I have a set of Spohn relocation bracket and I just bought a Strange Engineering 12 Bolt rearend. I was wondering if I can have the relocation welded while the rear end is out of the car and would I encounter any geometry problems or is it best to have the rear end in place then welded them? Which installation do you recommend?
Thanks: David

 

I have installed Eibach Sportlines and now the LCA relocation brackets are next but,

Like what DTL504 said "weld on frame or off ?"
..thnx

 

With the rear installed in the car. That way you can make sure than when you change the position of the lca in the bracket the rear still will be centered in the wheel opening.

Kat

 

I called Spohn and talked to their tech rep and he said it was ok to weld in the bracket while the rear was out of the car. There would be no geometry problems.

 

Good to know. Hey what are you gonna paint your rear ^^^^? I think i am gonna POR-15 mine black. I have a Moser 12 bolt.

 

I welded mine on my Moser 12 bolt out of the car since it was easier.No problems with alignment or anything!I measured from the stock control arm bolt hole to the lowest one on the Spohn brackets and made sure each side was even..and welded!

 

I painted mine Rust O Gloss Black, plus I have the aluminum cover.

 

#2

 

Um, isn’t Kat a spohn employee?

FWIW, it seems like you get a different answer about this depending on who you talk to at spohn since their brackets don’t really have a hard and fast point to reference against.

The answer that I got when I asked with the first set that I installed is “put the through bolt through the original pivot and the bracket and then push the bracket all the way forward and weld it there." From experience that is usually pretty close.

Real answer:
- prop the axle so that it is sitting at the same pinion angle that it would be in the car. If you don’t have a measurement in the car then something in the 1-2* down range is about right. If it’s in the car, well, it’s pretty much held in place at ride height and just try to make sure that it doesn’t change.
- Put the brackets on with a bolt through the upper bolt holes and the original pivot, use a level to make to find a perfect vertical line, when the brackets are in the right location, the lower pivot holes will be slightly (like 1/16”) forward of the original hole, and IDENTICAL side to side.
- Weld them in place.

Alternative answer, buy the BMR bolt on ones, use the bolt on feature to line them up and then weld them in place

Alternative answer #2: unless this is a serious drag car skip them altogether. These cars actually handle better with the rear LCA pivot slightly higher then the font and they hook OK that way also (not as hard as with them the other way around, but well enough).

 

lots of good info 83 crossfire TA, but in responce to alternate answer # 2, I had seriously bad wheel hop with 17s and global west LCAs before I got relocation brackets installed. After the instal I can sit and spin them all day nice and smooth.

edit: forgot to mention, I have sportlines so that might add to the bad wheel hop problem.

 

I’ve said it before… you’re not getting wheel hop unless something was worn out, loose or broken. When you installed your brackets you probably replaced whatever it was or retorqued whatever was loose…

 

I usually skip over erroneous information on this forum and just move along to the next thread, especially from people with post counts in the thousands, but I'd like an explanation on this one.

More specifically, I'd like a reasonable explanation as to why a car would hook hard at all when the rear mount of an LCA is slightly higher than the front mount. To me, it seems that when torque is applied and the rear end starts trying to push the car forward, the 'equal and opposite' reaction to this force would direct the entire rear housing of the rear end up and forward, towards the rear seats, and compressing the springs, which then gain potential energy and overpower the motion, smashing the wheels back down. Wheelhop is born.

Now with the rear LCA mount relocated downwards slightly lower than the front, that 'equal and opposite' reaction is leveraged downwards, towards the immovable ground, rather than upwards, against the movable springs, and the axle doesn't hop. In fact, the axle would have to move backwards (swing arm angle) against the entire forward force of the of the car in order to hop, effectively sandwiching the wheels down against the road, making them spin instead of hop.

I use BMR weld in relocation brackets.

 

The only thing I did to eliminate wheel hop was to ad relocation brackets. there was nothing worn out that was replaced. In fact the previous owner installed polly bushings all around.

 

Well, there’s a lot of people out there with thousands of posts that are at best flaming idiots… so I don’t see why that should weigh at all.

I never said that it would hook hard, I said “These cars actually handle better…,” and that is the truth.

Nutshell, remember that with the LCA’s at an angle, and especially with the angle changing your rear wheel alignment is changing. With the LCA’s angled slightly upward the rear axle effectively toes in on corner entry, and actually steers into a turn at speed, that is a stable condition. With the LCA’s angled downward the rear axle will steer out entering a turn which is an unstable condition the back end will try to come around as you enter a turn. Also, with the LCA’s angled down it exaggerates the difference between power on and off handling making the car more difficult to drive.

Traditionally, on a torque arm rear suspension all the torque reaction is handled by the TA, and the LCA’s are there only as locating members. This is roughly what is happening on the GNX setup.

On f-bodies, this is modified a little and you end up with a sliding link torque arm setup, which changes the suspension geometry and the location of the instant center. In this case most, if not all of the torque reaction is still controlled by the TA, but the locating feature of the LCA’s becomes more important and because of the sliding link the LCA makes the final determination where the instant center of the rear suspension actually is (on the traditional setup that is strictly up to the TA’s pivot location).

