CivicSi95

I have a jdm b16a sir2 swap with LSD. My commute to work is about 80 miles round trip. I am wondering if i can improve my gas mileage by swapping to a LS 5th gear to keep my rpm's down? My drive is 100% straight highway. Does anyone have any experience or info to help me out?

dcmatt

iTrader: (7)

My guess is yes. i dropped about 4mpg going from a ls tranny to b16 tranny. i mostly drive highway myself.

CivicSi95

i tried searching but cannot find anything. can anyone else help or any more information? i know someone on here has done this before.

94EG8

LS final drive is also a lot higher. running an LS 5th will help, but it's still not the same as running an LS 5th in an LS tranny. Also if you're paying someone to swap it in expect it to take a while to pay for itself.

David @ Synchrotech

iTrader: (1)

To change the 5th ratio from the Hydro B16A 0.848 to LS 0.714 you will only need to change the two 5th gears. 94EG8 is correct, this will drop the RPMs on the highway some but not to the level of an LS transmission since the LS has a 4.266 FD ratio vs the B16 4.40 FD ratio.

CivicSi95

what can i expect it to drop the rpm's down to? right now im turning around 4500 rpm's at about 75 mph. im looking at improving the gas mileage as well as not having my car as loud. my commute is 100% highway turnpike and the speed limit is 75. even if it takes 1 year to pay itself off, it will be worth it to me. thanks for the input so far.

David @ Synchrotech

iTrader: (1)

It should drop about 400 RPM

Honda Bull

It'll drop 300-400 rpm with just the LS gear. If you were to do the 4.266 final drive, another 300 probably.

darkvader0

I'm assuming you have the 0.848 5th with a 4.40 FD. But that would put you RIGHT at 4000RPM for 75MPH. You said you are at 4500 for 75MPH, so I am not sure what tranny you have. Maybe you have a 4.785 FD? That would put you at 4400RPM for 75MPH.

Anyway.... If you have a 4.40FD the LS 5th will put you at 3500RPM at 75MPH
And if a 4.785FD, you will be at 3800RPM at 75MPH

I used
http://www.superhonda.com/forum/f5/b...-codes-218900/
http://www.f-body.org/gears/

for resources. Cheers.

CivicSi95

actually my rpm's are at 4200-4300 rpm at 75 mph. i was mistaken but checked it on my way to work this morning

darkvader0

What size tires do you have? And what is stock for that year transmission? 185/60-14?

CivicSi95

195 50 15

its a obd1 b16a sir2 swap that i bought from hmotorsonline.com

93h2beg

i may get some flck for this but also a idea to help improve mpog is to geta good tune, and have ur fuel trim in 5th dropped a lil bit to lean it out to a safeer 16-1 afr, not too lean but helps a lot when doing freeway driving... a good tuner can do this quickly and easily. my h2b with an itr tranny in my eg gets about 27 mpg in 5th at 4500 rpms... napa to santa cruz, actual mpg
just dont put a heavy load on it at the low rpms where it is lean.

ef92b

92-93 YS1 cable tranny with 1-4th gear S4C(4.4FD) LSD hydro internals and LS 5th gear.
EF hatch/ 2nd gen B16 with 195/55/15's

i really don't care much about the gas consumption(super cheap in my location) but i hate a noisy fart can during long highway drives lol

arronabraham

i have a 96 hatch with a d16y7 is it possible to swap in a gsr tranny to this block and will i run into any problems

Honda Bull

A good tune is pertinent, but not every engine will like going that lean though. There are some engines that simply aren't set up for a lean cruising condition like that, given their dynamic compression, cam lift/duration/overlap, intake characteristics, et cetera. That's up to the tuner though on that judgement exercise. :p

And yes, load and lean = misfire. lol

SilentlyFast

I have a b16 tranny Ls 5th and the Ls FD,it does pretty good on the highway but I'm on 8psi too. It don't suck gas til I lay into it

the white sam

u cant swap a b series tranny in with a d series, wont line up (the holes i meam i already tryed it, and felt like a moron afterwords)

CanadianEF9

sorry for bumping a kinda older post and this one has some good info and i was thinking about doing the same thing but no one stated in this posting and i couldnt find it by searching what all do you need to do the swap and if it just fits rite in? thanks

Honda Bull

Acura 94-01 LS counterhaft 5th gear.
Acura 94-01 LS mainshaft 5th gear.

Fits right in 94-01 hydro and 92-93 YS1 cable transmissions.