Vy V6 Diff Change

[richierich]

Hi guys,

Thinking of changing my diff gears to 3.7 for better acceleration off the mark. Mid to high is not a problem. Its an auto with corvette servo and raptor s/c.Also cost alternatives on doing it.Is 3.7's best for a auto or 3.45's.

[sircruisealotVS]

im a noob on the diff ratio's for post-VT models but i know they're different to the earlier ratios...i think 3.46 and 3.73 or something?
anway - the best ratio is the one that suits what you want from it and what the car is used for man, id go 3.46 but thats just me.
one other thing, have you consider a small stallie? that will get you off the mark heaps quicker too - especially with the blower - it'll pop the rev's up right into boost in a flash
something small like a 2200-2400rpm stallie is all you'd need for results.

[chargedvx6]

cruisealot's right, those ratios are from earlier models. I would be looking into at least 3.73:1 considering its a cent charger (topend friendly). Economy wouldn't be that bad on the cruise with 2150ish revs@ 100km/h depending on rim size. 4.11s are going to put you in 2360-70 territory.

I have 3.46:1 gears in my VX but mine's a roots blower (M90) so it's a different kind of power and I still get more power than I need on takeoff. 3.73s is my suggestion

[richierich]

[sircruisealotvs
one other thing, have you consider a small stallie? that will get you off the mark heaps quicker too - especially with the blower - it'll pop the rev's up right into boost in a flash
something small like a 2200-2400rpm stallie is all you'd need for results.[/QUOTE]

sirctuisealotvs i'm looking at take off, you know what ecotecs are like,mines a bit sluggish off the mark until s/c kicks in.I'm a noob on stallies.What does the stallie do?Is it off the mark or as you suggested 2200-2400rpm stallie it kicks in at those revs.And the difference in price to diff gears.I dont take it down the strip (i'd like to one day).For e.g. the other day vs clubsport sounding very lumpy took off at the lights and got a full car length in front until the s/c kicked in and i hauled him in. + the sun was in my eyes and my response was a little slownot making excuses of course.

[richierich]

cruisealot's right, those ratios are from earlier models. I would be looking into at least 3.73:1 considering its a cent charger (topend friendly). Economy wouldn't be that bad on the cruise with 2150ish revs@ 100km/h depending on rim size. 4.11s are going to put you in 2360-70 territory.

I have 3.46:1 gears in my VX but mine's a roots blower (M90) so it's a different kind of power and I still get more power than I need on takeoff. 3.73s is my suggestion

The rims are 18,s.What's the damage on getting diff gears + speedo correction and i heared you need gear point shifts corrected also.

[sircruisealotVS]

[sircruisealotvs
one other thing, have you consider a small stallie? that will get you off the mark heaps quicker too - especially with the blower - it'll pop the rev's up right into boost in a flash
something small like a 2200-2400rpm stallie is all you'd need for results.

sirctuisealotvs i'm looking at take off, you know what ecotecs are like,mines a bit sluggish off the mark until s/c kicks in.I'm a noob on stallies.What does the stallie do?Is it off the mark or as you suggested 2200-2400rpm stallie it kicks in at those revs.And the difference in price to diff gears.I dont take it down the strip (i'd like to one day).For e.g. the other day vs clubsport sounding very lumpy took off at the lights and got a full car length in front until the s/c kicked in and i hauled him in. + the sun was in my eyes and my response was a little slownot making excuses of course.[/QUOTE]

the stallie will help alot with "getting out of the hole" on takeoff.
a stallie is just a torque converter with a higher than stock stall point. at the moment your stock one would be about 1800rpm i believe.
its tricky to explain so bare with me - but if the stall rpm point is raised, lets say to 2400rpm, then up untill that point the stallie will absorb a large part of the torque by slipping - once at 2400rpm all torque will be passed through to the wheels.

