Welcome to the North American Subaru Impreza Owners Club Saturday December 27, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Transmission (AT/MT) & Driveline

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 12-15-2004, 01:31 PM   #1
BadTrip
Scooby Specialist
 
Member#: 62211
Join Date: May 2004
Chapter/Region: South East
Location: Burlington, NC
Vehicle:
03 WRX
Sonic Yellow

Default Taller 5th gear for 5MT?

Anyone knw of any taller 5th gears available for the 5MT?
I do a lot of highway cruising/communting and would like to drop revs a few hundred rpm when cruising at 75-80mph.

Thanks in advance for any options you guys may know of.
* Registered users of the site do not see these ads.
BadTrip is offline   Reply With Quote
Old 12-15-2004, 03:02 PM   #2
pimpUall
Scooby Newbie
 
Member#: 55424
Join Date: Feb 2004
Location: Racer X Engineering
Vehicle:
2005 380hp LGT Wagon
Blue

Default

At that speed you are only turning @ 3000 rpms. That's not very high for such a small motor(2liter). It had hondas and even a '91 300 ZX and they all turned over 4000 rpms just to do 80mph. Smaller motor need more rpms to make power. If you run too low the motor can lug and shake and that is very hard on the bearings. My '64 Grand Prix w/ 389 with tri-power(3 X 2bbl carbs) turn about 2400 rpms after the tranny locks-up doing about 75 mph. But it makes over 430 lbs-ft of torque at 2800 rpms. Our car makes less power down low.
pimpUall is offline   Reply With Quote
Old 12-15-2004, 03:13 PM   #3
fireball_jones
Scooby Specialist
 
Member#: 67536
Join Date: Aug 2004
Chapter/Region: NESIC
Location: Side of the road, Somerville
Vehicle:
00 AW GM6
And a bunch of parts

Default

You mean shorter? I get stuck behind people on the highway, have to drop to 60, and downshift to pass. 3k is a good place to be for gas conservation and reasonable power on tap.

A 6 speed would really solve more problems.
fireball_jones is offline   Reply With Quote
Old 12-15-2004, 04:02 PM   #4
BadTrip
Scooby Specialist
 
Member#: 62211
Join Date: May 2004
Chapter/Region: South East
Location: Burlington, NC
Vehicle:
03 WRX
Sonic Yellow

Default

pimp - Ok...so I was fudging the numbers. I usually am running 80+. I understand how a small engine needs more rpms to run efficently, etc, and I think I'd get better mileage with a bit taller 5th gear.

fireball - No, I didn't mean a shorter gear. I've got plenty of power for highway passing. I'm interested in dropping the rpms, not increaseing them. And a 6MT has shorter gears, in that you are correct, but that would hurt mpg, not help it.

So...back to the question....anyone know of any options for a taller 5th gear other than having one fabricated?

Thanks,
BadTrip
BadTrip is offline   Reply With Quote
Old 12-15-2004, 04:29 PM   #5
Kha0S
Scooby Guru
 
Member#: 8808
Join Date: Jul 2001
Chapter/Region: NESIC
Location: Grantham, NH
Vehicle:
2011 WRX (DGM 5D)
2002 WRX/2003 SVTF

Default

I've never seen a higher 5th gear option for any Impreza or Legacy than the WRX 5MT.

The WRX 5MT 5th gear is an overdrive, at 0.738:1. All other 5MT Subarus that I have seen use a shorter gear (0.780:1, 0.860:1, etc.) which would only exacerbate your problem.

You could, theoretically, change your final drive ratio, but that would require some pretty serious modification all around (particularly because of the strange 1.1:1 center diff ratio on the WRX gearbox, resulting in a 3.90 front differential ratio versus a 3.545:1 rear differential ratio).

I think you're stuck in the boat of getting something fabricated, and you'd need both gears (drive and driven) gears made to match.

/Andrew
Kha0S is offline   Reply With Quote
Old 12-15-2004, 04:42 PM   #6
BadTrip
Scooby Specialist
 
Member#: 62211
Join Date: May 2004
Chapter/Region: South East
Location: Burlington, NC
Vehicle:
03 WRX
Sonic Yellow

Default

Thanks very much for the info Andrew!

