5 speed swap

[finn_logr]

Hi everybody,

I was looking at the different gear ratios between a 4 speed and a 5 speed manual in the late 80s Festivas. I have a carbureted '89 with the 4 speed and I get 42 mpg with it. Does anybody have experience with fuel economy increases by going to the 5 speed?? I am not doing any power adding, just simply looking for better fuel economy. If I only get one mpg increase, it probably isn't worth it. If I can get 5 mpg more, then it might be. Any experience/knowledge will help. Thanks.

[hawkdoc60]

Theoretically, yes, the 5th gear is a higher ratio, so therefore, if you were getting 42 with a 4 speed, it should improve with the 5 speed as long as it is in good condition.

[nonamekid]

There were two different 4 speed transmissions and you need to figure out which one you have. the best way to do this is with a tach and then tell us what the tach reads at 60 mph.

[FestYboy]

wait, that odd 4 speed you speak of was only issued in Cali and in the first 6 mos of production. the likelyhood of him having one of those is VERY slim.

4 and 5 spd ratios don't differ, you just get an extra gear with the 5 speed.

[nonamekid]

wait, that odd 4 speed you speak of was only issued in Cali and in the first 6 mos of production. the likelyhood of him having one of those is VERY slim.

4 and 5 spd ratios don't differ, you just get an extra gear with the 5 speed.

That is correct but you would be surprised how many are out there and where they show up.

[geezerstiva]

what was the difference? cause i have a 2 4 speeds--one gets over 40 mpg and one gets like 30-35.