Frpp M-5500 Rear Upper Control Arms, $200 Bucks?

Discussion in 'Fox 5.0 Mustang Tech' started by mikestang63, Dec 24, 2013.

  1. 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!
  2. 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.
  3. 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.
  4. Ok. I'l type it again s..l...o...w..... I'm talkimg about a DD. Tell me again how an adjustable upper makes a difference on a car that sees no track time.

    Great, you dropped 3/10. That wasn't my point now was it. Guys go well into the 12's with those "junk" control arms. Sure, you can run faster, but you missed the point.

    No, what does that tell me about Jack and MM, Sharad. Educate me please.
  5. 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.
  6. 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.
  7. 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.
    Noobz347 and mikestang63 like this.
  8. Sharad, I notice whenever you disagree with someone, you accuse them of being antagonistic or not liking you. Like I said, I dont know you and have no ill feelings against you. No need for the personal attacks. Like I said, I'm happy it worked for you. That doesn't change the facts guys have used the FRPP control arms for years- is it the best setup for racing? Of course not. I'm still waiting on what the advantages there are for a DD in using adjustable upper control arms over the FRPP ones.

    I'll leave the rest of your statememts alone. Everyone is entitled to their own opinion, and your statement is just that.

    Happy New Year to you regardless.
  9. 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.

  10. This is also how I've come to understand it. I do notice however, that this can change on even a street Stang depending on how sticky he is and how much torque he's generating.

    Everyone knows that as it gets higher, it becomes more of an issue. At some point in that torque/traction table, MM's setup does become the least durable. I'm one that doesn't have that exact factor nailed to a science, but I do understand that it will (and has) become a consideration.
  11. Better traction. As I mentioned before. Twice.

    Sharad is implying that Jack doesn't want you to buy UCAs because Jack wants you to run his 3-link setup.
  12. Yes, because everybody on the fence about spending $125 on UCA's is just dying to spend $700 on a TA/PHB instead, and a company who grew up around helping mustangs corner would never recommend anything to their customers that was actually better at cornering predictably than other solutions, even if they could make some bucks off those other solutions.
    Noobz347, jetmech807 and mikestang63 like this.
  13. 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.

    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.

    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:

    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.)
  14. That was very informative
    TOOLOW91 likes this.

  15. Great to see you around man. You should stop by more often. :nice:
  16. :chin Straight from the man himself. Seems clear to me. Thanks for the very informative post Jack.
  17. For me personally, this is one of those gray areas where physics and practical experience don't always jive. (like when the egg heads get online and try to explain that using the laws of physics, wider tires don't offer more traction than narrow tires) I might not consider myself an expert, but I've got over 20 years of Mustang experience, and I did go to college on a National Merit Scholarship majoring in Engineering Physics. To me, the Mustang experience is much more significant to this discussion.

    My short response is that I've regularly driven Foxes with solid bushings on all four arms, and they actually seemed to corner well in my opinion. At least they cornered much better than they did on the factory control arms. I'll concede that your TA/PHB setup handles better than the four link, but that's not what this thread was about.

    The double negative was amusing, but I knew what you meant. My opinion on upgrading the UCAs is that in general, any opportunity to replace the overly compliant OEM rubber bushings with poly bushings typically makes an improvement- whether it's the rear control arms, front a-arms, struts mounts, etc. I had an interesting conversation with someone a year or two ago who told it's not that the poly bushings offer more grip which results in faster lap times, it's that I feel more comfortable driving the car at its limit on the poly bushings, so I'm faster on the poly bushings than on the stock control arms. He went on to suggest that someone who was comfortable with the stock suspension, or maybe someone brave enough to keep pushing the car when the stock suspension's sloppiness really presented itself, would be just as fast on stock suspension as they would be on the poly stuff. To be specific, the conversation was about why I ran faster lap times around Sebring on upgraded control arms than I did on the factory control arms. (this was a true A-B test, with us upgrading the control arms in the pits, between sessions) It's an interesting discussion, but I'd consider it a moot point. Even if a person CAN be just as fast on the factory garbage as they are on the upgraded suspension (which I'd dispute), the fact is that *I* feel more comfortable pushing the car when the rear end doesn't feel like it's flopping all over the place. And when the car feels more settled, I'm able to drive it faster. That's what we all want, right? To go faster?

    And now I feel like I need to clarify one point- It could be misconstrued that I am trying to call your business practices into question. I am not. I simply meant that it doesn't make much sense for you guys to promote UCAs when your good setup doesn't even use them. That's common sense.
  18. Quick Update. Went to order the Steeda 555-4094 uppers from Blue Oval and call the guy. He says " Ford discontinued them a long time ago and I don't have any." So why the hell are you listing them on your site then? No answer.

    So, guess I will go with a set of stock replacement uppers unless somebody has a good set of the FRPP ones laying around.
  19. That's blue oval for you
  20. I know I am way late to the party buuuut, here is my .02. Save your 200.00. Go buy some urethane bushings and some steel plate. Box the arms yourself and replace the bushings. There, all 4 arms done for less than your 200.00 Ooooor, get a set of non adjustable chrome moly ones from UPR and call it good. IMHO, RARELY will you need adjustable control arms on a street car. Ok, now, I am going back to watching the Sandlot.