My only concern is Gearing

[LifeIsOnTheWire]

Hey everyone, I am pretty excited about this new kit-car. i've been really wanting to start a kit-car sometime soon. I think the idea of using a subaru drivetrain is great, except the choices of gearing out there.

personally, I always prefer longer gearing in my cars. IMO being able to hit 50-60mph in 1st gear is ideal for a car with a really good power:weight ratio, but i really just dont like rowing through 3-4 gears to get to a comfortable speed when im driving a very high power:weight car.

for a short period of time, I daily drove a 490whp turbo EF Honda Civic hatch, and I have to say it was one of the more frustrating car experiences in my life, to drive such a powerful car that takes 3 gears to get to 60mph, when the car could totally 'afford' to have a 1st gear that was 3 times longer.

this is just my personal preference, and I may be alone on this. what does everyone else thing in terms of gearing options for the Suby motors?

[crobin4]

Something very much on my mind is not needing to use first gear. I routinely start my 3000lb car in second and it does so well that, I believe removing 1200lbs will make first gear useless.
Second gear with WRX box will get you to 55-60mph with ~25 inch tall tire.

[Oppenheimer]

Get some tall tires?

[PhyrraM]

Such are the limitations of the budget. You would be suprised at how many low volume cars from major auto manufactures have the same issue. The original MR2 stands out. So does the Pontiac Fiero. No money for a new gearbox, so they used the original Corolla and Citation boxes respectively. IIRC reviews from the time complained about ratios too.

If your willing to do some expirementing, most of the 5 speed models can have gears swapped. There might be a combo out there that works well and is cheap too. There are also final drives as low as 3.7ish for the 5 speed and 3.5ish for the automatics (in the SVX). Might be others too. Knowing how Subaru thinks, there is a very small chance the Auto and 5speed front diffs are close enough to be modified to work. That would allow a 3.5FD in the manual box.

[crobin4]

Such are the limitations of the budget. You would be suprised at how many low volume cars from major auto manufactures have the same issue. The original MR2 stands out. So does the Pontiac Fiero. No money for a new gearbox, so they used the original Corolla and Citation boxes respectively. IIRC reviews from the time complained about ratios too.

If your willing to do some expirementing, most of the 5 speed models can have gears swapped. There might be a combo out there that works well and is cheap too. There are also final drives as low as 3.7ish for the 5 speed and 3.5ish for the automatics (in the SVX). Might be others too. Knowing how Subaru thinks, there is a very small chance the Auto and 5speed front diffs are close enough to be modified to work. That would allow a 3.5FD in the manual box.

Yep, been thinking about that too. Haven't had the chance to research.

[bbjones121]

Such are the limitations of the budget. You would be suprised at how many low volume cars from major auto manufactures have the same issue. The original MR2 stands out. So does the Pontiac Fiero. No money for a new gearbox, so they used the original Corolla and Citation boxes respectively. IIRC reviews from the time complained about ratios too.

If your willing to do some expirementing, most of the 5 speed models can have gears swapped. There might be a combo out there that works well and is cheap too. There are also final drives as low as 3.7ish for the 5 speed and 3.5ish for the automatics (in the SVX). Might be others too. Knowing how Subaru thinks, there is a very small chance the Auto and 5speed front diffs are close enough to be modified to work. That would allow a 3.5FD in the manual box.

It was a long time ago. But i think my old SVX sat around 2k rpm at 65mph if I remember correctly. It had some pretty long gears. I thought it got to 45 in first.

[mn_vette]

I have been advicating this as well. I think the proper fix would be to do the 1-2 gear swap for the 5-speed tranny. In the current setup 1st goes to 30ish and 2nd goes to 60ish, the problem is that the 1-2 shift gets you back into the 3400 rpm range. Starting in second would be great and get you right up to 60. But I think you would be faster if 1st got you to 45ish and 2nd got you to about 70.

