Best Diff Ratio for VN?

[Manual Calais]

Hey, I', just wondering what the best ratio to use in a stock vn would be?
Its manual, just got the exhaust and intake done.
Also whats the best way to go about getting a Lsd for my vn?

-Thanks

[Sabbath']

Doesnt matter what ratio is aslong as it's a locker or spooooool brah!

[Manual Calais]

haha i dont wanna mini spool iit, that would be cheaper and easier but #### that, deff putting lsd in when i can find one, but ownderign if i should get like 3.45 gears or keeep the 3.08, i recon the 3.45 would be better for at the lights n shit?

[havavb]

345's are pretty crap, only good for hitting limitor in 1st straight away lol, go 3.9's or 4.11's, and yeah spool/welded diff's get bloody annoying after awhile, I love em but I'd prefer LSD for everyday driving. But nothing beats a spool

[GRPABT1]

Best ratio is the one that has you crossing the 400m mark close to redline/torque drop off in 1:1 gear (4th)

[james1988]

4.11's man.
if your going through the trouble to change them, go the shortest.

cos if you go 3.7's and are like funk yeah this is siiik, then you will later wonder how much better 4.11's would have been.

rather be looking at wheelspin then looking for it.

[Manual Calais]

I see, 4 11 would rev like 3 grand in 5th at 100 wouldnt it? Im not looking to spin wheels i just wat a bit more pick up, like atm on 100 in 5th im revving 1750-1800 and someone tries to race me ill drop it to third and be ####ed by the time i get to the end of 4th, or as the other guy said, the torque drops off at 4th coz it 1.1 and therefor if i want to go any better ill have to mod more on my motor? sorry if im not making much sense here haha,

OR say im at the lights and someone will take off i wanna know what the best ratio would be for say getting to 100-120 quickest? I dont know a whole heap about this stuff thats why im askign for help :P maybe if i put it this way, im a everyday driver but dont mind giving it a squirt at the lights or down the freeway, what would be the best ratio to use?

Also would 4 11 chew fuel appossed to 3.08 or 3.45?

Thanks heaps for your imput guys

[james1988]

4.11's would probably be best for standing start acceleration.

On page two of this forum someone has asked pretty much the same thing.
And rpm at 100 increases is all about comparative percentages.
I'm just gonna cut paste what I said in the other guys thread. It's a bit to get your head around but it works. And u can get an idea of the differences in diff ratios.


well your diff at the moment has a 3.08 ratio. if you go 4.11 then thats a 33.5% increase/difference.

so your speedo is going to be reading 33.5% higher than your road speed.
so to do 100 km/h, you will have to have your speedo reading 133. so just find out your revs by that.
I dont know if the vn's had a speed governor. but for example its 180 km/h.
then 180 divided by 1.33 (because you have an extra 33 percent) is 135.
so you will max out at 135 km/h road speed.

and another way to find out what rpm you will be doing at a certain speed is
RPM divided by Current diff ratio Times New diff ratio
so just say at 100km/h your car revs at 1600rpm with your 3.08 diff ratio, and you want to know what your gonna be revving at with your 4.11 ratio
1600/3.08x4.11 = 2135 rpm

[Bizmark]

What do you use the car for mainly? If its a 1/8 or 1/4 mile strip car, 4.11's. If its a daily, and you travel on both suburban roads and highways, 3.45's will give you a decent mix of acceleration and cruising economy, 3.7's will lean a bit more towards acceleration.

However if you don't care about cruising economy, 3.9's or 4.11's are what you should be looking at. Just find a second hand diff in you desired ratio with an LSD and have it reco'ed, or if you like, buy a brand new lsd diff.

[WazzaVN]

My advise would be 3.7 or 3.9. 4.11s can get pretty impractical for an everydayer unless you have a 6 speed. I've got 3.7s I'm my vp auto and they go good. So 3.9s would probably go good with a 5 speed. Check out ebay, I got my 3.7 LSD fully reco'd for $900 with oil. And it's nice and tight.

[wamboin23]

I just recently installed 3.9's into my VS V6 with a T5 5 speed. Revs at a touch over 2500rpm at 110kph, which is right at the point where a V6 drones.

I'd go with 3.7's, but they are rare and expensive if you do find them.

[jakobe]

im selling my lsd from original bt1 v6.
give me private msg if u r interested.
pickup from inner east melbourne.

[monkeys437]

Why dont you just quickly make a spread sheet that will tell you road speed vs rpm for all 5 gears and check it for a variety of diff ratios.

I'd be checking road speed at red line in every gear, and your RPM at 110kph in both your 1:1 gear and overdrive gear for all the available ratios and decide whats best for you.