baspence

iTrader: (1)

pm sent

kramykram

iTrader: (135)

Ok finished my first tank of gas in my 08 with 351 miles. Thats with my 4.083 gears and jwt pop chargers i put on a couple of days ago. Not to bad on mileage even with the few times i hit the pedal hard.

jgregory124

iTrader: (13)

hmmmmmm.....i have been mulling over gearing as well....thanks for the info

blindmonkee

about how many miles did you get on your tank before the install?

NISMO_558

iTrader: (1)

I had 4.083 gears in my last Z, and that is WAY off. at 65 it sits at around 3200rpm, at 80 it's above 4K and 55-60 its around 2700rpm, you will lose alot of mpg with these gears

350Zimo

iTrader: (19)

that's the reason that refrained me of adding this mod. Although, i dont daily drive the Z, i still want to enjoy some "harmony". My exhaust note triples from 2000rpm to 4000rpm. It's annoyingly loud. However, the 4.08's are a great mod, if you want to shave some time off you 1/4, and drastically improve your acceleration. And besides i opened a savings for an FI, so the 4.08's are not in my list anymore

NISMO_558

iTrader: (1)

I actually heard this one story where both guys had a 2006 Z, one had stock gears and the other had 4.083's and the z with stock gearing was actually pulling away, so really their not worth it.

kramykram

iTrader: (135)

this was the first tank since i bought the car, i bought it switched my differntial from one z to the other. so all but about 20 miles was on the 4.083 gears.

kramykram

iTrader: (135)

lol wow thats about a bad way to make a judgement on getting gears or not. how do you know the driver who had the gears just didn't suck?

350Zimo

iTrader: (19)

No 4.083 gears would make a difference. I too think that the driver of the stock z really sucked

NISMO_558

iTrader: (1)

I cant say, i'm just throwing that out there, but there is logical explanations as to how that is.

Hoooper

iTrader: (5)

would love to hear THAT logical explanation

NISMO_558

iTrader: (1)

There was actually a post a while ago explaning the whole thing, but it really comes down to the fact that the Z with 4.083 gears has to shift more often than the one with standard gears.

We did a little experiment back when I had my '04 Z. what we did was, before a had the 4.083 gears installed we did an acceleration test, basically I'd be going the speed limit (65) in 5th and as soon I wen't underneath the lights at a 4 way I'd gun it, and directly in front of us was a bridge about 1/3 mile long, and when we hit the end of the bridge we would be going around 140 with stock gearing. With the 4.083 gears, it would only reach 120, so theoretically it got slower.

__jb

iTrader: (3)

Not true...

I have 4.08 gears and with a 285/35x19 rear tire 80 miles per hour is 3400 rpm. My last tank of gas averaged 18.6 miles per gallon with city and some highway driving.

4.08 gears are a great mod... and I don't even have an HR.

NISMO_558

iTrader: (1)

their ok, and I had the 4.08's in my '04 Z, not my current '07, and going 65 i WAS at 3300 rpm, and my gas mileage was horrible.

kramykram

iTrader: (135)

even in my 03 going down the interstate doing 70-80 mph i still averaged about 430 miles on a full tank with my 4.083. but then again i don't redline my car everytime i drive it either.

Hoooper

iTrader: (5)

you clearly had an inconsistency with the tests. you didnt have to shift in either one, so were the conditions the same? with shorting gearing you would certainly get there faster, thats just how it works

blindmonkee

by no means am i an expert in the matter. imo you should have timed your testing. just because you were going faster in the end doesn't mean you were going faster. we all know you loose top speed with this mod. you may have been going 120 at the end with the 4.083 gears but you may also have been going 120 for much longer. with the stock gearing it probably took you some time to get up to 140. maybe my logic isn't making much sense to you but from what i understand the point of this mod is to accelerate faster not to increase your velocity. theoretically you maybe have been slower in velocity but until you conduct testing over a period of time you can't technically say you were accelerating slower. i dunno just my $0.02

NISMO_558

iTrader: (1)

Actually I did, I started in 5th and soon after went into 6th on both accounts

sharaabi

you know what guys, i hear so much about this mod and i really want it but honestly speaking does anyone here have real in depth knowledge on how this will effect gas mileage??

so far i've read "horrible","terrible","not too much" and "inconsistency".

i clearly understand that this WILL effect gas milage but i just want to know on average by how much....and for someone to test this out stock vs modded will be hard/impossible to do just to prove a point but if someone has good knowledge of the physics of the gearbox and engine, please enlighten us.