With this you are still stuck rev-ing to 2700 if you want to cruise down the highway, typical for a 4 banger though. Hopefully we won't have a droning exhaust for this car. If you wanted to change the cruising RPM then you would need to change the center diff, but that won't fix the 1-2 shift rpm drop, regardless of speed you will be at 3400 after the shift.

[bbjones121]

I have been advicating this as well. I think the proper fix would be to do the 1-2 gear swap for the 5-speed tranny. In the current setup 1st goes to 30ish and 2nd goes to 60ish, the problem is that the 1-2 shift gets you back into the 3400 rpm range. Starting in second would be great and get you right up to 60. But I think you would be faster if 1st got you to 45ish and 2nd got you to about 70.

With this you are still stuck rev-ing to 2700 if you want to cruise down the highway, typical for a 4 banger though. Hopefully we won't have a droning exhaust for this car. If you wanted to change the cruising RPM then you would need to change the center diff, but that won't fix the 1-2 shift rpm drop, regardless of speed you will be at 3400 after the shift.

I think my Legacy shifts back down around my turbo's peak from 1st-2nd. That is just above 4k, not the low 3.4k of the wrx. Once I am off the line and getting boost, I never drop below my turbo spool point in any gear change.

[BrandonDrums]

Hey everyone, I am pretty excited about this new kit-car. i've been really wanting to start a kit-car sometime soon. I think the idea of using a subaru drivetrain is great, except the choices of gearing out there.

personally, I always prefer longer gearing in my cars. IMO being able to hit 50-60mph in 1st gear is ideal for a car with a really good power:weight ratio, but i really just dont like rowing through 3-4 gears to get to a comfortable speed when im driving a very high power:weight car.

for a short period of time, I daily drove a 490whp turbo EF Honda Civic hatch, and I have to say it was one of the more frustrating car experiences in my life, to drive such a powerful car that takes 3 gears to get to 60mph, when the car could totally 'afford' to have a 1st gear that was 3 times longer.

this is just my personal preference, and I may be alone on this. what does everyone else thing in terms of gearing options for the Suby motors?

True, but you could then start quick in 1st and short shift into 3rd lol.

I do it sometimes in my wrx...I short shift first and ride 2nd out in the power, in an STI I'd use 3rd...

[bromikl]

Starting in second would be great and get you right up to 60. But I think you would be faster if 1st got you to 45ish and 2nd got you to about 70.


If this car performs like my Buell, (and it should) you'll hit 60 in about four seconds. I'm all for doing that in one step. I'd prefer to cruise in 5th at slightly over idle going 70 MPH. With this power-to-weight there really is no reason for high revs; unless you're on the racetrack.

This situation reminds me of my friend's classic Firebird. It has two gears. What a beautiful machine!

[Steve91T]

I don't think it's going to be an issue. It won't be perfect, but it'll be just fine. Trust me, when you guys actually drive this thing, you aren't going to be worrying about the gear ratio. Someday if the budget allows, put new, stronger gears in it, whatever ratios you want.

Steve

[thebeerbaron]

I don't think it's going to be an issue. It won't be perfect, but it'll be just fine. Trust me, when you guys actually drive this thing, you aren't going to be worrying about the gear ratio. Someday if the budget allows, put new, stronger gears in it, whatever ratios you want.

Amen.

[mn_vette]

If this car performs like my Buell, (and it should) you'll hit 60 in about four seconds. I'm all for doing that in one step. I'd prefer to cruise in 5th at slightly over idle going 70 MPH. With this power-to-weight there really is no reason for high revs; unless you're on the racetrack.

This situation reminds me of my friend's classic Firebird. It has two gears. What a beautiful machine!

There's one problem with your statement. It has nothing to do with the power to weight, but the power at that RPM. Just over idle in a V8 you have TONS of torque and you just cruise. In a 4 banger with no boost at cruise then you have much less torque. You will be able to gain something because the car is lighter and most likely more aerodynamic than the donor, but you are still going to be well over 2k rpm while cruising to get into the torque of the small displacement motor.

