Suspension possibly bottoming out.

[StuOwen86]

Did Oulton on Tuesday and going round Shell Oil hairpin if I was 'keeping with the flow of traffic' so to speak I had a clunk noise from my front passenger side about half way round the bend (seems there is a little bump or uneven surface there) now I was wondering what I could do to help the problem I was almost fully hard (no rude comments lol) being about 2 clicks from full hard settings on my BC Coilovers, I'm not sure what kg the springs are on them or how I could find out?? The front isn't that low (it does need setting up properly). Only had this once I had switched too my spare set of wheels with 888's on (multi fit BK racing not sure of the ET) but I have never used 888 before this noise, I wasn't getting any problems with my 2118's with Michelin PS3 so not sure if I'm carrying extra speed into the corner and putting more load on the suspension as I was only getting it there on Shell none of the other corners where it's hard right like foolstones, knickerbrook or lodge. I had a look round the tyres when I was swapping back to the Michelin to drive home and no marks on the tyre or wheel that I could see. Only other thing different except using the 888 since my last day at Oulton is my PMS top mounts and strut have been fitted.

Also still after the spanners to adjust my coilover but had no luck finding out what size I need anyone have any ideas let me know, Cheers.

Any Ideas would be much appreciated, Thanks.

 

[imprezaworks]

I had zero issues with 195 and 37 et wheels.

I had rubbing issues with 205 and et 38 wheels

It isn't the same probably but that's my only input lol

 

[StuOwen86]

Both my sets of tyres are 195/50/15 not sure on the ET of either of them tbh.

 

[imprezaworks]

Maybe the wheels. How quick to you go round shell? Only ask as it's not exactly a quick corner. Just you saying carrying more speed. I'd be surprised if it's that. I may be wrong though

 

[StuOwen86]

Only marginally quicker with having the 888 on over the PS3. Not really noticed how fast in mph.

 

[imprezaworks]

This probably isn't the noise but this only happened with difference off set wheels and the 205 tyres. Other than that I dunno

 

[Steven103]

1) Check nothing's broken (any play in PMS bearings is an obvious one)
2) Raise ride height (lower ride height = less suspension travel = less chance for the spring & damper to do their job before you hit the bump stops - at which point the effective spring rate rockets)

With R888 vs PS3 you will generate more lateral grip = larger body roll angle = outside wheel goes further into "bump" = even less suspension travel left to deal with any mid-corner bumps.

Essentially you want to be soft enough to make use of the suspension travel you have, but firm enough to stay off the bump stops in normal cornering to avoid nasty mid-corner surprises. Did your BCs come with any bump stop packers? (usually plastic white discs on the damper rod below the top mount)

 

[StuOwen86]

My BC's were already fitted too the car when I bought it @Steven103 so not sure on the packers. I have had a look round to see if anything was loose and didn't notice anything.

 

[Steven103]

The idea of packers is to make the bump stops come into play at smaller suspension travels, effectively increasing the spring rate. Makes the whole system stiffer but results in less predictable handling. Relatively common trick played in race series that demand control suspension...

Worth having another look with the car jacked up. Sometimes "loose" bits can appear completely fine/tight with 300kg pressing up on it...

 

[bloke]

could be worth trying a bit more pre load on the front, other than that heavier springs.

 

[StuOwen86]

Cheers for the Info Steven, @bloke is the pre-load set on the top collar on the BC's? I'm assuming the dials on top of the coil over that come through the top mounts is the damping? Might have a look when I call over on Monday if you don't mind.

 

[bloke]

pre load is done by winding the collars under the spring up, may not help but worth a try. what pressure you running the 888s on?

 

[StuOwen86]

was 30 all round when hot

 

[StuOwen86]

Just read this on the BC website with regards to ride height with the BC, Not sure if too low though and it'll just be the bumper/bodywork hitting the ground lol I know I don't want it silly low for track anyway.

'Because ride height is determined by an adjustable bottom mount rather than spring platform you retain full damper travel regardless of the ride height run'

 

[Steven103]

Forgot BCs didn't adjust height via a spring collar, sorry. Doesn't yet rule out bump stop packers or the wrong bump stops, but I'd still be looking at simple things first. For rubbing body work, you can put a strip of duct tape in strategic locations (underside of splitter or edge of wing) and see if it gets damaged after a session.

Preload is an easy one, check that the springs can't rattle around between spring collars, then forget preload altogether. 99 times out of 100 it's just someone confusing it with ride height.

 

[bloke]

can take a few measurements on monday and have a quick mess with it.

 

[StuOwen86]

Sounds good too me.

 

[Jekyll]

If you look at your BC's, they have 2 collars under the spring. The lower one (once up against the upper one) will raise the car as the thread of the strut goes into the hub part. The upper collar with adjust the pre-load on the spring itself, then you just wind up the lower collar to lock it.

The adjusters that reach into the engine bay are damping adjusters.

 

[StuOwen86]

Found a little spot/egg shape in the passenger wing (if you imagine directly under where the fuse box would be sat in the engine bay area) looks like it has been rubbing and also bent the bumper bracket out the way as that had also looked like it had a slight rub on it, Gonna put gaffer tape over the lump in the arch on the next day and see what happens, might raise the car a little if need be.

 

[STEVE.M]

Found a little spot/egg shape in the passenger wing (if you imagine directly under where the fuse box would be sat in the engine bay area) looks like it has been rubbing and also bent the bumper bracket out the way as that had also looked like it had a slight rub on it, Gonna put gaffer tape over the lump in the arch on the next day and see what happens, might raise the car a little if need be.

There is something wrong if the tyre is making contact with the bodywork before the bump stop prevents this.
I cured a scuffing problem with spacers (20p washers actually)between the top mount bearing and the assembled leg.
Make sure they are a tight fit to the threaded part of the damper rod,or it could punch through the spring top cap.

Out of ignorance,I will ask what the third ring at the bottom of the front shocks is for?
If it`s to adjust the whole cartridge/spring assembly up or down for ride height adjustment then that`s neat,and I wish I had bought some of these.

 

[bloke]

it's for ride height. top is for adjusting preload.

 

[STEVE.M]

it's for ride height. top is for adjusting preload.

As a concept,that`s so much better than everything else out there.
Going back to OP `s problem,does the damper rod remain anchored,?allowing you to advance the threaded canister towards the bump stop?

 

[Jekyll]

Have you tried to contact a supplier to see if you can get just a set of C spanners?

 

[StuOwen86]

Yeah I emailed BC and I can order a set of their spanners. I'm not sure about the damper rod though Steve.

 

[STEVE.M]

Nooky`s nuts ?£9.50 for a set.

 

[StuOwen86]

Thanks @STEVE.M I'll have a look