VP Diff Question

[ozzieboy]

Hey all, Just wondering what would be the best LSD Diff to get for my VP series 2 S Pac. Its has irs aswell as bein an auto, ive been looking at these ratios but am still unsure what would be best 3.07 and 3.45. Im hoping hoping to gain a quickier take of and at the same time not chew through the fuel if thats possible. Please leave any feed back as im new to all of this. Cheers Matt

[azzfox]

welcome to JC... 3.07 will give more speed at same rpm as if it was 3.45 but will have to work harder. 3.45 will give you quicker take off but will rev higher at same rpm as if it was 3.07. id say 3.07 would be more efficient on long runs. not sure on take off tho. in easier words 3.07 will rev lower at same speed as 3.45.

[Doctor Sodways]

3.45 if your after take off, the easiest way to look at it is this,the higher the number in the ratio, ie; 3.08 and 3.91, the faster the car will take off, and the higher the revs when maintaining speed. 3.08 and 2.7 are ratio used normally in falcons and commodores as they have the best economy, 4.11 is used in drag racing and so forth for the take off and lower top speeds, but they get there faster. 3.45 in your car shouldnt be too bad, SS commos use a 3.46 these days, and most XR falcons use it as well, 3.7 is regarded by many as the best ratio as it delivers a fair punch off the line and some feasable economy to go with it.

Hope that helped

Doc

[1991_Vn2nV]

Doctor Sodways gave all the info ya need, but just so you know, you're car has a 3.08 ratio stock, so in terms of take off there would be no improvement with 3.07 gears. 3.45's would be a good set, minimal difference to highway fuel economy as well and no difference on economy around the city. If you dont do much highway driving then go for 3.7's i reckon.

[greenfoam]

Hey all, Just wondering what would be the best LSD Diff to get for my VP series 2 S Pac. Its has irs aswell as bein an auto, ive been looking at these ratios but am still unsure what would be best 3.07 and 3.45. Im hoping hoping to gain a quickier take of and at the same time not chew through the fuel if thats possible. Please leave any feed back as im new to all of this. Cheers Matt

This is the first time I've ever heard about a IRS V6 s-pac VP, must be quite the rare machine.

P.S 3.7 gears if you never leave town, otherwise 3.45's

[1991_Vn2nV]

IRS was standard on Calais and SS for VP's... So it must have been optioned on it.

[ozzieboy]

Hey Thanks for the info guys much appreciated. Just another question will a vt -vz diff 3.46 LSD fit straight into my car without any hassels ? Greenfoam I brought my car over a year ago from the original owner he told me when he purchased the car he had Holden put a SS steering wheel on and also the SS mags, he also got the IRS and ABS options to. Overall the car is in mint condition and im hoping to slowly mod the car to give the V8's a run for their money lol.

[1991_Vn2nV]

ABS woulda been rare as well, it was only an option on series 2 model V6's.

Not 100% sure if the diff centre from a VT-VZ will fit, but the gears will.

[Daniel Gray]

Uve gotta get a vp irs flange to rplace the vt/x one. then it will fit fine

[adam69]

What is a irs flange?

[Daniel Gray]

What is a irs flange?

The flange is the outside of the diff, it has holes in it for the abs sensors. If youve got a vt diff or something, id just take the diff to a specialist and get them to fit a vp flange, its harder than it sounds. Make sure u tell them if uve got abs as it is different, to none abs. wot r u fitting the diff that uve got to?