Any idea on ballpark costs for fabrication of gears like that? Or specific places you'd direct my inquiry?
Anyone make a Talladega gear?
Thanks again,
Trip
BadTrip is offline   Reply With Quote
Old 12-15-2004, 04:56 PM   #7
Kha0S
Scooby Guru
 
Member#: 8808
Join Date: Jul 2001
Chapter/Region: NESIC
Location: Grantham, NH
Vehicle:
2011 WRX (DGM 5D)
2002 WRX/2003 SVTF

Default

I don't know of any shops that I'd specifically reccomend for gear fabrication, but it's usually a pretty expensive proposition, especially given that the gears would need to be helically cut (as a straight-cut spur gear for 5th would be a commuting nightmare in terms of auditory overload ).

Parts back there are mostly interchangeable between Legacy, Impreza, and Forester 5MT transmissions dating back quite a few years, though, in order to go to a non-turbo 5th gear component in a turbo gearbox, you might need to swap some bearings and thrust washers to get all the alignment worked out ... certainly not a job for the faint of heart.

Still, I don't think any factory Subaru gear set will give you a ratio any taller than the stock WRX one, as the WRX, 2005 Legacy GT, and older STi with 5MT (which all share the same 5th gear ratio of 0.738:1) have the most powerful motors to date attached to a 5MT, I would suspect that there's nothing out there that would have a lower ratio.

Even so, if you find a place to fabricate a gear, you're looking at at least a few thousand dollars in specification, cutting, final machining, treatment, then more time to install, or money, if you plan on having someone else do it.

/Andrew
Kha0S is offline   Reply With Quote
Old 12-15-2004, 05:17 PM   #8
pimpUall
Scooby Newbie
 
Member#: 55424
Join Date: Feb 2004
Location: Racer X Engineering
Vehicle:
2005 380hp LGT Wagon
Blue

Default

the only other way is to bring down the rpms is to make the overall diameter larger.
pimpUall is offline   Reply With Quote
Old 12-15-2004, 05:47 PM   #9
Kha0S
Scooby Guru
 
Member#: 8808
Join Date: Jul 2001
Chapter/Region: NESIC
Location: Grantham, NH
Vehicle:
2011 WRX (DGM 5D)
2002 WRX/2003 SVTF

Default

That's a possibility too... run oversized tires ...

It'll throw off your speedometer, too.

/Andrew
Kha0S is offline   Reply With Quote
Old 12-15-2004, 08:54 PM   #10
ebeck
Scooby Specialist
 
Member#: 35585
Join Date: Apr 2003
Location: Scottsdale AZ.
Vehicle:
RIP I'll always be
The Ver8 Magistrate

Default

Perhaps the WRX and a used Ford Fiesta or something. Costs less than making new gears for the front. Adn gets better mpg. By far.

The rear is a 3.54. If you swapped out the transfer gear for 1.0.1 like the RS has, all you need to do is put in a 3.54 R&P. Question is, is there a 3.54 R&P that fits the front diff. IF so bingo.

Still a cheap Geo Metro as a second commute car will get 40mpg. Expect 2-3 mpg more at best with the 3.54. Oh, your 1-3 will truly suck. 4th is useless and so is 5th. You would have a good highway car with marginal mpg.

Taller gear in the tranny is the ticket. With out that you would destroy the use of the car. Hope you find what you are looking for.
ebeck is offline   Reply With Quote
Old 12-16-2004, 10:54 AM   #11
BadTrip
Scooby Specialist
 
Member#: 62211
Join Date: May 2004
Chapter/Region: South East
Location: Burlington, NC
Vehicle:
03 WRX
Sonic Yellow

Default

Thanks guys for all the info.

Looks like my best option by far is.....just slow down for better mpg.

I do have a beater 94 Nissan Sentra that gets about 32mpg......but somehow....it's just not quite as much fun to drive.

Thanks Andrew for the informative post.
BadTrip is offline   Reply With Quote
Old 12-16-2004, 12:21 PM   #12
Kha0S
Scooby Guru
 
Member#: 8808
Join Date: Jul 2001
Chapter/Region: NESIC
Location: Grantham, NH
Vehicle:
2011 WRX (DGM 5D)
2002 WRX/2003 SVTF

Default

No problem. Glad to help as much as I could.

/Andrew
Kha0S is offline   Reply With Quote
Old 12-16-2004, 12:58 PM   #13
tooocool49723
Scooby Specialist
 
Member#: 67127
Join Date: Jul 2004
Chapter/Region: MWSOC
Location: Belleville, MI
Vehicle:
3.3 I <3/h8 my GF3
1.8-2.5-2.2-2.5-2.2-3.3

Default

quit complaining, I run at ~3800rpm at 80.

