MM has lower control arms for real cheap as a deal of the day. I will be purchasing a set of the adjustable ones. Sale is today and today only!
I can't believe how many people use the OEM UCAs. This isn't about who my employer is. Even if the question was "should I run OEM or Brand X" I would always choose brand x, if it's a name brand competitor. The stock control arms are junk.
Tell that to Jack @ MM, and the thousands of guys that run them into the 12's with those junk UCAs. We are talking a street/DD application here.
I would gladly tell Jack that. In fact, I had a nice and polite conversation with the MM boys at NMRA BG a couple months ago. They're good guys. But the stock UCAs are junk, and that's why they don't run them. They remove the UCAs completely.
PS- Jack is not the only suspension expert on the planet, but he IS the only one who recommends keeping the stock UCAs (until you buy his torque arm). That should tell you something.
And as far as control arms on 12-second street cars go, I dropped three tenths off of my quarter mile time when I upgraded the control arms on my '89 with the stock 5.0. Ran 12.91 @ 103 with a 1.69 60-foot time on the stock motor and street tires.
You're so antagonistic Mike. Why are you so aggressive? Bad day? Or is it that you dislike me or something?
Anyway, I'll reiterate my point s..l..o..w..l..y..... my '89 was my daily driver at the time. I upgraded the control arms and went .3 quicker in the quarter mile. It hooked better on the street too. It was all around BETTER than those garbage factory control arms. And I would say the same thing about ANY name brand control arms.
What my statement tells you about Jack is that his opinion on that matter is slightly suspect, since none of the other industry experts agree with him about maintaining the factory UCAs.
I think what Sharad is saying is that this Jack gentleman doesn't want someone buying a companies stuff unless it's his. Correct?
It's like Summit telling you not to order from Jegs just because Summit doesn't want to lose business.
MM could make UCA's in their sleep and sell them by the truckload if they wanted to, but instead, they recommend that if you're going to run uppers at all, run factory style ones. I'm going to go out on a limb and guess they're the lone holdouts who recommend stock uppers for two reasons 1) They're one of the very few mustang suspension companies with any kind of presence whose business wasn't built around catering to drag racers, and the way the car will be used dictates a lot about how to set up the converging-upper 4-link like these cars have, and 2) One of their principal engineers (no longer there) actually took the time to measure how much wheel rate (spring rate, as seen by the wheel) was added as the suspension rolled using various combinations of bushing material. The stock uppers contributed the least additional wheel rate (aka "bind) when coupled with LCA's with a spherical bearing on at least one end.
I'm still waiting on what the advantages there are for a DD in using adjustable upper control arms over the FRPP ones
I sure hope that is not what Sharad is implying. In fact, MM is telling people to not spend money on any upper control arms for a street car, based on their research. Sounds like just the opposite to me.
To explain our position on the subject of UCAs, some back ground is needed.
Below is a link to some measurements we took years ago regarding rollbind. This is the roll stiffness of the rear suspension with no shocks or springs involved. All forces are the result of friction, bushing stiffness and the geometry being over constrained. In a perfect rear suspension, it would take zero force to roll the rear suspension.
It is very important to understand that the OEM 4-link rear suspension is overconstrained. This means that if all eight bushings were replaced with spherical bearings, all the control arms were infinitely stiff, and the mounting brackets for the control arms were also infinitely stiff, then the suspension would not be able to move into combinations of bump/droop and roll. In some combinations of travel and roll it will bind up solid. When moving through areas of travel and roll where it isn't totally bound, it will take much more force than if it were not overconstrained.
The only reason that Ford gets away with the 4-link design is that they use large, soft, rubber bushings in all eight locations. These allow the control arms, especially the UCAs, to change length keeping the system from being overconstrained.
http://corner-carvers.com/forums/showpost.php?p=902398&postcount=5
In the measurements linked above, you can see that just adding a somewhat stiffer bushing to either end of the UCAs, greatly increases the roll stiffness, since the UCAs can't change length as easily. Also note that in test #10 for example, the roll stiffness is very nonlinear. This means that the handling balance will change quite a bit with how hard the car is cornered. This makes the car very unpredictable and very easy to spin.
If you care about handling, ride quality and durability, you need to consider the roll stiffness of the rear suspension configuration in the car.
Some people don't care about ride quality or handling. These are usually drag racers. They may or may not be concerned with durability.
