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 )

> Regearing for a longer 5th gear, is it a reasonable thing to do?
SGB
post Nov 28 2006, 08:14 PM
Post #1


just visiting
****

Group: Members
Posts: 4,086
Joined: 8-March 03
From: Huntsville, AL
Member No.: 404
Region Association: South East States
(IMG:style_emoticons/default/piratenanner.gif)
I'm getting a tranny for christmas! (IMG:style_emoticons/default/chair.gif)

(IMG:style_emoticons/default/chairfall.gif)
no really, DR EVIL is rebuilding the ol' 901 for me, and I've been thinking
(IMG:style_emoticons/default/bootyshake.gif)
with my brain that a longer 5th gear would be really nice.
(IMG:style_emoticons/default/driving.gif)

With a speed limit of 70 (usually traveled by EVERYONE at 80), my car gets pretty buzzy after a while.

I know it can be done, and if I ever was going to do it....
A flipped 904 "I" 5th gear might work.... of course I've already been advised that cubic dollars are needed AND another mainshaft.
I'm just dreamin'... Somebody slap me with a reality stick. What else would be involved in this? Who has details? Or better, who has a 904 5th gear lying around needing a home?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
 Reply to this topicStart new topic
Replies
Dr Evil
post Nov 28 2006, 08:27 PM
Post #2


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

Group: Members
Posts: 23,002
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
ZD is what is in there now. I do not see how smaller tires will cause lower RPMs, Aaron (IMG:style_emoticons/default/huh.gif) If you put larger profile tires on your car you will lower your RPMs, not the other way around. Like a said before, you should be at 4000rpm at 89MPH in stock form. the 50 series tires should only bump the RPMs up a bit. Our engines are not like the water cooled type. Air flow is life, thus higher RPM under load at fast speeds = better cooling and less fatigue on your engine. This is why long hills on hot days are particularly bad for our cars (more so than many other scenarios). Lots of demand, hard to keep up RPMs AND speed. If you want to know what it will be like to drive with a taller fifth gear just go for a long drive up a steep hill (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/wink.gif)

<:edited because Aaron posted the damn chart first (IMG:style_emoticons/default/rolleyes.gif) :>
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Aaron Cox
post Nov 28 2006, 08:29 PM
Post #3


Professional Lawn Dart
***************

Group: Retired Admin
Posts: 24,541
Joined: 1-February 03
From: OC
Member No.: 219
Region Association: Southern California
QUOTE(Dr Evil @ Nov 28 2006, 06:27 PM) *

ZD is what is in there now. I do not see how smaller tires will cause lower RPMs, Aaron (IMG:style_emoticons/default/huh.gif) If you put larger profile tires on your car you will lower your RPMs, not the other way around. Like a said before, you should be at 4000rpm at 89MPH in stock form. the 50 series tires should only bump the RPMs up a bit. Our engines are not like the water cooled type. Air flow is life, thus higher RPM under load at fast speeds = better cooling and less fatigue on your engine. This is why long hills on hot days are particularly bad for our cars (more so than many other scenarios). Lots of demand, hard to keep up RPMs AND speed. If you want to know what it will be like to drive with a taller fifth gear just go for a long drive up a steep hill (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/wink.gif)

Here is Aarons chart for those of you watching at home and wandering where we pull these numbers from (IMG:style_emoticons/default/biggrin.gif)


taller gear = less rpm.
less rpm = less cooling.
shorter tire = MORE rpm

i dont think i said that mike....
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
SGB   Regearing for a longer 5th gear   Nov 28 2006, 08:14 PM
Aaron Cox   with at type 4 bad idea... what size tires? ZD w...   Nov 28 2006, 08:15 PM
Aaron Cox   BTW - you flip a second gear from a 4 speed 901/90...   Nov 28 2006, 08:16 PM
SGB   They are 50 series tires. Is ZD what is in there ...   Nov 28 2006, 08:17 PM
Aaron Cox   ya made me do it! here is the chart i config...   Nov 28 2006, 08:19 PM
SGB   I've alway had fine cooling, and could compens...   Nov 28 2006, 08:19 PM
SGB   AAAARGGHH!!!   Nov 28 2006, 08:20 PM
SGB   but its kinda COOL.   Nov 28 2006, 08:21 PM
Aaron Cox   your head temps will go up with less RPM turning t...   Nov 28 2006, 08:22 PM
Dr Evil   ZD is what is in there now. I do not see how small...   Nov 28 2006, 08:27 PM
Aaron Cox  
 

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

 

- Lo-Fi Version Time is now: 9th June 2024 - 05:04 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 ...