Beyond The Apex

[B C]

The creators of Gran Turismo have released an app only for iphone/ipad called "Beyond the Apex" . It has a reference and overview of all the cars featured in GT6 which is neat to read BUT it has a gem of an automotive engineering and racing technical manual. It digs deeper into the physics of automotive performance than what youd read in a car magazine tech article but it also does it in a concise way.

I highly recommend checking this out. Here are a few screenshots of the manual

[YoungCR]

I'll have to keep this in mind for when I get my new iPhone, looks like a good read.

[KaiserRolls]

its pretty neat

[Guest bigjae1976]

Actually...that article is flat out wrong for most BMWs when it comes to countering understeer. At least for an E36/46. You want more front suspension travel, more front roll stiffness and more negative camber. A well setup BMW will have very little to no rake. They will usually be close to level. This is to get the cross weights close to 50/50 and achieve more front suspension travel.

 

I'm not the only one who think this way. Turner campaigned some E46 325s which had a MASSIVE 40mm front sway bar and no rear sway bar.

[patsbimmer1]

Very interesting!  Nice little read!

[HipMF]

Actually...that article is flat out wrong for most BMWs when it comes to countering understeer. At least for an E36/46. You want more front suspension travel, more front roll stiffness and more negative camber. A well setup BMW will have very little to no rake. They will usually be close to level. This is to get the cross weights close to 50/50 and achieve more front suspension travel.

 

I'm not the only one who think this way. Turner campaigned some E46 325s which had a MASSIVE 40mm front sway bar and no rear sway bar.

 

This certainly seems to fly in the face of conventional wisdom. Not trying to nay-say but interested in learning more. Any more info on this? Sounds like a setup for someone whose more interested in putting power down coming out of the corner rather than carrying speed through the corner.

[Brian.]

Turner Motorsports has years of info to back up why they did it that way. And a decent collection of championships/trophys. They also run 3 cars usually in every race they enter. It also depends on the track grip!

[Guest bigjae1976]

This certainly seems to fly in the face of conventional wisdom. Not trying to nay-say but interested in learning more. Any more info on this? Sounds like a setup for someone whose more interested in putting power down coming out of the corner rather than carrying speed through the corner.

 

You can carry more speed at turn in and apex but if I'm on the throttle sooner then I'll be faster coming out of the corner. In many cases it means I'll be faster on the straight.  You want to be able to put power down in a RWD BMW. Braking and steering only scrub speed. Throttle makes you go faster. More throttle = more faster.

 

There are some assumptions in the conventional wisdom of car setup being used in that article. It does not take into account the dynamic camber change and its effect on toe...on the front and rear axle. The key to driving a fast BMW is reducing that dynamic camber change. Otherwise you'll tear up tires and just understeer through most corners. Which is why you want more front roll stiffness (reduce camber and toe change), more negative camber (maximize contact patch on turn in), and more front suspension travel (front engine car - more weight transfer underbraking).

[HipMF]

In many cases it means I'll be faster on the straight.

 

Well if I'm in an e21, then this is almost certainly true.   With 110hp (if I'm lucky) I don't need to worry much about wheelspin.

 

Makes sense though. So the real problem is the body roll + MacPherson strut front suspension?

[Guest bigjae1976]

Well if I'm in an e21, then this is almost certainly true.   With 110hp (if I'm lucky) I don't need to worry much about wheelspin.

 

Makes sense though. So the real problem is the body roll + MacPherson strut front suspension?

Its the dynamic camber change caused by the body roll that creates the issue.