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Old 01-31-2009, 09:18 PM   #1
FuJi K
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Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default Learning to Choose your Gearsets/Ratios

Information is subject to change as more information comes.

I have a ’05 WRX and I have NOW upgraded my turbo to a decent TD06H-20G-8cm^2, FMIC, EWG with ported heads, 272* cams, 9.0:1CR pistons, Cosworth rods/bearings and running 110oct. What I’m afraid of is breaking my transmission now. The car was tuned to 22psi up top and we push 364whp and 331wtq. I don’t know what gears I want to hold the power. Some were saying go PPG’s and others were saying ’07 STi 6spd.

WELL…. The MOST important question is, what are you going to be doing with your car? Gearing is determined by the car’s use. A person who drag races a car has much different gearing compared to a person who does circuit/lapping days. The stock gearing on the car is much different from BOTH of the guys who does the 1320 and track races.

A drag racer much rather prefer rolling through 1-2-3-4 on a typical 5spd tranny with an average 280-450whp. Gear ratios are much longer and further spread out. Less shifting means more time for acceleration. First gear for get up and go, second gear for gaining ground when there’s not enough wind drag yet, third gear to pull through with the power made, and forth gear to show “wassup” about TOP END.

A track racer much rather prefers rolling through 2-3-4-5 on a typical 5spd tranny with an average 280-450whp. Gear ratios are much shorter and closer to each other. Staying in the power band even after a shift means power on the tap 99% of the time so you can zoom out of a corner faster. Second gear is usually for slower turns, third gear to get you to the next corner, forth gear for that high speed turn, and fifth gear to pull through the back 1000ft straight. An autoX guy will like a nice short 2nd gear and 3rd gear, more like the STi 6spd 2nd gear and 3rd gear.

Now the Daily driver much prefers being able to go through all gears on a 5spd with an average 280-450whp. Gear ratios are much wider in the first 3 gears and shorter as they go up or get shorter as they go up to 4th and 5th gear would be a little longer. Less shifting in the lower speeds means more concentration on the ROAD, closer ratios from 3-4 means staying in the power band and NOT using a lot of gas, and a nice low ratio 5th gear for that NICE hiway cruising engine speed.

Now you should have an idea what you want now. Remember that these are the KEY POINTS in choosing the gear ratios that meets your needs. Don’t expect the Daily driver gearset to keep you IN THE POWERBAND all the time and don’t expect it to give you MAXIMUM acceleration getting up and going from a stand still on the side of the hiway.

This is where it gets technical. There are final drive numbers on each tranny can vary on year. Also are your engines’ powerband and window of RPM operation. The gear ratios will determine how much gap in engine revs there are between shifts and some speed. The final drive ratio will change the overall SPEED of each gear and how much overall speed once in top gear. Sometimes a tranny will have a short 4.444 final drive ratio, but its speed carried through the gears given the engine’s rev limit is really close to the same as one with a 3.900 final drive. The ’95 WRX STi Ver.II 4.111 tranny(3.454 2.062 1.448 1.088 0.825) and ’99 WRX STi Ver.VI 4.444 tranny(3.166 1.882 1.296 0.972 0.738) would be a good comparison; STi VerII 60mph@2880rpms and STi VerVI 60mph@2785rpms both in 5th gear.

Typical Subaru’s with an average 280-450whp will rev up to 6500-7500rpms. Most gear ratios out there will work fine with the factory final drive ratio given the engine’s rev limits. One would put STi RA 5spd ratios(3.083 2.062 1.545 1.151 0.825) in a ’06 WRX tranny(3.700FD). It’ll give you decent acceleration and still a forgiving 5th gear hiway gear running 60mph@2590rpm and 80mph@3455rpms. Putting the same STi RA 5spd ratios in a ’05 WRX(3.900FD) would mean a bit quicker running through the gears, however a slightly higher engine speed; 2730@60mph and 3640@80mph both in 5th gear.

Those who are running the PPG gears have all out acceleration performance through the straight with an average 280-450whp with up to 7500rpms rev limit. Let us look at these ratios; 3.08 / 1.87 / 1.32 / 0.95 / .738(OEM) with a stock final drive of 3.900 on ’02-’05 USDM WRXs. Running through first gear you’ll get to approx 41.3mph, second gear starting at about 4200rpms carrying speed to 68.1mph, then third gear starting at 4900rpms and carrying speed to 96.4, forth gear starting at 5000rpms and carrying speed to 134mph, then fifth gear starting at 5400rpms and carrying it up to 170mph if given enough straight shifting at about 7000rpms. You can carry enough speed through the quarter mile in 4th gear giving you plenty of time to accelerate shifting only 3 times for the drag racers.

