Relocation Brackets: Effect on Handling?

[J.Kidd]

Stock my car had terrible wheel hop. I installed a set of Steeda Sport lowering springs and the wheel hop is gone. The tires break loose a bit easier but I find that more predictable and easier to deal with than the wheel hop.

My question is, if I install relocation brackets to regain some of that traction, will they have a negative effect on the handling/balance characteristics of the car? I do not compete but do enjoy some spirited driving and don't want to disrupt the positive attributes of the car when it comes to handling.

Thanks for any input.

 

[Sky Render]

This has already been discussed at length in other threads. This article is a good summary, though.

http://www.motoiq.com/MagazineArtic...ptimizing-weight-transfer-and-roll-steer.aspx

 

[J.Kidd]

This has already been discussed at length in other threads. This article is a good summary, though.

http://www.motoiq.com/MagazineArtic...ptimizing-weight-transfer-and-roll-steer.aspx

Outstanding read! Thank you for the education (just what I was looking for).

After reading that, I totally understand why my car "feels" like it does during hard cornering (primarily when applying power in/during/out of a turn). I always felt like it was "pushing" wide but not with the typical "push" of plain old understeer (like my '92 5.0L does). I understand now.

 

[fdjizm]

I actually liked how my car took corners after the lca brackets, I believe it was called axle steer. but it "had more turn" if that makes any sense.

 

[Norm Peterson]

"Loose" axle steer will make the car drive like it's a slightly smaller car, if that makes any sense. Just make sure that it's appropriate behavior for all of the hard driving you anticipate doing.

At least this isn't an all-or-nothing aspect; one way or another you can set varying degrees of axle steer in either the understeer or oversteer direction. The alternate holes featured in many relo brackets is one way (probably the easiest).


Norm

 

[J.Kidd]

Added relocation brackets to my list. Now just have to settle on a lower control arm since I don't believe my stockers (Brembo package/GT500 arms) will fit in the highest hole of the brackets...which is probably where they need to go.

Leaning toward BMR with poly bushings on both ends. I know poly on both ends isn't ideal but this is my daily driver and I do not want to add any NVH commonly associated with the spherical rod ends.

BMR offers their "standard" set and now an "economy" version. For an extra $50, are the standard ones worth it?

I was also intrigued by J&M's with their "Patent Pending 3 piece Poly-Ball bushing combination".

Thoughts?

 

[sheizasosay]

Don't do the Polyball. It's good for "spirited driving", but if you ever take it to the track those polyballs are gonna get beat up.

J&M Street Extreme joint is what you want. If you are gonna get something from BMR then use the Poly/heim they offer.

I've owned heim jointed LCAs, polyball and street extreme. Never owned a poly/heim, but the J&M street extreme are easy to live with and work great.

 

[Apex50]

I also have Steeda Sport springs, using Whiteline relo brackets with the stock Brembo Brake package LCA's without any troubles. Sounds like you've decided on a different relo bracket, though...

 

[BMR Tech]

Added relocation brackets to my list. Now just have to settle on a lower control arm since I don't believe my stockers (Brembo package/GT500 arms) will fit in the highest hole of the brackets...which is probably where they need to go.

Leaning toward BMR with poly bushings on both ends. I know poly on both ends isn't ideal but this is my daily driver and I do not want to add any NVH commonly associated with the spherical rod ends.

BMR offers their "standard" set and now an "economy" version. For an extra $50, are the standard ones worth it?

I was also intrigued by J&M's with their "Patent Pending 3 piece Poly-Ball bushing combination".

Thoughts?

I honestly think our TCA032 LCA would work fine for you, at this point. I do like the idea of less binding, deflection - more articulation. That said, I put more emphasis on the articulation properties of the UCA System. I know you will read a ton about the negatives of the poly on each end of the LCA, but I'm not so sure I agree 100% with what the common opinion tends to be. Of course, a lot of it is based on other factors. For example, a bone stock car with just the addition of a poly/poly LCA....will typically make what people call "snap back" more noticeable. The less angle of the LCA, and the stiffer the roll - the less negative impact the poly/poly LCA will make.

The difference between the TCA032 and 019 is very minimal. The 032 is simply a lighter weight, smaller tubing design....and we mig weld it, instead of tig weld. Those two things allow us to rapidly manufacture the part, and lower the cost substantially.

I think the TCA022 or the TCA021.....would be "better" - but, I am not recommending them at this time. I truly believe the Poly/Poly will work fine. Trust me, if I didn't, I would much rather you spend $150+ more with us.

