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1997 Brighton 2.5
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Discussion Starter #1
I'm still making plans on the swap for my mighty Brighton. I have a guy who is willing to sell me everything from a 2002 RS, (entire engine, harness, tranny, driveshafts, diff, brakes, everything up to the wheels) for $2600 obo.

Just wondering how much HP you all think that tranny can take, vs. a WRX tranny. I mean, reliably, daily driving, and an occational auto or rally cross. I'm not looking to beat the stink out of it, just want it to be there when I need it.
 

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If it's a stick, second gear is the weak link when turbocharged, something like 300hp will kill them. Other than that, you should have no problems. However, I have heard guys with turbos and no problems, except they don't power shift from 1-2.

The automatics can handle oodles of power - something like up to 500 hp.
 

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1997 Brighton 2.5
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Discussion Starter #3
Yeah, manual for sure. If anyone wants to tell me how great an automatic is for a turbo RS, I already know. And I know I will never be happy with that setup.

300 HP seems to be the number I often see before WRX transmissions go pop. You think the RS tranny can handle that much?

Correct me if I am wrong, didn't the WRX get a little stronger tranny?
 

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13 Years of RS
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I don't think the WRX trannies were any stonger than the RS trannies, but the WRX doesn't make as much torque at the same HP level as a boosted 2.5L. Whick is why a WRX can put out 300hp and the tranny will be OK, but the RS can only make about 250-275 before the tranny pops. More displacement, more torque, especially boosted.
 

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1997 Brighton 2.5
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Discussion Starter #5
First, are you sure it's the same tranny? Why have I been thinking the WRX tranny had some stronger something? Am I making shit up, in my own head? I'm getting old.

Second, my thoughts on a Turbo are to use something that isn't going to hit until about 4000 RPMS. That's about the point that the RS falls all over itself. If the tranny can handle the torque up too that point, I figure it can handle it all the way to 6000 RPMS. I'm not talking about boosting up to ridiculous levels either. Just "correcting" a flat top end.

OK, here's my logic. Mind you, I am not of sound mind.

RS= 166 Ft/LBS at 4000 RPMS
WRX= 217 Ft/LBS at 4000 RPMS

Hmmm....they both hit max torque at the same RPM. Now, we know, the RS pulls stronger below 4000. We also know that HP and Torque curves are largely linear in any given engine.

So then, can we assume that in either a WRX, or a 2.5T, the tranny will be able to take the increase in torque, provided you do not increase the bottom end torque? As in, y'all been doin it wrong...get a "slower" turbo. Slower spool up, that is. That way you do not increase the already higher torque levels down low, when the engine is struggling against low inertia? Once you get things moving, then go ahead and pour on the WRX power. But never before.

My thought is that if the WRX can run up to 300HP, so can the 2.5T. You just need to put the power on in the right place. Also, it's very late, and I have not slept, so this all might be a figment of my imagination.

Whatcha think?
 

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1997 Brighton 2.5
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Discussion Starter #6
Hey, here's another sleep deprived thought. What do you think the stress of a lightened flywheel and crankshaft pully are on a tranny. Not so much the increse in power, but the severe off throttle abruptness in engine inertia. I've never driven a car that has seriously lightened the two, but I know that many people replace both, and I hear it makes for quite a difficult car to drive. As in, take your foot off the gas, and you get an engine braking effect equivilent to that of a big rig. Probably not too good to jerk gears in a tranny like that, I would think. Possible that this is contributing to some of the 2nd gear (coasting gear) failures? Or am I overthinking?

BTW, I always hear of second gear, and not first. Makes me think that people are just abusing it. Wouldn't first gear be even more susceptible to breaking, as it gets that low torque from a dead standstill? That is, vs second, which gets it when the car is at least rolling.
 

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First gear is physically larger than second gear in our trannies, so it can take more abuse. The problem is the power shifting from 1-2 which slams second gear and kills it. There is simply too much power and torque at the same time for second gear. First gear has plenty of power, but since it's geared differently, it's not a full torque load against the gear - it's more horsepower. Second gear is all torque though (basically) so it just kills it.
 

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there are a couple of comments i would like to make.

first, to the best of my knowledge, the WRX and RS gearbox is the same with the exception of the gear ratios. the WRX has taller gears and FD. for this reason alone i would take the RS gearbox over the WRX gearbox for a swap, unless you're big into highway racing :p

First gear has plenty of power, but since it's geared differently, it's not a full torque load against the gear - it's more horsepower. Second gear is all torque though (basically) so it just kills it
not true. the torque going through the tranny is the torque made at the crank multiplied by the gear ratio. it is later also multiplied by the FD ratio, but that's after the gearbox, so we don't care about it here :) first gear generates the highest torque output, plain and simple. this is true for just about any car. the reason people break second gear so often is that they are jackasses :) there is still lots 'o torque in second gear, as we all know. what is happening to break the gears is a nasty little bugger known as shock loading. what's happening is these people aren't shifting smoothly and not matching the revs properly, even on upshifts. they then drop the clutch and the crank and tranny are not at the same speed. when they are put together, they are forced to travel at the same speed. no doubt we all have experienced a poorly timed shift with the thunk and lurch. well if you don't let the clutch take up the slack over time and instead force the drivetrain to do it all at once, you end up producing HUGE amounts of torque. huge, and all of a sudden. this shears gears. you never hear of someone cruising around town in second gear making XXXbhp and then all of a sudden the gear breaks. doesn't work that way. its always on the shift because people can't drive in this country. there are lots of people making 300+bhp who don't have tranny problems. why? because they are smooth.

anyway, i need to go call the UK. basically, i think it sounds like a really good deal Josh. i'd say go for it. i know you know how to drive, so i wouldn't worry about it too much.
 

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13 Years of RS
2005 Toyota Corolla :(
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I've also heard that part of the reson that second gear breaks is because of the case flexing. When it flexes, it pulls second gear away from the main drive gear, and the extra play in the gears tends to shear the teeth off of second. I seem to remember Larry Ganz saying something like that, anyways.
 

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1995 AWD Brilliant Red Subaru
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I don' know a whole lot about transmissions. I know how they work, but on a very basic level. But, i heard the wrx had a closer ratio gear set that wasn't as tall as the RS's Since the Rs makes more than adiquite power down low while the wrx must wait for the turbo to spool up and this is reflected in the gear ratios and etc used by the wrx. I dunno..like i said..i don't know much about tranny's.
 

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actually, its the RS that has the shorter gearing (remember, the higher the number, the shorter the gear). not only that, but the final drive ratio is also shorter.
 

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found some numbers:

WRX
Gear ratio
1- 3.454:
2-1.947:1
3- 1.366:1
4- 0.972:1
5- 0.738:1

FD: 3.9

02 RS (i think its the same for the older ones as well, i know the FD is correct)
1st Gear Ratio 3.454
2nd Gear Ratio 2.062
3rd Gear Ratio 1.448
4th Gear Ratio 1.088
5th Gear Ratio 0.78

FD: 4.11

STi
GEAR RATIOS: 1st 3.636
GEAR RATIOS: 2nd 2.375
GEAR RATIOS: 3rd 1.761
GEAR RATIOS: 4th 1.346
GEAR RATIOS: 5th 0.971
GEAR RATIOS: 6th 0.756

FD: 3.9
 

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1997 Brighton 2.5
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Discussion Starter #13
soooooo....

any thoughts on my idea of fitting a 2.5 with a turbo that has lag up to 4000 rpm? It sounds strange to me, but think it's where the power needs to be to not break things.
 

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I have a wrx gear set in my rs . I think its supposed to be a little taller gears than the stock rs when put with the stock 4.11 (I havn't done the calculations to see how much) . You probably won't notice the difference anyways and both gearset seem to be made the same with no strength differences . Not 100% sure. Just get whatever is cheaper .
zaidoun
 

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2000 Slingshot RS-T
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My friend and I have had our RS-Ts for a few months now. Yes, we are under 300hp (Ludespeed Stg.2), but people have blown transmissions under N/A! I believe it is in the way the tranny is shifted. You can't do the same shifting on an AWD tranny as you would a FWD or a RWD car for that matter.

Thats just my thoughts, but what do I know. :rolleyes:
 

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1997 Brighton 2.5
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Discussion Starter #16
What kind of HP and torque numbers are you seeing, when do you feel the turbo really hit, and how long has it been on the car?

zaidallas-

Same questions to you. But isn't your car na?


And for both of you-

You think it really is just a matter of not doing 6000 rpm launches, and slamming it into 2nd?
 

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Streetman said:
What kind of HP and torque numbers are you seeing, when do you feel the turbo really hit, and how long has it been on the car?
I haven't dyno'd the car, supposedly wHP & TQ #s are in the neighborhood of 250hp/280tq with the kit. Turbo hits right under 4000, around 3700-3800. We've had them in for 4 months now.


You think it really is just a matter of not doing 6000 rpm launches, and slamming it into 2nd?
DEFINITELY! You do those things, and its bye bye tranny. With the turbo, you can actually FEEL the flexing of the drivetrain under load. And that is with all the mounts upgraded, pretty scary stuff. :)
 

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Discussion Starter #19
Turbo hits right under 4000, around 3700-3800. We've had them in for 4 months now.
Adding the squeeze right on top of the RS's peak torque, just my thoughts. I'm thinking that would be a nice kick in the ass, but a broke tranny could be a swift kick in the ass with that too.

Very serious, as dumb as it initially sounds, I think you would be wise to choose a "slower" turbo, which wouldn't kick until beyond the 4000 rpm peak. Can anyone tell me if I'm crazy?
 

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Well, the power delivery is rather smooth actually! I guess since the RS is so torquey before the turbo kicks in. I do get small signs of torque steer when I floor it in turns now! ;)
Oh, and its just the usual T3/T4 turbine there.
 
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