My 4th gear went (and took the rest of the transmission with it) at 20-21 psi 92 oct on a 71HTA which I would guesstimate is around 300-320 ft-lbs of torque, 320-330 hp. That was doing 30 minute sessions with 30 minute downtime between sessions. Prior, I had only done 20 minute sessions with 40 minute downtime between sessions and it had been working fine.

So, on the road course, until I setup the transmission cooler, the limit is 20 minutes/hour of on-course time. I also have the Shep upgraded gearset for 3rd, 4th and 5th now.

 

With the upgraded gear set what could you expect it to handle? im torn between ditching the 6 and going 5 because i do a lot of highway driving so 6th is nice

 

Shep hasn't said anything related to torque or heat. They have said previously 650HP with a cooler and 550HP without. But, that doesn't relate to torque.

 

hmm i may have to look into that because i dont plan on going over 650 hp

 

450

 

This is a huge misconception that you will magically get horrible mpg becuase you lost 6th gear. I had a 6spd until 90,000 miles then swapped it for the 5spd. The difference cruising on the highway is about 200rpms at lets says 70mph. So I wouldnt keep the 6 speed just based off highway driving

 

i've been doing HPDE and GTA with with power levels in my sig. usually right around 350whp and two at around 450whp. so far, so good. *knock on wood*

 

Just because this takes me 5 seconds...

With a 25.3" tall tire:

A Evo 9 5-speed at 70 mph: 3204 rpm
A 6-speed at 70 mph: 2923 rpm

A Evo 9 5-speed at 80 mph: 3661 rpm
A 6-speed at 80 mph: 3341 rpm

I drive my car 100 miles/day at mostly 70-80 mph. That rpm makes it quieter from when I had a 5-speed. I can't speak to any increase in mpg because I never paid attention when I had the 5-speed.

 

^ I think what was stated above is pretty significant. A drop in 500rpm cruising on the highway will make a significant difference. As for MPG that is more closely related to load on the vehicle rather than specific RPM. Not saying it wont help but its not linear in the sense that cruising at 1500 will yield twice the efficiency as cruising at 3000.

 

On my previous post, I accidentally had the JDM 5th ratio in my spreadsheet at the time... updated with Evo 9 standard 5th gear so the difference is actually around 300 rpm.

I should also add that since the 5-speed has to use 5th for cruising, Mitsubishi made the 4-5 gap pretty tall. The tighter 4-5 gap on the 6-speed is better for straightaways at the track. The JDM 5th in a 5-speed has a similar 4-5 gap as the 6 speed (albeit still larger).

Really, in the 5-speed, Mitsubishi picked a middle ground between a cruising gear and a decent ratio jump from 4th to 5th.

 

600+ wtq now, and still on the stock 6 speed, so I'll be following this thread closely.

 

Gnarly! Done any 4th gear pulls yet?

 

Yes! Thankfully the weather has been colder than usual here in Texas, so pretty safe from temp issues at this point. Also, I NEVER launch the car. We'll see what it's like this summer when it's hotter than hell again though.

 

GL. Makes me feel good about my lowly 450-ish ft-lbs.

 

Haha. It's all in how and/or when you apply the power right?! I honestly didn't feel any "safer" at 450 wtq than I do now.