Now when you put in aftermarket gears, you have a variety of ratios available. Knowing what YOU are going to do with the car will allow you to make the right choice in selecting the right ratios for you. You can also consult with a shop that specializes in rebuilding transmissions and they can help you narrow your gear sets down to the one that suits your application.

Now what about the 6spd? Oh when you go with the 6spd you are jumping into a whole different ball game. You have LSDs, DCCD, rear biased, and short gearing. The 6spd was made for track driving and was NEVER intended for 1/4mi use, however it will put a decent time. They come with and without DCCD depending if you get JDM stuff or USDM stuff. In Japan they have non-DCCD 6spds for the purpose of owners’ preference. DCCD 6spds will always be rear-biased except very few models and the newer models; 35:65, 41:59, & 45:55. The strength is also very incredible. You will be able to run the tranny hard and don’t have to worry about breaking gears with the average 280-450whp.

Gearing is changed a little bit for certain countries. For example the JDM 6spd is much shorter than what’s offered here when looking at ’07 models. For the ’04 STi that first came here in the USA, we had the same gearing 1-4 as the JDM 6spd, but with LONGER 5th and 6th gears. This was changed out for the ’07 models using longer gears that are the same as the Legacy Spec B 2-4th gears while retaining the same 1st, 5th, and 6th gear ratios. The USDM Legacy Spec B 6spd ratios are like the USDM ’07 STI, but with much longer 5th and 6th gear evening the spacing out.

For the guys who run and average of 280whp-450whp, the 6spd will get things done well for most applications. The gearing is short enough so you don’t have to worry about long gears when you run at the track. They are also long enough to enjoy rolling through the 1320. The longer ratio ’07 STI tranny is will suit those who do the 1320. The ’04-‘05 STi tranny will suit those who autoX and do circuit. The JDM STi 6spd will suit those who are doing PURE time attack and road course events. If the car has HIGH HP, the Legacy Spec B ratios will suit them better for its longer ratios.

Now selecting the ratios does go hand in hand with the amount of power as well as window of power with engine speed. For example would be if I wanted a QUICK & FAST street car running 540whp revving to 7500rpms on a built 2.5L, I would definitely do a 6spd and have Legacy Spec B 2-6 ratios installed. The car would have enough power to push through the longer ratio gears. The longer ratios also help because of the lower engine rev compared to the JDM models with the 8000rpm redline. If I was to have JDM STi 6spd I would run out of gearing so fast that I wouldn’t have anytime to use the power for acceleration. There’s just too much shifting with shorter ratios where you can have longer ratios to gain more ground accelerating. If it was a pure short/medium track or rally machine where top speed isn’t a factor but more so acceleration, the JDM ratios would fit right in. Anytime out of a corner power would be on TAP.

Last edited by FuJi K; 02-01-2009 at 12:18 AM.
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Old 01-31-2009, 09:19 PM   #2
FuJi K
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Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

General Idea of Gear Set for type of application

1320ft / Wangan

280whp-450whp or more


5speed transmission
PPG gearset
3.18 / 1.87 / 1.32 / 0.95 / OEM - Synchro 1st-4th Helical Cut Gear Set
3.08 / 1.87 / 1.32 / 0.95 / OEM - Synchro 1st-4th Straight Cut Gear Set
3.08 / 2.15 / 1.50 / 1.05 / OEM - Synchro 1st-4th Helical Cut Gear Set from Andrewtech
3.18 / 1.87 / 1.32 / 0.95 / OEM - Dogbox 1st-4th Straight Cut Gear Set
3.08 / 2.15 / 1.50 / 1.05 / OEM - Dogbox 1st-4th Helical Cut Gear Set

MFactory
3.454 / 1.940 / 1.350 / 0.958 / 0.769 - MFactory PRO Series Gear Set


6speed transmission
Subaru
3.636 / 2.235 / 1.521 / 1.137 / 0.891 / 0.707 - Legacy Spec B/Rallispec High Speed 2nd-6th Ratio Conversion
3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 - USDM '07 STI+

