Suspension settings

[mt308]

I have the new adjustable dampers (gold in colour). Ride height set by the factory, pretty standard I think (not too low).

Initial set up was 5 clicks all round on the suspension (bump and rebound) however it has grounded at the rear about 5 times, always on motorway/dual carriageways where there is undulation rather than potholes etc.

Its not hitting the lower most chassis rail (under the sump) but it hitting the rail right at the back (as well as the bottom of the clam No issues at the front.

Has anyone else had this issue? How many clicks are others running for normal road use? The ride is certainly not remotely hard at the moment so I am quite happy to make it a bit harder.

Many thanks

Mark

[LuckyP]

You need to get a camera strapped in and let us see this!! As mentioned on another thread, that is some movement!!!!

Something is not quite right here!!

Pete

Edited by LuckyP on Tuesday 4th June 12:46

[macgtech]

Can you post a pic of the car from the side and the rear damper -something sounds very wrong - I am not even sure how that is possible unless of course you are pulling a wheelie!

[ultimass]

Are you running standard springs at the rear.

The amount of movement at the rear end you must be having if the ride height is correct cannot be right.

[mt308]

Have just worked out how to reply from my phone rather than when I get home tonight.

The movement must be significant but not the full 130mm as the lowest rail under the sump shows no signs of grounding.

The back end must be catching the peak of the bump perhaps after the suspension recoils following a dip?

Again, this is not over rough terrain, this has happened on the M1 and on other dual carriageways.

I will try to take some photos of the set up and post them. Nothing looks obviously wrong though and the car was set up by the factory.

I just wonder whether the dampers I have are much softer than the previous models used and therefore need several more clicks.

[Paul.B]

mt308 said:

Have just worked out how to reply from my phone rather than when I get home tonight.

The movement must be significant but not the full 130mm as the lowest rail under the sump shows no signs of grounding.

The back end must be catching the peak of the bump perhaps after the suspension recoils following a dip?

Again, this is not over rough terrain, this has happened on the M1 and on other dual carriageways.

I will try to take some photos of the set up and post them. Nothing looks obviously wrong though and the car was set up by the factory.

I just wonder whether the dampers I have are much softer than the previous models used and therefore need several more clicks.

I honestly think you are mistaking existing scraps on the rear chassis rail for this scrapping you are experiencing! For that rail to ground out, before the sump one would mean something is very wrong. For this to happen on a motorway/A road would just not make sense as the sump rail is significantly lower. I suspect possibly seat mount bolts? Although the sump rail would still be lower.

Where in the UK are you?

[mt308]

Paul.B said:

I honestly think you are mistaking existing scraps on the rear chassis rail for this scrapping you are experiencing! For that rail to ground out, before the sump one would mean something is very wrong. For this to happen on a motorway/A road would just not make sense as the sump rail is significantly lower. I suspect possibly seat mount bolts? Although the sump rail would still be lower.

Where in the UK are you?

Thanks. I am near Esher in Surrey.

I am sure it is the rear, there were no scrapes and there is now. The noise is coming from the back and sounds like the chassis hitting the road.

I agree it is very odd! From the replies I appear to have a problem that others haven't experienced. I think I will have another chat to the factory to see what they think.

[F.C.]

Stupid I know but you haven't mixed front springs with rear have you?

[mt308]

F.C. said:

Stupid I know but you haven't mixed front springs with rear have you?

That would be stupid;-) but its a good point to check. I did the build myself and am pretty sure it was all clearly labelled. Maybe its not impossible that they are wrong though for whatever reason.

Thanks for that, it hadn't even crossed my mind!

[ROWDYRENAULT]

Could it be that the shock has an internal problem and is crashing into its self?

[barriejames]

Mark

I would hope the factory pre IVA check would have picked that up?

mt308 said:

F.C. said:

Stupid I know but you haven't mixed front springs with rear have you?

That would be stupid;-) but its a good point to check. I did the build myself and am pretty sure it was all clearly labelled. Maybe its not impossible that they are wrong though for whatever reason.

Thanks for that, it hadn't even crossed my mind!