[eagle98ak]

The 2.5 motors have a surprizing amount of torque off boost. With a 07 sixspeed installed in my 06 WRX wagon I can cruise at 40mph in sixth at about 1800rpm all day long without feeling like I am lugging it.

[PhyrraM]

The 2.0 in the WRX needs some revs, even on the highway. But it hardly phases it. I can leave it in 4th all day long without any indications of wrong-doing. In fact, left in 4th on the highway makes it quite the little point-n-squirt machine in light traffic. Low cruise RPM is not needed with the 2.0 and likely not with the 2.5 either.

[thebeerbaron]

In a 1800lb car, there are going to be far more annoyances on highway cruise than engine rpm. Annoyances like getting shoved around by the slipstream from the Geo Metro in front of you. I'm guessing you'll prefer to have power available for evasive maneuvers than "quiet" cruise.

[crobin4]

There's one problem with your statement. It has nothing to do with the power to weight, but the power at that RPM. Just over idle in a V8 you have TONS of torque and you just cruise. In a 4 banger with no boost at cruise then you have much less torque. You will be able to gain something because the car is lighter and most likely more aerodynamic than the donor, but you are still going to be well over 2k rpm while cruising to get into the torque of the small displacement motor.

I haven't seen any numbers posted yet with regards to lag, so I'll take a stab. I think we all know at this point, that on shifts when your "driving in anger" your not going to be off boost. Subaru gearing is VERY well matched to their powerband, NA cars and turbo cars alike.
From cruising, lets say second - fifth gear 2500-3000rpm (65-70mph in top gear)(with the stock turbo or reasonably sized upgrade (16g evo3, GT2871r, VF39, VF22 on the 2.5L, etc.). Your looking about a half second of lag to full boost.
It's not as bad as they used to be. I have no worries about lag, and I hate lag. There will be plenty of power and torque everywhere with such a small car.
The take away is don't use a great big turbo with this car it's simply not necessary and will likely make the car perform worse.
Stay reasonable and will perform very well.
I usually don't find myself at 1800 rpm where I can also give the full beans. Not in everyday driving. I found myself in that position autoXing. Not having shifted down and not being able to maintain enough cornering speed to keep the revs up.
This car should be able to generate the cornering speeds to make that scenerio unlikely.

[BrandonDrums]

In a 1800lb car, there are going to be far more annoyances on highway cruise than engine rpm. Annoyances like getting shoved around by the slipstream from the Geo Metro in front of you. I'm guessing you'll prefer to have power available for evasive maneuvers than "quiet" cruise.

Hahaha Good point!

I'm not worried about gearing with the 5 speed, the main complaint about the ratios is that they are too tall. In an 1800lb car they could be just right. 2 quick rips to 60 is quite quick. If they break then hopefully it will be after you know enough about how this car behaves to know what ratios to put in....

[LifeIsOnTheWire]

I don't think it's going to be an issue. It won't be perfect, but it'll be just fine. Trust me, when you guys actually drive this thing, you aren't going to be worrying about the gear ratio. Someday if the budget allows, put new, stronger gears in it, whatever ratios you want.

Steve

i've owned several cars with similar or better power to weight ratios (for reference, im imagining this 1800lb car to have around 300hp), and I wouldn't assume that I "wont be worrying about the gearing".

infact I can say without hesitation, that if a car with such a power:weight takes 2-3 gears to get to 60, I guarantee I will be complaining the first time I drive the car.

even with 97-00 WRX STi Type R gearing (the longest 1st gear available for 5mt subys) I know that I will be launching the car in 2nd every time.

[Gollum]

With this you are still stuck rev-ing to 2700 if you want to cruise down the highway, typical for a 4 banger though.

I just want to point out that where a motor likes to sit in it's RPM band has nothing to do with cylinder count. 4 bangers tend to have a higher redline, thus manufactures gear them to cruise on the freeway at higher RPM because the engine will "bog" at lower RPMs than a motor with a lower redline. It also has to do with the power/weight ratio of the car an how much RPM you need for the car to keep the car moving along without too much effort.

