Well, long story short....I forgot to unpack the boot after a home depot run and went for a spirited drive. It is AMAZING what (3) 40lb bags of water softener salt on the boot floor does for balance and handling.

The extra rear grip is great. No more obvious understeering however the rear end tends to drag down now (obviously with all that weight).

So if you want to try out what your car would be like with more rear end grip, throw some weight in the trunk. I am going to order a "proper" rear sway bar at once.

 

 

120 pounds of water softener salt in the boot? I wonder if the drive would be the same with 120 pounds of feathers.

 

DUH of course it wouldn't.

 

The weight of the feathers wouldn't be as close to the ground as the more dense salt.

 

120 pounds is 120 pounds!
Feathers or salt or concrete or chocolate cookies!

 

Guess I have a problem then cause even this didn't cut it

 

Just ordered a UUC 19mm rear bar, two position, powdercoated (aren't they all?) with zerk fittings for grease

 

wait a minute. A rear swaybar makes the inside rear wheel lift during cornering, giving your rear end less grip and your front end more grip....and your salt bags in the rear would give your rear end more grip.....

 

I see your train of thought and raise you this theory, With more weight in the rear the car is better blanaced front to back which in turn allows it to have a more neutral handling stance with better fron to rear weight distribution. Yes a rear sway will add the handling improvements without boggin you down as much and will even help keep both front wheels better planted in tight cornering, esp. helpful for those sans LSD and can benifit from a little more forced front end traction, but both will help the car rotate.

 

Umm, more weight in the back allows the rear to roll more, same as if you had softer springs back there. Theoretically it should cause more understeer at the limit.

But I do not doubt for a second that the car drove better below that, because the extra front caster (from the car tilting rearwards) greatly improves straight line stability, wheel return, and even produces more front camber in a tight turn. That and half the car is lowered

And a rear bar does not reduce grip in the rear, it allows the front to do less work at the same speed (by resisting roll that the front would otherwise have had to handle) so mostly works by giving the overloaded front more grip. At the same time it is actually giving the rear more grip too. How is this possible?

Imagine a wheel/tire upright on your garage floor. It's pretty easy to drag it sideways by pushing on the sidewall near the ground, isn't it? Now imagine trying to push it sideways when 800lbs worth of car is pushing it straight down. The harder the tire is pushed into the ground, the more grip it has, until it is overloaded (this is also why you don't want the roll center too high--instead of pushing the tire down it would put it in shear). With the rear of the car being so much lighter than the front, there's a lot more leeway before the rear gets overloaded so we can shift some of the work back there.

It's not the lifting of the inside wheel that improves handling but the fact that the outside tire is being driven harder into the ground to improve grip back there. Since the front also has more grip because the work is being more evenly distributed to both outside contact patches, you can go faster.

 

I think what you are experiencing is the added camber in the rear wheels do to the weight. The rear trailing arm suspension is much more susceptable to added camber due to weight than the front struts. Steve

 

Wait, did I read that someone has 120 pounds of chocolate chip cookies in their boot?!? Handling schmandling, I want some of those cookies!

 

The added weight in the boot has actually moved the center of gravity rearwards. In stock form, the C.G. is way too far forward on a MINI for maximum performance, the front tires are asked to do the majority of the cornering work (that is why we get steady state understeer....). With the C.G. rearwards, the tires are working more equally front to rear, (with all other variables being equal), leading to less of a tendancy to understeer. The extra weight is actually not giving you any additional grip, it is changing the car's behavior at the limit to more neutral.

I love this stuff!!

Jason

 

Not true! The weight distribution would be completely different with chocolate chip cookies. I would anticipate the weight would transfer forward at a rapid rate.

 

True! The weight of the cookies in the boot would have to be at least 50% of the cookie sitting in the drivers seat! If not, you may need to slowly shift the weight forward by slowly eating the cookies. Little by little I find that I eventually find the true COG within the hour. Sometimes the weight shift is more than I expected!

 

how about removing the a/c concenser and the evaporator, etc.
what do you think about that? would it give me better handling from
the reduced 30lbs or so from the very front of the car? Motoron
commented that i should just tear out my ac since it's not working
properly anyways and i dont use ac all that much while motoring my
MCS.

 

I'm going to go ahead and say that you can almost never go wrong increasing lightness

That might be a lot of effort for the street....but on the track it sure can't hurt.

Jason

 

Every little bit of weight removal helps, especially from the front, but I'm not doing without a/c.

Increased weight in the boot increases the centripetal force on the back end of the car. At the "limit", this weight pushing outward will overcome the traction of the tires, but may-or-may-not do so before the front end breaks traction. If they both lose traction at the same time, you're "balanced". While it might feel nice, I doubt a heavier rear end would make anyone "faster".

...and don't take that last line out of context ...

Weight = bad (in general)

As for the 120 lb = 120 lb theory, it's all in weight distribution. 120lb of feathers would have a Cg nearer the top of the car than 120lb of salt. 120lb of lead could be lower still. Try cornering with a full roof box on - yee-haw! 120 lb of cookies would not stay 120lb for long, as the weight would certainly gradually move forward (and to the left), then gradually exit the vehicle on longer trips.

I, too, love this stuff. Physics is fun.

 

jasonsmf, DixonL2- i see. humm... i might consider doing it if my dealer can't
fix the a/c on the 3rd try then.

i only understood the cookie part of this entire thread.

 

How are you going to cool those fresh baked chocolate chip cookies?

 

Physics is very fun, loved it in high school and then went into business in college.

PS I LOVE that we all took the feathers joke seriously enough to come up with scientific replies.

As for me, I can't wait to have more rear wheel grip from the sway bar. It was shipped out today and should be here tomorrow, yay !

 

Good luck with that Grfa, let us know how it goes. Now... what was this thread about, anyway?