Best suspension height for track work

bretauto · Postby **bretauto** » Fri Feb 27, 2009 6:35 pm

Hello, just playing with suspension heights with my NB8A,[ have BC adjustable shock units], New to this ashphelt stuff, [ came from dirt speedway ].
I am setting up the car for track days , it will see very little road use, [ only getting to the track ], it has all the normal stuff , haft cage ,hard top, sway bars and shocks. stock engine. It will be fitted with semi's after I get a bit quicker on the road tyres.
I'm very interested to hear what peoples throughts are on handling verses suspension height, so far I have come up with 10mm in the front lower then std, and 30mm in the rear lower then std, has seamed to work quite well. [ yes and wheel alined after each change.]
Not haveing alot of black top driving experience , and all this testing happening over different track days , climate conditions and how much sleep I had the night before,
I would like to hear what other people have experimented with. any help or advice would be appreciated.
Brett

Matty · Postby **Matty** » Fri Feb 27, 2009 8:47 pm

Rule of thumb - get the lower control arms horizontal

kazjim · Postby **kazjim** » Fri Feb 27, 2009 10:07 pm

Was about to post the same :wink:

The old rule of thumb is still used in all strains of motorsport (Except rally, those guys are weird :roll:

)

As level as possible with control arms and fully-race ready weight.

Enjoy

J

bretauto · Postby **bretauto** » Sat Feb 28, 2009 8:59 am

Yes looking at the front suspension geometry, with the lower arms parallel to the ground [ car is lowered approximatly 25mm] . the lower arms look correct but infacted , the centre line of the lower inner bush and ball joint centre are running up to the wheel, [as the ball joint is offset in the arm]. To run this centre line parrell to the ground you end up at the standard ride height. Something Mazda spent a couple million in development on. So lowering the front suspension advantages are;- looks , and lowering the roll centre , but is a lower roll centre an advantage over correct geometry?
To run the rear lower contrl arms parallel to the ground , the rear has to be extremely low.
But having the arms running down to the wheels would seem to make sence when you take into acount the squat under accelation, the extra and changing fuel and boot loads. [after all this is still a road car].
I have found lowering the rear of the car, to with in 5to 10mm of the front has made it a much more balanced vehicle [ less tail happy ]