PPG
3.080 / 1.880 / 1.350 / 0.960 / OEM / OEM - Drag 4 Gear Subaru 5MT Dog Gear Kit


Short Track / Road Course / Time Attack / Autocross
280whp-450whp or more


5speed transmission
PPG gearset
2.916 / 2.090 / 1.555 / 1.176 / 0.900 - GC8 Group N 5 Gear Subaru 5MT Dog Kit
3.08 / 2.15 / 1.50 / 1.05 / OEM - Synchro 1st-4th Helical Cut Gear Set from Andrewtech

KAAZ
3.167 / 2.267 / 1.667 / 1.250 / 0.964 - MCF2050 Close Ratio Gears

MFactory
3.270 / 2.286 / 1.667 / 1.238 / 0.958 - Close ratio Gear Set

6speed transmission
Subaru
3.636 / 2.375 / 1.761 / 1.346 / 1.062 / 0.842 - JDM STi
3.636 / 2.235 / 1.521 / 1.137 / 0.891 / 0.707 - Legacy Spec B/Rallispec High Speed 2nd-6th Ratio Conversion
3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 - USDM '07 STI+

PPG
3.636 / 2.375 / 1.761 / 1.346 / 1.062 / 0.842 - GroupN 6 Gear Subaru 6MT Dog Kit
3.333 / 2.284 / 1.750 / 1.333 / 1.040 / OEM - Group N 5 Gear Subaru 6MT Dog Gear Kit


Budget Daily Driver
up to 375whp or more if you are willing

Subaru
3.166 / 1.882 / 1.296 / 0.972 / 0.738 - USDM '05+ Legacy 2.5GT & JDM models
3.083 / 2.062 / 1.545 / 1.151 / 0.825 or OEM - JDM GC8 WRX/STi RA Version 3-6






http://www.rallispec.com/prod_trans.htm
http://www.kaazusa.com/partinfo_gearsets.html
http://www.teammfactory.com/products...0Ratio%20Gears
http://spda-online.ca/modules/tinyco...ite/tc_28.html

Last edited by FuJi K; 11-09-2011 at 09:37 AM.
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Old 01-31-2009, 09:19 PM   #3
FuJi K
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Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

Factory Gear Ratios for Reference

All-Wheel-Drive 5-speed Transmissions
USDM
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 3.900FD - '02-'05 USDM WRX; 3.545FD rear diff
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 3.700FD - '06-'07 USDM WRX
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 3.900FD - '08-current USDM WRX
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 4.444FD - '04-'08 Forester 2.5XT
3.454 / 2.062 / 1.448 / 1.088 / 0.780 / 4.111FD - '04-current Forester non-turbo
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.111FD - '05-'06 USDM Legacy 2.5GT
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 3.900FD - '07-'09 USDM Legacy 2.5GT
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.444FD - '05-'09 USDM Outback 2.5XT
3.545 / 2.111 / 1.448 / 1.088 / 0.780 / 4.111FD - '98-'01 USDM Impreza 2.5RS
3.545 / 2.111 / 1.448 / 1.088 / 0.780 / 3.900FD - '96-'01 USDM Impreza L/OBS
3.545 / 2.111 / 1.448 / 1.088 / 0.780 / 4.111FD - '96-'99 USDM Legacy 2.5GT
3.545 / 2.111 / 1.448 / 1.088 / 0.871 / 4.111FD - '96-'99 USDM Legacy Outback
3.454 / 2.062 / 1.448 / 1.088 / 0.871 / 4.111FD - '00-'07 USDM Outback
3.454 / 2.062 / 1.448 / 1.088 / 0.825 / 4.111FD - '08-current USDM Outback
3.454 / 2.062 / 1.448 / 1.088 / 0.780 / 4.111FD - '02-'04 USDM Impreza 2.5RS/'05 Impreza 2.5RS Sport
3.545 / 1.947 / 1.366 / 0.972 / 0.780 / 4.111FD - '93-'94 USDM Impreza 1.8L
3.545 / 2.111 / 1.448 / 1.088 / 0.825 / 3.900FD - '95 USDM Impreza 1.8L

