Anybody know where the front and rear centers of gravity are on this car, stock(ish)? Just wondering; I get bored when I sit in a hotel room with nothing to do. In the off season I might be able to spend enough time on one of our scale pad sets to define it myself, but if someone else has already done the leg work, that would be splendid.
For your car, In Lathrop, CA. Duh…
IIRC it is around your gear sets, top of trans.
Clever, sir. But really, I was wondering what the CG axis vs roll center axis looked like. Wondering how much better handling could be had with just some eccentric bushings here and there. So I would need to know pretty accurately. Looks like I’ll have to wait until the off season. Thanks; I figured it was front heavy.
that’s the centre of the B6/7 universe, not gravity
I don’t know where the centre of gravity is, but I do know that the engine is not dead centre, but is shifted a little towards the passenger side to help offset driver weight.
If I understand correctly snowtrooper is right its just above the transmission as the motor has been shifted 1" towards the passenger side to compensate for driver weight
If your looking for roll over data let me know I might be able to get some that data for you. If you look you can see the pontiac g8 is based off the b6 s4 so I know ill have access to lots of data like that
Is the G8 really based off the S4???
I’d be interested to see what the G8 and S4 have in common. It really doesn’t seem like much, though I was happily surprised that the S4 is factory claimed to be only 53% front weight. I’m sure it’s got a gigantic polar moment of inertia to achieve that, though. But anyway, I don’t see the center of gravity of another car helping me much. Even the Cg of an A4 wouldn’t be a help. But if you do have scale pad data for an S4, that would be quite helpful. I’d need one reading at level and another with one pair of wheels raised (with suspension locked to eliminate travel).
my info was based of stasis / mahle / cosworth / quattro gmbh data and to the best of my memory from 4 years ago. I remember the a4 (4cyl) comparatively was back around the tail housing and our challenge cars were a few inches lower and almost dead center in the wheel base after ballast.
when we are talking true center like down to a square inch or cm or even mm it is calculable yet honestly even in the highest levels of motorpsport you only need to know down to about a 6" sq area to be able to base you setup around it in a beneficial manner. beyond that is the multi million dollar data setups some teams run can actually tell you dynamically where the COG is based of travel positions of each damper calculated from the original known point, even with driver weight fluctuations from shedding body water weight during endurance racing!
we arent balancing precision things here when you really break it down at least not on these cars. a half gallon of fuel difference would throw off the true COG. just wing it and set it up to where it feels good. not what jives on paper.
Is it necessary? No, but it’s free to measure Cg, as our shop owns two scale pad sets, and it’s free to model the suspension, since I already have the software from a few years’ back, and it’s cheap to make some adjustments from there at least to push it in the right direction, since poly bushings are cheap to make. Right now I’m super tight on cash (house), so projects that are free catch my eye. I won’t have much time on my hands until after September, but the preliminary searching didn’t show me anywhere that someone had bothered measuring any of this, so I figured I’d ask. I think this site is supposed to be the center of good info, isn’t it? So good place to ask. I don’t need it to be within 1", but 6" is probably too far off for modeling purposes. And “I think it’s around the top of the trans” isn’t the same as “It is at the ridge of the trans 7” directly rear of the leading edge of the bellhousing". Again, it’s free to measure, so why settle? I just need to bug a buddy for some more of those strut blocks that come in on the new cars at the dealership, which they normally throw away anyway.