Stiff!

[fatbillybob]

I don't have too many complementary comments for the s550 but I am happy to report the chassis is rigid. I have had many wet noodle cars and thankfully this isn't one of them.

Sponsored

 

[dn1984]

yeah i can barely jack the car up without the other end coming up too

 

[boardkat]

yep. my garage floor isn't flat and the mustang always reminds me when it's off the ground and one of the jackstands is moving around supporting nothing!

 

[fatbillybob]

Not much droop...

Yeah I have not noticed that before but lame! That's just how it is with the MCS coil overs. It could be partly related to the shortened bodies for lowered cars? I still have not had a chance to get the new setup on track. I'm hoping for transformational change but skeptical...that's for a post to the other suspension thread.

 

[fatbillybob]

Generally a good idea to have ~2" of droop so that you maintain substantial load on the inside tire. If you have a shortened shock, you may need to run lower to get it.

yeah I guess the pic is an illusion because measured on flat ground there is plenty of droop. The picture is initially worrisome.

 

[Norm Peterson]

I don't have too many complementary comments for the s550 but I am happy to report the chassis is rigid. I have had many wet noodle cars and thankfully this isn't one of them.

You're probably getting something like a quarter of a degree of chassis twist as shown. You'll never see it with your unaided eyes.

I actually made a series of measurements jacking up one corner of my S197, just to get an idea. If anything, I'd expect the S550 to be slightly stiffer.


Norm

 

[fatbillybob]

You're probably getting something like a quarter of a degree of chassis twist as shown. You'll never see it with your unaided eyes.

I actually made a series of measurements jacking up one corner of my S197, just to get an idea. If anything, I'd expect the S550 to be slightly stiffer.


Norm

How did you measure it?

My S550 is fully caged with a design making for a stiffer chassis and more robust than the typical watson racing cage which is a good design.

 

[Norm Peterson]

I jacked the right rear of the car up an inch at a time (jack as far to the rear on the pinchweld as physically possible) and measured the height from the concrete to the wheelwell opening (at the axle lines) at each step. The difference in right to left slopes, front vs rear, would be the chassis twist. There was about 0.05° difference in the slopes with the car at rest (zero amount of lift).

I also made measurements of the height from the concrete to the bottoms of the wheel flanges. The "plane" of my driveway is flat enough to do alignment work to within about 0.1° on.


That was prompted by a discussion elsewhere, where one of the other thread participants kept insisting that adding a framework of small-size thinwall tubing underneath the car stiffened it to the point where the structural/mechanical stiffening was responsible for something like a 2 second improvement in lap times for an occasional-HPDE driver. Ummmm, no.


Norm

Sponsored