JDM
3.454 / 2.062 / 1.448 / 1.088 / 0.825 / 4.111FD - '93-'96 JDM Impreza WRX/STi
3.454 / 2.333 / 1.750 / 1.354 / 0.972 / 3.900FD - '93 JDM Impreza WRX RA
3.454 / 2.333 / 1.750 / 1.354 / 0.972 / 4.111FD - '94-'95 JDM Impreza WRX RA/STi RA
3.454 / 2.062 / 1.448 / 1.088 / 0.825 / 4.111FD - '93-'00 JDM Impreza WRX Wagon
3.083 / 2.062 / 1.545 / 1.151 / 0.825 / 4.444FD - '97-'00 JDM Impreza WRX RA/Type R/STi RA/22B STi
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.444FD - '97-'00 JDM Impreza WRX/STi


All-Wheel-Drive 6-speed Transmissions
3.636 / 2.375 / 1.761 / 1.346 / 1.062 / 0.842 / 3.900FD
- JDM Impreza WRX Spec C/STi/STi Spec C RA/V-Limted/S202/S203/S204/Spec C RA-R
- AUS Impreza WRX STi

3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 / 3.900FD
- USDM 2007-current Impreza WRX STi

3.636 / 2.375 / 1.761 / 1.346 / 0.971 / 0.756 / 3.900FD
- USDM 2004-2006 Impreza WRX STi
- UK/Europe/NZ Impreza WRX STi
- JDM Legacy 3.0R Spec B

3.636 / 2.235 / 1.521 / 1.137 / 0.891 / 0.707 / 3.900FD
- USDM 2007-2009 Legacy 2.5GT Spec B
- JDM Forester

NOTE: USDM '04/'05 R180 2way clutch type LSD with 3.900FD. USDM '06-current R180 torsen LSD with 3.545FD.




Calculators for Speed and RPM
http://www.car-videos.net/tools/speedrpm.asp
http://www.teammfactory.com/gearcalculator.php
http://forums.nasioc.com/forums/show....php?t=2566895



http://spda-online.ca/modules/tinyco...ite/tc_28.html
http://www.ausubaru.com/wiki/index.p...e=TRANSMISSION
http://www.rexnet.com.au/forum/index...howtopic=29168
http://www.cars101.com/

Last edited by FuJi K; 10-30-2013 at 11:01 PM.
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Old 03-22-2010, 01:07 PM   #4
DuckStu
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Join Date: Aug 2006
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Vehicle:
2004 WRX STI
Silver

Default

Quote:
Originally Posted by FuJi K View Post
Factory Gear Ratios for Reference

All-Wheel-Drive 6-speed Transmissions
3.636 / 2.375 / 1.761 / 1.346 / 1.061 / 0.842 / 3.900FD
- JDM Impreza WRX Spec C/STi/STi Spec C RA/V-Limted/S202/S203/S204/Spec C RA-R
- AUS Impreza WRX STi

3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 / 3.900FD
- USDM 2007-current Impreza WRX STi

3.636 / 2.375 / 1.761 / 1.346 / 0.971 / 0.756 / 3.900FD
- USDM 2004-2006 Impreza WRX STi
- UK/Europe/NZ Impreza WRX STi
- JDM Legacy 3.0R Spec B

3.636 / 2.235 / 1.521 / 1.137 / 0.891 / 0.707 / 3.900FD
- USDM 2007-current Legacy 2.5GT Spec B
- JDM Forester STi

Something is wrong in here. The '07 USDM STI does not have the same FD ratio as the earlier years,...and I think the 5th and 6th gears are the same.
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Old 03-25-2010, 11:20 PM   #5
FuJi K
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Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

Quote:
Originally Posted by DuckStu View Post
Something is wrong in here. The '07 USDM STI does not have the same FD ratio as the earlier years,...and I think the 5th and 6th gears are the same.
The tranny runs a 3.900FD. The rear diff of the '06+ STI's run 3.545 with the 1.1:1 step-up transfer gear in the transfer case.
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Old 03-26-2010, 02:11 PM   #6
03SEDAGON
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Platinum Silver Metallic

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Hey guys had a question I was hoping to get some help with. My 03 wrx wagon's rear diff is gone. I was looking at Fuji K's list of gear ratios and trying to figure out if I can use a diff from another subaru with the same 3.900FD or do I have to use a 02-03 wrx rear diff? Also, when I bought the car the transmission's gears had been rebuilt with 06 wrx gears. Any help would be greatly appreciated, thanks
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Old 03-26-2010, 08:40 PM   #7
FuJi K
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Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

