM.




zpost
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST