Learning to Choose your Gearsets/Ratios

[FuJi K]

Originally Posted by Hiryu

Primarily at this point, yeah. Right now, I tend to cruise around town in fifth gear, for example. I recently drove my cousin's stock 2003 WRX, and starting in first gear of that car reminded me of starting in third in my car.

I don't need to go 60mph in first, but it'd be nice to be able to get there in second--especially when you compare the gearing to other sports cars with the same power/weight ratio (some of which in fact do 60 in first). The high speed gears look like a nice improvement, but I'm curious if the ratios wouldn't still be a bit too short...

I don't know your engine setup. I don't know your powerband. Daily driver you say. Want wider gear spacing? Do you have a V8 LSx swap?


Really you should be choosing the tranny/gearing what you're using the car for. You can't have it all sir. I find it that the long gears suit a lot of what people are using the car for here in the U.S.

Here is Ben's 20G xtr with long gears with a redline of 7000.

2011 WRX - STI 6 Speed Swap with Spec B Gears - YouTube

2011 WRX - STI 6 Speed Swap with Spec B Gears - YouTube

Here it is shifting at 8000rpms.

2011 WRX - NF Performance: Stage 1 - YouTube

2011 WRX - NF Performance: Stage 1 - YouTube

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[Hiryu]

Originally Posted by FuJi K

I don't know your engine setup. I don't know your powerband. Daily driver you say. Want wider gear spacing? Do you have a V8 LSx swap?


Really you should be choosing the tranny/gearing what you're using the car for. You can't have it all sir. I find it that the long gears suit a lot of what people are using the car for here in the U.S.

This is the car:


It's got a USDM STi AWD powertrain (with the USDM 2005 6-speed gearset ratios) but weighs a lot less. It's still got the stock turbo but has a front mount, custom full 3" exhaust, and AP custom tune. It's not that it's putting out that much power, but the fact that there's a lot less mass that needs to be moved around (especially since the STi powertrain is relatively torquey). I always felt the 6-speed in a stock STi was a bit shortly-geared for cruising, even more so in a modified STi, and especially so in a modified STi-powered car that's even lighter.

I think the high speed gears are probably great; it's just that on paper I can't tell if the ratio differences are enough to notice in my application? I know that an optimum gearing solution requires taking the exact powerband nature into account, but even just by feel, the car feels like the gearing could be at least another 30% if not even 50% taller and feel a lot better during its daily driving duties. I was just curious if there are any gearsets that might be closer to those ratio changes, as the high speed ratios are only around 6% to 18% higher (not sure what you meant by 'wanting it all'?).

Thanks-

[FuJi K]

The spec B's gear spacing when shifting at lower RPMs seems tight but when you shift at higher RPMs the spacing magnifies and is further spread out. If you're looking for a daily driving cruising gear set then grab a 5spd. Just know that it won't be as beefy nor well geared for what looks to be a performance vehicle built for track use.

I just hate to see a performance car dogged down for something other than what it was built for. That car in my eyes screams 8000RPMs 500bhp.

[Hiryu]

Originally Posted by FuJi K

The spec B's gear spacing when shifting at lower RPMs seems tight but when you shift at higher RPMs the spacing magnifies and is further spread out. If you're looking for a daily driving cruising gear set then grab a 5spd. Just know that it won't be as beefy nor well geared for what looks to be a performance vehicle built for track use.

I just hate to see a performance car dogged down for something other than what it was built for. That car in my eyes screams 8000RPMs 500bhp.

Thanks again for the info. I guess everybody has different tastes; I got this car to be an enjoyable and reliable cruiser and show car:


(I got this other one to be the high-strung, track-day beater/screamer...I can do the short ratios and 8000rpm redline with it: )

[Jmoneyzzz]

Okay so how exactly how would an 06 sti gears compared to 05 sti, 07 sti and the spec c gears. I have a swapped GC8 with 06 sti drivetrain and engine and alright it is great on the track it's a bit of a drag on the streets. I was going to make my L a project but I'm gonna make it my daily instead.