From the measurements above, it is easy to see that if the stock 4-link suspension has spherical bearings or any other bushing configuration , that doesn't allow the control arms to change length, that the suspension is going to be very difficult to move and the loads at the control arm mounting locations will be really, really high just to move the suspension. Forget about including the forces needed to accelerate the car.
Mark Ortiz, an engineer that writes a monthly column in Racecar Engineering, wrote about this issue in his newsletter linked below. In the case below, he is talking about an RX-7 rear suspension which only has the UCAs angled a little bit in plan view. The Mustang is a much worse case.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDEQFjAB&url=http://www.eviltwinmotorsports.com/wp/wp-content/uploads/2012/01/Chassis-Newsletter-2011.11.pdf&ei=6JzDUv6YNtfdoATWi4HwBg&usg=AFQjCNGBmbf33WdMqMKKu_KNjV0Mh_ufzQ
Bill Shope, one of the original Ramcharger engineers from the 1960's, discusses the 4-link bind problem and a lot of other related stuff on his excellent website:
http://www.shopeshop.org/contentsDrag.htm
I do not doubt that if one installs UCAs in a Mustang that have stiffer bushings, the car is going to have better forward grip when accelerating from a stop, in a straight line. This is a virtual certainty. The important thing to do is to understand why.
With any solid axle, rear wheel drive car, when the car accelerates the driveshaft torque is reacted by the rear suspension. This means that as driveshaft torque increases, one rear tire will have more vertical load on it and the other rear tire will have less vertical load on it. When any pair of tires share the load more unequally, they have less total grip available. With a solid axle drag car, the goal is to have the rear tire loads equal during the run. This gives the car maximum forward grip from the pair of rear tires.
What needs to be done to make the rear tire loads equal all the way through the run? When the ratio of rear to front suspension roll stiffness is infinite, the rear tire loads will always be equal. This occurs when the car is a tricycle with one front wheel. The front suspension has zero roll stiffness, since the front tire is free to roll from side to side with zero resistance. In this case, when there is any roll stiffness in the rear suspension, that makes the ratio of roll stiffness infinite.
The physics behind the last two paragraphs can be understood if you read through Bill Shope's website above. You may need to read through all of it more than once.
It should be clear now that installing aftermarket UCAs in the Mustang suspension, which almost always have a bushing configuration which results in more roll stiffness, results in more forward grip in a straight line because it increases the ratio of rear to front roll stiffness. The downsides are that the stiffer the UCA design is, the more load is placed on the control arm mounts and bushings. In addition the car will ride worse and will have a lot of oversteer when cornering. How bad these affects are is a function of how stiff the UCA configuration is.
If one cares about forward grip in a straight line, they could just as easily install a stiffer rear swaybar. This has the advantage of not damaging the car, rides much better and can be adjusted/disconnected for street driving so as to not make the handling scary. Note that this is only one way of achieving the same thing as the stiffer UCAs do.
In our opinion using UCAs with stiffer bushings is usually the wrong thing to do since it has the most negative side effects and the same positive affects can be had with other solutions that have virtually no downsides.
The only reason we don't manufacture UCAs is that we think it is the worst solution to making the rear suspension better. We could make them just as easily as the RLCAs we make. We don't not make UCAs in an attempt to upsell people to a TA/PHB combination. (I know that was a funky double negative, but I'm too tired to figure out how to fix it now.)
Sharad is implying that Jack doesn't want you to buy UCAs because Jack wants you to run his 3-link setup.
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In our opinion using UCAs with stiffer bushings is usually the wrong thing to do since it has the most negative side effects and the same positive affects can be had with other solutions that have virtually no downsides.
The only reason we don't manufacture UCAs is that we think it is the worst solution to making the rear suspension better. We could make them just as easily as the RLCAs we make. We don't not make UCAs in an attempt to upsell people to a TA/PHB combination. (I know that was a funky double negative, but I'm too tired to figure out how to fix it now.)
It is very important to understand that the OEM 4-link rear suspension is overconstrained. This means that if all eight bushings were replaced with spherical bearings, all the control arms were infinitely stiff, and the mounting brackets for the control arms were also infinitely stiff, then the suspension would not be able to move into combinations of bump/droop and roll. In some combinations of travel and roll it will bind up solid. When moving through areas of travel and roll where it isn't totally bound, it will take much more force than if it were not overconstrained.
The only reason we don't manufacture UCAs is that we think it is the worst solution to making the rear suspension better. We could make them just as easily as the RLCAs we make. We don't not make UCAs in an attempt to upsell people to a TA/PHB combination. (I know that was a funky double negative, but I'm too tired to figure out how to fix it now.)