Another DIY Sachs Rebuild/Service

[hoolio]

That's very interesting. I've found them outstanding on really awful road surfaces, country B roads Gloucestershire, Shropshire, Worcestershire area where it's far from marble smooth track like surfaces. Conversely I also run a Clio 200 with the cup chassis and I even started a tread on Clio197/200.net about how to improve the damping without spending silly money.

A 200 cup chassis as standard is awful at speed on the type of roads I mention above. Really crashy, bouncing all over the place, skittery and banging in the cabin, not confidence inspiring at all. Zero compliance. It's like it attempts to smash the road into submission, whereas the Trophy is like a magic carpet floating above it all.

The interesting contrast is that at very slow speed (0-20mph) the Trophy will knock your teeth out, but the 200 is more composed, turn it up to illegal speeds and the Trophy is so lithe and composed. The 200 seeming to struggle with any surface imperfection.

Jean Ragnotti was a specialist tarmac rally driver after all, so perhaps he knows a lot about damping for imperfect surfaces we don't...

Totally agree with Gordon here. The faster you travel in the T the more the damping comes into it's own.

 

[Rik Perry]

The low speed rebound curve seemed to be the place where it was most over damped so that makes sense..

 

[hoolio]

Rik what did you work out the spring rate to be? I worked it out years ago and iirc it was fairly low.

 

[Gordon]

The low speed rebound curve seemed to be the place where it was most over damped so that makes sense..

Yea, at manoeuvring speed it's like the Princess and the Pea, you can feel the slightest surface imperfection. At speed it's simply mighty and glides over the worst road surfaces.

 

[Rik Perry]

No real correct answer to that as is progressive

 

[hoolio]

No real correct answer to that as is progressive

I can't find the thread anymore, conversation with GeorgeK (Koopman) in which it was possible to get an idea even though it is progressive. (contradictory as that sounds)

 

[hoolio]

http://www.cliotrophy.co.uk/threads/trophy-springs.46365/#post-335603

 

[Rik Perry]

Yes its good info.. Around the 180lb mark .. complicated by the rising rate and aeon rubber should it get into that area..
Pretty soft to be honest on springing... I was expecting it to be higher TBH...

 

[Gordon]

I like the bit from George (miss him on this forum) relating to the better the damper the softer the spring rate that can be deployed. Which (in my tiny mind) would make sense regarding the high speed compliance of the Trophy. It can soak up rough tarmac with soft spring rates and all is kept under control by amazing damping. Perfect tarmac rally car set up. Keeping the wheel in constant contact with an awful road surface at high speed.

If I compare the 200 Cup chassis, I'd think the way it's set up is with a far harder/higher spring rate and the damper can't cope with the rebound at speed; hence the crashing and perception of the car attempting to batter the road into submission. They don't have wider shafts, nor a remote reservoir; turn it up and unless on a marble smooth surface it gets out of sorts.

 

[hoolio]

I like the bit from George (miss him on this forum) relating to the better the damper the softer the spring rate that can be deployed. Which (in my tiny mind) would make sense regarding the high speed compliance of the Trophy.

.

Yes I do too. He was able to explain complicated things in a way that I was able to understand. We kept up email contact for a while, he retired from Xtrac a while back but still hill climbs the Intrgra.

 

[MarcB]

Can I ask if bits / parts are needed are you using genuine Sachs parts or just off the shelf parts?

What would happen if you needed to replace a vital part like the piston due to it being scored ?

 

[Mikeyjp]

@Rik Perry

What type are gas are using in the dampers?

 

[Rik Perry]

Mikey I used Nitrogen..
Mark for my rebuild I sourced Sachs parts.. If I needed a shaft however I would get a batch made up.. To F1 standards so no problems with quality..

 

[NathanH]

Nice one! I did this with my dampers, a bead of black silicone. Also, the spring cups I use are stainless, they pull out quite easily if press the ball in and 'hook' it out.

 

[Rik Perry]

Ah great minds think alike ... Thanks for the info on the detents .. I will look into that a bit further now .. Cheers

 

[NathanH]

No worries, they are only about 50p each.

 

[Rik Perry]

If I PM you can you let me have a supplier ??

 

[Rik Perry]

So the first set of " Customer " dampers arrived yesterday for the Rik Perry treatment.
Although they look a big grubby they seem to be in good shape, de gassed but tidy..
I'm sure we can have these fit and well in no time ...

 

[TonkaTruck]

Cracking work Rik, keep us updated with pictures on the 'customers' refurbishment!

 

[NathanH]

I didn't think it would be long
I've popped some of those Spring plungers in the post for you btw.