you might think - why is that good? well it allows you to "jump" to that rpm very quickly, without having to rev through the doughy lower rpm range which doesnt do much for speed. likewise after shifts, the rev's will go straight past the low rpm range to the stall point and start working their way through the rpm range from their - which equals more power instantly after a shift.
for standing start launches the stallie will allow you to get straight into the business end of the revs if you stab the throttle - think of it like dropping the clutch on a manual from 2400rpm - you'll get a much quicker take off than if you easied out the clutch and took off from an idle rpm.
with a stallie you can also "stall it up" by applying brakes and throttle (this is more for a track car with a 4500rpm+ stallie) meaning you can raise the revs to just before the stall point without doing a static burnout and will launch from that rpm once you release the brakes.
i hope that makes sence, lol, its hard to explain. dont be scared of stallies - alot of people associate them with drag cars, etc, but they can be super friendly for the street too - especially if its just a small one like 2400rpm.

driving normally you probably wont really notice the difference with a stallie installed, except maybe less drop in revs after a shift. but start giving it some stick and you'll realise how sweet a good stallie can make an auto.
the price for a stallie can vary alot - mine cost about $350 from red diamond, then there is the cost of install.

[richierich]

sirctuisealotvs i'm looking at take off, you know what ecotecs are like,mines a bit sluggish off the mark until s/c kicks in.I'm a noob on stallies.What does the stallie do?Is it off the mark or as you suggested 2200-2400rpm stallie it kicks in at those revs.And the difference in price to diff gears.I dont take it down the strip (i'd like to one day).For e.g. the other day vs clubsport sounding very lumpy took off at the lights and got a full car length in front until the s/c kicked in and i hauled him in. + the sun was in my eyes and my response was a little slownot making excuses of course.

the stallie will help alot with "getting out of the hole" on takeoff.
a stallie is just a torque converter with a higher than stock stall point. at the moment your stock one would be about 1800rpm i believe.
its tricky to explain so bare with me - but if the stall rpm point is raised, lets say to 2400rpm, then up untill that point the stallie will absorb a large part of the torque by slipping - once at 2400rpm all torque will be passed through to the wheels.

you might think - why is that good? well it allows you to "jump" to that rpm very quickly, without having to rev through the doughy lower rpm range which doesnt do much for speed. likewise after shifts, the rev's will go straight past the low rpm range to the stall point and start working their way through the rpm range from their - which equals more power instantly after a shift.
for standing start launches the stallie will allow you to get straight into the business end of the revs if you stab the throttle - think of it like dropping the clutch on a manual from 2400rpm - you'll get a much quicker take off than if you easied out the clutch and took off from an idle rpm.
with a stallie you can also "stall it up" by applying brakes and throttle (this is more for a track car with a 4500rpm+ stallie) meaning you can raise the revs to just before the stall point without doing a static burnout and will launch from that rpm once you release the brakes.
i hope that makes sence, lol, its hard to explain. dont be scared of stallies - alot of people associate them with drag cars, etc, but they can be super friendly for the street too - especially if its just a small one like 2400rpm.

driving normally you probably wont really notice the difference with a stallie installed, except maybe less drop in revs after a shift. but start giving it some stick and you'll realise how sweet a good stallie can make an auto.
the price for a stallie can vary alot - mine cost about $350 from red diamond, then there is the cost of install.[/QUOTE]

You definitaly know your stuff,totally understand.Thanks for that.Now the decision. Diff gears or stallie.Diff gears i suppose are cheaper at this stage.

[sircruisealotVS]

no dramas man, id probably go diff gears at this stage if i were you. then maybe do the stallie later if you still want more kick on launch and snappier acceleration.

[nick_]

I've been quoted anywhere from 700 to over 1000 to give a workshop my LSD, my gears and my car (for them to fit the rebuilt LSD to) and those are drive in drive out quotes.. That includes all labour, new bearings, tightening the LSD, fluids and speedo/trans' adjustment..
HTH,

-Nick.

[sahib11]

thaxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx