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-   -   WRX max hp on stock internals/stock tranny? (http://www.wrxtuners.com/forums/f121/wrx-max-hp-stock-internals-stock-tranny-30409/)

najeezy 03-11-2011 12:46 AM

WRX max hp on stock internals/stock tranny?
 
Hello everyone. I'm in the market to buy a 2011 wrx hopefully within this year, and ive got a few questions. sorry for the abrupt first post :[

anyways, ive been on the site a while, and i searched a bunch of threads, but i cant seem to find a definitive answer. What i was wondering was around how much whp does the stock tranny on the '11 wrx handle? i assume this is the weakest point while upgrading the car, along with the internals. Which brings me to my second question: Max whp on stock internals?

i know there isnt one definitive answer, but a ballpark figure for both would be nice. Im trying to figure out a mod list where i build FOR a turbo swap (internals, injectors, intercooler, tune etc etc...), so that i dont waste any money or time. If a turbo upgrade is in my plans in the future, then what transmissions should i consider? ive heard of some STi tranny swaps into wrx's but im not sure exactly what is replaced, unless its the whole transmission unit.

Anyways, i know its alot of questions, but im trying to gain as much knowledge as i can before i actually pull the trigger on the car. Any help is greatly appreciated. Thanks for the help!

pzr2874 03-11-2011 05:47 AM

This has always been everyones concern (tranny).

It all depends how you treat it. No hard clutch dumps (even though I never did and mine took a dump) maintainence, getting mods together to help the drivetrain, etc....

STi swaps are very costly, if you do any modification to the 5 speed in the WRX, get a strong set of gears and clutch and flywheel combo. Go to andrewtech.com for details on the tranny.

To make a long story short, get the tranny done FIRST, then do the power and handling mods next. Save the headaches.

Welcome to the forums.

RcrsWetDream 03-11-2011 10:29 AM

Meh, power holding really hasn't been determined on the 08+ transmission yet. By that I mean there haven't really been any cases of a gear blowing up yet. There have been a couple reports of syncro issues, but they're few and far between. There are a good number of guys pushing over 400whp/tq through them as well.

Internals would be where I start (and am) if you want to add a lot of power. If you stick to the stock turbo the internals should be ok given a good tune. The pistons are the weak point and they don't like a lot of knock, so a good tune is key.

If you plan on upgrading the turbo, however, I would do some forged 2618 pistons at a minimum. They can withstand a lot more abuse/power than the stock cast pistons. Generally though, 350whp is where you can start to worry about your pistons.

IF you want to do the transmission the big name is PPG and you can budget anywhere from $3,500 just for the gears all the way up to $6,000 for the gears, shafts, forks, decent clutch, differentials and installation. Other brands some people use are Albins (also good like PPG), Mfactory (not the best).

pzr2874 03-11-2011 11:10 AM

09-10 WRX's are in fact having gear issues, though not sure of the 11's.... A couple folks on here and several on NASIOC.

Why chance it.

Hondafan 03-11-2011 11:54 AM

+1 for what Chris said. The pistons are a weak spot. Mine went before 20K. You're planning on modding the car, so there's no chance that the dealer will cover a blown ring land at that point. The transmission can handle the power if you're not dumping the clutch. Look at BoostAddict's build. He was pushing a lot of power doing drag races, along with a lot of torque, but he stayed with the stock clutch for a while acting as the "fuse". I never have had a problem with a transmission on a WRX (nor my STi - knock on wood) even doing autox. I would focus on internals, then go for the transmission.

synolimit 03-12-2011 11:49 AM

[quote=pzr2874;257802]09-10 WRX's are in fact having gear issues, though not sure of the 11's.... A couple folks on here and several on NASIOC.

Why chance it.[/quote]

please link, ive never seen any. if fact ive come aross a half dozen guys that like to drag race, have ACT HDSS clutches, and over 400TQ some using E85 and all is well! however i have seen above 375HP blow motors with pistons breaking apart.

RcrsWetDream 03-12-2011 12:48 PM

If anything I've seen isolated syncro issues, which is a far cry from stripping the teeth off third gear like years past.

I can't say I've heard of an actual destroyed gearbox.

synolimit 03-12-2011 02:06 PM

what does rebuilding a tranny do with the syncros? like does PPG have there own thats stronger than OEM?

EDIT think i found my answer. not sure if they come with the new gears but i do see PPG makes stronger ones.

as for their gear ratios, all of PPG's are smaller than OEM, that mean your in each gear longer or shorter?

mosc 03-12-2011 04:01 PM

PPG's aren't really smaller than OEM, they have a tighter ratio (shorter, more closed) which means they redline at a lower speed.

RcrsWetDream 03-12-2011 04:30 PM

I think andrewtech has their own ratio (not all the time, just when they can get them) that is actually longer than the oem 5-speed, to the point that there isn't a very big jump at all from the ppg 4th to the stock 5th gears. Good for big turbo's that like being in gear.

Shorter gear ratio: faster acceleration, lower top speeds, more shifting, good for road courses with more turns than straights (auto-x for example)
Longer gear ratio: slower acceleration, higher top speeds, less shifting, better for drag or road courses with long straights and less turning

I'm not sure how the ppg syncro's compare to oem subaru stuff, but I believe they are carbon reinforced so they are stronger.

operadude 06-03-2011 02:51 PM

I have hundreds of quarter mile runs on my 300whp WRX. I changed the clutch once because it was no longer good enough to hold the power. I then installed the ACT Stage II clutch and Streetlite Flywheel. it lasted 10k KM. Problem was not abuse. Some of the spot welds from the pedal assembly broke causing the clutch to not engage properly. I had to tear out the dash, sand down to the metal, reweld, etc. Intalled new clutch, no trasnsmission problems.
My bottom end did blow up though at 75K KM and I since installed an EJ257 short block with CP forged pistons. We checked the transmission again when we took out the motor.
Dont buy a transmission until it blows. If you want to play, have about $15K in reserve for when your motor and possibly transmission blows.
The transmission seems stronger than a lot of people will have you believe. It doesn't mean it won't break though so start your budget now before modding the car.
My opinion is the pistons are a weaker link than the transmission. This was my personal experience, yours may vary.

turmic 06-07-2011 09:24 PM

Well, 02-07 transmissions will break much easier than the LGT gears.


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