Using digital level for camber checks

[Ross Nicol]

I spent a whole day yesterday working on the suspension setup in preparation for the race meeting this weekend. My friend Lindsay who is a real
setup Guru has been telling me for quite a while I haven't got enough negative camber, and I'm only using 1/2 the width of the tyres during cornering, hence I have uneven tyre wear and in Lindsay's words" you've paid for the whole of the tyre width, why not use what youv'e paid for?" Boy I have to agree with that statement. Also I've been having to rotate the tyres on the rims to average out the uneven wear. Ok so we started making adjustments and I was taking camber measurements with my trusty level when I must have bumped a button on it because it no longer was reading from zero when in the vertical plane. This got me thinking and I had to pull out the instructions. It took a while but it finally dawned on me there are 2 scales 1/ angle in degrees and 2/ angle as a percentage of 45 degrees.
Now I had incorrectly been using the percentage scale and all my readings in the past have been incorrect. What I thought was 3 degrees neg camber on the rear wheels was in fact only 1.7 degrees. Not an earth shattering discrepancy but enough to destroy handling in a racing environment. I will post a pic of the level for others to be careful of this and add that I now have 2.5 degrees negative camber on all 4 wheels and it is definately correct.
Ross

 

[roaldin]

Thank's for the update and correction Ross.
Interestingly, you are now running rear camber closer to my car (3.25).
I also have 2.5 on the front.
It seems all roads may lead to Rome after all.

I have found the rear end to be much more progressive in corners, with extra grip; the only downside perhaps a loss of straight-line traction.

Tim.

 

[Ross Nicol]

Hi Tim
I may well end up with more camber on the rear yet, as with yourself, it will come down to the temps and tread wear from this point on. I am aware the car will be more twitchy down the straights but this is a small price to pay for corner grip. The opposition have always murdered me in the corners and this shows up at Phillip Island the most with it's fast corners. The turn in did improve with the uprating of the springs but I'm looking forward to Sandown at the weekend now. By the way apart from that hi tech camber gauge of mine all our other measurements were done with string lines, measuring tape, and 2 blocks of wood and lengths of RHS steel. And this is the only alignment tools required by a racer at the track eh Tim.
Ross

 

[roaldin]

Hehe. It's been a while since I've been as hands on as you but I suspect we went to the same tool store.

Tim.

 

[Clayton]

Hi Ross

Not sure if this would work or not, but if you lowered the rear top link inner pivot point a fraction you could increase the camber gain so you didn’t need as much static camber (negative). Hope this make sense.
This would also change the roll centre, for good or bad I don’t know.
Just thinking out aloud.
Good luck on the weekend.

Clayton

 

[Ross Nicol]

Hi Clayton
2.5 degrees is not excessive static neg camber, most of the Porsches I race against appear to have this amount of static camber. When I get time I will be checking the roll centres. It's been a very busy year but I have done a lot to the car though.
Ross

 

[Bill D]

Good thread.
Would these numbers be good for a mostly street GT40 (like mine)?

 

[Ross Nicol]

Bill
You wouldn't need as much static negative camber as this on a road car.Probably .5 to 1 degree negative would be enough.
Ross

 

[Bill D]

Thanks Ross

 

[Bill Musarra]

My Corvette race shop forman confirmed that all you need is around .7 to 1 neg. camber for the street, otherwise would be rather "darty" as he put it.

Bill

 

[Ross Nicol]

Yes that's right Bill I've driven a 240z on the street with a lot of camber and apart from being darty the car tends to track with ruts in the road, making it difficult to steer straight. I'll drive my 40 on the street with the new camber settings and let you know it's characteristics.
Ross

 

[roaldin]

Mine tramlines a bit but I've driven a lot worse.

Tim.

 

[Clayton]

Hi Ross

No worries mate, keep up the good work : )

Clayton