4 speed or 5 speed?

[Guest Anonymous]

I have a 4 speed on my 240z even though it has a 280 motor, I want to switch a 5 speed in it, but I've heard that the 4 speed is actually better due to the gearing, does anyone agree to this or what??? I don't know anything about these cars, so some help would be appreciated

[RedNeckZ]

The five speed is best for the street and some times on the track. Depending on what geared rearend you are useing. On the street it will give you more gas mileage or acceleration. I have a 3:90 geared rearend in mine and a 280zx 5-speed (great for coming off the stop light). It is set up for the track, but I all so use it as a daily driver. It has great acceleration, but doesn't get that great a gas mileage. But that has more to do with the three sidedraft carbs and cam then any thing. You can use a 280Z 5-speed or the 280zx 5-speed, they each have a differenet set of gearing in them. You can look at most of the big Z-car sites, and find out more info on which year transmission and gearing that will fit your style of driving. Also think of rearend gearing and what you want to do with the car. They both have to come together to do what you want. The sky is the limit on the combinations. The four speed is used by most racers who don't need that fifth gear on the track. So what you go with is up to how you plan on driving it. Good Luck.

[jeromio]

RedNeckZ makes several good points. The reason you may have heard that the 4spd has better gearing likely has to do with the stock, R180 ratios, which are 3.36, that the 4spd is matched to. If you switched to a ZX 5sp, off the line acceleration would be terrible. You could switch to a 280Z 5sp, which has ratios matched to a 3.54 rear.

 

Bryan Little's "Datsun Garage" website had a wealth of information on all the various trans and diff ratios. Unfortunately the link is broken .

 

If you're up for a rear diff swap at the same time, you can mix and match (depending on what you can find forsale) and come up with a set of ratios that will best suit your driving needs - highway cruising and gas mileage vs off the line acceleration. For instance, a 280Z or early Maxima 5sp matched to a ZX 3.9 (or the rarer 4.11 200sx turbo) would give you screaming acceleration, but your revs at 65mph would be a bit higher.