17 replies to this topic

[imaparana]

Hi all,

Myself and a friend are starting a tarmac rally hornet build, the car is obviously currently on wet suspension which will be going,

does anyone have any experience that can suggestion some suspension for this application, e,g shocks cones,arb?

also ive read that in some applications the wet top arms are favourable over the dry, would this be the case in this situation?

 

cheers

[cal844]

Pm cooperman on here, in fact he may well comment later today

He rallies minis, and has done for years

[Cooperman]

Presumably the car is for Historic rallies. Will it be for tarmac special stages or tarmac road-rallies?

 

On my 'S' I have always used standard OE rubber cone springs and the ride height is set about 1.5 cm higher than standard.

 

I use SPAX dampers, but GAZ do a good alternative at reasonable cost.

 

On the rear I have about 0.25 degrees negative camber with 2 mm toe-in. This is set by using shims and filing the holes in the end brackets and welding a large washer on to keep the settings. I don't like adjustable brackets as they have been known to fail.

 

For the front I use adjustable tie bars and 1,5 degree negative lower arms. You can get offset lower arm outer bushes to dial-out any inaccuracies in camber. Set the caster to between 2.75 and 3.25 degrees. Use standard tie bar rubbers to avoid shock loading the tie bar locating 'ears'. In fact it is wise to weld triangular plates about 4mm thick to the tie-bar ears to avoid them bending or breaking of.

 

Make sure the damper mounting brackets are bolted to strong metal. It can get rusty behind the brackets. I don't rely on the trapped nuts inside the inner wings. I add two reinforcing strips of 4mm steel, then bolt right through and use Nyloc nuts on the inside.

 

On the rear it is wise to cut access holes in the vertical rear seat panel for easy access to the top of the dampers. One hole each side if you have twin tanks. Make up cover plates and seal with bath sealer. Use RivNuts and socket head cap screws to secure the plate(s).

 

Let me know my PM if you need any more help.

[imaparana]

Presumably the car is for Historic rallies. Will it be for tarmac special stages or tarmac road-rallies?

 

On my 'S' I have always used standard OE rubber cone springs and the ride height is set about 1.5 cm higher than standard.

 

I use SPAX dampers, but GAZ do a good alternative at reasonable cost.

 

On the rear I have about 0.25 degrees negative camber with 2 mm toe-in. This is set by using shims and filing the holes in the end brackets and welding a large washer on to keep the settings. I don't like adjustable brackets as they have been known to fail.

 

For the front I use adjustable tie bars and 1,5 degree negative lower arms. You can get offset lower arm outer bushes to dial-out any inaccuracies in camber. Set the caster to between 2.75 and 3.25 degrees. Use standard tie bar rubbers to avoid shock loading the tie bar locating 'ears'. In fact it is wise to weld triangular plates about 4mm thick to the tie-bar ears to avoid them bending or breaking of.

 

Make sure the damper mounting brackets are bolted to strong metal. It can get rusty behind the brackets. I don't rely on the trapped nuts inside the inner wings. I add two reinforcing strips of 4mm steel, then bolt right through and use Nyloc nuts on the inside.

 

On the rear it is wise to cut access holes in the vertical rear seat panel for easy access to the top of the dampers. One hole each side if you have twin tanks. Make up cover plates and seal with bath sealer. Use RivNuts and socket head cap screws to secure the plate(s).

 

Let me know my PM if you need any more help.

thanks for the reply Cooperman, you have a PM

[rally1380]

Hi all,

Myself and a friend are starting a tarmac rally hornet build, the car is obviously currently on wet suspension which will be going,

does anyone have any experience that can suggestion some suspension for this application, e,g shocks cones,arb?

also ive read that in some applications the wet top arms are favourable over the dry, would this be the case in this situation?

 

cheers

 

I'm pretty sure the bloke who won the Minisport Cup last year (tarmac championship) used Bilstein shocks.  Unsure of the cones, but i'd guess at uprated ones similar to the Red dot ones you can buy.

 

'Wet' top arms are suggested due to bigger bump stop platforms are they not? Or at least something like that.

 

As for front Tie Bars - Don't use cheap ones!!!!!  I had a front nut come off one at the finish line (lucky it wasn't part way through the test!) on the Vale of Clwyd Classic a few years back.  Pulled the drive shaft out and did some weird stuff with the lower arm.  Luckily it was a transport section to follow so I had a bit of time to jack the car up and put it right.  Found the nut, washer and bushes on the finish line so all was well although the geometry was out a little for the rest of the day.  I've now fitted Minisport Group A ones and they are superb.

 

 

I think a lot of things with suspension setup is really down to personal choice.  What suits you might not suit me and vice versa.  It really is a case of trial and error to some extent to dial in what makes the car work underneath you.  But Cooperman's suggestion as a base setup wouldn't be a bad start though.

[Cooperman]

The best way to secure the front tie-bar front nuts is to use a castellated nut with a split pin and drill the tier-bar to suit.

A Nyloc nut can be used, but for that safety-critical application Nylocs must be regarded as 'single-use' items. Replace every time the tie-bar is removed.

Bilsteins are top quality dampers, but they are not adjustable, or so I believe.

[rally1380]

Bilsteins are top quality dampers, but they are not adjustable, or so I believe.

 

Correct....and expensive too.  But folks are using them so I assume it's because they are good.  I'll stick to my Gaz ones until they cry enough!

[Cooperman]

I had GAZ dampers on my Rover 214Si rally car and they were super. They lasted well even on really rough terrain.

I have SPAX on the 'S' and they have worked well over the years. They are easy to adjust during an event and are not expensive.

[rally1380]

I had GAZ dampers on my Rover 214Si rally car and they were super. They lasted well even on really rough terrain.

I have SPAX on the 'S' and they have worked well over the years. They are easy to adjust during an event and are not expensive.

 

What is the reasoning behind the use of 'Wet' top arms Pete?  Is it to do with bump stop platforms being stronger or something?

 

Agree that GAZ and SPAX are both good brands.  Always found SPAX to be stiffer even when wound back. I think the Bilsteins are popular due to them being rather fancy inside.  Yes they are non adjustable, but if they are right then they won't need adjusting I suppose.

 

AVO and KONI are also brands for the OP to consider.  Then there are those fancy dancey race derived ones that cost uber amounts too (brand names fail me though).

[GraemeC]

The wet top arm has the knuckle joint cup slightly further towards the top arm spindle, thereby increasing the leverage, hence stiffness, of the suspension slightly.  

For the same suspension travel at the wheel, the cone will work in a slightly smaller envelope of movement too, so reducing the initial 'softness' and ultimate 'hardness' at either end of the stroke.

[minisi35]

I am the same as Cooperman in the fact I also use the standard cones and they have always served me well

 

Other bits on it are 1.5 negative arms, fixed but heavy duty tie bars using polybush on the back and standard bushes on the front.

 

Would love a set of bilsteins ,better start saving !!!

[imaparana]

I am the same as Cooperman in the fact I also use the standard cones and they have always served me well

 

Other bits on it are 1.5 negative arms, fixed but heavy duty tie bars using polybush on the back and standard bushes on the front.

 

Would love a set of bilsteins ,better start saving !!!

Thanks all for the replies and imput I value it all,

am I looking at the wrong set but the bilsteins seem similar in price to spax?

http://www.minispare...rbers.aspx|Back to shop

 

http://www.minispare.../Spax.aspx|Back to shop

[minisi35]

Looking at that link then there is not such a price gap as there was a couple of years ago

[GraemeC]

using polybush on the back and standard bushes on the front.

That sounds the wrong way round - the rubber should be on the back so there is a little more compliance under braking

[tiger99]

If the knuckle is nearer the top arm, the lever ratio is INCREASED and so the suspension is LESS STIFF. Maybe that is what is needed, as a competition car will not be carrying 4 occupants plus a full load in the boot?