Hey all,
I am about to finalize my next mod! I have a 2008 Nismo, and so far I have X02 Dual Exhaust w/ x pipe, Labree Resonated Test Pipes, Stillen gen 3 intakes and an Osiris tune. I want to upgrade my final drive! 4.08 seems a bit too far stretched for me for the routine driver and such. I don't want to shift THAT much. I was told the 3.7 final drive from the 370z will fit no problem. Also, I am very interested in the 3.9, but the price is very high, but if the increased benefit over the 3.7 is worth it, I will just go that route. What are your opinions? Will I notice a difference with the 3.7? Or should I go with the 3.9? I found a place that will install the gears for $480, providing I provide the gears and the install kit. Thanks!

 

You can workout the new speeds and shift points using a calculator here: http://www.wallaceracing.com/Calculators.htm

 

I would suggest the 4.08 as they are so close to the 3.9 and usually less expensive. I have this on my Z, fantastic mod, instant torque multiplier. This mod is something that is VERY noticeable in the butt gauge.

Send a pm to Adam at Z1 Performance, he can set you up, very knowledgeable.

 

You would recommend this? Is the difference such a way that it can be annoying? Would this be a "lethal" setup for the street, ie. taking off at lights, and possibly a 20 mph pull to 100 mph if i needed to upset some other cars? haha. Also, with a 7600 rpm like my car is set to, what could I expect the MPH in first gear to top out at? 35 mph? or higher? With the governor removed, am I able to go past 160 mph with the 4.08? I agree the 4.08 is more feasible regarding price...

 

The term "annoying" is purely subjective. Some people consider driving a car with only two seats as being annoying.

The answers to your other questions can be answered by you doing a little leg work of your own. A gear ratio calculator like the one I believe DavidV posted above (admittedly I did not click on the link he posted) is all that you should need.

 

searching is to damn hard!

 

The link brings me to a bunch of various tools, I'm not entirely sure which one to click? I think I am just gonna go with the 3.9 Upon reading many outside sources from other forums, its a solid way to go.

 

https://my350z.com/forum/4390297-post1.html

3.9 works fine, but it is much more expensive than the 4.08 and not typically stocked in the US anymore. 4.08 is a small change (4%), in stock, and far less costly...and it compliments the HR perfectly

 

I found it on vividracing.com's site for 579.99. Even if its not in stock, they say they can ship it from japan. But for the price, I think thats very very fair. Just pick up an Install Kit for 30 bucks and call it a day.

 

Just let me know if you'd like to order it

 

LOL just go with the 4.083. I have just built another differential with it for my car and I am in love all over again. Just need some wider rubber to hold her to the ground. =X maybe some better tires.

 

I have the 4.083s waiting for install. All I need are for my bearings to get here. The shop that is building mine wouldn't do it without all new seals and bearings.

 

i just reused my old bearings. they seemed fine. had less than 20k miles on them. just ordered new seals and crush sleeve. you are gonna love them.

 

if you usually do around 80-85mph on the highway you wont be doing that anymore with the 4.08 and thats where it becomes a tad bit annoying if you are making a 30 min trip to work or something on the hwy. really depends on your driving i guess but this mod is great makes driving the car a bit more fun cause ur sliding when u stomp on it in second. you kind of notice that you are shifting more often (sooner). but all around definetly go with the 4.08 or bare minimum 3.9. i mean if your going to make a difference u might as well feel it and get the 4.08. i dunno what else i can say here if you have questions let me know ive had the 4.08 for a few months now.

 

8 hour drive to atlanta with my 4.08 with no problems. depends on how loud your exhaust is. lol putting the silencer in took care of that problem right away.

 

I have pondered this myself lately. I guess the real question is, at what RPM are each of the gearsets at 80mph? Stock 3.5 is around 3k, I've heard that 4.08 is around 3400RPM?

 

let this not go to waste!

 

I would kill myself going on a drive longer then an hr and have to do less then 120kmh cause at 130 which is about 85mph the car revs at 3500 cruising at that rpm i dunno im not an expert but doesnt feel safe who knows. Depends how u drive i guess

 

The 4.08 at 80 is like 3400