[FuJi K]

Originally Posted by Jmoneyzzz

Okay so how exactly how would an 06 sti gears compared to 05 sti, 07 sti and the spec c gears. I have a swapped GC8 with 06 sti drivetrain and engine and alright it is great on the track it's a bit of a drag on the streets. I was going to make my L a project but I'm gonna make it my daily instead.

Run the ratios in the calculator.

[capwilly]

You're prowess regarding this subject is impressive but leaves my particular questions somewhat on a cliff. I am a former racer from over 30 years ago ( Lotus 47, 289 Cobra, Jaguar e-Type ) and not without technical acumen and have a 02' bugeye wagon now which I love and am in the process of tricking out. The departure here from my experience and my past and it seems all others is that for the moment I am choosing to use an a/t transmision in the car. Today's technology with paddle shifiting , etc. blows away traditional manual transmisions and it is no longer possible for the human to compete with the computer quickness available. So,,,, barring my spending a fortune on this new technology, and assuming I decide to remain attempting to use an a/t transmission,,,, what would your advice be on the most effective gearbox, gear ratios and most importantly, torque converter to aproximate the sophistication of this most current equipment. Thanks kindly, Capwilly

[FuJi K]

Thank you for the kind words.

There are a few autos that Subaru offers in their lineup. However getting them to work require some merging likely of wires and TCUs.

If all possible, I'd like to try the Tribeca's 5spd auto. Some people however just build a 4spd auto for drag racing purpose.

Originally Posted by capwilly

You're prowess regarding this subject is impressive but leaves my particular questions somewhat on a cliff. I am a former racer from over 30 years ago ( Lotus 47, 289 Cobra, Jaguar e-Type ) and not without technical acumen and have a 02' bugeye wagon now which I love and am in the process of tricking out. The departure here from my experience and my past and it seems all others is that for the moment I am choosing to use an a/t transmision in the car. Today's technology with paddle shifiting , etc. blows away traditional manual transmisions and it is no longer possible for the human to compete with the computer quickness available. So,,,, barring my spending a fortune on this new technology, and assuming I decide to remain attempting to use an a/t transmission,,,, what would your advice be on the most effective gearbox, gear ratios and most importantly, torque converter to aproximate the sophistication of this most current equipment. Thanks kindly, Capwilly

[pit99]

Hi im looking inf about this gear ty752vrcaa from impreza 2.0 n/a 1997. and legacy II 2.0 n/a1994 ty752vraaa

this gears have the same ratios?? ??

i wanna put gear from impreza to legacy becaus gear from legacy is dead

[FuJi K]

http://www.scoobynet.com/drivetrain-...tml?styleid=26


3.9 final drive ratio
Legacy,
3.9 Final drive the ratios are:
3.55
2.11
1.45
1.09
0.87

Your Legacy:
http://www.scoobynet.com/drivetrain-...y752vraaa.html

Originally Posted by pit99

Hi im looking inf about this gear ty752vrcaa from impreza 2.0 n/a 1997. and legacy II 2.0 n/a1994 ty752vraaa

this gears have the same ratios?? ??

i wanna put gear from impreza to legacy becaus gear from legacy is dead

[pit99]

thenks for help

I can put gear of the impreza to legacy ? the same ratio

[FuJi K]

final drive ratios are not the same. You can swap the rear diff to match.

Originally Posted by pit99

thenks for help

I can put gear of the impreza to legacy ? the same ratio

[pit99]

Originally Posted by FuJi K

http://www.scoobynet.com/drivetrain-...tml?styleid=26


3.9 final drive ratio
Legacy,
3.9 Final drive the ratios are:
3.55
2.11
1.45
1.09
0.87

Your Legacy:
http://www.scoobynet.com/drivetrain-...y752vraaa.html

but i have ty752 VRAAA not VBAAA

[FuJi K]

Originally Posted by pit99

but i have ty752 VRAAA not VBAAA

I don't have experience with transmisions out of country in other countries besides Japan.
Being NA, my only guess is it may run a 4.111/3.900 of that generation. If AWD you can simply rotate the driveshaft to the rear and count how many rotations of driveshaft to axle. It'll give you the final drive at least.

