enhance gears for the subaru WRX
enhance gears for the subaru WRX
(OP)
As most of all you know the gears on the WRX transmission are really weak. In 06-07 WRXs the 3rd gear is specially weak and is the only one that fails. I'm just wondering what will take to make the 3rd OEM gear out something stronger like steel 9310? What will it happen to other gears? Do you know of any gear vendors that can do this?
thanks
thanks





RE: enhance gears for the subaru WRX
RE: enhance gears for the subaru WRX
1-2 are really beefy, 3 is not, 4-5 are not a problem. I will have to make 3-4 because they are assemble together.
thaks
RE: enhance gears for the subaru WRX
Regards
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RE: enhance gears for the subaru WRX
I'm looking for input of what I want to do, I don't what to buy the whole tranny I want to fix what is breaking and go from there. Please help
Thanks
RE: enhance gears for the subaru WRX
You unduly minimize the cost and risks of reverse engineering. It's not that easy, and a CMM doesn't make it easier.
Mike Halloran
Pembroke Pines, FL, USA
RE: enhance gears for the subaru WRX
Two ways you can increase the life of the 5spd WRX transmission are:
1. go to dog cut gears, this will allow the gears to tolerate the higher misalignments present in the 5spd when at 2x the factory torque output.
2. Do NOT sidestep the clutch. Ever.
How did you select 9310 steel? why do you say its strong....
teh helical cut and involute tooth profiles require a multi Axis wire machine, then a full heat treating process, and finally finish grinding to provide the accuracy required.
you could expect to pay >$5000 for a one off part, made right........
nick
Nick
I love materials science!
RE: enhance gears for the subaru WRX
Hopefully sanity will prevail.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: enhance gears for the subaru WRX
Google is your friend
If MFactory made a close ratio gears with custom ratios and sell 1-5th with a main shaft made out of 8620 for about $2300. Why copying 3-4th gear and make it out of 9310 and mass produced will be more expensive?
Are you from NASIOC? why are people on that board so close minded? Is like when along time ago I make a thread about using E85 and they were like no is not worth it etc,y
Now if you go to EVOM a good number of cars are running E85 and making more power than car on meth and race gas lol. Soon my WRX with a VF39 will be on E85 and it will be faster than car runing 20gs and greens on pump gas lol. And when they say that VF39 will not make more power at 20psi, now the fastest ones are running 25psi and more safely.
Any ways I am looking for input on the process that I need to follow in order to make this happen. Also I am looking for gear vendor that maybe one of you guys know. Please don't make comments that this will not work that will be to expensive, let find this for myself.
Thanks
RE: enhance gears for the subaru WRX
Half a dozen custom gearsets is "small lot manufacture". There are guys who do this sort of stuff, but if you expect them to invest in tooling, you have to be able to show them that you'll be back, in a day or a week or a month for another half dozen... or you have to buy the tooling for them. It will make custom gears look cheap.
At this point, searching for suppliers is pointless; what you need first is _customers_, lots of them.
Mike Halloran
Pembroke Pines, FL, USA
RE: enhance gears for the subaru WRX
My position now is you can have your money back.
No further comment.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: enhance gears for the subaru WRX
RE: enhance gears for the subaru WRX
RE: enhance gears for the subaru WRX
ISZ
RE: enhance gears for the subaru WRX
The issue with the WRX transmission is more a design issue than a materials issue. The basic design is almost 30 years old. it was designed for motors whose torque output was ~50% of the 2.0l in my 2002 USWRX.
With the 2.5l motor in the current model the ability to modify for higher torque is verging on ridiculous. At these torque levels the case flex becomes severe, causing the stock helical cut gears to fail.
That said, the modern 6spd subaru transmission is from all reports, quite stout.
JuanMedina- There you go. If you do decide to go with a custom gearset I would reccommend using S7 tool steel hardened to ~55HRc. This would be an optimum material. The heat treat is far simpler than that required by 9310, a carburizing/nitriding grade. Also S7 was developed for shock loading, since you're likely a drag racer.
As an aside:
I have 160,000miles on the stock subaru 5spd. All I've ever needed to do is use good gear lube, Redline heavyshockproof w/75W90. I've competed in over 5000miles of "brisk" TSD Rally, and done some really silly stuff with this car. I have no problems with the synchros, gears, or shift linkage. I have blown the center diff viscous retaining ring, that happens after thousands of full throttle slippery surface starts. I will be replacing it with the more aggressive STi GrpN component soon. I love my WRX, and no You cant have her.
Nick
I love materials science!
RE: enhance gears for the subaru WRX
RE: enhance gears for the subaru WRX
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ISZ
RE: enhance gears for the subaru WRX
What is the second biggest transmission misconception? Case flex occurs within Subaru transmissions.
RE: enhance gears for the subaru WRX
Anyway, for juan's purposes there is nothing short of unobtainium that can solve a gear breakage problem on a 5spd WRX transmission.