Don't do the Polyball. It's good for "spirited driving", but if you ever take it to the track those polyballs are gonna get beat up.

J&M Street Extreme joint is what you want. If you are gonna get something from BMR then use the Poly/heim they offer.

I've owned heim jointed LCAs, polyball and street extreme. Never owned a poly/heim, but the J&M street extreme are easy to live with and work great.

I do agree, if he is going with BMR, I think the Poly/Bearing combo IS the best choice for suspension performance. That said, I honestly don't think he would notice much of a difference with the Poly/Poly.

I also have Steeda Sport springs, using Whiteline relo brackets with the stock Brembo Brake package LCA's without any troubles. Sounds like you've decided on a different relo bracket, though...

Our LCA Brackets will accept the OEM LCA. Our middle position is similar to the single position of the WL brackets, so - he would need to use the middle.

 

[Ike]

My research of 75-100 opinions ended with me getting adjustable BMR bars and brackets over whiteline, for the bushing reason as well. I haven't installed them yet.

I did though get the Whiteline watts though for the same reason over other watts. Will have to hear others' opinions on BMR's watts when it comes out.

 

[sheizasosay]

What is a good test for measuring resistance for an LCA throughout its movement? J&M claims to have built a fixture for such a test. Could you disconnect the rear swaybar, remove the rear springs and disconnect the rear shock (stiction reasons only) at the bottom and put a serious scale on a jack and jack it up at the axle where the lca mounts to the rear axle? Do a heim jack and a poly/poly jack test?

Or would measuring the range of motion of a heim LCA from droop to bump and then do a Norm Peterson equation(tm) on the compression of the poly bushing's durometer throughout the same range of motion as the heim LCA?

Or take a heim UCA, PHB/watts and LCA car that is set tuned to barely understeer at mid-corner and then add a poly/poly LCA and see if it pushes it over to oversteer. You would never yield a wheel rate answer, only that it increased.

The Testing:

We built a fixture which simulated a factory control arm mounting and tested how much force was needed to make the control arm articulate (twist) in those mounts and the results where astounding.


Poly-Ball Bushings:

5 degrees of total rotation = 26.1 foot/pounds of torque

7.5 degrees of total rotation = 35.8 foot/pounds of torque

10 degrees of total rotation = 41.7 foot/pounds of torque


Standard 2 piece setup using only 85 durometer bushings:


5 degrees of total rotation = 124.7 foot/pounds of torque

7.5 degrees of total rotation = 156.4 foot/pounds of torque

10 degrees of total rotation = not measurable with fixture. The 1/2" grade 8 bolt twisted in half at 9.2 degrees which was 210 foot/pounds of torque.

I love standardized forms of measuring like spring rates. But all I got is "how it felt". And before anybody flames me for posting that J&M info, I'm not saying it is something that should be considered "official data". Only that I agree with the trend off my experience.

Anybody off-hand know how much wheel rate a front LCA poly bushing is worth over OEM rubber?

Edit- Kelly I doubt you guys have built a fixture to measure anything like the above, but I would be curious of what ideas you had about measuring it or the numbers J&M arrived at.

 

[dontlifttoshift]

I would like to see ft/lbs per degree of twist for a stock control arm....for comparisons sake.

Also for the sake of conversation, 5 degrees of roll is a lot, like '86 Grand Marquis slaloming.

 

[sheizasosay]

I would like to see ft/lbs per degree of twist for a stock control arm....for comparisons sake.

Also for the sake of conversation, 5 degrees of roll is a lot, like '86 Grand Marquis slaloming.

I don't think you can equate 5 degrees of body roll to 5 degrees of LCA joint articulation. This ties into what Kelly says about a soft sprung car feeling snap oversteer more. And I agree that would matter. I just don't tune my springs around bushing bind. I just remove the bind and tune to the contact patch.

 

[momstmg78]

if you get adjustable lower control arms, make sure that you get an alignment and have them zero the thrust angle.

 

[Norm Peterson]

What is a good test for measuring resistance for an LCA throughout its movement? J&M claims to have built a fixture for such a test. Could you disconnect the rear swaybar, remove the rear springs and disconnect the rear shock (stiction reasons only) at the bottom and put a serious scale on a jack and jack it up at the axle where the lca mounts to the rear axle? Do a heim jack and a poly/poly jack test?

You've basically described the test that Maximum Motorsports did somewhere before 2001. Obviously it wasn't for an S197, but I think the general trends don't change too much as long as the wheel rate from the Fox/SN95 pair of UCAs isn't large.

