Hi Guys

I've done a lot of searching to try and get to the bottom of this, basically I'm looking to raise therear suspension on my KH Verada sedan when towing a my boat (1 ton total). When the boat is completely empty it has a towball weight of less than 100kg and I'm always careful loading up the front of the boat.

Anyway, long story short, after much research I like the sound of the poly air bag suspesion system to compensate for a soft back end. They seem pretty easy to install and versatile - which is exaclty what i'm after. All the searches I've done on the forum only seem to yield experiences of people using them on wagons, however.

My question is: Has anyone looked into these for the 3rd gen sedans? I dont know a lot about the suspension setup on magnas so I'm reluctant to just ring poly air and have them quiz me for further information.

Any help or guidance that you can share would be great.

Cheers

Matt

The major issue is that wagon rears have separate coils from the dampers, you "just" rip out the coils and chuck in the aircoils. Sedan rears, and sedan/wagon fronts, are macpherson strut assemblies, which have the damper running through the middle of the coil. Which for an air setup, means a special aircoil is required that can seal around the damper piston. Dunno if PolyAir make any of these, and if not, whether they'd be interested in making a set for you.

The major issue is that wagon rears have separate coils from the dampers, you "just" rip out the coils and chuck in the aircoils. Sedan rears, and sedan/wagon fronts, are macpherson strut assemblies, which have the damper running through the middle of the coil. Which for an air setup, means a special aircoil is required that can seal around the damper piston. Dunno if PolyAir make any of these, and if not, whether they'd be interested in making a set for you.

I apologise for being pedantic and ensuring you have all the correct info, the sedans did not have Macpherson strut rear suspension. They had a multilink rear end. Macpherson struts are typically only used on the front end as they use the damper axis as the steering pivot. Another advantage is they can be made as an integral separate unit ready to be bolted in. Oh they are cheaper than multi link or double wishbones.

I think airbag suspension is a pricey complicated expensive solution to a simple problem that has plagued people that tow stuff for years. Best most cost effective solution is to get a pair of higher rate springs (stiffer) and throw in a new pair of suitable dampers while your at it.

Yes as has been alluded to the combined spring damper set up on the rear end will make airbags difficult if not impossible.

No worries your explanations make perfect sense. I guess I was hoping to avoid the higher rated springs in case that led to uncomfortable ride when unloaded. I guess I wanted the best of both worlds :(

When you say it's a cheaper option, is that if you do the work yourself? Or does it require specialist tools like springs clamps etc? Perhaps I'll search for posts on this topic and see if I can find some people who have had the same experience.

Yeah by cheaper I met in mass production of cars, Macpherson struts are cheaper than multi link or double wishbones. The Magna differed from the related Japanese Diamanté In that it had Macpherson struts instead of a more sophisticated multilink front suspension. This allowed Mitsubishi Australia to develop and market the car at a competetive price against its rivals.

If you have the tools inparticular spanners, socket set, trolley jack, stands and spring compressors. It may be worth giving it a go and you will save some money. A workshop manual is also a good investment.

I suggest getting someone with experience to help with using the spring compressors. A compressed spring letting go can be deadly.

Good luck.

There may be airbag shocks available from Monroe - they do much the same as Polyair bags. A decent WDH (weight distribution hitch) should level your sedan as the max allowable towing weight is 1500KG for the sedan with a WDH fitted and the factory says you can have a max towball weight of 150KG with the WDH.
So in theory, towing a boat that weighs 1 tonne with a ball weight of 100KG is well within the towing capablities of the sedan so long as the car is fitted with a WDH......nothing else is required....no stiffer springs or poly air bags. Hayman Reese have 4 bar WDH units for under $400 and they can also be picked up 2nd hand for half that price. The WDH is simply bolted to your existing towbar. This presumes the boat trailer is fitted with brakes (required for trailers over 750KG) and your towbar is rated for loads in excess of 1.00tonne.
The above figures that I've quoted are extracted from the Magna TL operators Manual page 6-41.
Fitting stiffer springs will still require the fitting of a WDH to keep it legal however the factory operators manual makes no mention of stiffer springs being required or recommended.