Hello,

With the nice-ish weather today here in DC, I finally could go for a test drive with my new 5th gear. Not just a new synchro... a whole new gear set of a different ratio than stock

The stock US spec 3rd gen 5th is 0.719 and I put in a 0.806 from an RX-7 special model in Japan.

This helps out with highway cruising and keeps you from having to downshift so much.

For example by my calculations...

At 75 mph, my new 5th gives me 40% more force at the wheels
At 100 mph, my new 5th gives me 20% more force at the wheels

I got these numbers by putting in my car's torque numbers from a dyno run and graphing the power to the wheels in every gear ratio in Excel. Your numbers for YOUR car might be a little different, but I think you see the point.

I _do_ lose some top speed, but even with this gearset, I won't run out of RPMs until 180 mph... I think that's enough.

Fun fun fun!

Brian

 

How about actual shifting, i assume the grinding is entirely gone?? Do you know if the j-spec ones will wear over time like the US ones?

 

My car never had a 5th gear grind. But just to be safe, I replaced the synchro with the standard US updated part number. I also replaced the shift select spring thing to the updated stiffer one.

Brian

 

Nice job wargasm. The weather has been crappy lately here in MD, but it seems to be clearing up. I can't wait to get the FD fixed up, and back on the road for spring.

 

Hows the highway cruising RPM? I would love to do the 5th gear swap myself since I know I would love it on the track, but I also take a lot of trips in the car and I think the rpm of 5th gear at 80 is about perfect. You mind checking your RPM @ 80 for me?

Any regrets at all? Sounds like fun!