Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

2 Pages V  1 2 >  
 Reply to this topicStart new topic
> Transmission Gearing..., I'm completely confused...
Carlitos Way
post Jan 7 2008, 11:01 AM
Post #1


I did it MY WAY
***

Group: Members
Posts: 1,337
Joined: 14-September 04
From: Simi Valley, CA
Member No.: 2,757
Region Association: Southern California
Well, the more I drive my teener... the more I realize... the gearing is less than "ideal" for my driving preference/style.

I've found, especially when driving around the twisties, I'm always right in the middle of second and third. As far as I know, I just have a STOCK 914 tranny.

Is there any alternatives for this? I'm sure I could use a tranny rebuild soon, as my first gear synchro is going anyway.

Trying to decide which way to go now...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Trevorg7
post Jan 7 2008, 11:05 AM
Post #2


Senior Member
***

Group: Members
Posts: 1,242
Joined: 7-December 04
From: Highland Village, TX
Member No.: 3,241
Region Association: Southwest Region
You should have made the drive to the Dr. Evil Clinic (IMG:style_emoticons/default/poke.gif)

There were a couple of guys who re-geared.


T
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Carlitos Way
post Jan 7 2008, 11:06 AM
Post #3


I did it MY WAY
***

Group: Members
Posts: 1,337
Joined: 14-September 04
From: Simi Valley, CA
Member No.: 2,757
Region Association: Southern California
Thanks, but that wasn't in the schedule for me. I'm in SOCAL.

C:>
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Trevorg7
post Jan 7 2008, 11:20 AM
Post #4


Senior Member
***

Group: Members
Posts: 1,242
Joined: 7-December 04
From: Highland Village, TX
Member No.: 3,241
Region Association: Southwest Region
QUOTE(Carlitos Way @ Jan 7 2008, 09:06 AM) *

Thanks, but that wasn't in the schedule for me. I'm in SOCAL.

C:>


Yep, I know just a (IMG:style_emoticons/default/poke.gif)

That said Rubber Boa did drive down from Oregon for the event. I am sure Dr. Evil will chime in here soon...

T
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Borderline
post Jan 7 2008, 11:22 AM
Post #5


Senior Member
***

Group: Members
Posts: 720
Joined: 8-February 05
From: San Juan Bautista, CA
Member No.: 3,577
Region Association: Northern California
Chris was at the clinic and was talking about doing some gear changing. Something about flipping 3rd and 5th and swapping them. That would give you a lower 3rd and lower 5th. Not sure what he was doing for 4th. maybe he'll chime in when he gets back from the snow.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Joe Ricard
post Jan 7 2008, 11:23 AM
Post #6


CUMONIWANNARACEU
*****

Group: Members
Posts: 6,811
Joined: 5-January 03
From: Gautier, MS
Member No.: 92
Either make more power or or flip a ZD 5th into 3rd spot.
I did both and it rocks.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Jan 7 2008, 12:23 PM
Post #7


Send me your transmission!
***************

Group: Members
Posts: 22,999
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
Here is a gear chart for ya to consider. Let me know if I can help you with your tranny or rebuild it for ya.


Attached thumbnail(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Jan 7 2008, 12:31 PM
Post #8


Send me your transmission!
***************

Group: Members
Posts: 22,999
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
Here are 2 graphs: Stock vs flipped ZD in 3rd. Flipping a ZD and adding it is cheap and easy and it puts your lower 3 gears closer together as demonstrated in the graph.


Attached thumbnail(s)
Attached Image Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Carlitos Way
post Jan 7 2008, 01:11 PM
Post #9


I did it MY WAY
***

Group: Members
Posts: 1,337
Joined: 14-September 04
From: Simi Valley, CA
Member No.: 2,757
Region Association: Southern California
Thanks for the reply. Some good stuff in there. How's your 6 surgery coming along?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Jan 7 2008, 01:16 PM
Post #10


Send me your transmission!
***************

Group: Members
Posts: 22,999
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
The 6 is still awaiting parts. I told Clayton (Twystd1) to enjoy his holiday season instead of locating me a part. He will likely look for the part this week and get beck to me. I have all the new seals and stuff and it is ready to go.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
race914
post Jan 7 2008, 01:30 PM
Post #11


73 914-4
***

Group: Members
Posts: 1,006
Joined: 31-October 05
From: Nipomo, California (Central Coast)
Member No.: 5,027
Region Association: Central California
Good info above!

To help me assimilate and analyze all of the data I put this excel sheet together to help me "see" the shiftpoints and RPM/MPH range for each gear as compared to stock.

This model lets you build a 'virtual' gearbox with your tire diameter and your shift points to see if it meets what you are expecting (e.g. getting that 'right' gear in between your stock 2nd & 3rd)

Attached File  914_901_gearcalc_080107.xls ( 104.5k ) Number of downloads: 241


Also, here's a short write-up on one way to approach a re-gearing project. Definitely not the only way.. and probably not the best way, but it's the way I did it.

