I want to go SC with my stock engine (with minor changes). I'm thinking about getting a smaller/bigger (I'm noob in the subject) 6th gear to go lower RPM at the same speed. With this and with the stronger engine, I want to get a higher mpg on cruising. Is this possible? If yes, what kind of and size of 6th gearing should I need to buy?

 

Let me get this straight you want to make 6th gear a taller gear? You want to tear apart your transmission just to get a little better MPG? Why not just sell your car and buy a prius to get better MPG?

 

Because I love my car agility, but I also use it for my work too. I need to drive a few thousand miles every month. Just to be straight, it maters the work to get a better MPG.

 

I dont know for sure but ill bet it will cost you a few grand to change your gear ratio's. For that money you could but a cheap *** civic to drive to work then you could keep you Car with low miles.

 

I hope you are not right. The labor would be not a problem because it's relatively cheap here.

 

Well it's over $500 just to get the gears to change your Final Drive. I would be willing to bet it will be atleast that to change the gears in your transmission, then you need to find some one who will due it for you. I would say just bite the bullet on this and either deal with your current MPG's or buy a beater to drive. Thats my .02.

 

http://www.**********.com/forums/148...om-ratios.html

Just to give you a ball park on what its going to cost to get gear sets with different ratios on the z.

Its not worth it IMO, i am sure there are other companies that do it, that was just what i pulled up on google in 2 seconds lol

 

Just curious, but what speed are you driving to work at that warrants a taller 6th gear that will take you to 155mph (more if you remove the limiter). As previously mentioned you've bought the wrong car, its a sports car, not a petrol sipper. Not sure about the cost of fuel in Hungary but maybe you need a Prius.

 

Thanks for the link. For that price, it's not worth it.

I'm driving on highways 100-120 mph and it would be much better with a lower RPM. Here I can buy 100 octane fuel, which is 2 USD one liter (0.53 gal).

 

Wait.. you are doing 120 mph going to work?

 

Not going to, but during my work. I need to visit other regions. I like to go fast on the highways. The 100 mph is normal, I just go occasionally 120+ mph, if I'm late.

 

Just get a rear 3rd member out of an Auto , it will give you a 3.3 final drive, and drop RPM's about 400

 

Sorry, but I don't understand. What do you mean by "get a rear 3rd member out of an Auto"? (I'm noob)

 

Meaning, change the final drive ratio by changing the ring & pinion gears. 350Z with an automatic transmission comes with a taller final drive (3.3:1) than one with a manual transmission (3.5:1). Accordingly, the engine speed will drop in the same speed and the same gear position. In order to accomplish this, the ring & pinion gears need to be replaced with the set from an automatic car keeping the same differential and its housing. This is a job not for a beginner or even an intermediate level mechanic.

Alternatively, you can find a differential assy out of an automatic and swap the one in the car. This is a much easier job and more sanitary; no dealing with gear oil. While this is still not for a beginner, an intermediate level mechanic can handle.

Another method you can use to gain a taller overall gearing is to use oversized tires. This is less effective due to the limitation of space and clearance with bodywork and suspension components. You can run tires that are 1" larger than the stock OD (Outer Diameter) safely. If it's not enough, 2" oversize can be used but I have no experience with this. I assume tire widths will need to be kept conservative. Consequently, the speedometer and odometer readings will be affected; your true speed will be higher than the indicated speed.

How do registration or road taxes and fees work in Hungary? Is it prohibitively expensive to own another car? Are the taxes and fees increased progressively for the second or third car? Is insurance coverage mandatory?

 

Thanks for the really detailed answer. I think it's not my "level" the changing of gears.

The taxation is based on the pollution of the engine (category EURO 1,2,3,4,5) and the power (kW). I don't want to buy a second car because then the Z will be unused due to the lack of time...

 

This is a third member for a Z, if you get one just like this picture out of an automatic, it will be a simple and easy swap. 21 bolts to remove it, I can do a 3rd member swap on the garage floor in 1.5 hours.

 

Thank you very much! You helped me a lot!

 

OR you could just slow down...

I got 32.5mpg going 65mph with the a/c on.

 

What's sorta funny, and maybe I only know this because I ran a procharger for a few years, but the car behaves completely OEM unless the system is in boost, once the system senses boost it adds fuel. I can't prove this but IIRC I was high 20s during normal driving with that kit...

I like the getting a inexpensive civic or fuel-friendly car ESPECIALLY if you're going to drop the $8k-$10k you'll spend on:

because

is exactly what you want to do on a car that is modified...

OP, are you in Europe? shouldnt you be talking about kilometers for distance? and liters per 100kilometers for fuel economy? and since youre looking to save a euro on each tank of gas how are you going to ship the supercharger out while watching your pocketbook?

 

Yes, I live in Europe, but because most people are here from the US, I converted the units to mpg, mph etc.
I don't know why is so impossible to understand, that I want to be as economy as possible, just what can be manly reach. I don't what an another car, I want my Z to be a daily SC car with the lowest consumption in the 6th gear on highway. That's all.