Point being: The statement above was a gross overgeneralization and I just want to make sure people don't see the WRX motor as a typical 4 cylinder, because it's not. These motors will make peak torque well under 4,000 rpm and won't be making power up top without head work/cams. Point - It makes power VERY low down compared to most 4 cylinders.


Just over idle in a V8 you have TONS of torque and you just cruise. In a 4 banger with no boost at cruise then you have much less torque.

Torque alone isn't powerful. Torque and RPM IS powerful, and that's called POWER, or horsepower. A large V8 doesn't feel "torquey" because it has loads of torque really, but rather has a lot more POWER than other motors do down that low. A motor with 400 foot pounds of torque at 1,200 rpm will had TWICE as much POWER as a motor with 200 foot pounds at 1,200rpm.

But that is why most lower displacement motors are high revving and have more gears that end sooner. Because they don't have displacement to create huge amounts of torque, they go for RPM instead, effectively giving you similar results. 50hp available if you go full throttle after gear engagement is the same feeling of power weather is a V8 just off idle, or a high HP small displacement motor.

I could also write you guys a book about gear ratios and torque multiplication but I don't see the need to yet. I'm just trying to get across the fact that there are many stereotypes that we're touching on here and I hope this is a grown up enough forum that we can look at the REAL facts and translate them into REAL world experiences. Not just throw around mis-information as though it was fact.

Fact: The subaru motor is a low revving 4 cylinder, and has NO problem moving the large 4 door WRX and STI around.

Fact: Shave a WRX down to 1800 pounds and you'll be able to take off in 4th gear if you wanted to.

Fact: If FFR is really going with a smaller wheel diameter, gearing will be a problem for MANY people, not just a few that don't like to shift.

I personally think the easiest solution, though not cheap, is to just throw in a LSD for the front diff and while it's being taken apart put a different ratio gear set in it. Get it down into the lower 3's and most of the issues brought up will be solved.

[LifeIsOnTheWire]

well put Gollum. I like your last idea, about using a different ratio differential. that is the idea that has been going through my head.

although one will need to be careful what ratio one chooses. a ratio that accommodates gears 1-2-3, might create unfavorable performance in 4-5.

im going to have to do some homework here to decide which OEM suby gearset best accommodates the different differential ratios that are available, to create the best balance of performance in all the gears.

[PhyrraM]

Fact: If FFR is really going with a smaller wheel diameter, gearing will be a problem for MANY people, not just a few that don't like to shift.



Explain please?

[LifeIsOnTheWire]

Explain please?

what he means is, a smaller wheel diameter will effectively determine the true 'final ratio' of the vehicles drivetrain (technically speaking, the wheels and tires are a component of the drivetrain, and their diameter directly affects the speed achieved given 'XYZ' rpm).

if FFR gives us really large wheel wells, that gives us the opportunity to use larger diameter wheels/tires. that effectively changes the drive ratio, and in effect gives you longer gears.

[thebeerbaron]

what he means is, a smaller wheel diameter will effectively determine the true 'final ratio' of the vehicles drivetrain (technically speaking, the wheels and tires are a component of the drivetrain, and their diameter directly affects the speed achieved given 'XYZ' rpm).

if FFR gives us really large wheel wells, that gives us the opportunity to use larger diameter wheels/tires. that effectively changes the drive ratio, and in effect gives you longer gears.

Right, what I don't get (and what I think Phyrram is questioning) is that these ratios (determined by the gearbox, the final drive, and the wheels) all work just fine on the WRX. If they're not changed for the 818, why is this suddenly a problem? Lighter weight means the car will accelerate faster, sure. You'll reach redline faster, but redline in 1st will still be Xmph, redline in 2nd will still by Ymph, etc.

I suspect someone is going to say something about turbos and "spool", which is going to make me shake my head and reread Maximum Boost (http://www.amazon.com/Maximum-Boost-Turbocharger-Engineering-Performance/dp/0837601606/ref=sr_1_1?ie=UTF8&qid=1301787492&sr=8-1). If Corky Bell can't teach me, nobody can.

