I've searched the posts and there;s a lot on "how-to", but not much on if it's worth the effort...

What are the pros & cons of changing to a 5-speed?

JP

5-speed allows you to have a 5th gear for cruising on the free way, better gas milage at higher speeds, and occasionally lower 1st and second gears for quicker take offs.

I'll never go back to a 4-speed now that I have the 5-speed in the 70' 240Z.

Definately worth the effort and very easy to swap.

Dave.

JP,

Unless you want to keep the car purely stock, I would say no. If not, you should do it. The '71 918 Orange Z that I recently sold was very close to be being almost pure stock with the exception of just a few things and the 5-speed was one of them. The 5-speed was already in the car when I bought it, so I really don't know how easy or difficult it is to install. All I can say is that I liked the 5-speed for the same reasons Dave mentions in his post. My other two Zs have the original factory 4-speeds which I plan to keep.

I really don't see much downside to having a 5 speed in a 240Z. The possible need to enlarge the tunnel hole for the shifter (in a '70 or '71) would be a bummer, but there is a way around that.

On the other hand, I try to avoid driving on the freeway anyway, preferring to drive on the back roads instead. For that driving the four speed is fine.

The 240z came with a 5 speed in every other market except the USA, so its pretty much just a bolt in job.

The non USA S30 used a type A trans and the majority of the conversions done here use the type B. Still not a difficult conversion and there are many posts about that on this, as well as other sites.

I did mine for the mileage factor, but only gained 1-2 mpg more and i do 90% freeway driving, it is quieter on the hwy though because of the lower rpm.

That's 15-30 extra miles per tank using a 15 gallon tank for example sake. You really can't expect much more gain than that unless you chage the differential ratio also.

They all had a 1:1 fourth, so whether you have a 5th or not doesn't significantly affect the 1-3 ratios

That said there are different lower ratios (slight changes year by year - quite a mess if you want to figure out just what you are getting) - just not big differences.

You can refer to this:

http://www.geocities.com/z_design_studio/transmission.html

That's 15-30 extra miles per tank using a 15 gallon tank for example sake. You really can't expect much more gain than that unless you chage the differential ratio also.

Already have the 3:34 rear end, was just hoping to get a little better mileage, 15-30 miles per tank equals about 1-1.25 gal which is about 3 bucks in savings per fill up, which i fill up about once a week, so it should only take me about a year to break even from the swap cost b4 i start to save money. By then the v8 sbc will be in there, then fuel mileage wont matter.

Get the 5 speed from a zx 81-83, the ratios are close and the 5th is the lowest and it is stronger than the 5 speeds from the 280z's. Worth the effort? Yes. I did it for the close ratio aspect and the extra strength of the zx unit over the older z unit.