Suspension upgrades this weekend - fine tuning/alignment queries

[Newbers]

'Her indoors' is off to Paris at the weekend so I'm going to get as much of my new suspension bits and pieces sorted as possible. As this is going to include the rear trailing arm limiters and lowering (KW coilovers) I'm going to need to get my alignment etc. sorted.

Unfortunately my drive is very uneven so setting ride height and corner weights is going to be a bit tricky (unless the fairies break in and tidy the garage )

1. I spoke to KW and they say to set up so that all corners are the same height (rather than worrying about corner weights) and not to worry about loading up the driver seat. I guess I'm just going to have to take a spirit level and a jack and drive round until I find a nice flat area and do some fine tuning of the ride height. I've really got to get this right before worrying about alignment - is there a better way? Will a garage have a better way of doing this?

2. Can anyone recommend a decent outfit near St Albans to do the alignment? Closest I found is R-Tec Auto Design, Lyon Way, St Albans, Herts, AL4 0QU. Anyone had any experience with them?

3. In terms of settings, I intend to be running a little lower than Sport suspension (don't want to be scraping anything or rubbing the arches). I need fast road (but not track day) settings. I've read that the general recommendation is to ask for Z4M alignment (on my non-M coupe) does that sound right? I really like the neutral balance at the moment so wouldn't want to veer too far from that.

 

[hopz121]

Hounslow tyres are good mate and not a million miles away

 

[Steve84N]

Alignment wise I'd aim for the following:

Max front camber out by removing the pins - should end up around 1.2-1.5 degrees
Min rear camber - should end up around 1-1.5 degrees
Around 0.02 - 0.06 total front toe in, close to parallel but slightly in as opposed to out for stability
Around 0.04 - 0.10 total rear toe in if you don't want the rear swinging everywhere

That's what I use on my 3.0Si Coupe with B12 which is a similar ride height to what you're suggesting.

Something like a multi-storey car park might be a good place to get a level piece of ground. Then measure arch gaps.

 

[Newbers]

Is that in a weighted car or empty? I presume camber particularly becomes more aggressive when there's a fat bloke in the driver's seat.

 

[Steve84N]

Unweighted.

I'm only about 70kg and there was little difference with me in it or not. My wife is within 5kg too so when we're both in the car it is very evenly weighted.

 

[Newbers]

Quick update. KW's on. All of the the old shocks were absolutely knackered (less than 70,000 miles, mostly motorway). In comparison the ride is now a lot bumpier and less wife friendly. I've been progressively reducing the rebound which has helped. It's now at 6 out of 20 clicks front and rear - I will try reducing to 4.
I did 250 fast miles on Saturday on every mix of road surface. It is definitely a lot more confidence inspiring, particularly on good roads.
One thing I have noticed is that the steering feels what I can only describe as a bit dead. Not bad - no tram-lining or wandering just a bit flat and lacking in communication perhaps even with a tendency to carry on the way it's pointing (rather than tending to return to centre).
The car is going in on Friday to have the bushes and then alignment done. In the meantime apart from disturbing everything (whilst swapping springs and shocks) I haven't adjusted anything that would affect the alignment other than the ride height. Anyone recognise this?

 

[Artful-Bodger]

'Her indoors' is off to Paris at the weekend so I'm going to get as much of my new suspension bits and pieces sorted as possible. As this is going to include the rear trailing arm limiters and lowering (KW coilovers) I'm going to need to get my alignment etc. sorted.

Unfortunately my drive is very uneven so setting ride height and corner weights is going to be a bit tricky (unless the fairies break in and tidy the garage )

1. I spoke to KW and they say to set up so that all corners are the same height (rather than worrying about corner weights) and not to worry about loading up the driver seat. I guess I'm just going to have to take a spirit level and a jack and drive round until I find a nice flat area and do some fine tuning of the ride height. I've really got to get this right before worrying about alignment - is there a better way? Will a garage have a better way of doing this?

2. Can anyone recommend a decent outfit near St Albans to do the alignment? Closest I found is R-Tec Auto Design, Lyon Way, St Albans, Herts, AL4 0QU. Anyone had any experience with them?

3. In terms of settings, I intend to be running a little lower than Sport suspension (don't want to be scraping anything or rubbing the arches). I need fast road (but not track day) settings. I've read that the general recommendation is to ask for Z4M alignment (on my non-M coupe) does that sound right? I really like the neutral balance at the moment so wouldn't want to veer too far from that.

You need to do your ride height with your body weight in the drivers seat and half fuel, or if you regularly carry passengers, with your weight and average passenger weight, to see how much the weights change with just the driver have a look at this-

http://www.z4-forum.com/forum/viewtopic.php?f=2&t=91217&p=1343338&hilit=corner+weights#p1343338

I'm assuming here you don't have a ramp to work off so you can use a little initiative to get the job done.

To set the ride height once loaded you need a flat pad, don't worry it's nothing complicated, all you need is a long builders level and a set of hardboard 24" squares and two lengths of MDF 24" wide by the width of your track or a little more, you either find a relatively level area in your garage or drive or somewhere you can work on the car.

You simply drive the car onto the level area then chalk around each tyre to mark where your wheels will be, then move the car off and using the builders level put one of the boards across the front and chalk marks and one across the back, you then slip hardboard squares under the lowest side until you have the board level, you can do this front to back as well but it's not critical for height setting.

Next drive the car back onto the boards and measure the height from the bottom corners of the subframe at the front where you can get to it, and the chassis rails where the RTAB's bolt up at the rear to the levelling board (you will need to remove the plastic covers in the arch probably) once you have noted the measurements then you can take the car off the boards get the wheel off and then make adjustments, don't get perfectionist and try to get it perfect to the millimetre, it makes no difference when the weights in the car change constantly dependant on who's in it!

What ride height you use is your business but a quick geometry check on my own car shows the M Sports ride height being optimum for the factory geometry.

 

[Newbers]

That's very interesting and an excellent idea for making a level platform. I really ought to get on and do the drive but may be I'll concrete some level pads in the meantime!

I actually have a load of jerrycans here so I could simulate me fairly easily. I think I ought to check with the garage that they will be willing to work the same way when they do the alignment.

 

[Newbers]

After all my chat I completely ran out of time. Just picked car up from SCC who have fitted the last of the bushes, set the ride heights and done the alignment. Regarding the alignment, I didn't exactly chicken out but....

I thought it was probably best to start with a reasonably known reference point so I had them dial in the Z4M settings. I'll see how I get on with these after driving it for a bit with a view to then making changes, probably after I've changed the tyres and finally got the strut brace fitted. N.B. Pins are still in the front top mounts and apparently he couldn't get full adjustment on one of the rears. Not sure whether I need to be concerned about half a degree camber variance left to right. Probably not ideal that the bias is left on the front, right on the back.....



What I can say is that with the bushes done in the short drive home it felt like a new car