(this is very specifically not directed at anyone in particular, but is something that's been on my mind) I wish there was an easy way to tell who on the internet actually knows what they're talking about (and is expressing it effectively) and who doesn't. Without it, I keep having to re-read stuff to make myself an expert on it again so I can tell who's talking out of their tail. I've got far too many projects going to be constantly reading up on all this stuff! Alas, this is no easier on the web than in real life!

[Gollum]

Explain please?

I'm saying we don't have any hard evidence as to what wheel height they're going to design the suspension around. My personal hunch is that they're going to keep it under 25" and might end up shorter than a stock WRX.

If you're asking why I'm saying it will be a problem for MANY people, I'm hinting towards the fact that nearly every lightweight car like this I can think of uses a close ratio gearbox for a reason. A wide ratio box just wastes gears at the bottom since it doesn't take much to get the mass of the car rolling. If you have a large V8 with a broad power band and 4,000 pounds to move a wide ratio box is AWESOME. But it simply won't match this application well.

Thus I'm stating that the stock box will most likely end up not being well suited to the 818 as completed. With the power/weight ratio it's going to have, it's going to have way more gear than it needs. I personally would suggest dropping the diff ratio enough to make it basically a 4 speed on the track, with a 5th gear for cruise. There's just no need for the high ratio of the stock WRX or STI.

I know a lot of gearing comes down to personal preference, but it's not something to be overlooked.

[Steve91T]

Please stop worrying about the gear ratio. It will be just fine. There's nothing we can do about it. Like I said earlier, when the budget allows, simply put a different gear set in it.

Of course there will be those who drop $50,000 on this thing. You know they will have the perfect gear ratio.

[LifeIsOnTheWire]

Right, what I don't get (and what I think Phyrram is questioning) is that these ratios (determined by the gearbox, the final drive, and the wheels) all work just fine on the WRX. If they're not changed for the 818, why is this suddenly a problem? Lighter weight means the car will accelerate faster, sure. You'll reach redline faster, but redline in 1st will still be Xmph, redline in 2nd will still by Ymph, etc.

what you are explaining is exactly my complaint.

my complaint is that because of the lighter weight, the car will accelerate through the gears much faster, meaning i'm now spending more time shifting, than accelerating. if the power:weight ratio justifies making these gears longer to allow 1st gear to cover the same range of speed as 2nd gear did, as long as it doesn't bog down the performance at lower speeds, why not eliminate a gear change to get to 50-60mph?

[LifeIsOnTheWire]

Please stop worrying about the gear ratio. It will be just fine. There's nothing we can do about it

I don't want to get all defensive, but please don't feel obligated to follow this thread if we're bothering you. its not like we are discussing this in your livingroom.

nobody is worrying here, we're just bouncing ideas around.

[PhyrraM]

I see the issue. We are defining 'Problem' differently.

There are adapters already on the market to mate the Subaru engine with Porsche, VW, and Audi gearboxes. Between the 4 (including Subaru) and all the companies that make gears for them, the perfect set of ratios for each individual is out there. For the perfectionist with a wallet there is nothing to worry about.



Edit: Upon rereading, this sounds harsher than intended. It's intended as tongue-in-cheek. Theorizing is good, the design thread is full of it.

[LifeIsOnTheWire]

Porsche transaxles would be a great option for gearing, except that now you venture into new territories. A whole lot of questions immediately come to mind: does the transaxle physically fit? do the axle outputs relatively line up?

Aside from that, Porsche transaxles (G50 specifically) are getting hard to find, and they are very expensive to pay to have them modified to be used backwards. The costs of using a different brand of transaxle would probably run you more than just having a WRX tranny custom built with custom gear ratios.

The Audi 01E transaxle is relatively cheap, but it has the same 'problem' as the WRX tranny, the gears are very short.

