How do you figure out what rpm you are at a certain speed w/ the JDM final drive, lets say around 70mph?

Oh yeah and another thing, I've never been autoxing before but I plan to in the future. Would switching to a JDM final drive cause you to shift gears alot more since the gearing is shorter while autoxing. Wouldn't having a tall second gear be more beneficial in a autox.

any help would be much appreciated.......

 

the jdm final will increase your revs about 8% at any speed at any given rpm. stock (with stock size tires), you will tach 4,500 rpm at 80mph in 5th. with the jdm final, you will tach 4,860 rpm at 80mph. doesn't seem that bad, does it? i had the jdm final, but i swapped to a 4.93 (+12%) and it still does not rev that bad on the highway. i tach about 5,000 at 80 in 5th. doesn't seem like much, but boy does it make a difference in acceleration! get the car into it's powerband much quicker. the only downside is reduction in gas mileage and some more revs on the highway. no biggie. go for it.

 

Having tall gears anywhere will reduce the amount of shifting you do, but I can't really say that's a benefit. The less shifting you do, the more time you will be out of the powerband. the JDM tranny is a more agressive layout, meaning it is designed to be faster overall. You shift early and often, and you keep that sucka in VTEC...

 

isn't it bad for your valves to be going 80mph for awhile and having it at 5k rpms...and what about long trips where u don't want to go 60mph...this wouldn't be too convienent if i go on alot of long trips right?

 

JDM spec gearing is actually the shorter final drive (4.785) with the GSR 5th. This way, you get the benefits of the the shorter gearing, and don't buzz yourself to death on longer trips.

 

'98 spec JDM also utilizes the 4th gear from the GSR as well.

 

You can always put a LS fifth gear if you want to maintain lower revs on the highway.