How much of a difference do aluminum control arms make? I have a basic understanding of what unsprung weight is, but unlike a car's curb weight or the rotational mass, I don't see how to measure the advantages of unsprung weight.

Lowering a car's rotational mass (even by a few pounds) will help to improve acceleration, because this weight isn't just being carried by the car, it is also being manipulated by way of force. And though losing rotational mass is exponentially more beneficial, I know you can also hedge some tenths of a second off your quarter mile time by losing some curb weight--although it will probably take hundreds of pounds to see any real difference. But it seems like unsprung weight's importance lies somewhere in between sprung weight and rotational mass...sort of a gray area. I mean, does it only help with your car's ability to react more quickly to turns and over bumps? Does the maybe 20lbs. you save by opting for coilovers and aluminum control arms make a differnce for a daily driver, or is the effect only felt in autoX and hardcore cornering?

I want to reduce my car's overall curb weight, and will buy lighter seats, exhaust, etc. I will also go with smaller and lighter wheels to reduce rotational mass. However, considering the cost, I don't quite see if a few unsprung pounds should be a priority for me. Example: Alta exhaust saves 24lbs. and costs $699. For the same cost M7 aluminum control arms will save 3.75lb. It just seems disproportional. That is unless the handling is night and day. Any feedback, experiences, or "corrections" is appreciated.

 

Consider all your unsprung masses; control arms and shocks are only "half" unsprung weight. Wheels, TIRES, and brakes are all unsprung mass. Tires are the biggest concern, as they have the most rotational inertia.

HTH,
Ryan

 

Lose unsprung weight and you'll stop quicker and accelerate faster.
Just ask all those guys in their Escalades how well they stop since they put on those 24's that weigh twice as much as the O.E. setup.

 

I replaced upper and lower rear control arms with the aluminum Altas. I don't know that I feel a difference with the wieght savings, but I feel a huge difference in the overall handling of the car. One of the better mods I've made, and the Hiem joints are NO problem at all on the street.
So, ... I would do the controle arms for their improved handling rather then weight savings, but both add up to an even better investment.

I also have done what I could lowering the weight and have replaced the wheels, tires and brakes. This I CAN tell the difference for sure.
I'm now putting in a roll bar which is painful in one sence, as I'm now adding on about 60 lbs.

 

I checked out the Alta rear control arms. They sound good for $169, but I don't think there is any weight savings. They are made of steel. The M7 front control arms on the other hand do save you some weight, but they are $699.
-Should I just concentrate on the rear, or the front too?
-In either case, should I be looking for one's made with aluminum or just be concerned with a stronger more rigid product?
-With coilovers, would you suggest I do control arms or sway bars first?

 

For items like control arms, their weight is only 'partially' unsprung compared to wheels, tires and brakes. Since the arms pivot from the chassis, only the end of the arms connected to the spindles are truly 'unsprung' weight. The frame attached end is considered part of chassis weight, and since it's usually the heavier of the two ends (many front arms, including the ones on the MINI, are triangular in shape with the bigger end attaching to the frame) the total weight reduction with lightened arms is really less than half the arm weight in 'unsprung' weight. You still benefit from an overall weight reduction from the total wehicle weight with lighter arms.

 

Alta is slow to update their website. The control arms are now aluminum and are about $200 a set of two . I got mine from Randy Webb.

It's hard to concentrate on the front as their is only one person making an A arm that I know of, and I hear that it's not always a succesful mod.

 

Cool. I'll probably go with the Alta rear aluminum control arms and a 22mm rear sway bar. Hopefully, the front end doesn't feel too neglected.

 

M7's front control arms serve more than weight loss. Their primary function is to provide improved geometry throughout the jounce... better and more predictable response to steering inputs They may be expensive but you get what you pay for

 

Are you using these Sid? Two out of three that I've heard use these have removed them. I never heard how that third person felt about theirs.
They look cool and I've considered them, but have been warned not to do it. I don't even remember know what the problems were, buy I think one was a BBK clearance issue. If anyone here uses them, I would love to know your thoughts.

 

No...can't afford them right now:smile: Would like to go with TCE BBK next

 

According to Randy's site, the Alta aluminum camber links (rear control arms) are 3 pounds each. Did he maybe mean 3 lbs for a pair?

I say that because from my notes, the stock rear control arms (lower pair) weighed-in at 6.8 pounds. And my H-Sports (again, a pair) weighed 5.8 pounds - or .2 pounds less than the Altas which Randy says are the lightest on the market, at 3 pounds each? At 3 lbs/pair, for sure...

http://www.webbmotorsports.com/suspension.php

Supporting this possibility is that Helix says theirs, also aluminum, is 50% lighter (unsprung weight) than stock:

http://www.helix13.com/html/products...ew.php?p=1&h=m

This would put the Helix units at 1.7 pounds each, or 3.4 pounds per pair/set. I think Randy meant to say 3 pounds per pair, not each...

The price delta is about 50 bucks...

 

I can say this, and I'm generalizing for sure; every front wheel drive car that I have played with, gained sobering improvements with the use of harder lower control arm bushings. The trade-off has been a bit more harshness when traversing expansion joints for example. But the grins with every application have out weighed the trade-offs. The above mentioned arms also reduce weight, nice. Did I say nice!