DSMAddicted

Guys,
I drive a '93 CX Hatch with pre-98 JDM ITR swap.
85% of my driving is highway @ 70-80mph. I drive a LOT.

As you can imagine, my ITR 5th gear is driving me nuts (mpg/noise/engine stress), so I ordered the 5th gear from 94-01 Integra LS and planned on dropping the car off at my friend's shop this weekend.

I just stumbled across a couple of threads that worried me a bit.

According to this gentleman, the tallest LS 5th is only found in the 90-93 Integra LS (gear is now discontinued):
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/faq-how-ls-5th-gear-install-guide-jdm-b16-s1-555929/

The above thread is from 2003. Is this still the case, or have people realized that the 5th gear from the 94-01 LS (the one I ordered) has the same ratio? I would prefer to use the TALLEST 5th I can find, so if it means I need to return the 94-01 5th I just ordered and go look for old Integras at the junkyard, I will be willing to do so.

The 2nd thread talks about final drive. According to these guys, my 5th gear will never drop as much as the LS 5th because of the final drive. They are saying something along the lines of 3-400 rpm:
https://honda-tech.com/forums/transmission-drivetrain-127/ls-5th-gear-b16-transmission-2879988/

This worries me because it might not be worth it for me to go through all this trouble and spend so much time/money if I am only dropping 400rpm. 700rpm is borderline but I think would make a difference... 400 not so much. Do I have to change my final drive too in order to be able to drop that much rpm in 5th? Does that also mean that 1-4th will be longer? Sorry guys, I have a good understanding on how engines, VTEC and differentials work and could explain it to anyone very easily... but transmissions are a whole different topic for me and I don't understand them well.

Please let me know your thoughts guys, I need to act quick.

Thanks!

-Walter

Aquafina

iTrader: (3)

90-91 5th doesn't work in 92+.

You need the FD as well if you want the RPM to drop a lot. FD will make 1-4 longer. You'll probably notice you get worse mileage after the 5th swap.

Honda Bull

The 94-01 LS 5th (.714 ratio) is the tallest OEM B-series 5th gear.

I can't remember the slight differences with the 96-97 ITR transmissions. You probably have essentially B16 gearing (4.400 final drive and .848 5th gear).

If so, that 5th will drop your RPM at 70 mph around 600 rpm. Final drive options on top of that would be OEM 4.266 plus MFactory 4.05 and 4.2x, but you have to remember that doing the final drive will affect EVERY gear. So they won't be AS responsive with the lower final drives just to drop another 200-300 rpm on top of the LS 5th.

DSMAddicted

After some more research, it turns out that the LS FD won't work in my ITR tranny.
Really? Could you please elaborate on this?

Thanks man, this makes sense. Your thoughts about ratio are correct too, according to this: http://www.teammfactory.com/gear-calculator

I would think that any rpm drop of 600rpm or more is worth it in my opinion. The noise and reduced engine stress alone would be good enough reasons, but an mpg improvement would be very welcome as well. Any thoughts on that?

-Walter

Aquafina

iTrader: (3)

Higher RPM (due to gearing) while cruising = less fuel needed to keep the car moving = better MPG. Myself and others have confirmed this.

The LS FD won't fit your ITR LSD, but an MFactory 4.26 FD will.