Some observations on rear camber & a goodwood vid

[TomK]

I've had a set of turner adjustable camber arms lying around for ages now, due to the amount of work required to fit them really. Recently I finally bit the bullet and had them installed along with an SSK (as the exhaust really needs to be dropped for both jobs).
My idea was to increase the rear negative camber which we wound up to about 2 1/4 degrees over the 1 1/2 stock setting with the hope of increased rear traction on corner exit. All other settings kept the same. So I went to Combe a few weeks ago (my local track which I know fairly well) and to my surprise found the car felt particularly unruly. The transition to oversteer was really pronounced and fast mid corner and exit, not ideal at all. In fact it felt pretty dangerous. Perhaps it was due to the combination of slight toe out that I run at the rear but I knew with a Goodwood trackday fast approaching I needed to get it adjusted again. So back for another alignment this time to the stock camber setting Bit of a wasted exercise, however I know the adjustable arms will come in useful when I eventually get round to lowering the rear on an adjustable setup.
Anyway, off to Goodwood last monday and thankfully the car felt back to it's normal entertaining yet pretty stable set up, I was pleased particularly as it was my first time on track there. Moral of the story I guess is if it ain't broke don't fix it, though it was an interesting (if expensive) experiment!
Short vid here from the day, what a great circuit and facilities, it looks amazing there, a credit to Lord March.
[youtube]oNkSRNJvgJU[/youtube]

 

[RedUn]

For ref, I run 2 degrees on the back with some toe in and it's perfectly fine

Sounds like the toe out caused the issue?

 

[TomK]

For ref, I run 2 degrees on the back with some toe in and it's perfectly fine

Sounds like the toe out caused the issue?

Yeah you may well be right, it had crossed my mind. Thing is with the stock camber I've had previously I've found a little bit of toe out really helps turn in and I'm wary of loosing that by going back to stock-ish toe in. Inner rear tyre wear was pretty severe with that setup I was running briefly so something clearly wasn't right though.
I would love to be able to adjust all of these things track side (obviously the camber is easy enough now with the arms), it's fascinating what a small difference in one dimension makes and the effect it has on others. My shop had the idea of bringing their rig down to a track day to do exactly that, hasn't happened yet though.
You have adjustable arms to get to that camber, or are you just lowered?
Cheers

ETA: I'm running about -2 1/2 degrees up front with minimal toe in/out, and about 1mm toe out either side at the rear.

 

[Ed Doe]

Aah Tom you should have posted up beforehand - I'd have popped down to watch!

How did you find the circuit? It's quite easy to memorise but hard to perfect in my experience!

 

[RedUn]

For ref, I run 2 degrees on the back with some toe in and it's perfectly fine

Sounds like the toe out caused the issue?

Yeah you may well be right, it had crossed my mind. Thing is with the stock camber I've had previously I've found a little bit of toe out really helps turn in and I'm wary of loosing that by going back to stock-ish toe in. Inner rear tyre wear was pretty severe with that setup I was running briefly so something clearly wasn't right though.
I would love to be able to adjust all of these things track side (obviously the camber is easy enough now with the arms), it's fascinating what a small difference in one dimension makes and the effect it has on others. My shop had the idea of bringing their rig down to a track day to do exactly that, hasn't happened yet though.
You have adjustable arms to get to that camber, or are you just lowered?
Cheers

ETA: I'm running about -2 1/2 degrees up front with minimal toe in/out, and about 1mm toe out either side at the rear.

Interesting, sounds like something wasn't right before, my tyres are wearing reasonably well even with plenty of road miles? (mpss)

Im also running 2.5 design on the front with no toe, turn in is good but I have widened the front track more than the rear by 4mm in total which has probably helped?

No adjustable arms, just lowered on clubsports using standard adjustment.

Did you corner weight? That made quite a big difference on mine?

 

[TomK]

Interesting, sounds like something wasn't right before, my tyres are wearing reasonably well even with plenty of road miles? (mpss)

Im also running 2.5 design on the front with no toe, turn in is good but I have widened the front track more than the rear by 4mm in total which has probably helped?

No adjustable arms, just lowered on clubsports using standard adjustment.

