i have a si hydro b16 tranny and was wanting a better highway gear so i was thinking ls 5th gear. Or will a gsr 5th gear be better sense it doesnt drop so much in rpms. I have looked around and keep getting mixed signals. Thanks for the help.

 

ttt

 

ttt

 

bump for this.

i have a JDM Y21 and bought a S4C (LS Tranny) to use the 5th gear from. (my y21 blew 5th)

will it be straight swap of the worn gears or syncros??

i think a lower revving 5th would be good. (for highway, not so much track)

 

Stock. Lower RPM does not mean better economy.

 

Friend had a stock B16 trans in his car and was getting mid-high 30's on the highway. We changed to LS 5th and he got high 30's and 40-41 a couple times.

Now, that said, if your car does not have the power to pull that gear, you will actually be using more fuel as Aquafina stated. I'm a sucker for LS 5ths myself...

 

Customers ITR with Mugen gen 2 wing. 1.000 5th, 4.05 FD, 23.07" tires, RM M22XX cams (big primaries) 25mpg city 32mpg highway that is while not babying it.

 

My coupe has 4.785 FD, LS 5th, basically stock ITR. I get 35-37 highway and 29-32 highway.

Good MPG on the 1.000 5th especially what's done to car.