The torque reaction is not a fore and aft thing as much as a rotational thing. If you prevented the front of the TA from sliding and had perfect traction on both sides you could remove the LCA’s and the suspension will still control the torque that is being applied to the tires/suspension.

Now as far as “hooking hard,” well, that depends. Increasing the downward angle of the LCA’s does increase the antisquat of the rear axle, it effectively turns the torque reaction, the rear suspension’s attempt to control the axles trying to twist, into a downward force, pressing the tires against the track surface harder.

That’s great, IF you have tires on the back of the car that can absorb that extra energy. If you’re running slicks or something with soft sidewalls then the sidewalls flex and absorb/store that energy. In the extremes, you’ll sometimes see a car that will push down on the tires so hard on the launch that it will completely squish the sidewall and the rim will actually hit the track surface (most commonly you’ll see this on mustangs running Lakewood bars… which are effectively LCA’s + relocation brackets as one package).

OTOH, if you’re running radials, forget it. The suspension tries to apply the energy to the tire, the tire has a stiff sidewall with no give and you get what feels like the most aggressive launch that you’ve ever felt but still get wheel spin (in realitly you actually just launched hard out of the hole, so hard that the tires actually bounced coming out and you loose traction after the initial torque reaction). And this is why I said “unless this is a serious drag car skip them altogether…”

Like a lot of other things that people swear by around here… feels great, but doen’t work.

 

uh hu, and part of my original quote:
”When you installed your brackets you <snip other possible explinations> retorqued whatever was loose…" Unless of course you believe that everything the athe previous owner did was perfect...

 

So with that Final quote, I'm going to say that you agree that relocation brackets actually assist the car in hooking better, by preventing wheelhop and allowing the only question in traction to stem from how good your tires are and weight transfer.

But even if you're not Johnnydragracer, And your car is a street car, I still think most people would prefer wheelspin over wheelhop. There is no greater loss of traction than when the rubber departs the road.

 

Neither one of these situations is optimal, the LCAs should be parallel to the ground when you launch.

 

You can tack it on the car for geometry without having to break out the tape measure. Weld it off the car or with the rear hanging down for more room and access. That's the easiest, especially if your car is already running. You can weld it on the car, but people I know like to drop it for better welds all around.

 

I understand what you are saying, But I installed global west LCAs and new rear shock when I got the car. IT STILL HAD WHEEL HOP. So a few wheeks later I bought RLBs and helped weld them in. After that, there was no more problems.

I am just saying to the best of my knowledge there was nothing loose right before I had the RLBs put in. If someting i loose, it is still loose becasue I haven't done anyhting else.

 

Uggghhh the brackets are the only thing of Spohn's that I haven't installed. Thats the way "I'd" install them when I do get them for my car, cause I feel that is the best way for "me" to make sure stuff is aligned..

better?

 

So you didn’t remove the LCA bolts to install the LCA relo brackets?

I believe you that “to the best of your knowledge” nothing was loose, and I’m not suggesting that you did something wrong, but I’m telling you for sure that something was loose or worn out.

I’ve owned 4 of these cars at this point and the one that sat the highest, my current formula, at it’s highest had eibachs with the rear spring isolators removed. My 83 parked next to it made the formula look like a 4x4, I’d bet that it sat lower then 99% of the cars on this board. My point is that I’ve had lowered cars and I can assure you that none of them has ever wheel hopped, and all of them have had A LOT of passes made in them (and I’ve also installed LCA brackets and have them on one, soon to be 2 of my cars, so it’s not like I’m unfamiliar with them).

I also work on these cars regularly and EVERY time I’ve gone through this it’s the same thing:
“my car wheel hopps…”
“Something is broken, check it out”
“I checked everything, my car still hopps”
“Something is broken or loose.”
“No it isn’t”
“Bring it by and let me look at it”

When I see the car I ALWAYS have found something that was broken or loose. As a matter of fact, one of those cars that I had this conversation about is the one that I posted pictures of in another thread with a torn front subframe rail. The owner couldn’t see it and could not apply enough force to it to make it move (I’m 6’4” and 300#, if something can move I can move it).

 

Honestly, and this is nothing personal, I don’t care….

I’ve gotten the same inconsistency with Spohn’s stuff before I even knew you existed and even going back as far as the first Spohn stuff that I bought, probably 7 years ago now. As far as I know, you don’t design their products or do tech support, so that doesn’t reflect on you, and I’ve already expressed my opinion about spohn stuff in other threads.

At this point I’d either make them fool proof (the bmr bolt ons when welded are close to it) or very carefully measure everything out. In the case of the ones that I put on my current project, I decided to just cut some steel, extend Moser’s brackets, lay out where the holes really should be with some machinist’s dye and a scribe and then drilled the holes EXACTLY where I feel they should be. Then result is the holes being more accurately located then anything that you’ll get with a pre drilled bracket that indexes against a bracket that has been beat up/exposed to the elements for years, and I have a usable pivot hole every inch from the stock location to the bottom location that the aftermarket relo brackets have (the reason that this is significant is that given the choice, on a lot of lowered cars expected to handle I feel that you really need a hole roughly 1” down from the stock location, right where the weld or seam falls on all the aftermarket brackets).