3" bump/droop is roughly 3°, so the numbers would need to be scaled based on the angle between MM's and J&M's results before attempting any comparisons. For real-world purposes, suspension travel and roll angles for anything of interest will be closer to MM's data.

Quick and dirty, two times J&M's numbers (because of two LCAs) divided by the rear track dimension (and corrected for the difference in angles) ought to give something of a wheel rate.

Disclaimers - strictly speaking, this sort of test measures wheel rate for some combination of roll + heave, since one wheel is held at a fixed vertical position relative to the chassis rather than moving an equal amount in the opposite direction as you'd expect for pure roll. There is also the difference between having a single UCA and a pair of skewed UCAs, which affect some of the MM cases more than others.

While bind is only one of many parameters determining the handling characteristics of a suspension system, it is useful information, and has been a subject of great debate on these message boards. As part of the research we did in developing our rear suspension system, MM has actually done quite a bit of roll-bind testing. I can offer some hard numbers for everyone to consider. I will define ‘bind’ to be any resistance to wheel movement in a roll situation that is not from the spring or sway bar.
Let me say that this information is not intended to be negative toward any particular system, but should be used to gain understanding of the way cars with different setups feel/handle. This information can help everyone to optimize whatever setup they may have.
Of the tests we have done, following are the tests relating to the rear suspension systems most often discussed. All tests are with the sway bar disconnected, cycling one wheel through 3” bump/droop as if in a roll situation. The results are organized in order from least bind to the most bind.
1) 4 Link - LCA with spherical bearings or rod ends at both ends / Stock UCA’s 6lb/in Linear
This shows the stock upper arms introduce 6 lb/in of wheel rate.
2) 4 Link – MM LCA 3 piece poly, spherical bearing / Stock UCAs 9lb/in Linear
This shows an additional 3 lb/in resistance from our 3 piece urethane compared to a rod end.
3) MMTA/PB – LCA with spherical bearings or rod ends at both ends 10lb/in Linear
Here we removes the 6lb/in from the UCAs, but adds 10lb/in due to lateral deflection of the TA during roll (see above post).
4) 4 Link – Stock LCA / Stock UCAs 11lb/in Linear
This shows that the stock LCA adds 5 lb/in of wheel rate, which is actually more than our LCA of case 2.
5) MMTA/PB – MM LCA 3 piece poly, spherical bearing 13lb/in Linear
Again illustrating an additional 3lb/in additional resistance of our 3 piece urethane compared to the rod ends in case 3.
6) 4 Link – LCA with 3 Piece Urethane at both ends / Stock UCAs 26lb/in Linear
Case 6 shows that the 3 piece poly (or any LCA) works best with a spherical bearing at one end. 17lb/in is added over case 2. Note that the effect of adding a 3 piece urethane at only one end adds 3lb/in. Add it at BOTH ends and the increase is 17lb/in… NOT 6 lb/in as one might expect.
7) 4 Link - LCA with delrin, spherical bearing / Stock UCAs 30lb/in Linear
This shows that delrin does not allow necessary angular deflection resulting in an additional 21lb/in over case 2.
8) 4 Link With PB - Stock LCA / Stock UCA In the first 1” travel 47lb/in Between 2-3” of travel 30lb/in Decreasing Rate
In case 8 & 9 the Panhard bar defining a new lower roll center is forcing control arms to travel a new path of higher resistance.

9) 4 Link With PB – MM LCA / Stock UCA In the first 1” travel 50lb/in Between 2-3” of travel 30lb/in Decreasing Rate
10) 4 Link – Stock LCA / UCA with rod end at chassis, stock rubber at axle
In the first 1” travel 63lb/in
Between 1-2” travel 39lb/in
Between 2-3” travel 20lb/in Decreasing Rate
Case 10 represents trying to locate the axle with a stiffer bushing configuration on the upper control arms. Since the upper arms need to have an effective length change, the rod end in this case actually creates MORE bind.
11) 4 Link – LCA with urethane at both ends / Stock UCA’s 67lb/in Linear
Case 11 is similar to case 6, but shows that a standard poly/poly control arm does not allow much angular change.

Norm

 

[BMR Tech]

Edit- Kelly I doubt you guys have built a fixture to measure anything like the above, but I would be curious of what ideas you had about measuring it or the numbers J&M arrived at.

Hmmmm....

Well, I am not so sure why Brand J chose those figures for measurement. 5 degrees does seem somewhat excessive. Nonetheless, I don't blame them. KISS.

Let's put those #'s into perspective, real quick.

If you had say, 5 degrees of body roll - that would equate to roughly 6" of movement along the axle. So, 3" down on the left, 3" up on the right. (or stationary on the left, and up 6" on the right) 7.5 degrees would be about 8"....so, basically burying the tire in one fender, and a 6" gap on the other side.

