Pic of the race car at Summit Point

[Nick M3]

There's quite a lot of body roll - I'm going to have to put the stiff spring set back in.

http://www.nrubenstein.com/albums/album10/Summit_Point_BMW_Club_Race_8_5_6_06_005.sized.jpg

[FT@SGP]

Why is body roll bad? Running out of camber?

[clyde]

Why is body roll bad? Running out of camber?
It's a BMW with a macstrut...what else could it be?

:eeps:

[rumatt]

Body roll? What body roll?



http://forums.carmudgeons.com/attachment.php?attachmentid=1315&stc=1&d=1156186106

[Nick M3]

Why is body roll bad? Running out of camber?
Shitty transitional response. Camber is also an issue.

[rumatt]

I'm going to have to put the stiff spring set back in.

Why did you take them out?

[Nick M3]

Why did you take them out?
Seemed like a good idea at the time.

[Sharp11]

Body roll? What body roll?



http://forums.carmudgeons.com/attachment.php?attachmentid=1315&stc=1&d=1156186106

Or more accurately, roll stiffness.

And just think, all that positive right side camber with double wishbones ;)

Ed

[ff]

And just think, all that positive right side camber with double wishbones ;)

Ed

Wouldn't it still be negative until the moment where the car loses traction and goes airborne? With all the weight of the car on the right wheels, I'd think there's be even more negative camber.

[Nick M3]

Wouldn't it still be negative until the moment where the car loses traction and goes airborne? With all the weight of the car on the right wheels, I'd think there's be even more negative camber.
Not really. Negative camber means that the top of the tire is angled towards the car. Strictly speaking, it's always negative unless you hit something or have truly unbeleivably bad geometry. Whenever we say "goes positive" we're referring to the tire's relationship with the road. In this case, unmitigated body roll has that car cornering on the sidewalls. Since it's FWD, it's much harder to cure without creating lots of understeer.

And Ed, don't give me any of that worthless crap about how that particular DW suspension is set up. DWs have far greater potential than struts, but only if they're set up to take advantage of it.

[FT@SGP]

It's a BMW with a macstrut...what else could it be?

:eeps:

:lol: :lol: :lol: you are going to re-start that thread again :ack:

Shitty transitional response. Camber is also an issue.
Could the slow transitional response may be caused by the shocks rather than steady body roll? Just thinking out lound, I am sure I missing something here.

[Nick M3]

:lol: :lol: :lol: you are going to re-start that thread again :ack:


Could the slow transitional response may be caused by the shocks rather than steady body roll? Just thinking out lound, I am sure I missing something here.
Not so much. The car still has to move from lean to lean. Also, I tend to run a fairly high slip angle on track, and that just seems to work better with a nice stiff suspension.

[Sharp11]

And Ed, don't give me any of that worthless crap about how that particular DW suspension is set up. DWs have far greater potential than struts, but only if they're set up to take advantage of it.

Ummm...it was a joke - lighten up.

Ed

[John V]

And just think, all that positive right side camber with double wishbones ;)

Ed

Actually the outside front tire looks pretty flat to the concrete in that pic!

[Pinecone]

Nick, you went to softer springs because Summit main is pretty bumpy. And when the tires bump off the surface due to too stiff, you do lose a bit of traction. :)

And Summit only really has a couple of places of serious transition. 4 to 5 is a throw away anyway. So you have 7 to 8 and 8 to 9.

[Nick M3]

Nick, you went to softer springs because Summit main is pretty bumpy. And when the tires bump off the surface due to too stiff, you do lose a bit of traction. :)

And Summit only really has a couple of places of serious transition. 4 to 5 is a throw away anyway. So you have 7 to 8 and 8 to 9.
Felt very smooth to me, and I couldn't pitch the car into 10 the way I have in the past. Stiffer springs will definitely be on for the next one. :)

[Pinecone]

Just don't go TOO stiff. :)

[Nick M3]

Maybe I should get a set of 1300/1500s. ;) ...once you hit a certain point, what's another couple hundred pounds of spring?