5 speed upgrade?

initial D · Postby **initial D** » Tue Feb 26, 2013 7:50 pm

Pushing 250hp in the rear wheels in nb8a just wondering if i should upgrade the gearbox like the cogs?

timk · Postby **timk** » Tue Feb 26, 2013 8:12 pm

Going by what the US people say on miataturbo.net, the 6 speed seems a lot stronger. I've broken a 5 speed in my NB8A so replaced it with a 6 speed. I was accelerating on the highway and *bang* 4th went. Drained the oil and found a tooth in it.

initial D · Postby **initial D** » Tue Feb 26, 2013 8:32 pm

true does the car go fast with the 6 speed
Thanks

Postby **NitroDann** » Tue Feb 26, 2013 8:55 pm

With a 5 speed, 4th gear is straight through (1:1 gear)

With a 6 speed, 5th gear is straight through (1:1 gear)

So that means theres an extra gear all the way to the 1:1 gear, and then another one.

In other words each gear 1-2-3-4 Will each be a little closer and pull a little harder.

Dann

timk · Postby **timk** » Tue Feb 26, 2013 9:20 pm

Worth noting 5th on the 5 speed is taller than 6th on the 6 speed though, so your cruising in top gear will be slightly higher RPMs.

spikes · Postby **spikes** » Tue Feb 26, 2013 9:53 pm

Here's a good read

16bit · Postby **16bit** » Wed Feb 27, 2013 9:52 am

what condition are your engine mounts in?

Sean · Postby **Sean** » Fri Apr 19, 2013 10:36 pm

Are you asking from a reliability standpoint?

Most guys with that sort of power aren't breaking things unless they're in race cars and heavilly stressing the box in a race environment. As aluded to earlier, a lot of the yanks stiffen up the mounts to keep everything better aligned, this seems to keep things together longer in race cars, and also seems to help with high rev shifting.

Much cheaper solution than a 6 speed, particularly if it's not a race car.