Gearing

Cam1379

Couldn't find anything on this. Does anyone have experience with changing the gears in their z? If so please post what you installed, your top speed and what rpm you are at around 80 mph..

Felix 808

There are a few threads around here. Do you have an auto or manual? What gears are you looking into? Top speed is not going to be an issue, in fact you may gain top speed with lower gears due to wind drag

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luigi90210

Potential Speed Calculator

just enter the FD you want to install along with tire diameter and the gear you are in(IE 1:1) and it will calculate out the top speed, just google your stock gear ratios and plug the numbers in

wait...what?
if you are going with longer gears you will gain top speed but shorter gears will reduce top speed(not by much really), also gears have no effect on drag

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Cam1379

BTW Semper Fi Brother!! I am not sure on the gears yet. Was looking for insight.. I just want more acceleration with my n/a 370. any thoughts? Top speed is last on my list btw

luigi90210

if you plan on keeping it N/A, get 4.08 gears from the frontier

other than that, i suggest FI if you really want more acceleration

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Felix 808

On paper yes, but in the real world, your stock motor is not going to have the power to pull to redline in top gear. You would be doing over 200MPH, not possible, but the mechanical advantage gained by lower gears you can actually gain top speed

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luigi90210

again what?

gears do not add power it only changes how your car puts down power, and you wont gain top speed, top speed is lower on a car with shorter gears than on a car with longer gears, this is provable in both real life and paper

all gears will do is allow you to get to a certain speed faster(IE a 370z with 4.08 gears will get to 60 faster than a one with the stock gears), if you mean trap speed than yes, you will trap a higher speed but you wont gain top speed, your car cant physically go faster than whatever it will top out at because you are out of RPM as opposed to the car with longer gears, there is no if ands or buts about it, physics and math dont lie

heck you can test it out in the real world yourself, a 6mt 370z will do 155mph in 5th(i know first hand it will), change the FD and it can only do 142mph(assuming your tire diameter is 25.59in like mine is)

now being realistic, will it effect anything we average drivers will experience? no it wont, in fact only thing people will notice is higher RPM at certain speeds which is to be expected since you changed to shorter gears

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Felix 808

Luigi I see your not grasping the concept of mechanical advantage & apparently you were shorted a gear being you only mention 5th gear. I have proven this concept on 2 wheels more than once or twice. Merry Christmas

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luigi90210

care to explain how it raises topspeed than?

id like for you to prove me wrong, as shorter gears(in this case final drive since thats what OP is asking about, i dont think OP is really gonna go out there and regear his entire tranny) do not allow you to go faster speed wise, it only allows you to get to a certain speed faster(IE a car with 4.08 gears will get to 80 faster than a car with the stock 3.69 gears)

im also using 5th gear(1:1) as an example, the same can be told for every gear, final drive swaps lower your top speed as you run out of RPM

you have yet to explain this mechanical advantage that some how magically allows you to exceed the maximum speed possible, id really love to hear it(really i would)

like i said before, physics and math do not lie

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Rusty

I've done the same thing on a motorcyle too, using a gps and radar to see the difference.

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Felix 808

Thank you Rusty

l

Luigi, The question was about top speed. Will > 10% of us ever see top speed in these cars, I would venture to say doubtful. As I stated before, your car is not going to pull to readline in top gear, thus the simple math of gear ratios can not be played out in life as on paper. If you use a proper gear calculator, you will see that on paper with stock gearing it's > 200 MPH. The motor does not have enough power to over come the drag factor & carry it to redline & is unable to reach it's paper speed expectations. This is where using lower gearing can give a mechanical advantage to let the engine reach redline while also increasing top speed. Can you over gear & loose speed, absolutely, we do all the time in the 4x4 world, it is what we want when dancing in the rocks. Take for example Land Rover for decades they used anemic 4 bangers but made it work with lower gearing providing the mechanical advantage so the motor would perform the task at hand. Yes this is not a speed example, but it is a gearing example of mechanical advantage being used to overcome a lack of brute power to perform work which HP is a measurement of.

With that I think we have both wasted enough space in this thread. I am sorry if I was unable to properly explain how this works, but Rusty & I have both seen this work first hand.

To the OP I apologize for this taking over your thread. Semper Fi Brother & have a Merry Christmas everyone

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luigi90210

i still dont understand but im going to leave it at that, i understand there is more to top speed though than just gearing, tire size, ect. i was trying to use testable examples that every 370z can test out whether its tuned, stock with gears, ect.

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Chuck33079

Luigi, think about it like this. The gears will absolutely lower the theoretical top speed of the car. But there's nowhere near enough power to hit that top speed. Unless you drive off a cliff, a Z will not be hitting 200mph without the addition of a ton of power. The gears will raise the actual top speed of the car, the speed the car has the power to hit.

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L33T Z34

'07+ Nissan Frontier 4.36 ring 'n pinion. Nissan part number: 38100-0C860. I've gotten her up to 120MPH a time or 2. My RPMs @ 80MPH is ~3,600 in sixth gear.

diddy535

First time I've seen the 4.36 used anyone else have experience with it? Also how's first with that?

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