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Old 05-07-2002, 12:04 PM   #1
kastle
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Default RS-T tranny thoughts

First, I've spent the last few hours doing some searches... and yes, I know the general idea behind this thread is tranny stuff, but I want to discuss this with my RS-T Brothers....

OK, I was thinking that it might be a decent idea to convert my RS-T from AWD to RWD in light of the recent tranny issue's that I've had. So I did some searches and all I got was that Trey Cobb had a center diff that he was using to change out to RWD.... That's about it.

So, what do you guys think? I'm pushing 10psi in my car (or will be when I get the tranny sorted out) and was thinking that my stock tranny would be better off in RWD mode. This way, as the torque increases, it will break free the tires instead of some gears....


Here are a few questions that I have about it?
1) Is this a viable alternative to the dog box or STi 6 speed tranny?

B) Cost aside, what would the long term effects be?

III) Anyone else thinking about this?

Peace.
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Old 05-07-2002, 12:10 PM   #2
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hmm...

I think converting to RWD would solve some of the problems, but it does ruin some of the fun an AWD turbocharged car gives you. What clutch are you using? And what trannys have you tried?
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Old 05-07-2002, 12:21 PM   #3
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I am running the Clutchmaster Stage III clutch with a Jun lightened flywheel.... I have used the stock RS tranny and I recently had my Chalak 1/2 dog with Quaife front diff and Subaru 12G center diff blow up....
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Old 05-07-2002, 12:31 PM   #4
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STi 6 speed? All i can say is if you have the $$$$$$ do it!.

Andy
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Old 05-07-2002, 12:33 PM   #5
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I had posted about this a while back on RS25.com. Not sure how much the thread will be of help to you, but here -- http://www.rs25.com/Forums/showthread.php?threadid=572
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Old 05-07-2002, 12:42 PM   #6
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Thanks 8... that is some good reading..

Andy - I'd rather put a STi 6 speed and engine into a TS wagon, less cutting.... which is my plans for after I sort out my RS-T mess

All, I don't auto-X my car at all. I'm too much of a wuss to do it... same time with rally-Xing the car... All I do is some light street runs and I enjoy going out to the drag races and running the car on occassion.
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Old 05-07-2002, 01:14 PM   #7
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i had simm thoughts but in a differnt context .. converting a SVX to an manual... (the expensive part of which is custom length front drive shafts)

my only thoughts would hinge on that when shiv was tuning WRXs for he converted his cars to FWD not RWD... was that for ease of mod or for sound mechanical reasons?
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Old 05-07-2002, 01:16 PM   #8
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Ya know...iI understand why your doing it but again, then your loosing half the fun of the RS. I mean our cars are AWD that is a major point to the car, there are more cars with better potentional that are RWD. you think you could mabye control the boost in first...mabye 2 psi and in 2nd 5psi and in 3rd 10psi 4th 10psi and 5th 10psi... I think this would be a better way to handel it...I mean supras do it this way (kinda) so they could get traction...so why don't we try that idea? again I do understand why... I hope my opinion you don't find offensive.
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Old 05-07-2002, 01:52 PM   #9
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I've been debating this also , not much options there but I didn't do too much research either . I personally wouldn't mind some RWD action . but then you gotta do the drive shaft/rear diff/ and axles too .
Who said the STI 6spd. is good ?actually isn't it made weaker becasue of the presence of the 6th gear requires smaller gears , or are their gears made stronger or cryoed (I think only RA's are)? I know the silvia guys would rather not use their 6spd.
Also , a general Q's maybe even more tranny involved : Someone said that there's NO driving style that will prevent the tranny from breaking at more than 300 hp's (before you say it ,I know torque is the problem) , but I was driving for a while with maybe over 300 hp's internally and tranny felt fine (knock on wood) , now with my built engine and more boost coming I'm thinking maybe shifting easier alone will still be o.k for my tranny , is that a somewhat valid assumption? I got a not-so-grippy ACT and a JUN flywheel . I'm recalling some RS-T's and rex's having way more than 300 hp's at the flywheel with no problems with their trannys . I really don't want to stay stock tranny forever , just until a more reliable and proven source is present other than the expensive holinger box .
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Old 05-07-2002, 03:14 PM   #10
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This tranny stuff is the question of the ages.I also have no clue as to what I want to do with mine.No matter what gears I get the are issues either with drivability or with lack of overall strength.Not to mention that by the time you get gears,diffs and labor it gets over 5 grand.I am thinking STi 6 speed swap now as well just for the fact that it was meant to handle the high power and it gives mne a better highway gear for mileage.

