3.9 or 4.11 diff gears?

[vr304]

Hi guys I have a 2001 vx ss 6 speed manual with otr exhaust and tune done to it, I'm going to get my diff rebuilt and geared down from the 3.46 ratio I'm looking at either 3.9 or 4.11 and am not sure which way to go any opinions on them? How much difference is there between the 2?

 

[Immortality]

4.11's have about 5% more rpm over 3.9's. So at 100km/h about 87 rpm more.

 

[vr304]

Day to day driving tho round town etc is there much difference between the 2? Much difference in acceleration?

 

[Immortality]

don't know unfortunately.

 

[NPreston]

I have 4.11 in my V6 powered 5 speed track car and I would opt for 3.9 for the road.

 

[Immortality]

I have 4.11 in my V6 powered 5 speed track car and I would opt for 3.9 for the road.

The T56 has a much taller 6th gear OD (0.5:1) so they rev much lower in 6th than a 5 speed does in 5th. 4.11's/T56 with 235/45/17's tyres would only be doing about 1700rpm @ 100km/h in 6th gear.

I want to do a T56 conversion in my Senator, if it ever happens the diff will get some 4.11 gears to match.

 

[NO HOON]

Although i haven't tried either, i'd reckon 3.9 would be great for a street car. 4.11's seem like you'd loose traction too easily.

I made a thread a while ago discussing what ratio i should get, it may help you a bit: http://forums.justcommodores.com.au/general/239425-looking-buying-new-diff-gears.html

 

[greenacc]

3.9 will be a bit easier to drive and give it very slightly longer legs in each gear .,,,,,,,,, so more time with the throttle down and less time with the clutch in...

 

[Mike Litherous]

I have 4.11 in my ve and they transform the car. If they made even shorter gears I probably would have got those. The only minor issue with the 4.11 gears is a slight whine at speed. It makes 6th that much more usable. Before with the 3.46 gears I barely saw much more than 4000rpm where now it's banging into the 6700 limiter like a euro v8 (well almost).
With the new found acceleration enjoyment u tend to use more juice just cos u seem to drive it harder.

 

[markalan1two]

I have 4.11 in my ve and they transform the car. If they made even shorter gears I probably would have got those. The only minor issue with the 4.11 gears is a slight whine at speed. It makes 6th that much more usable. Before with the 3.46 gears I barely saw much more than 4000rpm where now it's banging into the 6700 limiter like a euro v8 (well almost).
With the new found acceleration enjoyment u tend to use more juice just cos u seem to drive it harder.

I have 3.9s in a vf and around town if your driving normally iget better fuel economy than with the standard gear also as mentioned above you can actually use sixth