Feroza SX11 rear suspension

thehappyidiot
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Feroza SX11 rear suspension

Unread post by thehappyidiot » November 14th, 2014, 6:43 pm

Hi guys,
I recently bought the 94 Feroza SX11, and I'm looking at the suspension - particularly the rear...
At the moment, I can't drive with the sunroof open, otherwise I'm in danger of being catapulted out of the car when I hit a speed bump, even at 5 or 10km/h... The front seems OK, just the rear seems quite highly sprung.

I suspect the rear suspension is a bit knackered - I can 'bounce' the rear quite easily around 50mm by standing on the towbar (I'm around 80kg), but it only 'bounces'' a couple of times once i step off..I vaguely remember the Vic Police roadside roadworthy included a large copper 'bouncing' the corners of the car, and if it bounced more than couple of times after he stopped, it got the canary...
The rear springs are sitting almost 'flat' and straight when standing on level ground, with only around 60mm between the buffer and the top of the axle-stop.
I am looking at a Tough Dog lift kit (mentioned in other posts as probably one of the most suitable all-rounders) which has leaf springs, nitro gas shocks, torsion bars and fittings with adjustable rear shocks for around $1500...
I have attached a couple of pictures - any thoughts on a) does the suspension in the photos look right or wrong, and b) tough dog lift kit - good or ordinary??
I suppose question c) is - are there any traps or tricks to installing the new lift kit myself? I'm reasonably tech savvy and have re-built old motorbikes and a few old cars in the past...
Main use is on-road, gravel roads and some light 4 x 4 in the Otways- nothing too strenuous and no 'rock-hopping'...
Best regards
Pete
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...keeping the Shiny side up is probably best....

Peter Aawen
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Re: Feroza SX11 rear suspension

Unread post by Peter Aawen » November 16th, 2014, 3:54 pm

Hi Happy, that rear suspension is looking more than just a little tired!! And I'd suggest that the 'flat springs' back there are why you are getting such a bad ride, even if the shocks aren't dead too (altho it does sound like they will be as well!!) So yeah, it's probably time for some work on the rear suspension, & the Tough Dog lift kit for the Feroza's is a pretty good way to go. If you don't mind the ride up the front, you could (possibly) save some dollars to put towards a Long Range Fuel tank by sticking with the original Torsion bars & just doing the front shocks - aftermarket torsion bars tend to make the ride up front a fair bit harsher (cos they are only stiffer/heavier springs) which is going to be bad enough anyway due to the Short Wheel Base. And besides, a good suspension/wheel alignment mob should be able to re-set the height & wheel alignment with the original torsion bars once you've fitted the new shocks & give you the best possible combination of ride/handling & height up front without having to foot the bill for new torsion bars. The other thing to bear in mind is that with Torsion Bar IFS, you aren't really going to improve your wheel travel unless you do a far bit more (& a fair bit more expensive) things than just changing the torsion bars/shocks; so unless the torsion bars simply aren't holding the front suspension off the bump stops anymore or working as springs at all, save your $$ & get a proper wheel alignment from somewhere like Pro-Axle etc where they will fix the camber properly if they adjust the height to suit the new rear ride height.

We've run a few Feroza's over the years, & on our latest '94 Feroza SXII F310 Wide Body we did a 40mm lift up front with the appropriate Nitro Shocks to suit, leaving the original Torsion bars in place but with the height adjusted (& wheel aligned) properly to match the taller rear ride height. We run the Tough Dog 50mm HD lift with the Adj Shocks in the rear; but we do have a 100 Litre Long Range fuel tank up the back so the Heavy Duty bit is pretty necessary to carry the extra 50 odd kg's that's there all the time. All up, it works pretty well, & the std torsion bars didn't even complain too much about the extra weight from the small winch, bull bar, & the addition of a second battery. The 40mm lift up front is pretty much right on the max safe/legal limit in the way of lift that you can get out of this sort of suspension, at least without resorting to doing extra things like changing upper/lower arms, modifying chassis mount points, dropping diffs, &/or fitting longer spindles etc; (& we have done all of that before, so it can be done if you want, but it isn't cheap or all that easy to do safely/properly!!) but with 35-40mm lift up front on the OE Torsion Bars/new shocks & 50mm in the rear with new Springs/Shocks it does give the Feroza sufficient clearance to fit slightly bigger tyres (just be careful you don't go too big or you'll lose driveability & low range gearing/crawling...) & gain a fair whack of capability reasonably cheaply & safely.... And even if you add a long range tank to increase your driving range to somewhere near 1000km or so, the ride/handling will still be pretty good! ;)

