88 HF, getting 47mpg, going to put in a dx trans with hf 5th in it, any idea what rpm change ill see, i've tried two trans calculators, and got two different answers. Also, just curious what kind of fuel mileage difference i'll see. I've searched and it sucked.
What Mileage do you get from your CRX DX?

 

Depends on the driving you do. If most of your driving is highway in 5th. Then I think that your loss will be minimal.

P.S. I would love a HF 5th in my DX tranny!

 

I'd love to have HF fifth on my Si. 4000rpm at 125kmh SUCKS ***!

 

I love the dx tranny but then again im boosting on it ... You could probably maintain close to 40 mpg if your good about crusing

 

Well I got it done all in one day! it lost about 400 rpms at 55. shouldn't kill my mileage too bad, but its alot more fun to drive now. Wish I had done this a few years ago. I'll know the fuel mileage in about 400 miles!

 

cool post it up when ya get it, did you end up swapping out the 5th gear also?

 

yes, i changed the fifth gear. quite easy to do.

 

I have a SI Tranny in my 89 HF, I still get ~45 - 50 MPG. 5th gear @ 70 mph ~3k rpm. I still get great gas mileage and the gears aren't so long. I'd like to have the 5th gear of an HF but that's about it.

 

well the first tank got 37, next one was 44, last was 42. mostly my wife driving it, and she drives it pretty hard. i'd tell you what it gets with me driving, but i don't get to much anymore. I'm hoping in a month or two to get my 93 hatch going, then maybe she'll drive that.