Shortening/stiffening(?) shock absorbers

[joostvdw]

I'm looking at shortening my current shock absorbers because I can't buy shorter ones and I have no travel left in my suspension at the moment. So I've already disassembled them, shortening the body is a piece of cake but I'm not so sure about the strut rod, any ideas on that?

I would also like to increase the dampening of the strut, making it stiffer. I know you can just put thicker oil in it, but what viscosity range are we talking about? 10W? 30W?

Finally, it's a gas filled shock normally and I could just pump it up with a bicycle pump after assembly, but at what pressure?

Thanks!

[goldenwonder]

What car is this for?
I'd be surprised if there wasn't something out there to make life a bit easier

[joostvdw]

It's for a Subaru XT turbo, shares the suspension (and lots of other stuff) with the L-seriesII or LeoneII. I'd be very surprised if there was something out there to make life a bit easier I've had this car for over 5 years now and the only thing I've come up with so far are koni rear shocks which I have but are still a bit low, but I can live with them, it's the fronts that are either too soft or too long.

Are there generic shock inserts available?

[grasser26]

Hi-It isn't something I've personally tried but years ago I was advised that motorcycle fork oil was the best to use to stiffen up standard shocks,this was for a fiat front strut,in 1998.At the time there was a few different types/viscosities available.Have you also considered moving the mounts-maybe space the top mount upwards???

[rodney]

cut the rod down and re tap it,.

[dude]

Just cutting the strut rod down doesn't really do anything, you'll have to shorten the damper body, and rod accordingly. But i really doubt you'll get a set of gas shocks to work the way they're supposed to after having opened them up.

I'd search for a set of another car that have the same mountings, but are shorter, or if it's mcpherson struts, a shorter damper insert. Or make a set of cheapo ebay coilovers fit.

For oil i'd just go for 80w90 ;D But as said, i think gas shocks need the gas too to work close to normal, but as you've allready have them apart, give it a go!

[goldenwonder]

I know for some Toyotas that inserts don't exist, people fit them from other cars, such as mr2 rear inserts in front starlet struts, or mk1 golf inserts.
Have you got the inserts out to measure up & see how they compare to others out there?

[composimmonite]

Aren't gas shocks filled with nitrogen or similar ?
A quick Google finds loads of firms making custom shocks to order, for example -
www.titanshocks.com/

Paul H

[popuptoaster]

Gaz will make dampers for any application, I'm sure other companies would do the same, many years ago my mate got some lowered and fully adjustable front struts made up for a Renault 25.

[joostvdw]

I have a spare set cut up to measure and see whats what. originally its not a insert type shock, but I'm sure it can be made that way;)

are ebay coilover sets always with inserts? a quick search learns me that mk1 golf has very short insert available, could i get a coilover set for a mk1 and build something from that?

[joostvdw]

Oh and about the nitrogen, couldn't i just pump in some.compressed air? surely it wont rust with all that oil in it? question is how much pressure should i put in?

[RobinJI]

I couldn't say if all cheep coilovers use inserts, but I'd expect most of them do. Mk1 Golf ones will anyway.

As for re-pressurising them, as far as I'm aware, the reason they use nitrogen is because it's volume is more stable under temperature changes. Shocks naturally produce heat as they work, so to keep the damping consistent both the oil and gas in them should remain as constant viscosity and volume/pressure as possible to keep the damping consistent.

Normal air would work if you can get it in there, but it'll be less consistent. It sounds like they have a normal Schrader valve from the way you keep mentioning bike pumps? It'd be unusual if they do, but I guess it's an unusual car. The other option if they do have a schrader valve would be to go to a tyre place and ask them to fill them with nitrogen. A lot of tyre places will fill tyres with nitrogen for a small charge for the same temperature stability reasons (as well as some other reasons that I suspect are largely BS.)

I'm really not sure what sort of pressure you'll want to go to, I'd imagine it'll vary from manufacturer to manufacturer quite largely. Maybe try and get them to require a similar amount of force to a standard damper to compress when there's no spring on there? You could play around comparing them to get the pressure right using air and a bike pump then get a tyre place to fill them with nitrogen once you know the pressure you're after?

[joem83]

Is this a front one?

If it is, post up the dimensions - I'm sure someone on here will be able to find something from another car to fit.