But i'm n/a, so I probably still get better MPG.
tooocool49723 is offline   Reply With Quote
Old 12-16-2004, 03:25 PM   #14
BadTrip
Scooby Specialist
 
Member#: 62211
Join Date: May 2004
Chapter/Region: South East
Location: Burlington, NC
Vehicle:
03 WRX
Sonic Yellow

Default

Quote:
Originally Posted by tooocool49723
quit complaining, I run at ~3800rpm at 80.

But i'm n/a, so I probably still get better MPG.
Was I complaining?
BadTrip is offline   Reply With Quote
Old 06-05-2008, 03:53 PM   #15
AbACUZ
Scooby Specialist
 
Member#: 101898
Join Date: Dec 2005
Chapter/Region: SCIC
Location: So Cal, Long.Beach, Whittier
Vehicle:
1905 NINETWO EX AIRO
Prodriv.Hotchkis.Stromng.

Default

Back in 2004 this was not possible, but now I think it is. I'm trying to find out how.

BUMP !!!
AbACUZ is offline   Reply With Quote
Old 06-05-2008, 04:24 PM   #16
Arctic Penguin
Scooby Specialist
 
Member#: 119532
Join Date: Jul 2006
Vehicle:
2006 WRX

Default

Quote:
Originally Posted by AbACUZ View Post
Back in 2004 this was not possible, but now I think it is. I'm trying to find out how.

BUMP !!!
taller tires
Arctic Penguin is offline   Reply With Quote
Old 06-05-2008, 04:40 PM   #17
AbACUZ
Scooby Specialist
 
Member#: 101898
Join Date: Dec 2005
Chapter/Region: SCIC
Location: So Cal, Long.Beach, Whittier
Vehicle:
1905 NINETWO EX AIRO
Prodriv.Hotchkis.Stromng.

Default

and 30" rims with spinners too

SUBADONK WRX & SAAB 92DONK

har , har , har
AbACUZ is offline   Reply With Quote
Old 06-05-2008, 04:52 PM   #18
sluflyer06
Scooby Specialist
 
Member#: 111641
Join Date: Apr 2006
Chapter/Region: MWSOC
Location: St. Louis, MO
Vehicle:
2014 BRZ Ltd - DGM
E30 318is

Default

You won't save any gas with a longer 5th. If you want to try ANYTHING get larger tires.

I averaged 22.4mpg exactly on cruise control 80mph on the 5 speed

Now 90lbs. heavier and a shorter top gear with a 06' 6speed swap.

Guess what my mileage is at 80mph and cruise control?




22.4. And I'm cruising around 3,300rpm.

On my Jetta I used to have 80mph was 4,000rpm and I got 35mpg.
sluflyer06 is offline   Reply With Quote
Old 06-05-2008, 05:59 PM   #19
AbACUZ
Scooby Specialist
 
Member#: 101898
Join Date: Dec 2005
Chapter/Region: SCIC
Location: So Cal, Long.Beach, Whittier
Vehicle:
1905 NINETWO EX AIRO
Prodriv.Hotchkis.Stromng.

Talking

Quote:
Originally Posted by sluflyer06 View Post
You won't save any gas with a longer 5th.

......

22.4. And I'm cruising around 3,300rpm.

On my Jetta I used to have 80mph was 4,000rpm and I got 35mpg.
22.4 That is horrible, Hahaha , I get Over 30mpg hwy 25mpg+ city on my 235whp wagon , and yes , a taller 5th would save gas in long trips,

and your point that a different engine, on a different car, with different transmitions , with different tires, and different compresion, and different fuel injectors gets different mpg at differnt speed, WOW, no .. really ! thats shocking ! you sir get 2 awards in one post.
AbACUZ is offline   Reply With Quote
Old 06-05-2008, 06:10 PM   #20
sluflyer06
Scooby Specialist
 
Member#: 111641
Join Date: Apr 2006
Chapter/Region: MWSOC
Location: St. Louis, MO
Vehicle:
2014 BRZ Ltd - DGM
E30 318is

Default

Quote:
Originally Posted by AbACUZ View Post
22.4 That is horrible, Hahaha , I get Over 30mpg hwy 25mpg+ city on my 235whp wagon , and yes , a taller 5th would save gas in long trips,

and your point that a different engine, on a different car, with different transmitions , with different tires, and different compresion, and different fuel injectors gets different mpg at differnt speed, WOW, no .. really ! thats shocking ! you sir get 2 awards in one post.
I think your the award winner.

1 car. 1 engine. 1 set of tires.

Only change relevant in my example is I now have a shorter overdrive gear and the mileage has not changed at all, in fact I have 2 variables working against me that SHOULD theoretically lower mileage...A. Weight B. gearing. yet magically it didn't drop.

