The AUSubaru.com.au Forums

hi guys, just wondering how hard it is to change the 4 speed gearbox in my 1985 brumby to a 5 speed... with the rising fuel prices im wondering if this mod will save me fuel with the overdrive, or do you think the cost of the conversion will outweigh the benifit.

Subie Snax wrote:or do you think the cost of the conversion will outweigh the benifit.

You said it Mate

i think the final gears in both had the same or similair ratios anyway. so no difference for highway crusing

ok thanks,, im planning on an ej20 or ej22 n/a conversion, and hooking it up to the original box with one of those adaptor plates.. if i dont have to change th gearbox it would be better(easier)..

Well an EJ is a different story. coz depending on how u drive the 4speed will have a Limited life span behind an EJ engine

i first did mine with the EJ and the 4speed but changed later as no 2nd gear makes for interesting driving with the sh*thouse ratios of the 4 speeds.

Matatak is correct. Your Brumby 4 speed is already overdriven in 4th gear so for top gear cruising a 5 speed conversion wouldn't make any difference. Bear in mind that dropping a Subaru engine's revs will not nessessarily save fuel due to it working harder. Being able to drop back to forth is good for overtaking though. If you are planning an EJ conversion in the future, budget for the EJ 5 speed then for sure.

save petrol ? CARBY ONES ANYWAY ~ hook up a vacuum gauge (very simple esp if you not need to see it in the dark) just one tube to the inlet manifold. To watch it while highway driving helps educate the loud pedal foots actions while achieving better vacuum states . I got a 70's Ford six motor from 27 to 30 MPG just by watching and obeying vac gauge and lost no time in the travel time