VE diff gears???

[davo_SSV]

I'll soon be getting a cam package installed in my ute. It will be a fairly big cam though not big enough to make it a real pig on the road. While gettin quotes a couple places suggested doing diff gears at the same time, probably 3.9s. The question is how will this affect driveablity and fuel consumption?? I'm not up on the terminology but I'm guessing it will be geared higher and therefore be revving higher than it would with standard diff gears at a given speed....?

[Nathan89]

I have 411's and it's fine brings the tourque in nice and early sits at 1800rpm from aposse to the standard 345's at 1500rpm so 3.9's would be around the middle. I can get 9.5l to 100km on flat road but can average between 12.6-13l per 100km through down if I'm not up it when I'm giving it a hard time can see upto 22l per 100km

[BLACKVE]

I'vegot a 239/247 cam and heads ute and with 3.7's it's more than enough any lower and 1st would be to low

[Wonky]

There are heaps of threads already on VE diff gears. Is yours a manual (I assume given the recommendation for 3.9s) or auto? I've gone from 2.92s in my A6 to a set of 3.45s from a manual and love them! Exits corners and roundabouts so much better and bugger all affect on economy because it takes less effort to get the car going. For example even with a small cam I've been down to low 9s per 100km, not bad for a mid 280s rwkw cammed A6.

It's easy to calculate your rpm increase as it's just a straight ratio calculation. For example, assuming your car is currently M6 with 3.45 diff your new rpm at any speed will just be your current rpm x new ratio/3.45. If your car currently does 1500rpm at 100kmh and you put 3.9s in it will then do 1500 x 3.9 / 3.45 = just under 1700 rpm.

From what I've read going even 3.7, let alone 3.9 or 4.11 which are only available aftermarket and not from HSV/Holden increases your chances of whining and premature failure. There are quite a few guys on here who've put brand new HSV 3.7 shot peened complete diff centres in their SS/SSVs only to have problems for some reason and my understanding is the chances of that increase when you go even higher numerically eg. 3.9 and 4.11.

Everybody has their own views on going extreme on diff ratio changes - some love it, some hate it. Do a search on diff ratio changes, even on pre VEs and you'll get a wide range of views. Best thing to me is to wait till after your cam is done, drive the car around for a while and then see how you feel. Doing the diff later should make no difference to the price of doing it and the cam together. See if you can get a drive/ride in similarly powered cars with the diff ratios you are considering.

[davo_SSV]

Thanks fellas much appreciated. One more question if I were to do cam then diff gears later would it require a retune??
I assume the speedo is in the front end so I'm guessing a tune wouldnt be needed...

[DCV1NU]

No you wont need a retune, just get your tuner to recalibrate your speedo.

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[peter b]

Speedo on a VE comes off your rear wheel speed sensors speedo doesn't need to be recalibrated. VT-VZ needed to be recalibrated but VE's don't.
I have 4.11's in my own car and whilst I have just demolished a set that is not due to the gears and is all to do with setup. BE VERY CAREFUL who you use to do it as it would appear that some people are more relaxed with the setup and will make them too tight which will make the gears try to climb each other (for lack of a better term) they wont mesh correctly and the teeth will basically dig at each other. This eventually will cause the gears to lose their teeth.

[Micks]

Not entirely correct, not all Ve's operate that way as far as ABS wheel sensors measure cluster speed.
Our MY10 had ratio change from 2.92 to 3.27 & did infact require a recal. If you reckon yours is correct I would have it checked!

[peter b]

Not entirely correct, not all Ve's operate that way as far as ABS wheel sensors measure cluster speed.
Our MY10 had ratio change from 2.92 to 3.27 & did infact require a recal. If you reckon yours is correct I would have it checked!

My car went from 3.45:1 to 4.11 speedo reads 5 km's lower which it always did. The rear wheel speed sensors read off a trigger wheel in the rear wheel hub so measures real rear wheel speed. And yes I have had mine checked VE's do not work or read the same as VT-VZ
The speed difference doesnt worry me soo much due to amount of speed cameras around etc is my own safety measure so to speak.

[Micks]

My car went from 3.45:1 to 4.11 speedo reads 5 km's lower which it always did. The rear wheel speed sensors read off a trigger wheel in the rear wheel hub so measures real rear wheel speed. And yes I have had mine checked VE's do not work or read the same as VT-VZ
The speed difference doesnt worry me soo much due to amount of speed cameras around etc is my own safety measure so to speak.
All Ve's are fitted with a VSS which transmission mounted regardless of being Auto or Man, if what your saying is the case it would negate the necessity of the VSS.
Have heard some people don't require a recal but not in all cases!

[peter b]

All Ve's are fitted with a VSS which transmission mounted regardless of being Auto or Man, if what your saying is the case it would negate the necessity of the VSS.
Have heard some people don't require a recal but not in cases!

could be something between an 08 model vs 10 model if in doubt run up on dyno and check as mine most certainly did not need and recalibration.