VF SS diff gears

[Brandon22]

Save money for a cam, do you know how much changing diff gears costs?

No idea man hahah I work at a panel shop/ mechanic shop but I ain’t the mechanic so they look after me with that stuff hahah

 

[losh1971]

Retail would be around $1100, plus gear set. Plus centre, if looking to upgrade that too.
My suggestion was grab a SH complete manual diff, if you're have auto. Although I haven't priced one up, so might not be cheap.

 

[MrBags]

Personally I would 100% go the 3:45, it is a worthwhile and noticeable change.
Not cheap, but also a quick full bolt in replacement if you don’t want the truetrac centre.
Keep in mind you will likely need the shift points redone and Speedo calibrated too.

 

[RevNev]

best gears to suit my car would be 3.27 or just go abit more ?

I think 3.27 is perfect with an auto. It's doing 1750rpm top gear at 100kmph and isn't too tall. 3.27 suits the trans ratios well but I think 3.45's are on the edge of revving too hard on the open road. 2nd gear seemed a bit a low on low speed corners with a 3.45 and 3rd too tall where the 3.27 in 2nd is spot on. I definitely wouldn't go lower than 3.45 on an auto and prefer the 3.27 with an LS3.

 

[daves8]

I think 3.27 is perfect with an auto. It's doing 1750rpm top gear at 100kmph and isn't too tall. 3.27 suits the trans ratios well but I think 3.45's are on the edge of revving too hard on the open road. 2nd gear seemed a bit a low on low speed corners with a 3.45 and 3rd too tall where the 3.27 in 2nd is spot on. I definitely wouldn't go lower than 3.45 on an auto and prefer the 3.27 with an LS3.

I recently went from 2.92 to 3.45

at 100 I’m doing about 1800 rpm, which is noticeable from the more comfortable rpm from the 2.92.

around town the 3.45s are heaps better. Cruising at 60 is good (where we do most of our driving)

would like to see what 3.27s are like but happy with my 3.45s

 

[daves8]

Also fwiw I bought a brand new complete unit from holmart for $1850 and install and recalibration of shift points/ speedo was $550

 

[RevNev]

I recently went from 2.92 to 3.45

at 100 I’m doing about 1800 rpm, which is noticeable from the more comfortable rpm from the 2.92.

around town the 3.45s are heaps better. Cruising at 60 is good (where we do most of our driving)

would like to see what 3.27s are like but happy with my 3.45s

I think the HSV LSA gear ratios are a good combination in manual and auto and the auto is the same as the VF2 LS3. The LS3 manual gear ratios I think are lousy being too low in 1st and second, too much gap into 4th and 5th and 6th is too tall in other words, ideally needs the LSA ratios in all manual V8's. Surprisingly, the LS3 auto ratios with the 3.27 diff are better configured than the manual and feels right except for the 1st to 2nd upshift at 13 kmph. I changed mine (HP Tuners) not to upshift into 2nd below 19kmph and replicates where you'd normally shift in a manual.

I don't traditionally like autos and ended up with a deal on my auto SSVR ute too good to pass at the time and thinking I'd always wished it was a manual, I've got to like the auto with paddle shift I often drive manually for fun and the overall ratio spread with the 3.27 diff I think is pretty good! The 3.45 LS3 auto I drove I thought was too low in 1st and 2nd to drive like a manual and the 3.27 in that regard felt better suited to the LS3 torque. A 3.45 might be better in a 6 litre (VF1) combo perhaps but the LS3 I think can pull a 3.27 diff easily without performance loss. 2.92's a shocker and doesn't work optimally at any level and definitely a good thing to change to a lower better usable diff ratio.

 

[moveage]

Stock 2.92 ratio and car’s two tonnes needs 500kg less weight or about 50 more engine torques (600Nm), which you’re not likely to get (in a streetable range) with a typical cam. Quite the opposite.
Same era Corvette uses 2.73 NA and 2.56 Z06 with 6l80 in transaxle, CTS-V and Camaro 3.23 in a huge pumpkin, drag tests by John Lloyd in WA proved 3.27 gets you over the line in a VF without going into overdrive, and Rick Crawford who holds record for “full weight” G8 did so with fully forged bespoke motor at 7.5k rpm stacked with drag rubber on 3.45.
I’ve done stock clutch and trutrac LSD 3.27 3.45 and settled on back to stock ratio with trutrac and tuned mods for just a bit more streetable torque.
Defo with typical late IVC performance cam in mind for later 3.27 is perfect.