Quote:
Originally Posted by 03SEDAGON View Post
Hey guys had a question I was hoping to get some help with. My 03 wrx wagon's rear diff is gone. I was looking at Fuji K's list of gear ratios and trying to figure out if I can use a diff from another subaru with the same 3.900FD or do I have to use a 02-03 wrx rear diff? Also, when I bought the car the transmission's gears had been rebuilt with 06 wrx gears. Any help would be greatly appreciated, thanks
If the gears are just the ones that got replaced, then your final drive should still be 3.900 in the tranny, meaning the rear diff stayed the same. You need to find a rear diff from an 02-05 WRX.
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Old 04-28-2013, 09:00 PM   #8
Fierysun
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2003 WRX Wagon

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Some of these (maybe some others as well) final drives are incorrect. Such as...


Quote:
Originally Posted by FuJi K View Post
Factory Gear Ratios for Reference

All-Wheel-Drive 5-speed Transmissions
USDM
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 3.900FD - '02-'05 USDM WRX
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 3.700FD - '06-'07 USDM WRX
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 3.900FD - '08-current USDM WRX
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 4.444FD - '04-'08 Forester 2.5XT
3.454 / 2.062 / 1.448 / 1.088 / 0.780 / 4.111FD - '04-current Forester non-turbo
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.111FD - '05-'06 USDM Legacy 2.5GT
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 3.900FD - '07-'09 USDM Legacy 2.5GT
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.444FD - '05-'09 USDM Outback 2.5XT
3.545 / 2.111 / 1.448 / 1.088 / 0.780 / 4.111FD - '98-'01 USDM Impreza 2.5RS
3.545 / 2.111 / 1.448 / 1.088 / 0.780 / 3.900FD - '96-'01 USDM Impreza L/OBS
3.545 / 2.111 / 1.448 / 1.088 / 0.780 / 4.111FD - '96-'99 USDM Legacy 2.5GT
3.545 / 2.111 / 1.448 / 1.088 / 0.871 / 4.111FD - '96-'99 USDM Legacy Outback
3.454 / 2.062 / 1.448 / 1.088 / 0.871 / 4.111FD - '00-'07 USDM Outback
3.454 / 2.062 / 1.448 / 1.088 / 0.825 / 4.111FD - '08-current USDM Outback
3.454 / 2.062 / 1.448 / 1.088 / 0.780 / 4.111FD - '02-'04 USDM Impreza 2.5RS/'05 Impreza 2.5RS Sport
3.545 / 1.947 / 1.366 / 0.972 / 0.780 / 4.111FD - '93-'94 USDM Impreza 1.8L
3.545 / 2.111 / 1.448 / 1.088 / 0.825 / 3.900FD - '95 USDM Impreza 1.8L

JDM
3.454 / 2.062 / 1.448 / 1.088 / 0.825 / 4.111FD - '93-'96 JDM Impreza WRX/STi
3.454 / 2.333 / 1.750 / 1.354 / 0.972 / 3.900FD - '93 JDM Impreza WRX RA
3.454 / 2.333 / 1.750 / 1.354 / 0.972 / 4.111FD - '94-'95 JDM Impreza WRX RA/STi RA
3.454 / 2.062 / 1.448 / 1.088 / 0.825 / 4.111FD - '93-'00 JDM Impreza WRX Wagon
3.083 / 2.062 / 1.545 / 1.151 / 0.825 / 4.444FD - '97-'00 JDM Impreza WRX RA/Type R/STi RA/22B STi
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.444FD - '97-'00 JDM Impreza WRX/STi


All-Wheel-Drive 6-speed Transmissions
3.636 / 2.375 / 1.761 / 1.346 / 1.062 / 0.842 / 3.900FD
- JDM Impreza WRX Spec C/STi/STi Spec C RA/V-Limted/S202/S203/S204/Spec C RA-R
- AUS Impreza WRX STi

3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 / 3.900FD
- USDM 2007-current Impreza WRX STi

3.636 / 2.375 / 1.761 / 1.346 / 0.971 / 0.756 / 3.900FD
- USDM 2004-2006 Impreza WRX STi
- UK/Europe/NZ Impreza WRX STi
- JDM Legacy 3.0R Spec B

3.636 / 2.235 / 1.521 / 1.137 / 0.891 / 0.707 / 3.900FD
- USDM 2007-2009 Legacy 2.5GT Spec B
- JDM Forester STi


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Old 01-31-2009, 09:19 PM   #9
FuJi K
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Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

Videos of various gearing combination's



Legacy spec B ratios shifting about 9000rpms


3.636 / 2.375 / 1.761 / 1.346 / 1.061 / 0.842 / 3.900FD
JDM 6spd ratios on big turbo


3.636 / 2.235 / 1.521 / 1.137 / 0.891 / 0.707 / 3.900FD
High Speed gears, Legacy Spec B


3.636 / 2.375 / 1.761 / 1.346 / 1.061 / 0.842 / 3.900FD
JDM 6spd ratios


3.636 / 2.375 / 1.761 / 1.346 / 0.971 / 0.756 / 3.900FD
'04-'06 USDM STi 6spd shifting at about 3000rpms


3.636 / 2.375 / 1.761 / 1.346 / 1.061 / 0.842 - 3.900FD
'04 JDM DCCD 6spd shifting at about 7000rpm


3.08 / 1.87 / 1.32 / 0.95 / 0.738(OEM) - 3.900FD
'02 WRX, PPGs straight cut 1/2, helical cut 3/4, OEM 5th, 7000rpm shifts


3.545 / 2.111 / 1.448 / 1.088 / 0.871 / - 4.111FD
'03 WRX, '97 Outback NA 5spd, '01RS VLSD 4.111FD R160, 7000rpm shifts


3.166 / 1.882 / 1.296 / 0.972 / 0.738 / - 4.444FD
'99 CANADA OBS EJ20G swap STi Ver.IV tranny


3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 / 3.900FD
'07 USDM STi 6spd BPU


3.454 / 1.947 / 1.366 / 0.972 / 0.738 / - 3.900FD
'02 WRX stock 5spd BPU

3.270 / 2.286 / 1.667 / 1.238 / 0.738 / 3.900FD
MFactory 1-4

3.270 / 2.286 / 1.667 / 1.238 / 0.738 / 3.900FD
MFactory 1-4


3.083 / 2.062 / 1.545 / 1.151 / 0.825 / 4.111FD
STi RA 5spd with 4.111 tranny



...............

Last edited by FuJi K; 05-05-2014 at 02:31 PM.
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Old 02-01-2009, 12:15 AM   #10
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Old 02-01-2009, 09:28 AM   #11
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hi FuJi K, currently my car is running 350whp revving to 7000rpms on a built 2.5L, what kind of gearset do u recommend for my MY07 2.5wrx so that it can be a Quick and Fast street car?? currently my 5mt gearbox is running on stock 3.454/1.947/1.366/0.972/0.738 with 4.111FinalDrive. on top of being quick and fast, i am also looking to strenghten the gearbox.
many tks
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Old 02-01-2009, 11:53 AM   #12
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Quote:
Originally Posted by snowmanwrx View Post
hi FuJi K, currently my car is running 350whp revving to 7000rpms on a built 2.5L, what kind of gearset do u recommend for my MY07 2.5wrx so that it can be a Quick and Fast street car?? currently my 5mt gearbox is running on stock 3.454/1.947/1.366/0.972/0.738 with 4.111FinalDrive. on top of being quick and fast, i am also looking to strengthen the gearbox.
many tks
You can't go wrong with doing the LGT 1-2-3 gears in with yours if you're on a budget. You happen to have a 4.111FD which I find IMO to be great medium matched for gear sets that's are available at the moment.

MFactory's mainshaft has upgraded so there's HOPE in a stronger hold. A handful of people are running that gear set at the moment. Early buyers had problems with that mainshaft flexing but should now if replaced with the NEW one and guys with them installed recently shouldn't have a problem either.
The ratios are a little longer in 1st gear but shorter when you roll through them. Shifting into 5th gear will yield a big gap. If you don't mind the hiway RPM and want a decent gap you can have the USDM Subaru Outback's 5th gear installed with the MFactory's 1-4; Outback 5th gear ratio is .871.

... you have the option of jumpin to the 6spd if you want.
BTW do you have a USDM WRX? a 4.111FD in that tranny doesn't seem USDM to me.
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Old 02-02-2009, 07:24 AM   #13
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Quote:
Originally Posted by FuJi K View Post
You can't go wrong with doing the LGT 1-2-3 gears in with yours if you're on a budget. You happen to have a 4.111FD which I find IMO to be great medium matched for gear sets that's are available at the moment.