[mt308]

barriejames said:

Mark

I would hope the factory pre IVA check would have picked that up?

mt308 said:

F.C. said:

Stupid I know but you haven't mixed front springs with rear have you?

That would be stupid;-) but its a good point to check. I did the build myself and am pretty sure it was all clearly labelled. Maybe its not impossible that they are wrong though for whatever reason.

Thanks for that, it hadn't even crossed my mind!

I have emailed a photo to the factory. I don't think the springs are the wrong way around and am sure this would have been picked up by them as they do give the car a very thorough check and obviously know more about them than I do!

Doing a bit more looking around this evening the scraping is pretty bad (bare metal exposed but not actually dented), and knowing that I built it and had't damaged it during the build, together with the scraping noise I keep getting over bumpy rods led me to the conclusion I made.

However 2 things make no sense - as many have pointed out it would be very difficult to hit the rear rail without hitting the one under the sump which is much lower, also the rear clam has a couple of small chips in the middle right next to the scraping on the chassis rail, but has no damage on the left or right where it is actually lower down than at the centre.

I will talk to the guys at the factory tomorrow. One thing I am thinking is that rubbing down and painting the damaged chassis coating will at least make it smooth again and next time I get what I think is a scrape it will then be obvious by checking whether any damage has ocurred.

Thanks to all for the suggestions.

I am loving the car by the way - performance and handling are truly mindblowing (though I have only scratched the surface so far) and it gets a great reaction on the road and at Goodwood alongside some real classics (I was parked between 2 Jaguar XJR15s at the weekend and I got as much attention if not more than they did!)

Mark

[Storer]

Mark


Measured the gap in my rear springs and it is only 70mm in total.

Check yours - there are 6 gaps of between 10 and 12 mm each with no load - even less when the car is on the ground. So how you end up with 160mm of movement I don't know?


Paul

[LuckyP]

Mark,

Have you let the car be driven out of your sight? IVA onto brake tester or park it up in customer parking bay with the rear chassis member sat on a curb?

Post a pic of the scrapes and I bet we can deduce the issues.

PS I'm in Hampton Wick just up the road from Esher

[TuxMan]

Sounds to me like the compression on the shock is too soft , have you stiffened them up a bit more ? The Protechs have 12 clicks .

Tux

[mt308]

LuckyP said:

Mark,

Have you let the car be driven out of your sight? IVA onto brake tester or park it up in customer parking bay with the rear chassis member sat on a curb?

Post a pic of the scrapes and I bet we can deduce the issues.

PS I'm in Hampton Wick just up the road from Esher

Thanks, have sent you a pm as you are so local.

The damage is akin to reversing onto a curb but I definitely haven't been near any curbs! If its not grounding i am also still getting a nasty noise over bumps.

Bopefuuly will get to the bottom of this...

[Paul.B]

TuxMan said:

Sounds to me like the compression on the shock is too soft , have you stiffened them up a bit more ? The Protechs have 12 clicks .

Tux

Why you not read whole thread? Read whole thread before say silly stuff!

[DHGTR]

Is it possible that the noise and the damage are separate issues?

Is the noise a really nasty metal on concrete noise or a deep scraping noise.
I have an issue where my rear arch inner covers aren't quite straight, so that when suspension is set soft (when the other half is a passenger) the inner arch can rub on the tyre wall, mainly around corners. Could that be the noise?

I would think if the springs were so soft that it was grounding on undulating straight roads, it must feel like a boat going around corners, wallowing.

Are the spring ratings printed on your springs, mine are but i run a different setup to yourself, that may be something very obvious to check but can be ticked off the checklist very quickly.

Why not just adjust the damper to max hardness and still see if you get the problem, you may not have any teeth left afterwards, but it may shed some light.

Dave

[356Speedster]

Sounds like an odd state of affairs..... and I've got the same question you asked further up too:

What do the group recommend for double adjustable shock settings?

I don't think it'll help your case, but worth knowing anyway (and I'd like to know what's recommended for road use).

[ultimass]

I have Nitrons fitted, on the road 4 clicks on both comp. and rebound at rear and 5 at the front.