Guys

Since I got the 2 cars on LPG recently I am just wondering if I should fit a heavier
spring/shock in the back to compensate for the extra weight??

Now should I fit a shock or a spring or both, not sure how it works?

The KJ sits ok but my KL seems to dip in the back a little now??

Any ideas of what type of shock or spring etc, something cheaper but not RUBBISH

I don't think you should worry about the extra weight.Do remember that lpg is much lighter than petrol so the weight difference isn't much.

The tank weighs around 8-10kg and 1L of lpg is around 0.5kgs of weight.
So with a full lpg tank at 60L - the extra weight would be 30kg + 10kg's for the tank. That's not really something to be worried about. The back shouldn't really sag down because of that.
Together the tank and the lpg in it would weight about as much as two wheels in the back.

If you are really worried, next time you have to replace them put in high quality boge or kyb shocks. They are a little more pricey but good shocks

Try the dobsons springs, seeing springs set the height..but at around 50 to 60 kg for a filled gas system, its not much to worry about.
I'll go dobsons next time, the kings are a bit light duty for a kitted out TW.

Cheers guys, will just live with it for now I guess. Do like those kyb shocks though, tasty

KYB are rubbish, they are over gassed, harsh as many have found and do not last anywhere as long as the Boge

Boge are high quality european units that are often used in many top end vehicles

my TW wagon is on gas, and has the spare on the right. it sits lower on the right. My AUIII Falcon wagon on gas did the same thing. Each had a towbar, and sagged at the back. In both cars I fitted polyairs and I would run the right at a higher pressure than the left which evened up the ride height. Can't comment on a sedan.

A new set of rear springs will likely solve the problem. My TJ AWD was sagging in the back when I bought it at 162K and this was before I had LPG installed. After the LPG was fitted, I had all the springs replaced with aftermarket standard height springs. The spring manufacturer offered a "heavy duty" rear spring for LPG applications and when I asked what they meant by heavy duty they said the springs were stiffer and "might" raise the rear ride height. As I didn't want the car to sit higher at the back, I didn't go for the heavy duty springs. IMO, a set of aftermarket (there's a number of brands on the market) standard height rear springs will do the job so long as you want to try and maintain the original ride height.

In relation to shocks, I've recently replaced KYBs with Boge. Personally, if you're thinking about replacing shocks, I would spend the extra and buy the Boges.

Thanks guys, point taken and will hunt around for some boge ;)

Just scrolling fleabay, what do guys think of Monroe gt gas?

I've had them before but not on a Magna. Personally, I think they're too expensive for what you get quality-wise. When I bought my AWD I was quoted $605 by a local retailer for Monroe GT Gas front struts and rear shocks. 18 months later, I bought Boge items from Madmagna for around $600. No comparison. If you're looking to buy on fleabay, you can probably find at least one other brand that is cheaper than Monroe and just as good or better. IMO, the best person to talk to is Madmagna.

I've had them before but not on a Magna. Personally, I think they're too expensive for what you get quality-wise. When I bought my AWD I was quoted $605 by a local retailer for Monroe GT Gas front struts and rear shocks. 18 months later, I bought Boge items from Madmagna for around $600. No comparison. If you're looking to buy on fleabay, you can probably find at least one other brand that is cheaper than Monroe and just as good or better. IMO, the best person to talk to is Madmagna.

I have heard that boge is owned by sachs, is that true and are sachs good shocks as well?

One thing, the dampers or shocks will not in any way adjust the ride height if that is what you are after

If you do the boge in the rears, you are best to also do them in the front as well