There are way too many variables to estimate. More than the wrx transmission under similar conditions.

 

very good, but could you help me with some convenient modifications so that my transmission can support the 500whp?

 

It may handle it, it may not.

You are asking for it to hold 2.5 times the OEM output for which it was designed. It might be fine: the STI transmission is pretty overbuilt, but no guarantees.

Sent from my SM-G960U using Tapatalk

 

If we can link YouTube videos on here there’s a video of a master Subaru transmission rebuilder And if I remember correctly he says the six speed sti transmission begins to fail at 625 hp. I would assume that’s based on a solid, well functioning starting point. I’ll have to find the video to confirm what he said though. So don’t quote me.

 

^^ I liked this post.


To be nitpicky, the Automotive Engineers prefer to think in BMEP rather than what you have called "compression ratio," but I get your point.

 

I was wrong. This guy talks about 900 hp is where the STI 6 speed starts to show failure. If you follow Bader Built he’s dragging 1100 hp on a stock sti transmission.

 

That is cool.

 

I am just shaking my head. 1)I actually own a 650HP / ~570ish rear wheel HP car. It's 10L90 transmission is rated for 900 pound feet of torque. That is the manufacturer's rating. I would guess that Subaru would have a similar type of rating number that can be found for the STI. That's just a guess.

The thing about building any car is that you are always finding the next weakest link.
Brakes? What type of rotors? What type of pads? What type of brake fluid? What type of brake lines.

Cooling? What type of radiators? How many (transmission, steering, eDiff)? My Bucket of Bolts has 11 and a very tasty carbon fiber heat extractor as part of the hood. It has three radiators across the front section, alone.

Differentials, half-shafts, motor mounts, clutch, drive shafts, etc. Break one, fix it and then find the next weakest link.

Costs? Cost of the car? Cost of the build? $25,000 reserve funds to fix what breaks as they do break.

I do have just a little bit of experience with automobiles, tracks and strips. I have seen my share of professionally built cars oil tracks and strips across a fair sized piece of our country. Yes, you sit in the paddock, in your run group, waiting to cross the white line as the clean-up crew goes about the very important job of cleaning the track and making it safe for the rest of the event. I think at NCM Raceway, that cost was $1,500-$2,500. COTA is stupid expensive. You pay that before you leave.

 

I am just shaking my head. 1)I actually own a 650HP / ~570ish rear wheel HP car. It's 10L90 transmission is rated for 900 pound feet of torque. That is the manufacturer's rating. I would guess that Subaru would have a similar type of rating number that can be found for the STI. That's just a guess.

The thing about building any car is that you are always finding the next weakest link.
Brakes? What type of rotors? What type of pads? What type of brake fluid? What type of brake lines.

Cooling? What type of radiators? How many (transmission, steering, eDiff)? My Bucket of Bolts has 11 and a very tasty carbon fiber heat extractor as part of the hood. It has three radiators across the front section, alone.

Differentials, half-shafts, motor mounts, clutch, drive shafts, etc. Break one, fix it and then find the next weakest link.

Costs? Cost of the car? Cost of the build? $25,000 reserve funds to fix what breaks as they do break.

I do have just a little bit of experience with automobiles, tracks and strips. I have seen my share of professionally built cars oil tracks and strips across a fair sized piece of our country. Yes, you sit in the paddock, in your run group, waiting to cross the white line as the clean-up crew goes about the very important job of cleaning the track and making it safe for the rest of the event. I think at NCM Raceway, that cost was $1,500-$2,500. COTA is stupid expensive. You pay that before you leave.

Appreciate your common sense being put forward....and in terms of the 'next weakest link' ...and then there is the cost of your life passing focused on a car.