SV6 Diff Upgrade - 3.45s

[mattsv6]

I have been reading various threads about Diff upgrades for the SV6 Auto 5-speed and have a couple of questions:

> 1. Does traction control/ABS/IRS impact which Diffs will work with a SV6?

> 2. Will a diff from other Holden/HSV models fit a VZ SV6? If so, which models?

> 3. What is the process for recalibrating the speedo and shift points after the ratio has been changed? I know holden can do this, but is there anyone else (potentially cheaper?)

> 4. Would it be cheaper to buy a 3.45 ratio gear set (not the complete diff) from ebay and pay someone to do the changeover?

Thanks diff guru's!

[monaro327]

1. no the diff change wont affect abs/irs might make traction control kick in more often though

2. don't know sorry anything on a vz hsv etc will fit not sure if vy had the same diffs.

3. any vcm tuner can recal the speedo and fix up the shifting probably better then holden can.

4. highly doubt it.

[andyman]

2, any vx2 upwards diff with the 3 bolt flange for the rubber uni will fit

4, generally no, the 3.46 gear set is an 8 inch diff, the v6's have a 7.5 inch, so you will need the complete carrier setup to bolt back in,

id recommend a reconditioned unit, there was a mob selling them on ebay dor 700 i believe, just a straight bolt in unit,

the holden lsd is a piece of poo in design, so dont expect wonders from it,


as prospective with 3.46's on my manual first gear is about 50km/h at 6700rpm

[mattsv6]

So I'm guessing that means a VE diff would fit ok?

[Kal123]

Nope, only VX2 to VZ. VE is different.

[mattsv6]

What about a VY monaro Diff? Holden commodore VY monaro LSD DIFF hsv vx vz SS 3:46 - eBay, Other Car Parts, Accessories, Car Parts, Accessories, Cars, Bikes, Boats. (end time 07-Nov-09 12:43:07 AEDST)

Btw I have dibs on this if it will fit

[andyman]

certainly will, go for it

[blackdoggg]

the the monaro diff a good diff? would that be the best one to get? or a vz hsv?
dont mind me just butting into this thread :P
when ive got the penny want a new diff to be the 2nd thing i get. (first being brakes)
have an 05 exec.

[HoZy]

Alloytec V6 Ratio: 3.08:1
Alloytec 190 V6 Ratio: 2.87:1
V8 Automatic Ratio: 3.07:1
V8 Manual Ratio: 3.73:1
V8 Monaro Automatic and Manual Ratio: 3.46:1

[mattsv6]

Alloytec 190 V6 Ratio: 2.87:1

Why holden.... Why!!

[andyman]

Alloytec V6 Ratio: 3.08:1
Alloytec 190 V6 Ratio: 2.87:1
V8 Automatic Ratio: 3.07:1
V8 Manual Ratio: 3.73:1
V8 Monaro Automatic and Manual Ratio: 3.46:1

v6 live axle models manual, are 3.46 auto still 3.08

[andyman]

the the monaro diff a good diff? would that be the best one to get? or a vz hsv?
dont mind me just butting into this thread :P
when ive got the penny want a new diff to be the 2nd thing i get. (first being brakes)
have an 05 exec.

all the same paperweights from the same factory

[bigdaddycool]

I just wacked in a 3.46 diff in my VZ Exec.... well worth it, however it is frustrating the hell out of me trying to move my shifts.

Essentially what happens is the "shifts" arnt really the problem, it's the "Optimal Torque Table" as it controls how much torque is where n at what rev range. Problem is there's a heap of little points where u can see the torque has been dropped for a gear change.

Essentially I figure you just need to copy the effect and move these up 200rpm roughly to fix it.......... big job.

[Exidor]

I just wacked in a 3.46 diff in my VZ Exec.... well worth it, however it is frustrating the hell out of me trying to move my shifts.

Essentially what happens is the "shifts" arnt really the problem, it's the "Optimal Torque Table" as it controls how much torque is where n at what rev range. Problem is there's a heap of little points where u can see the torque has been dropped for a gear change.

Essentially I figure you just need to copy the effect and move these up 200rpm roughly to fix it.......... big job.

Thought you would only need to change the cluster PPK
with the ratio change?

[bigdaddycool]

You change the diff ratio on the ecu tune (to get the spedo to read correctly)........ in the spedo section. but it doesn't change the over all tune layout which effect the torque n shift points.

[andyman]

i didnt bother, if the diff ratio is changed aswell as the ppk, it should self adjust, i never had any problems with driveability