What I also am waiting to hear is if it handles 350+ HP as well as everyone thinks it will.(Not to mention cost is a little high right now)
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Old 05-07-2002, 03:30 PM   #11
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Quote:
Who said the STI 6spd. is good ?actually isn't it made weaker becasue of the presence of the 6th gear requires smaller gears , or are their gears made stronger or cryoed (I think only RA's are)?
STi 6 speed is a completely redesigned transmission. As such, it doesn't fit in a GC8 car. You however can "make" it fit with some modification of the chassis, namely the trans tunnel. Other after market kits for changing the 5 speed into a 6 speed use the same size gears. You do not have a reverse gear, as that is where the 6th forward gearset goes. They made the 5 speed from the 4 speed by adding a "tail" to the transmission for more space. They were not produced by putting smaller gears in the same case.

The STi gears are nearly identical in range as the regular 5 speed. They do not have an "overdrive" gear, they are just spaced better, so when you shift from one gear to the next you so not have such a large fall in RPM.

If you take the RWD road, make sure to tone down the suspention a bit, the car will be almost impossible to drive straight down the road if you have a relativly neutral set up in AWD then only power the rear wheels. Definatly not a time to have a 22mm rear bar.

People haven't been talking about anyone breaking an STi 6 speed gearbox yet, so it is hard to tell what the relative strengh is compared to what is available aftermarket.

Thats a shame that the gears broke at only 10 PSI.

cheeRS,

Greg
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Old 05-07-2002, 03:34 PM   #12
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Section 8 - Tranny broke @ 6psi... I've since had a new spring installed for 10 psi

my biggest concern with the STi gears, and any of the dog boxes was the amount of torque the 2.5 RS-T's put out. I don't want to spend 5k on a STi 6 speed and destroy it.

Anyone know if the rear diff on the RS is a R160 or R180?
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Old 05-07-2002, 04:17 PM   #13
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Nick (Imprezer) drove his RS-T on the stock tranny for 20,000 miles. He has recently decided to buy a dog box, and tore down the stock box to check for ware. He noted that the synchros showed SOME ware, and the gears appeared to be fine.

I think that if you just take it easy on the stock box and don't shift like an idiot, you will be O.K. for while.

As far as the RWD conversion is concerned, I have some mixed feelings about it. Right now I like DoctorNicks theory of running lower boost in 1st and 2nd, then upping it in the "less prone to breaking" upper gears. This will probably also apply to the RWD, as the incredible amount of torque will want to spin the wheels all the way up to third, so you may have to run the lower boost.

Kastle, my opinion resides in the Chalak Synchro Gear camp. These gears seem extremely promising, as people who have them seem to have nothing but good things to say. Depending on how much HP you are looking for, they are something to consider. I REALLY want to see someone break a set in a 2.5 RS-T so we can get a gauge on what these things can take. The price seems quite reasonable too.

Graham

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Old 05-07-2002, 04:33 PM   #14
kastle
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Graham -- Some things your got wrong in your post...


Nick does not equal Imprezer. Nick is Nick. Imprezer is Alex.
Alex is in a WRX. WRX = 2.0l, not a 2.5l RS-T


Those items being sorted out, if someone wants to donate a set of PAR Syncro gears, I'd use them and see if they break. I've already spent $2200 hundred on gears, I'm not spending another $2000 on a set. That's what I call a waste of my money.
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Old 05-07-2002, 04:57 PM   #15
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Umm, yah I'm retarded, just listen to what Kastle said (I really wasn't sure who was who).

Regardless, if you don't want to spend money on gears, then why are you even considering the STi 6 speed gears, they cost THREE times as much? I guess you put more faith in them.

I imagine that any next step you take is going to be a costly one, unless of course you decide to use the stock tranny.


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Old 05-07-2002, 05:06 PM   #16
kastle
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Just want to clarify something from my first post...

Quote:
Here are a few questions that I have about it?
1) Is this a viable alternative to the dog box or STi 6 speed tranny?
I don't want to, and am not suggesting/thinking about, buying a dog box or STi 6 speed. If I want a STi 6 speed, I'll put it into a MY02/03 wagon when I buy that.
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Old 05-07-2002, 05:36 PM   #17
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Here's a thought, STOP DRAG RACING. This is the center of all your concerns. If you really want to continue drag racing, launch the car in second gear. The shock loads produced by quick, nasty one two shifts are the main reason RS trans are blowing up.

I've blown two trannies, both because of 1st to 2nd shifts. They both happened one after another, two years ago. Since then I have quite drag racing completely, and haven't had one problem. Over 25,000 miles sense the last trans rebuild, and still running strong. Even if the trans blew now, a replacement is both cheap and easy to come by.

But, hey if you need to prove how fast we all know your car is, by all means by a hollinger gearset. It will solve your current problem and bring up a host of driveability issues.

Cheers,

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Old 05-07-2002, 06:22 PM   #18
kastle
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Hollinger = dog box.

I'm not interested in spending $6k on a tranny. Drop it.
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Old 05-07-2002, 07:13 PM   #19
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Well, I have to agree with Matt on this one, stop racing and you'll be fine, he's proof of it.



Quote:
I don't want to, and am not suggesting/thinking about, buying a dog box or STi 6 speed.
Well then, I think your clean out of options, so go ahead and convert to RWD and let us know how it turns out.


Graham
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Old 05-07-2002, 08:22 PM   #20
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the way i look at it is, what good is all the power you have if you can't use it to its fullest because you have to worry about blowing the trans. I'm almost in the same boat as kastle here. I blew my motor at only 7psi and am in the process of having a motor built. I plan on running 15-20 psi everyday and am in need of a solution to my trans. problem and do not want a dog box. Sure I could baby the stock trans. but what fun is that.
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Old 05-07-2002, 08:48 PM   #21
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You'll hate this solution.............


Slushbox.



But or coarse,with 350horses in a 2700lb car I'm sure it would still be fun.

Also,cant the center diff be welded and the front diff removed to make a RWD?
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Old 05-07-2002, 09:05 PM   #22
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As I understand the process, the center diff is welded and you can remove the front diff / axle.

But I'm not 100% sure on that.... Anyone answer this for me.... Is our rear diff a R160 or R180?
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Old 05-07-2002, 10:18 PM   #23
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again, I think the issue is Boost control. think about it. we don't need all of our power in 1st...heck we got awd. We will pull no matter what off the launch, then second and third and going into forth and fifth you can up the boost. Realy the problem is...why have full boost in first? we don't need it.
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Old 05-07-2002, 10:26 PM   #24
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The thing that keeps bugging me everytime I think about this is that I bought a AWD so That I could avoid wheelspin and get all my power to the ground,Not to mention that I wanted the ability to drive the car all year round despite rain,sleet or snow.

To convert to RWD will take all these variables and toss them in the trash.There has top be a better way.
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Old 05-07-2002, 10:37 PM   #25
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I understand completely..... I really enjoy AWD... I don't have to worry about rain, snow or sleet here in AZ... but I like AWD none the less...

I really am not sure what to do. I want to run ton's of boost, but it's looking more and more unlikely. I'm rather disappointed to say the least....
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