ZLadie2000

iTrader: (12)

^^ JB get those gears installed yet?

__jb

iTrader: (3)

Not yet.

They should arrive via UPS tomorrow, but it looks like I'm going to have to wait until November 12th to get them installed at Lokey.

Chasecbc

iTrader: (2)

what about from rolls or highway pulls?

Z1 Performance

iTrader: (564)

gears work no matter what speed you are at, what rpm you are at, or what gear you are in...the difference in acceleration is fixed

ACEMAN

iTrader: (29)

I think what people are not understanding about gears is. It does not change your HP what it does is shorten each of your gears.

With stock gears say it takes X amount of time to wind out 3rd gear. You change that final drive gear out and now you have just shortened all of your gears. So you will run through the gear much faster. Thus getting to the meat of your powerband quicker. And in return make your car quicker.

Rough example:

Stock 3rd gear
111222333444555666777888999

shorter Final drive 3rd gear

112233445566778899

All 6 of you gears will react the same with the change of the final drive. So if your in 6th gear you will hit the meat of your powerband faster and thus make your car pull harder on the interstate. If you have stock gears and you are on the interstate you would drop it a gear for the same results.

Hope this helps
Todd

marques1

iTrader: (5)

what is your top speed with these gears just wondering. Sorry if this question has already been asked did not want to go through a million post to find this info out.

ACEMAN

iTrader: (29)

Read the first post

Todd

marques1

iTrader: (5)

k thanks

hasemanr

iTrader: (9)

I was wondering what are the negatives with adding the 3.917 gear with a 350z that has a turbo? I was planning on getting the turbonetics kit and the gear will there be problem? Please help this final drive thing is pretty new to me.

9kFever

iTrader: (9)

Had a similar discussion on s2ki about gears. Remember also that at higher speeds with OEM gears the Z practically shifts into the Peak HP and stays there longer than aftermarket gears. With aftermarket gears your RPMs will be right at or above peak hp and will go out of peak hp quicker. This is why gears make less of a difference on the freeway and could actually make an oem geared car start pulling if all other things remain the same.

So if you are starting from a high speed roll (i.e. 70 MPH) it can be advantageous to have an OEM geared car because you can shift into the meat of the powerband (3rd gear) AND you will stay in the meat of the powerband longer. I beat this to death on s2ki. After 100 mph the gears no longer do anything.

Your example doesnt make sense because you might be getting out of third gear quicker but your getting out at a slower speed as well.

Mountain Runner

iTrader: (10)

Should both front & rear pinion bearings be replaced when changing the rear gear? I've also heard pinion nut, pinion oil seal, & pinion spacer housing should be replaced...is there anything else? Would the side bearings & side oil seals be affected at all?

Skidfive805

iTrader: (4)

Since the "Nissan" final drive only comes in the 4.0 and the 3.7 for the $430 price, I will be choosing one of those.

Yes, I know some people are against nitrous while some are for it, but that argument is reserved for another discussion.

I am planning for a 100 shot plus tune just for some personal fun and a track day here and there.

my question is would it be better just to get the 3.7 and shorten my final drive a little or go ahead and get the 4.0 with nitrous. Pretty much im thinking that the nitrous acceleration may be to much for the 4.0?

thanks,
Jon

ZLadie2000

iTrader: (12)

^^ nitrous and 4.0 sounds sooo fcukn scary!! LOL Id get 3.7 if you HAVE to shorten the gears....might not be worth the time, labor/$$ to only go to 3.7 though...

GA_VQ

It seems like running through the gears fater would actually slow you down in a quarter due to the extra shifting. My friend is willing to swap rears with me (3.9XX i don't remember) and I am really wanting to do it. If I understand correctly, a shorter final drive will say, get me to 130 faster than stock but a stocker will run me down around by 145ish due to longer gears?

Z1 Performance

iTrader: (564)

all the permiatations of the gears vs speed vs rpm are on the first page of this thread

IMHO, gears are something best coupled to an increased redline to maximize the benefits

sentry65

iTrader: (11)

I disagree with a few things

The gearing having the most advantage is always going to vary from situation to situation or track to track.
The primary fun factor with shorter gearing is the lower gears give you more oomph and make the car "feel" more responsive and fun to drive
The shorter final drive "forces" the and and the car to be driven more aggressive because rpms rise faster and you shift sooner and usually more often than taller gearing. Even your top gear will have more response and be higher in the powerband when just cruising the highway at 60-80mph



it flips back and forth who would have the advantage all depending on what speed you start a race at and what speed you race up to

at 70mph, yes, the stock 3.5 FD would get the jump. but at higher speeds, the 4.083 could make up for that initial loss depending on what speed you race up to.

If you raced up to 120mph, the 3.5 would have the advantage both at launch and the end of the race peaking at high rpms in a lower gear than the 4.083 would end the race in

If you raced up to 130mph, the 4.083 FD would be at the higher rpms while the 3.5 is at lower rpms. This would make up for the 3.5 getting the initial jump at 70mph


Or what if the race started at 60mph? Then the 4.083 FD would get the jump and the 3.5 would be in a position where it had to catch up

If a 3.5 and 4.083 FD Z raced up to 160mph from 0, the 4.083 FD car would slaughter the 3.5. Both cars would shift 5 times, but the 4.083 FD car would reach 160 seconds before the 3.5 FD - probably (get this) 14% sooner



On another note, I have a 3.9 FD and then later added a vortech supercharger. I was assuming traction in 1st gear was going to be worthless no matter what because 1st gear is so short anyway - that I figured a shorter final drive would get me out of first gear faster and into 2nd where I could start getting traction and going WOT.

Had I went with a 3.3 FD and optimized first gear by possibly having traction in it, because it's so much shorter than the other gears (like a reverse exponential graph), when 2nd gear would kick in, it would feel really long and boring. Especially for a vortech where you don't want to be at low rpms very long if at all

In the future, I have custom gear ratios picked out that I want to use...not going to be cheap though

Z1 Performance

iTrader: (564)

a 3.9 and a Vortech is almost made for each other, as a Vortech really does not affect the low rpm range whatsoever, as it makes all its power up top

sentry65

iTrader: (11)

traction will be more difficult
turbo power already comes on so quick, giving you less time to react to throttle inputs
it will also give more opportunities for the turbo to lose its spooling with more shifting
since you'll be flying through gears faster, you won't be keeping the turbo fully spooled as long

gas mileage will also obviously be worse with the 3.9 too

IMO with a turbo, stay stock FD or go 3.3 after you reach 450-500whp, though it can depend on how good your tires are if the 3.5 or 3.3 is better

sentry65

iTrader: (11)

just unhook the fuse behind the shifter. VDC will be more responsive than "off" (which isn't truely "off") - because it'll be completely disabled and still maintain ABS etc

VitViper

iTrader: (1)

Agreed, not only in theory but from experience.

Not on the 07. Stock 07 2nd stops at ~71 or so, so he has to start in 3rd just like the 4.083 gears. The biggest different? 70 in 3rd for the 3.5 is 5200 rpm, where as the 4.08 is at 6k rpm. 4.083 jumps hard (being he's in the meat of his powerband already and the 3.5 isn't) and owns the 3.5 to any speed... 120, 130, 140, 160, whatever.

This only holds true for 07 vs 07... if it's 07 vs 03-06, 07 has it hands down (given equal mods, so stock for stock but one has gears and the other doesn't) no matter what speed (primarly due to the wider powerband and higher redline).

07 vs 07 the 3.5 has the jump since he's at the top of second gear (but only for about one second, the 4.08 will destroy afterwards).

Simple physics/math/etc.