Attached File  Regearing.doc ( 72k ) Number of downloads: 132


I used this excel sheet and approach to build two 901 boxes, a Ka-Q-V and a M-S-X and got exactly what I expected from the model runs. No suprises! No 'do overs'!

Hope this info helps
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Brando
post Jan 7 2008, 03:25 PM
Post #12


BUY MY SPARE KIDNEY!!!
****

Group: Members
Posts: 3,935
Joined: 29-August 04
From: Santa Ana, CA
Member No.: 2,648
Region Association: Southern California
easiest way to change your gearing is with tire sizes. In most instances, it is also the cheapest. Tearing into a 901 and regearing is nearly as costly as regearing a 915 box. Not to mention the cost of gears for 901 boxes... Porsche sells original gearstacks AFAIK with the stock drive ratio. As for the other gears, no clue.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Jan 7 2008, 03:31 PM
Post #13


Send me your transmission!
***************

Group: Members
Posts: 22,999
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
Not necessarily, I sell ZD sets for $50 and can install them for far less than a new set of wheels ($150 if you send me the stack). If there is other work to be done in the box then the cost may increase, but it has nothing to do with the gear swap at that point. Carquest sells gears as well, but at a significant premium (especially compared to me).
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
PeeGreen 914
post Jan 7 2008, 05:10 PM
Post #14


Just when you think you're done...wait, there is more..lol
**********

Group: Members
Posts: 10,219
Joined: 21-September 06
From: Seattle, WA... actually Everett
Member No.: 6,884
Region Association: Pacific Northwest
I am thinking of doing a A F ZD S ZD in my box for AX. I want the other ZD for fifth because I drive to the event and don't want to burn out m transmission. How does this sound to you AX gearbox gurus? What would you do? I have all stock gears plus a S and M and X. If it sounds good or you disagree please tell me as I would love to know your thoughts before I do it. Oh, and I have five boxes to work with so I do have multiples of every gear.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Jan 7 2008, 05:23 PM
Post #15


Send me your transmission!
***************

Group: Members
Posts: 22,999
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
Please let us all know how it goes (IMG:style_emoticons/default/biggrin.gif) I am always interested in hearing how different gearings work out.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
PeeGreen 914
post Jan 7 2008, 06:59 PM
Post #16


Just when you think you're done...wait, there is more..lol
**********

Group: Members
Posts: 10,219
Joined: 21-September 06
From: Seattle, WA... actually Everett
Member No.: 6,884
Region Association: Pacific Northwest
Will do, but if anyone has any other gearing advise or something that may work better please let me know. Oh, and remember that there is a torque biased diff with this as well.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
So.Cal.914
post Jan 7 2008, 07:11 PM
Post #17


"...And it has a front trunk too."
*****

Group: Members
Posts: 6,588
Joined: 15-February 04
From: Low Desert, CA./ Hills of N.J.
Member No.: 1,658
Region Association: None
QUOTE

I've found, especially when driving around the twisties, I'm always right in the middle of second and third.


The simplest answer has been overlooked...Go Faster.

(IMG:style_emoticons/default/biggrin.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
PeeGreen 914
post Jan 8 2008, 11:41 AM
Post #18


Just when you think you're done...wait, there is more..lol
**********

Group: Members
Posts: 10,219
Joined: 21-September 06
From: Seattle, WA... actually Everett
Member No.: 6,884
Region Association: Pacific Northwest
Wow, Greg, race914, just sent me a sheet on what it would look like if I were to do the gearing I would like. Looks good to me (IMG:style_emoticons/default/biggrin.gif) Thanks a lot Greg. (IMG:style_emoticons/default/aktion035.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
race914
post Jan 8 2008, 01:40 PM
Post #19


73 914-4
***

Group: Members
Posts: 1,006
Joined: 31-October 05
From: Nipomo, California (Central Coast)
Member No.: 5,027
Region Association: Central California
Glad to help!

Here are the charts generated by the gear ratio sheet available for download a few posts up

Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
J P Stein
post Jan 8 2008, 05:54 PM
Post #20


Irrelevant old fart
*****

Group: Members
Posts: 8,797
Joined: 30-December 02
From: Vancouver, WA
Member No.: 45
Region Association: None
QUOTE(Blood red 914-6gt @ Jan 7 2008, 04:59 PM) *

Will do, but if anyone has any other gearing advise or something that may work better please let me know. Oh, and remember that there is a torque biased diff with this as well.


We AX gurus (IMG:style_emoticons/default/rolleyes.gif) look at things a bit different.

Look at your most frequently run AX venue. What is the top course speed on average?
Does it (like many SCCA courses) have a slower starting section?
What do I need to cover this land with the least amount of shifting?
Can I shift my 901 down into 1st at any speed (no exceeding redline,eh)?
How many rpms can I turn with with my motor?

Now look at a gear chart........
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

2 Pages V  1 2 >
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 17th May 2024 - 08:04 PM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...