re-gearing

[losh1971]

I am about to buy some 3.45s and am wondering what my revs will be at 100kph? Currently I can do 110kph at 2k.
I'd also like to know what speed my speedo will read at 60kph as I understand it will be out, once I re-gear. Lastly will 3.45s be the best in terms of a little extra pull and improvement in economy? I am pretty sure the standard gearing is too tall in a stock V6 but not how much by.
I don't want to go too short as I'm not looking for huge gains in pull, just a little and hopefully some economy improvements. Basically trying to gear how Holden should have geared from factory, which I don't think 3.08 was the best choice.

 

[keith reed]

My vh with turbo 700 in overdrive is about 2300 at 100 k with 3.45 gearing. Yours if auto should be about the same. I think that 3.45 is about the best for overall driving. With my ute which has the same gearing I drove from Ipswich through Brisbane and about !00 k up north ( 100 and 110 k areas) return and got 10 kilometres per litre. You should do better than that depending on how you drive with a v6.

 

[losh1971]

Thanks @keith reed that is decent improvement. At my best calculation I'm getting 11lph as is. Stock I was getting around 14lph. As I suspected it does sound like the stock gearing was always too tall.

 

[Lex]

My vt with a v6 & 3.46 diff at 100 kph is 2000 rpm.
On a trip up to NSW fuel averaged 9.3 (no a/c). Return trip (with a/c) 9.4.
The cluster has been setup for the correct pulses per kilometer too. (don't know how the vr speedo works?)

 

[losh1971]

Yeah VR speedo works differently. I pretty much have to live with it being out. I'm not tech savvy enough to make the speedo corrector box.

 

[_R_J_K_]

VR speedo uses pulses too. The speedo box is usually a kit which tells you where everything goes or you can buy them already assembled, you just have to intercept the two speed sensor wires. You just change the speed by turning a couple of potentiometers and just compare against the GPS speed on your phone. It's really not that hard even if you have to build it.

 

[losh1971]

Sounds technical. I could fit a box easy enough if they can still be bought. My phone doesn't have GPS speed only Google Drive. No room on the phone to update Apps so won't be able to download proper GPS.

 

[losh1971]

Any idea where to buy a speedo corrector box? And is that what they are called?

 

[VS 5.0]

Any idea where to buy a speedo corrector box? And is that what they are called?

Jaycar has this BUT there are numerous results on Google complaining about it not working

Best to do some research.

 

[losh1971]

I was of the understanding that Jaycar no longer have one suitable for the VR. Apparently the old unit they had that works on a VR worked very well.