MFactory's mainshaft has upgraded so there's HOPE in a stronger hold. A handful of people are running that gear set at the moment. Early buyers had problems with that mainshaft flexing but should now if replaced with the NEW one and guys with them installed recently shouldn't have a problem either.
The ratios are a little longer in 1st gear but shorter when you roll through them. Shifting into 5th gear will yield a big gap. If you don't mind the hiway RPM and want a decent gap you can have the USDM Subaru Outback's 5th gear installed with the MFactory's 1-4; Outback 5th gear ratio is .871.

... you have the option of jumpin to the 6spd if you want.
BTW do you have a USDM WRX? a 4.111FD in that tranny doesn't seem USDM to me.
nope, its a EURO wrx. was thinking of the PPG gearset as its pretty close to stock gear ratio. my main concern is to have a strengthen gearset to be able to withstand punishment. what say u???
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Old 02-01-2009, 03:47 AM   #14
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Nice Info Fuji. Now can you make me a copy with your autograph? haha =P
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Old 02-02-2009, 01:24 PM   #15
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Very Nice Thread, a definite sticky

Fuji- I have a few other gear sets for you, I'll try and compile the ratios for you so you can add them

-Dylan @ DS1
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Old 02-02-2009, 05:39 PM   #16
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Quote:
An autoX guy will like a nice short 2nd gear and 3rd gear, more like the STi 6spd 2nd gear and 3rd gear.
That surprises me. I thought STi autoxers would prefer a longer 2nd, so they didn't have to mess with 3rd gear at all. Shifting is generally thought of as time given up.
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Old 02-02-2009, 06:53 PM   #17
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Originally Posted by snowmanwrx View Post
nope, its a EURO wrx. was thinking of the PPG gearset as its pretty close to stock gear ratio. my main concern is to have a strengthen gearset to be able to withstand punishment. what say u???
If you are looking at the PPG for Quick Street Fun, IMO I'd suggest this
3.08 / 2.15 / 1.50 / 1.05 / OEM - Synchro 1st-4th Helical Cut Gear Set from Andrewtech

It'll keep you in the powerband and you don't have to worry about that big gap on the 1-2 shift, 3rd and 4th as acceleration gears.



Quote:
Originally Posted by DS1 Motorsports View Post
Very Nice Thread, a definite sticky

Fuji- I have a few other gear sets for you, I'll try and compile the ratios for you so you can add them

-Dylan @ DS1
Keep me posted!


Quote:
Originally Posted by leecea View Post
That surprises me. I thought STi autoxers would prefer a longer 2nd, so they didn't have to mess with 3rd gear at all. Shifting is generally thought of as time given up.
AutoX courses can be REALLY SHORT, or they can be really long and depends where the even is held. AutoX done here in my town uses small lots and only a few at larger facilities. In small lots having a 2nd gear like the WRX's would really suck because your RPM is so low you can't pull out of corners. The STi's shorter 2nd gear helps a lot in these situations. I AutoX'ed at the Miller Stadium with the SCCA Milwaukee Region Solo Autocross in Milwaukee WI. When I was still NA with my Impreza L wagon running a 2.5RS tranny, my 2nd gear was a TAD long. Had it been a JDM WRX STi RA VerIII tranny with the 4.444FD, I would have LOVED IT!

Going 2nd to 3rd would only be on the slalom and higher speed turns. It really is matched well IMO, but then others may disagree. The STi does have a lot of torque running its mighty 2.5L and fast spooling VF39.
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Old 02-03-2009, 04:05 AM   #18
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[quote=FuJi K;25427535]If you are looking at the PPG for Quick Street Fun, IMO I'd suggest this
3.08 / 2.15 / 1.50 / 1.05 / OEM - Synchro 1st-4th Helical Cut Gear Set from Andrewtech

It'll keep you in the powerband and you don't have to worry about that big gap on the 1-2 shift, 3rd and 4th as acceleration gears.


alright, tks.
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Old 02-03-2009, 11:25 AM   #19
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I just found out that the '08 WRX uses the LGT gears and runs a 3.900FD.


