VY or VZ LSD into VT

[adamc11]

Hi,

My cousin has a modified 99 VT Berlina Wagon 5.7 and is thinking about putting in an LSD. Would a VY or VZ SS Sedan/Wagon diff bolt straight onto the car without any modification? Also would the gear ratio in his current diff be the same as an LSD?

Thanks,
Adam

[clubsport_replica]

supose that all depends on the vehicle it came out of wether same ratio manual/auto etc, wagon sedan same centres and been a ls1 wagon it should bolt straight in just check the diff flange make sure it is the 3 bolt kind to take the rubber coupling the later model vy/vz have.

hope that helps mate

[QldKev]

Yes it will fit, since the VT has the 5.7L engine it is a series II; with the 3 bolt flange setup being the BW80 diff.

With the ratio it depends, auto / manual etc. You need to give specs of both cars. Bit of luck he may be moving from the crappy 3.07 to a better ratio, 3.45 or even better a 3.73. All that will be needed is a speedo re-calibration. If he has a modified car I assume he already has a tuner in mind that should be able to do it fairly cheap.

Also we are assuming that the new diff is what the car had stock.
My car had 3.07 stock, but is now 4.11

QldKev

[adamc11]

Thanks for the replies. The car is an auto. What ratio would it have? He doesn't want to up the ratio as he does a lot of highway driving. Would an auto VY/VZ SS have the same ratio? What is the ratio of the manual VY/VZ SS?

[QldKev]

Thanks for the replies. The car is an auto. What ratio would it have? He doesn't want to up the ratio as he does a lot of highway driving. Would an auto VY/VZ SS have the same ratio? What is the ratio of the manual VY/VZ SS?

VT Berlina Auto = 3.07
VY/Z SS Auto = 3.07
VY/Z SS Manual = 3.45
VY/Z Clubby manual = 3.73

Even for a lot of highway driving I would still look at a 3.45.
At 100km/h 3.07 = 1790rpm, a 3.45 = 2017rpm, only 227rpm more. But heaps better around town.

QldKev

[adamc11]

Thanks for the responses. He is now thinking of 3.45 or 3.73

What sort of price would a second hand diff cost and how much for fitting? He also has the option for going for something like an eaton or higgins diff... what are your thoughts on these?

Thanks again for the help.

[QldKev]

Thanks for the responses. He is now thinking of 3.45 or 3.73

What sort of price would a second hand diff cost and how much for fitting? He also has the option for going for something like an eaton or higgins diff... what are your thoughts on these?

Thanks again for the help.

Since he is also looking at a 3.73 the rpm at 100km/h would be 2175rpm

I got my recon lsd 4.11 from ebay for $950 + $90 postage. It took me and a mate about 4 hours to fit it, and neither of us had done this style of diff before. There are a few step by step guides on the net on how to swap them over. So that was about $50 for beers. You will also need to get the speedo recalibrated, it costs $50 from my tuner. Finally allow some $ for 1.7L of fresh diff oil. I'm running a cheaper oil for the first run in period and will dump it and put a full synthetic in it at 1,000km (very soon).

Eaton, higgins and trutrack are excellent diffs. They are better than the stock cone setup, but unless he is running some huge HP, or is going to enter every burnout event, or does a lot of track work I would not bother. For my street runner with about 225rwkw I went the standard one.

When I added the extractors/cat/exhaust + mafless tune + OTRCAI to my LS1 I loved the change in response the car had, and made it feel like a real V8. Now I have the diff as well it is a new car.

QldKev

[MR_VX]

im glad i seen this. I also wanted to know if a VY SS LSD would bolt in to my v6 VX, ill be giving it ago most likey this weekend any ways

[QldKev]

im glad i seen this. I also wanted to know if a VY SS LSD would bolt in to my v6 VX, ill be giving it ago most likey this weekend any ways

You will have a BW78, the SS will have a BW80 diff. Better diff and it will fit no problems.

QldKev

[MR_VX]

great to know thanks dude

[clubsport_replica]

so whats a vy clubsport diff BW80 im guessing im stealing my mates one that has 3.9 ratio as he now wants 4.11 anyway will be miles better than my current 3.08 kinda lsd in the vt i got now

[QldKev]

so whats a vy clubsport diff BW80 im guessing im stealing my mates one that has 3.9 ratio as he now wants 4.11 anyway will be miles better than my current 3.08 kinda lsd in the vt i got now

Yep all VT series II onwards V8, until VE had the bw80.

If your old diff is a lsd that sometimes will single wheel you will probably find it is just the oil. A lot of lsd diff oils such as Catrol saf-xa have the maximum level of the friction modifier in them. You are better of using a 80w140 base oil and adding the Sturaco 7098 in to a level what suits your lsd. ie. add in a bit and try it, if it chatters too much add a bit more, until you have a tight but not too noisey diff.

3.9 will be an awsome upgrade from the old diff

QldKev

[clubsport_replica]

cheers mate yeh sometimes goes single on me will try that before i rip it out yeh i reckon 3.9s will get it moving along abit better of the line.