Alot of great ideas here :) it definitely seems as if the best option is to get a WRX transaxle, and simply change the drive ratio by getting an aftermarket front LSD.

[bbjones121]

I don't understand what the problem is with the wrx tranny. Get a lgt transmission. I have never had a problem with it and my bigger turbo.


Porsche transaxles would be a great option for gearing, except that now you venture into new territories. A whole lot of questions immediately come to mind: does the transaxle physically fit? do the axle outputs relatively line up?

Aside from that, Porsche transaxles (G50 specifically) are getting hard to find, and they are very expensive to pay to have them modified to be used backwards. The costs of using a different brand of transaxle would probably run you more than just having a WRX tranny custom built with custom gear ratios.

The Audi 01E transaxle is relatively cheap, but it has the same 'problem' as the WRX tranny, the gears are very short.

Alot of great ideas here :) it definitely seems as if the best option is to get a WRX transaxle, and simply change the drive ratio by getting an aftermarket front LSD.

[LifeIsOnTheWire]

I don't understand what the problem is with the wrx tranny. Get a lgt transmission. I have never had a problem with it and my bigger turbo.

is your Legacy GT transmission currently installed in a 1800lb car? i dont doubt that the LGT gearing is great for a Legacy GT. try the same gearing in an 1800lb car with the same HP, and you will see my source of concern.

Legacy transmissions have almost the same gearing to all other EJ-series Subaru 5mt transmissions, just some of them had different final drive ratios.

Turbocharged Legacy GT's have the same trannys as WRXs
Non-turbo Legacy's have the same trannys as non-Turbo Imprezas.

[bbjones121]

Well I feel like I will just need to learn to shift quicker. I figure I have it down pretty good though, probably quick enough to handle it in a lighter vehicle.


is your Legacy GT transmission currently installed in a 1800lb car? i dont doubt that the LGT gearing is great for a Legacy GT. try the same gearing in an 1800lb car with the same HP, and you will see my source of concern.

Legacy transmissions have almost the same gearing to all other EJ-series Subaru 5mt transmissions, just some of them had different final drive ratios.

Turbocharged Legacy GT's have the same trannys as WRXs
Non-turbo Legacy's have the same trannys as non-Turbo Imprezas.

[LifeIsOnTheWire]

although, it might be worth mentioning... if anyone is dead-set on having a 6-speed, because they like to show-off or something... a possible cheap option for a 6-speed transmission that might fit, is the new 2010 Legacy 2.5i with the 6-speed transmission (its available as an option in the US i think, here in Canada it is standard equipment)

it is a 6-speed transmission that is NOT related at all to the STi 6-speed, nor is it related to the Legacy GT Spec-B 6-speed. it is based on the standard WRX 5-speed housing. so the overall dimensions might be identical?

my suspicion is that it will follow the trend of subaru giving shorter gears to non-turbo cars. so it may have even shorter gears than the non-turbo Impreza 5-speed. which does nothing to address my concern over gearing, but it may help someone with their heart set on having a 6-speed..

[thebeerbaron]

Ok, I may have been out drinking*, but let me see if I get this straight:

Gollum is worried that the WRX gears are too long for the application.

LifeIsOnTheWire is worried that the WRX gears are too short for the application.

Now that we are all on the same page.

Gollum, I don't understand this:
With the power/weight ratio it's going to have, it's going to have way more gear than it needs. It's probably because I'm an idiot and need things explained to me several times, so please help me understand where you're coming from.

This is my train of thought, please correct me if I'm wrong: Lightweight cars with very little power use a very short gearbox to optimize street-oriented acceleration at the expense of top speed. I don't think my old Sentra got to 60 until well into 3rd gear, but it felt snappy because the first two gears used lots of engine RPM to accomplish a few MPH. If you had suddenly doubled my engine HP at every RPM, first gear would have been a useless cloud of smoke and second and third would probably have been usable. If you had then added 2000lbs to the car, I probably would have wanted 1st gear back to get the car moving.