Did you corner weight? That made quite a big difference on mine?

Sorry, perhaps I didn't explain it well, but before adding the extra camber tyre wear has been pretty even.
So for sure this extra camber combined with the toe out is not a great idea for handling or tyre life! Lesson learnt.
Was 2 degrees the least you could get with your lowered set up on the standard arms?
No corner weighting for me as I'm just running non height adjustable B12s at the moment.have

Aah Tom you should have posted up beforehand - I'd have popped down to watch!

How did you find the circuit? It's quite easy to memorise but hard to perfect in my experience!

Sorry Ed, I didn't think to as not many people have mondays off, next time I will.
I really enjoyed the track, it's damn fast in places so certainly focuses the mind.
The place itself is fantastic, I must get myself to the revival this year...

 

[Ed Doe]

Any excuse to pop down i always try :lol: it's my local and I'm down there as much as possible!

Yeah Tis fast, first time I drove it was in a 911 GT3RS 4.0 that wasn't mine - that certainly focused the mind!!! The coupe felt a bit pedestrian after that :lol:

 

[flimper]

Nice vid two questions: why only one glove & what camera set up do you use?

 

[RedUn]

Interesting, sounds like something wasn't right before, my tyres are wearing reasonably well even with plenty of road miles? (mpss)

Im also running 2.5 design on the front with no toe, turn in is good but I have widened the front track more than the rear by 4mm in total which has probably helped?

No adjustable arms, just lowered on clubsports using standard adjustment.

Did you corner weight? That made quite a big difference on mine?

Sorry, perhaps I didn't explain it well, but before adding the extra camber tyre wear has been pretty even.
So for sure this extra camber combined with the toe out is not a great idea for handling or tyre life! Lesson learnt.
Was 2 degrees the least you could get with your lowered set up on the standard arms?
No corner weighting for me as I'm just running non height adjustable B12s at the moment.have

Ahh sorry, yeah sounds like the camber and toe out isn't a good combination!

I think the adjustment was around 1.8 degrees minimum from memory?

 

[TomK]

Nice vid two questions: why only one glove & what camera set up do you use?

Thanks flimper. The camera is just am old gopro 3+ with an external mic in the cabin, mounted on the bulkhead.
The glove! Ha, I didn't get them on in time before the start of the session so tried to on the 1St lap out and almost ran off track attempting the 2nd so left it! As you can see in the vid I suffer from seriously sweaty hands!

 

[Fishy Dave]

...... with the hope of increased rear traction on corner exit. All other settings kept the same. So I went to Combe a few weeks ago (my local track which I know fairly well) and to my surprise found the car felt particularly unruly. The transition to oversteer was really pronounced and fast mid corner and exit, not ideal at all. In fact it felt pretty dangerous.

Hi Tom,

I'm a bit late with my reply. Yes, the rear camber really changed the handling with understeer to begin with until mid corner then it almost felt it tipped over and suddenly lost traction at the rear and snapped very quickly to oversteer. It didn't seem as bad when you were driving but I could see you were being more tentative about getting on the power. I would say that the set up you had at that previous trackday was just about perfect for balance.
Nice goodwood video, it's a good track for the Zed, plenty of opportunity for power and to demonstrate the cars balance.

 

[Anonymous]

Nice work tom
Had my car geo done toady and A.c.
1.8 camber on rear and slight toe in

 

[Mr Tidy]

Sorry Ed, I didn't think to as not many people have mondays off, next time I will.
I really enjoyed the track, it's damn fast in places so certainly focuses the mind.
The place itself is fantastic, I must get myself to the revival this year...

Hi Tom,

Looks like you had some fun - Goodwood is certainly a quick circuit, just a bit short of run-off!

Got lucky when my mate took me round in the 65 Mustang fastback he used to race - on slicks and it started to drizzle, but we slid off on one of the few left-handers! My BIL was a bit less lucky - he was in an XR3i when it went off-track and rolled into a tyre barrier. But thankfully it was a race car with proper seats, harnesses and a cage.

I'd love to drop by if you (or Ed) are down there again - I can get most days off! :lol:

 

[Ed Doe]

I'll make sure to let you know next time I'm down Mr Tidy