[Northwest97]

Fuji, you seem to be insanely knowledgeable on this so thank you for helping all of us. I'm looking into a gf8 project right now and I'm trying to figure out the best transmission to hold the power. From what I have seen the six speed swap is the way to go but since I'm a high schooler I was looking more towards budget for now.
The numbers I'm looking at pushing are 350-400whp. Most likely going with a hybrid 2.0L head Ej257. Would a legacy gt gear set be the way to go or should I look into a RA STI 5 spd? I read most of the thread but the information I gleamed was mostly about FD so I apologize if this question has already been asked and I skimmed over it.


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[FuJi K]

Since you are in highschool and on a budget you need to be easy on the power. It'll save you on broken gears and also gas and other to be broken parts. The 5spd gears are getting to cost as much as the 6spd Long Gears.

The STi 6spds can be had for cheaper nowadays. It wasn't like that when I bought mine 2yrs after highschool. If you're lucky you might get a 6spd setup to the knuckles for $3000.

If you had to get a 5spd, mate it to a WRX pull type 5spd. Use 4.111FD or if you can find a 4.444FD do that with the RA gears if not the regular STi 5spd gears.

But at 350-400whp is pushing the limits of the gears. They are rather small compared to 6spd stuff.

Originally Posted by Northwest97

Fuji, you seem to be insanely knowledgeable on this so thank you for helping all of us. I'm looking into a gf8 project right now and I'm trying to figure out the best transmission to hold the power. From what I have seen the six speed swap is the way to go but since I'm a high schooler I was looking more towards budget for now.
The numbers I'm looking at pushing are 350-400whp. Most likely going with a hybrid 2.0L head Ej257. Would a legacy gt gear set be the way to go or should I look into a RA STI 5 spd? I read most of the thread but the information I gleamed was mostly about FD so I apologize if this question has already been asked and I skimmed over it.

[Northwest97]

Originally Posted by FuJi K

Since you are in highschool and on a budget you need to be easy on the power. It'll save you on broken gears and also gas and other to be broken parts. The 5spd gears are getting to cost as much as the 6spd Long Gears.



The STi 6spds can be had for cheaper nowadays. It wasn't like that when I bought mine 2yrs after highschool. If you're lucky you might get a 6spd setup to the knuckles for $3000.



If you had to get a 5spd, mate it to a WRX pull type 5spd. Use 4.111FD or if you can find a 4.444FD do that with the RA gears if not the regular STi 5spd gears.



But at 350-400whp is pushing the limits of the gears. They are rather small compared to 6spd stuff.

I'm starting to realize the unrealistic goal I had set now that I bought the project car.

I'm still fairly new to the car world, so I have a question about what you a said. What do you mean by mating it to a WRX pull type 5spd?
For the 4.11 would you recommend looking at LGT transmissions or older JDM 5spds?

Thank you Fuji. I really appreciate you taking your time to help answer my questions!

[FuJi K]

Originally Posted by Northwest97

I'm still fairly new to the car world, so I have a question about what you a said. What do you mean by mating it to a WRX pull type 5spd?
For the 4.11 would you recommend looking at LGT transmissions or older JDM 5spds?

Thank you Fuji. I really appreciate you taking your time to help answer my questions!

I prefer the pull type clutch wrx tranny (i.e. 02-05 usdm wrx). Don't have to worry about the clutch fork breaking.

The 4.111 is a nice medium final drive for the gearing that we have available on the 5spd trannys. You can go 3.900 or 4.444 if you need it to suit what your application is. I was saying you can get this ring and pinion from NA 5spds if needed.

[spoolinsti05]

I want the long gear but don't want to rev over 7800 making 650+whp on mustang dyno 26" tall Nittos. Even just the tall 6th would be nice for my long road trips I'm so indecisive..