Now, during that 5 degree (6" of travel) there is no way that the LCA ends will see said 5 degree. As a matter of fact, I don't really think they would see half of it. The pivot of the LCA is not necessarily working against the articulation of the rear axle, in all phases of the movement. The first few measurements/moments of travel, will be exerted through the pivot points vertically.

As for measuring, we do not have a fixture like that, because we do not need to - really. If someone is concerned about articulation properties, we have plenty of options for them. We have (6) available part #'s for LCAs alone, for the S197. Three of which, measuring resistance during movement is pointless.

Also, something else about that "test". I see mention of the two-piece bushing "only" being 85 durometer. Well, 85 durometer is actually pretty stiff. We use some of the highest durometer bushings out there, at 90 and 95 on some pieces. I can tell you, in your hand....it is hard to differentiate an 85 from 90-95.

Durometer for durometer - I really don't see that poly ball system being much more efficient in terms of articulation.

There is still a substantial amount of material on each side that the sleeve has to work with. The ball seems to just be taking up space, IMO. If those end pieces were the same 85 durometer, then.....I don't think the measurements would have ended up like they did. I could be wrong, but, I am skeptical. The only way I see the poly ball system allowing for much less resistance, is if it is much lower durometer. Like, 65 for example. I guess my point is, I don't see why the poly ball is any more effective, "durometer for durometer".

We have been offering 3-piece bushings for years, and years. We also release our 11+ UCA with a 3-piece bushing. Then, it failed - epically.

Here is our UCA bushing, that failed.

We are firm believers that the best solutions are simply poly/poly.....poly/bearing.....or bearing/bearing.

If someone reaches the point in which a poly bushing isn't the right choice, I don't see why a poly/bearing combo wouldn't be the next logical choice. I've got daily drivers all over the world rolling around on our poly/bearing components.

 

[BMR Tech]

Norm, thanks for sharing! You always bring some good data to the table! Where you hide your collection of info, it must be insane.

Sheiza/Norm - I have actually been toying around with a test similar to what is mentioned above, just to share. In all honesty, I want to know what will happen in that test, as much as anyone.

Regardless of the numbers that are provided after testing, it is just like anything else - it really depends on the end user.

I've had numerous road course guys call me to order bearing LCA - that are replacing poly/poly. When we get to talking, often times the customer likes the poly/poly.....but simply chose to upgrade because of having troubles with splitting or distorting poly bushings. No lie, one person in particular called me back months later to tell me that he actually preferred the poly/poly. You guys know who he is, too.

 

[csamsh]

If you had say, 5 degrees of body roll - that would equate to roughly 6" of movement along the axle. So, 3" down on the left, 3" up on the right. (or stationary on the left, and up 6" on the right) 7.5 degrees would be about 8"....so, basically burying the tire in one fender, and a 6" gap on the other side.

A comment/observation: this picture is from Big Bend at MSR-Cresson, granted, on street tires, but this is probably about as articulated as my axle can get on any of the courses around here. It doesn't look to me like I have anywhere near 3" of of "axle up, body down" on the loaded side here in the picture...maybe 2.5-3 degrees? It seems ok?

FYI I'm running Ford's Boss 302R poly-poly lowers- the bushing is in two pieces, with a void in the rear of the arm between the bushing halves. I look at them occasionally, and they seem to be holding up well.

See how one sleeve is longer than the other, but the bushing halves are the same width? I don't know if this is by design or to make it cheap, but it seems to work?

I'm having a very different experience with poly lowers than I did with the poly upper, which was verifiable hell, so I'm spherical-spherical there now, which is awesome, and awesomely loud.

Just my $.02, which may or may not be relevant to this conversation, but whatever.

 

[BMR Tech]

Thanks for sharing sir.

Our bushing design is very similar. There are a few things that we incorporate into our design, that somewhat set them apart....but the function of a two piece bushing is pretty basic.

The void you are referring to, is simply a spot for grease to hang out. In a design, like ours, with a grease fitting.....that void is there simply to allow for grease to enter the assembly - then disperse.

And yes - articulation characteristics of the single centered UCA are much different than that of the outer mounted LCAs.

I don't think many people would actually claim a large difference (negatively) with a poly/poly LCA and bearing UCA, compared to bearings at each and every pivot point. Some companies even recommend using poly/poly lca for cornering activities, especially for the entry level enthusiast.

 

[BMR Tech]

And yeah - that roll in the pic you posted is "nothing"