So I can see the 818 creating tire smoke and banging off the rev limiter since it will have more power in certain gears at certain speeds than it needs, and it will move from one RPM to another faster too. But I don't see where that is a crippling problem, except for requiring judicious use of the right foot and more shifts per second of acceleration. After my last post, I started wondering whether the turbo would have enough time to get up to speed between gear shifts, but those mathematics are beyond my comprehension today.

Gollum, can you offer your most thorough and detailed outline of exactly what it is you fear? Because I don't think I'm the only one who's lost here.




* when I do drunk posts, look at them for their amusement value, rather then their intellectual content. Because I'm trying to be funny, not smart. Smart walked out the door a long time ago and hasn't been back since.

[Gollum]

Tuned STI running stock turbo. Look at that flat top end power curve. You've got nearly a 3k RPM window of peak power!
http://i22.photobucket.com/albums/b346/Gollumandsmeagol/Photography%20Class/STIDyno.jpg

I just graphed out the 2006 WRX 5 speed gears, and the only transition that comes close to dipping bellow that peak HP range is 1st to 2nd. But you can practically shift from 2nd to 4th and still be in peak power, making 3rd nearly worthless.

That's the "problem" or "issue" whatever you want to call it that's being brought up. Some people don't want to waste time rowing through gears when it's not needed.

I've owned and driven CRX's with a measly 160-200hp that with their close ratio transmissions and insane gear ratios could out run (out of the hole) most relatively stock modern V8 muscle cars. With their low weight and close ratio tranny they could keep at that peak HP very easily. The downside is that they cruise down the highway at over 4k and topped out in 5th gear before 160mph.

I brought up changing the diff ratio because it WON'T break the bank on one of these builds. I also think that just like the Roadster and other builds, there will be what you CAN build it for, and what people actually DO spend building it because of options THEY chose to have. Most have said they'd be willing to pay more for a hard top. Same goes with LSD and diff ratio changes. You'll spend over $1,500 on an option LSD most likely, so what's another $300 on diff ratios?

Another good point to think about for those of you that like over-gearing a car. Remember that no matter what response between shifts in a turbo car will never be like in a NA car. Now, I've seen the above dyno'ed STI enough to know that even with the 6 speed it's not a big deal if you're a good shifter. But if you're on a track where every tenth counts, you don't want to waste precious time between gears. The WRX motor HAS the potential for a nice big fat power band. Let's use it! :-D

Also, I agree that this isn't some huge problem that NEEDS to be fixed. It's just a discussion worth having so that possible solutions could be known ahead of time, to further help those that will be looking for this information in the future.

[LifeIsOnTheWire]

Ok, I may have been out drinking*, but let me see if I get this straight:

Gollum is worried that the WRX gears are too long for the application.

LifeIsOnTheWire is worried that the WRX gears are too short for the application.



i think you have that wrong. Gollum and I seem to be in agreement that the WRX gears are too short.

I think what has you confused is that somewhere he said "it's going to have way more gear than it needs." i dont want to speak for him, but I think what he meant is that "more gear" refers to the numerical gear-ratio (for instance, 1st gear on a WRX tranny is 3.51 or something) a higher number means a shorter gear.

this is my take on the misunderstanding, I'll let Gollum speak for himself :P

[wjfawb0]

I know on monster miatas (~2500lbs) the T5Z with a 2.95 first is desirable to handle the V8 torque and small tires versus the 3.XX in the typical T5 meant for V6s or older V8s that made less than 300 lb-ft in a 3000lb car. Shifting didn't bother me so much with the AWD, but the STI 6 speeds I owned required a lot of shifting for drag racing or "spirited" street driving. I regularly skipped gears in those cars just like I did with my 03 Cobra mustang, but the instant torque in the mustang was much more satisfying.

[PhyrraM]

IIRC, the ring is pretty standard. However the pinion and shaft are long, about 12", and travel inside the countershaft from the center diff.

I'd guess about $1000 for custom ring and pinions, with an order of ten or so. $750 for 20.

[Benji]

If it hasn't already been noted you can probably bank on the wheel wells being able to accommodate the stock wheel sizes at a bare minimum so to be able to re-use the stock wheels from the donor, whatever they may be (18's?).

[Gollum]

More Gear = More reduction. A 1:1 ratio would be "no gear" like most front engine rear wheel drive car's 4th gear. If one 1st gear was 3.5:1 and another was 3.0:1, the 3.5:1 would be considered to have "more gear" because it has more assistance from the gear ratio, or more offset. I find this terminology to be more descriptive than the usual tall, short, deep, wide, ect that get used poorly all the time.

I really doubt it's going to cost $1000 for a ring and pinion, because I doubt it will be custom. I'll have to do some research, but I bet mix and matching some OEM pieces can get us some favorable ratios. If not mistaken, I'm sure there's some aftermarket ones considering the ratios being sold for the rear diffs.

[LifeIsOnTheWire]

If it hasn't already been noted you can probably bank on the wheel wells being able to accommodate the stock wheel sizes at a bare minimum so to be able to re-use the stock wheels from the donor, whatever they may be (18's?).

this is what I'm thinking too. stock WRX wheels were mostly 16".

[PhyrraM]

this is what I'm thinking too. stock WRX wheels were mostly 16".

'02-'05 - 205/55 R 16
'06-'07 - 215/45 R 17

Not sure on STI, but still 17" until the new bodystyle in '08.

[thebeerbaron]

Gollum, LifeIsOnTheWire, thanks for clarifying. This thread makes much more sense now. Great to know that the gearbox will keep the engine in its sweet spot, and I get your point that third may be useless.

I'm just glad we all seem to agree that this will be a down-the-road problem rather than a "the sky is falling NOW" problem :)

[bbjones121]

Gollum, LifeIsOnTheWire, thanks for clarifying. This thread makes much more sense now. Great to know that the gearbox will keep the engine in its sweet spot, and I get your point that third may be useless.

I'm just glad we all seem to agree that this will be a down-the-road problem rather than a "the sky is falling NOW" problem :)

Agreed, these are all theoretical assumptions. See how it goes, then fix later.

[LifeIsOnTheWire]

yup, just things to think about. you'll have better things to panic about when you actually start your build, trust me :P

[boarder2k7]

If gearing is so annoying and such an issue, whats the problem with just skipping a gear?

In my BMW 318i I regularly shift 1-2-4 when I'm going up to cruise at most road speeds. While driving I also very rarely use 1st gear unless I'm getting below about 5 mph.

If you want performance and max acceleration you'll want to use every gear, but if you're just streeting it, which is where I think most people find short gears annoying, you can always just skip them.

-B

[LifeIsOnTheWire]

If gearing is so annoying and such an issue, whats the problem with just skipping a gear?

In my BMW 318i I regularly shift 1-2-4 when I'm going up to cruise at most road speeds. While driving I also very rarely use 1st gear unless I'm getting below about 5 mph.

If you want performance and max acceleration you'll want to use every gear, but if you're just streeting it, which is where I think most people find short gears annoying, you can always just skip them.

-B

this wouldnt be a daily driver for me. i dont have any problems skipping gears, but that doesn't fix the performance side of things.

[bbjones121]

It would be a daily driver for me. I don't have any problems using a manual transmission and having to shift. I also don't have the budget to be burning tires up, so I don't see me having to shift gears an exaggerated amount of times as quickly as I can.

[boarder2k7]

this wouldnt be a daily driver for me. i dont have any problems skipping gears, but that doesn't fix the performance side of things.

Yeah I guess it just comes down to you can spend as much money on customizing it as you want, and hopefully it will be good enough on its own. ::shrug::

-B

[StatGSR]

I got a great resource for you guys wondering about subaru gear ratios....

http://www.gearhack.com/docs/Subaru%20Transmission%20Chart.html.files.hidden/Subaru%20Tranny%20Chart.pdf

enjoy!