Big 3 Upgrade

[siz1]

Hi Guys,

I am considering to do the "Big 3" upgrade. In other words, upgrading the following cables:

1) alternator positive to battery positive
2) battery negative to chassis
3) engine ground to chassis

There is plenty of stuff online about it but wondering if anyone has done this on a Vectra C? this may give me an idea of cable lengths and generally if its straightforward or not.

I Hope to get some tips

[XPCobra]

I thought it was only older cars which befinited from this treatment?

I added a ground wire from the alternator area to the O/S/F strut top - Didnt really make much difference.

[MiniVauxhall]

It benefits any cars charging system, you can get up to 0.5v from doing the big three.

[siz1]

Well I am considering the upgrade to improve my after market sound system, ive noticed the dash dimming slightly when i crank up the volume. It seems the factory cables are already 4 gauge, so could probably upgrage to 0 gauge

[merikiito]

Wouldn't it be better to upgrade the alternator?

What Vectra do you have?

[siz1]

I dont think Ill need a new alternator, im pretty sure Ill get away with the 120A stock alternator. I have a 2.0 DTI..

[merikiito]

Well the CDTi 1.9 one I think is 140A if you go that route

[Mr Owens]

I've only ever bothered upgrading the battery earth and chassis earth on other cars as I always run a 2nd battery for my sound system, hopefully I can make a start on mine this weekend, I might upgrade the alt power cable when I do mine as I get slight light dimming issues as it is.
If the current draw is too much for your standard battery then you may want to look at adding a 2nd one

[Leemarksmith]

How do you wire up a second battery? Series or parallel?

[MiniVauxhall]

Parallel (+ to +, -to- ) think you just have to make sure its the same as the one in the front otherwise the smaller one will drag the bigger one down.