Enjoy
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

thehappyidiot
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Re: Feroza SX11 rear suspension

Unread post by thehappyidiot » November 19th, 2014, 12:02 pm

Hi Peter,
Thanks for the comprehensive response.
I think I'll go with your suggestion and try to re-use the OEM torsion bars..
Looking at the tyre size increase, I might just go up to a 235/75 tyre from the 225/70, which should give me a little bit lower revs at highway speeds without too much detriment to the very light bush work...

Just as a matter of interest, where did you get the LR tank from, or are they an 'off the shelf' item?
...keeping the Shiny side up is probably best....

Peter Aawen
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Re: Feroza SX11 rear suspension

Unread post by Peter Aawen » November 21st, 2014, 12:11 pm

I got the LR Tank from Opposite Lock in Adelaide, it was a listed product line & came from one of the big tank suppliers; Long Range Autmotive I think (car's not here atm so I can't go look at the placard on it, sorry... :( ) but it's been a great investment - tha tank's even outlasted a few Feroza's!!

As for the tyres, you'll want to check your speedo error before & after any tyre size change, cos they are notoriously inaccurate anyway (the ADR allows them to read up to 10% over your actual speed, but not under... ) but you can get in the brown smelly stuff with the Authorities if you rely on the speedo being anywhere near accurate once you've put bigger tyres on! And it can give you a real scare if you've been using the Odo/trip meter to work out your fuel economy, making you think it's suddenly started using a lot more fuel than it really has!!

You shouldn't have too much trouble driving 235/75's fitted, especially if you've got reasonable extractors & a free flowing exhaust instead of the OE exh manifold (renowned for cracking) & the restrictive OE exhaust & muffler. BTW, don't be suckered into taking that dirty great big air box thing off the top of the engine - the OE air cleaner is a Donaldson type & is very effective/efficient (& you can get a Finer Filter insert for it to improve airflow & filtration too) & the black box thing in the inlet tract is essential to make sure the engine doesn't lose a LOT of mid range grunt!! So the air inlet side of things is pretty good on the Feroza, but it can benefit from improving the outlet/exhaust side of things a little! ;)

Back to tyres, I reckon those 235/75 tyres will have your speedo & odo reading something close to 10% SLOWER than your 'real' speed/distance travelled, and if those devices were reading faster/further than actual with the stock/original tyres fitted like most of them, it can make for what seems to be a Biiig diference to fuel economy & your avg Hwy speeds when you swap to bigger tyre sizes. But if you know how much 'better' than actual it was making things seem before you changed the tyre sizes, & if you manage to drive at the same actual speed with the bigger tyres instead of the same 'indicated speed' as well as correcting your distance travelled to actual distance travelled after you've fitted the bigger tyres, then your fuel economy shouldn't work out to be too much different; in fact it could possibly see you getting better fuel economy with the bigger tyres due to the fewer Revs per Km required, just so long as you keep the revs in the torque band/sweet spot (around 3-4000 rpm) & use the gears to give you the road speed required. You should be readily able to get somewhere around 10l/100km (or if you like, 10km per litre) - maybe even a tad better if you don't push it too far beyond 100-110 kph all the time or let the revs drop below the torque band so it lugs around, especially when you are in the higher gears! A good GPS that shows your speed & records the distance travelled can be a real help with all this, altho a 'Speedo Match Box' or the 'right' drive cog for the trans end of the cable can make your speedo & odo/trip meter a lot more accurate too! ;)

Have Fun!
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

Photog009
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Re: Feroza SX11 rear suspension

Unread post by Photog009 » January 18th, 2015, 1:49 pm

gr8 read guys very informative!

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