Your saying a longer overdrive gear will increase mileage...that is NOT a car specific claim to make...so it makes no difference my car is different than the OPs.

22.4mpg is 80mph cruise control always in vacuum from a fresh tank no stopping until empty. City average is around 16mpg with 95% in vacuum.

Gotta pay to play...you don't get 355whp and 30mpg. But thanks for thinking my mileage sucks. I won't hold my breath while you find cars with 420+ CHP that get 25mpg in the city...maybe you should have some fun with your car cause you sure aren't enjoying the fruits of boost averaging 25mpg.
sluflyer06 is offline   Reply With Quote
Old 06-05-2008, 06:19 PM   #21
prometheum
Scooby Specialist
 
Member#: 92003
Join Date: Jul 2005
Chapter/Region: International
Location: Tatooine
Vehicle:
04 bicycle!

Default

not speeding will save you quite a bit of fuel too
prometheum is offline   Reply With Quote
Old 06-05-2008, 06:29 PM   #22
efmd3
Scooby Specialist
 
Member#: 120985
Join Date: Jul 2006
Chapter/Region: South East
Location: Birmingham, AL
Vehicle:
2002 Impreza WRX
Midnight Black Pearl

Default

stick it behind someone going close to the same speed as you. helps me squeeze a few more MPG out of my car.
efmd3 is offline   Reply With Quote
Old 06-05-2008, 06:44 PM   #23
ciper
Scooby Guru
 
Member#: 15543
Join Date: Feb 2002
Location: san francisco, ca
Vehicle:
90BJ Legacy LS ABS
AWD 946 Rio Red Jpn built

Default

Why not get larger diameter tires? It's essentially the same as changing your final drive.
ciper is offline   Reply With Quote
Old 06-05-2008, 07:21 PM   #24
AbACUZ
Scooby Specialist
 
Member#: 101898
Join Date: Dec 2005
Chapter/Region: SCIC
Location: So Cal, Long.Beach, Whittier
Vehicle:
1905 NINETWO EX AIRO
Prodriv.Hotchkis.Stromng.

Default

Quote:
Originally Posted by sluflyer06 View Post
Gotta pay to play...you don't get 355whp and 30mpg. But thanks for thinking my mileage sucks. I won't hold my breath while you find cars with 420+ CHP that get 25mpg in the city...maybe you should have some fun with your car cause you sure aren't enjoying the fruits of boost averaging 25mpg.
Congratulations on 355 WHP , that is a great figure and your car does sound like a monster .


so You got an ok 22 mpg before, and You got an ok 22 mpg after, your mods.
These are not close to being efficient consumption numbers, or significant numbers to cause variables since what affects effiency is a big number of factors. Your assuptions are not correct, dont get mad, just pointing it out , read below.

1)
MAX HP is not equally related to MAX mpg efficiency at X load at Y speed.


2)
Some one who is trying to get more efficeint at cruising at freeway speeds must mean that they never enjoy the car, you see this shows a narrow view of who I am and what I do, you judgment of people is too strong, you must think very highly of yourself, please get of your high horse.

I got 8.5 mpg last time at buttonwillow race track, 125 miles to empty the tank. oh yes that was fun
AbACUZ is offline   Reply With Quote
Old 06-05-2008, 11:58 PM   #25
FuJi K
Scooby Guru
 
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

hA! so funny.
I seem to get better gas mileage with the rpms running at about 2800-3100 running about 70mph because the engine doesn't work as hard, and not high in the revs.

pimpUall pretty much hit the point.

If you really want it to be longer this is what you need.
RUN A '06+ WRX TRANNY!!!!!! You need the clutch disc, pressureplate, , throughout bearing, slave cylinder, and rear diff. 3.700FD for you. If this doesn't satisfy you, get the Legacy Spec B 6spd. .707 6th gear and a 3.900FD.
FuJi K is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
aftermarket taller 5th gear? jam69007 Transmission (AT/MT) & Driveline 5 05-14-2010 09:16 AM
Taller 5th gear for 04 FXT 5M? Seayak Transmission (AT/MT) & Driveline 13 05-03-2006 01:16 AM
Higher 5th gear for FXT? Seayak Forester Forum 8 04-22-2006 01:11 AM
USA STi gets taller 5th and 6th gear Jude DeMeis STi Forum Archive 18 03-16-2003 06:42 PM
5MT different for original Outback? (Shorter 5th gear?) Patrick Olsen Normally Aspirated Powertrain 8 05-09-2001 08:20 AM


All times are GMT -4. The time now is 10:32 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.