mperdue

Thanks Royce! I was hoping the difference in gas milage wouldn't be too much. This car will eventually be a "daily driver" except that I'll probably continue to take the train/bus about half the time, so maybe I can deal with losing a little milage. The car still has the stock 240Z rear diff for a '73 (3.54?) so I think I will switch to the 4.11 - when I get the money that is - and when I get to the point where I need it again. Right now my top speed is 0mph! Michael

I was just looking through this post for about the 5th time and I'm still not sure about one thing. Is the final drive ratio (listed in the article) mean the number of engine revolutions per wheel revolution? If so that means the 4.11 diff in a ZX 5-sp requires 3.18 engine cycles per wheel cycle but the 3.9 is only 3.01? Seems like a significant improvement in cruising RPM with the 3.9 but I don't really have a grasp on how that really affects the milage. I'm trying to decide what rear diff to put in my car and I like the idea of greater acceleration but I don't want poor milage on the highway. Does anyone know how much REAL difference the milage would be for these 2 w/ 81ZX tranny. Is it a difference of 1mpg or 4-5mpg (for highway driving)? Thanks for the help, and thanks 2MZ for the tech article Michael

Oh mine's from a 73, and meaning smaller on I meant the one that connects right up by the filler hole. They're both off the same car and in good shape. I don't know what year models are the same or different.

I have a gas tank (both the large and small). how's $25? Michael

Leif - i've got some black interior plastic panels I'd sell cheap. Pretty good condition (one is cracked). PM me if you're interested. MIchael

I still need to buy the cdrom - when I have some extra $$. I think I could really use it though

not for me. it says I must log in. as far as I can tell, I am logged in (main page says "welcome mperdue" and all that...) ????