E89 chassis aligment part quatorze

[B21]

After having fitted a variety of suspension / steering parts..Ohlins R+t, M3 steering linkages, monoball steering bushes, M3 trailing arm bushes, H&R ARBs, Meyle HD steering arms, Powerflex rear camber arms, front camber plates, I've had the guys fitting them re-align things, but not very well..the last guys got the ride height fairly well but I could see visually the rear wheel cambers were off.

They were so bad in the end I used a spirit level against the tyre wall and an iphone app to try and get them closer to OE spec.

Having failed locally to find anyone up to it /willing I was recommended Automek in East Kilbride.

Had a happy morning there today..top notch folks with state of the art kit and very very knowledgeable.

As you can see (although the red colour is not necessarily an overall indicator) the front cambers were different, the front LHS toe was out not in and the rear LHS toe was massively out.

Despite lots of adjustablity from the parts I fitted, we couldn't get the rear camber in on both sides without assymetrical rear toes..so we agreed to focus on rear toe and let the camber come out a bit.

Have to say the drive back from East Kilbride down to Moffat and then past Marys Loch was sooo much better..

[B21]

New adjustable toe plates to be fitted on my return visit, next year..

[Marcoose]

I’d thought you’ve gone with more than 1.7° negative camber in the front. Or am I misreading the printout ?

What is your turning style ? Brusque to rotate the car, or smooth along the arc ? I wonder if that influences your choice to set up negative camber. (I’m a smooth turner and feather-brake thru the apex.)

[B21]

I’d thought you’ve gone with more than 1.7° negative camber in the front. Or am I misreading the printout ?

What is your turning style ? Brusque to rotate the car, or smooth along the arc ? I wonder if that influences your choice to set up negative camber. (I’m a smooth turner and feather-brake thru the apex.)

I’m at a loss to explain the variation between the stated end measurements after session 3 on the Jaguar / Land Rover aligment system with what appeared to be a shift in a number of variables after that period and then what session 4 on the super duper alignment system then found.

For sure the rear camber had changed a lot during that period..I used a phone app and a spirit level to try and get them to something close to OE spec prior to session 4.

My primitive app n spirt level measurements was actually not that far of what the super duper machine said…within 0.3 of a degree on all 4 wheels.

Whether a lot of very bumpy high speed roads and literally flying over some bumps with heavy landings had moved things around I’m not sure but the car by the end was very unpleasant to drive.

To come to your point I guess I normally slow down gently for the corner, feed it in progressively, maybe with some trailing brake then at the apex smoothly apply power out.

I realised with lots of camber that whilst the turn in was easier the penalty was straight line instability.

The chaps at session 4 are clearly subject matter experts in setting sports cars up..lots of Porsches, Astons, Lotus on their pages pay testimony to their credentials.

Over a 2 hour period the meisterschaft explained that for BMWs and especially E89s lots of rear camber as applied by the factory is a safety factor to avoid the rear oversteering…they explained their focus was first and foremost correct toe, especially symmetrical toe in…my figures were all over the place with different settings and both toe in and out.

The rear camber is more than I would like but that was defined by the available toe in..so with adjustable toe in plates there would be a little more toe in and a bit less camber ..to under 2 degrees.

The front as far as they are concerned is what they consider best for my stated purpose..high speed over very bumpy roads with a focus on stability..I rarely have roads that are high speed smooth curves..

The drive back over some of those type of roads showed excellent stability with no obvious issue apart from what felt like more effort to turn in but with a nice sold feel and good feedback.

The castor has been pulled out from a factory figure on 5 ish degrees to 7 which helps straight line stability.

The guru suggested that narrower tyres would help turn in and reduce tram lining as would a change to 18” tyres.

The stiffer front end components plus better spring / dampers and ARBs all play their roles.

So it’s a complex picture..what I can say is that a piece of road that I was comfortable on the original set up at say 65-75 mph now feels comfortable at 85-90 mph..so quite a change..

This is most obvious in overtakes with an upcoming bend..pre I’d feel very wary about such a manoeuvre…now I would contempl7it much more often.

Hope that try’s to explain all the variables…

[Marcoose]

Thank you. Geometry, as many/most things, it's down to lap time. I don't track the E89, that's what the MX-5 is for, and even that, it's been a while since it's seen daylight. So the next measurement is confidence in the local roads. If you feel more confidence (and comfort and fun), then mission accomplished.

I'm due for an alignment. The last one was -2.35 degrees all around, and gave me that extra confidence. I reckon I will repeat it. (If it ain't broken, don't fix it.) I'm surprised the gurus you saw stopped at -1.7 degrees. But if you're happy, that's all that is.

[B21]

Thank you. Geometry, as many/most things, it's down to lap time. I don't track the E89, that's what the MX-5 is for, and even that, it's been a while since it's seen daylight. So the next measurement is confidence in the local roads. If you feel more confidence (and comfort and fun), then mission accomplished.

I'm due for an alignment. The last one was -2.35 degrees all around, and gave me that extra confidence. I reckon I will repeat it. (If it ain't broken, don't fix it.) I'm surprised the gurus you saw stopped at -1.7 degrees. But if you're happy, that's all that is.

I did previously try 2.7 front and 3.5 rear…on the camber..who knows what the toe in was..it was great for turning into slow / medium speed corners but tramlined horribly especially as the rears wore down..great on smooth roads but that’s not the type of the roads I drive on…

The gurus view was that for my profile of requirements that was as much camber on the front as I would need..it’s more or less what the G29 has..I’ll tighten the rear camber up once I get the toe in plates. They had to leave the rear camber large due to inability to get the required toe in in both sides.

Have to say although turn in is not as light or fast with now a stiff front end there is no nodding or wandering as there was originally….

I live with the slower but sure turn in..

As we both agree it’s whatever suits you and where and how you drive..I now realise that going around corners at high speed is not the profile that relates to my type of driving.

I’ll get the toe in polished off next year and we will see what the 2023 season brings.