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Last edited by FuJi K; 02-19-2011 at 01:23 AM. Reason: correcting info on '08 WRX final drive
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Old 02-20-2009, 10:25 PM   #20
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Quote:
Originally Posted by FuJi K View Post
I just found out that the '08 WRX uses the LGT gears and runs a 4.111FD. I wonder if it is the same tranny.... more likely.
Same exact part numbers for the mainshaft, 1st and 2nd gear idlers. I know because we just installed them in a box today. Though I've always thought it was a misnomer that people call this the LGT swap. These are the same ratios that were in the v4-v6 JDM STi's and WRX sedans. They aren't new ratios, though they are new to the US market, and of course we get them with a different FD ratio than the 4.44 they see in Japan. There's a certain US vendor who has been selling these for years as a complete 5 spd kit calling it v5/v6 STi. Though, they force you to buy all 5 gears in that kit, and you end up with an additional 0.738 5th gear, which you've already got if you drive a USDM WRX. Now, with these in US cars, you are free to just buy the 3-4 gears that you need. We're building a bunch of these boxes.

However, there is one difference with the '08 WRX gears. It's a shorter 5th. They've tightened it up to a 0.780 like were used on the GC chassis 2.5RS and first generation of Outbacks.

Also, there's just a couple of minor errors in your ratio charts. The ratios you attribute to 96-99 WRX-RA/ Type RA/ 22B etc are actually 97-2000 ratios. Also, same for the WRX/STi reference directly under that in the list. Those ratios, which are the ones we are discussing above were for 97-2000 as well. Just a one year shift off of what you've got listed.

Otherwise fabulous thread. When I have more time I'll come give some of my personal input on choosing ratios and applications. Even now with all this new stuff, Subarus are still pretty restricted on what we can do with these boxes. On the Porsche gears I am making we average 12-20 different ratios for each individual gear position. At the same time, on Porsches you are generally only working with 2 final drive ratio options instead of the 3 we have with Subarus. That reduces the number of gear ratios you need to have to reach the same end. Though there's a tradeoff there and if you adjust a final drive it forces you to move all ratios the same percentage at the same time. A shorter R/P ratio that might make your 2-3-4 better might take your 1st and make in pretty much worthless.
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Old 02-21-2009, 11:32 AM   #21
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Can anyone comment about the effect of final drive on the stress the gears see? The way I interpret it is that the higher final drive the less stress the gears will see due to mechanical advantage, but a more technical explanation would be great.
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Old 02-18-2011, 03:21 PM   #22
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Quote:
Originally Posted by FuJi K View Post
I just found out that the '08 WRX uses the LGT gears and runs a 4.111FD. I wonder if it is the same tranny.... more likely.
Can you change this in post #3 please?
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Old 02-19-2011, 01:26 AM   #23
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Originally Posted by roadtrip1098 View Post
Can you change this in post #3 please?


corrected info. The final drive a 3.900
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Old 02-23-2011, 01:28 PM   #24
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Quote:
Originally Posted by FuJi K View Post
corrected info. The final drive a 3.900
Did Subaru make a mistake?

http://www.driveperformance.subaru.c...x_spec_dim.asp

Using these figures on the gigantic link below http://www.teammfactory.com/gearcalc...ission+1+%26+2

Yeilds nearly identical top speeds for the WRX and STi of 181 and 182 respectively. I know this is not accurate for the WRX. Mine is pushing about 165ish around 6500-6800 mark. It also does about 65 in second when pushing close to redline - not the 71 MPH stated by the calculator.
In fact the Speed vs RPM in my WRX matches perfectly with the gears listed, but a 4.1 final drive. To me it makes more sense mathematically and practically if the WRX has a 4.1 FD and the STi has a 3.9.

Last edited by roadtrip1098; 02-23-2011 at 03:36 PM.
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Old 02-23-2011, 03:46 PM   #25
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Quote:
Originally Posted by roadtrip1098 View Post
Did Subaru make a mistake?
Simply put, no. In a lossless situation, your car should hit 169mph at 6500RPM. However, keep in mind that you're driving a car with aerodynamic qualities that are less than optimal, to put it nicely. Counting in wind drag, I'd be surprised if you're only losing 4mph at those speeds. The 181mph is a purely theoretical number, meaning it takes no mechanical losses, drag, or or power limits into play. In a real world situation, hitting 165mph at 6800RPM is pretty spot on.
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