Rear Crossmember Raising

[Chopper]

Looking for info on raising the rear crossmember. If anyone has done this and how they accomplished the mod. thanks

[INDY510]

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I have seen slightly raised Rear control arms ....... ... . but my control arms hit the body,,, and they aren't even raised

 

 

the rear frame rails hold the differential, and the rear crossmember, , , , , , Essentially,, you would be re-engineering the entire rear structure of your 510...... ..

[freekwonder]

Why would you want to raise the rear crossmember?

[Everat]

never heard of doing this on a 510. It works great on bugs, the drag racers cut their frame at the torson housing and raise the whole rearend up 5 inches or so.

[philcas1987]

Doesn't the penultimate crossmember raise the control arm mounting points. Savage washers pushes it up against the body. It's a good start

[Chopper]

Why would you want to raise the rear crossmember?

 

If you raise the crossmember up you will effectively move the suspension pickup points up, as well as keeping the differential more in line with the hubs. If you just raise the pickup points and don't move the diff then the axle angle becomes excessive causing vibrations from the u-joints. What I was thinking about doing is removing the outer crossmember flanges from the crossmember and rewelding them in a lower position, thus raising the crossmember. I believe that you can also flip the moustache bar which will raise the rear of the diff aprox 3/4". The outer portion of the unibody and stiffener rails as well as the inner stiffeners are the only obstacles to getting it any higher. Of course a little notching of the inner fender well will be needed. Even if all you can get out of this mod is a 1/2" it will be a major help with axle angle on a lowered car. This would also be an ideal way to move the front crossmember: however the limitation is the oil pan. And then you have to get the TC rod up and bump steer the box and idler.

 

I was trying to get a feel on what mods if any had been done to the rear crossmember itself. I have done the mods to the pickup points, but this only addresses the camber/toe issues that come with lowering.

 

Thanks for any input guys

[Chopper]

In reference to the savage washer mods. This is a great inexpensive mod which tightens up the crossmember, and can be accomplished without removing it. It is better and more effective to use a Poly or solid bushing in these outer and inner mounts. If you have ever removed the CM bushing you will find out why the rear end of a 510 moves around so much. Top End Performance Poly bushings move the CM up a little and locate it fairly solidly. The Poly mounts made by Whiteline are also a good product, they don't raise the crossmember quite so much as TEP, but they are formed to use the stock lower washer and also have a inner sleeve more like the stock setup, this providing more isolation to prevent NVH (noise, vibration,and harshness)

[Jesse C.]

Just get the adjustable inner pivot points from Brian over on the realm and do a CV axle conversion to eliminate the U Joints.

 

http://www.the510realm.com/viewtopic.php?f=10&t=6946&hilit

[Chopper]

I think you mean Byron...his brackets are very well thought out. The only issue with these are the need to use the stock bushings, or spherical bushings. If you use the stock bushings the centerline of the swing arm pivot is changed so that it is no longer in a straight line with the bracket bolt centerline. This puts an undue amount of stress on the bushings and they will eventually begin to separate. Poly bushings are worse and will wear out even faster. The best solution to this binding problem is to move the brackets so that they are more in line with each other which will limit to an extent the amount of binding or stress on the original rubber bushings. Datsport has addressed this issue with their bracket kit. The outer brackets are approximately identical to the stock ones other than having room for toe adjustment, and the inners have lots of room for camber adjustment. But the real help with binding comes from the install process. The brackets are mounted to the swing arm in the central positions for camber and toe adjustment before being welded to the crossmember. What this means is that the brackets are welded to the crossmember with a little bit of "preset positive camber and toe in" and the centerlines of the swing arms are a lot closer to the centerline of the brackets bolt centerline. With a lowered car ' which almost all of us have" this means less binding and wear depending on your choice of bushings. Of course if you use spherical bushings traditional slotting of the crossmember would take care of needed adjustments and the centerline of the swing arm would be a straight line drawn through the bushings and not dependent on the location of the bracket bolt centerline.

 

The CV axles are also a great solution to the misalignment of the hubs to the differential when lowering. That is why I am interested in trying to raise the entire assembly. If you can raise the assembly then you effectively lower the car without the side effects we need to correct for.

 

Any thoughts are welcome...thanks

[Jesse C.]

Yes, you are correct, it is Byron. Brain fade!

 

I am planning to grab a set of brackets from Byron soon and install them along with outer brackets that pivot ala Penultimate rear end. There will be some bind but not as much as having stationary outer points and I can use Poly bushing without too much risk of them failing. Rubber is great but has too much give and spherical bearings are kinda harsh for a street driven car.

 

My buddy and I once talked about moving it all up into the car to lower everything and keep it all in almost stock spec and we even came up with making a whole new rear crossmember but it was just too much work we just forgot about it. But, that is another idea, make a new crossmember.

[Chopper]

Yes, you are correct, it is Byron. Brain fade!

 

I am planning to grab a set of brackets from Byron soon and install them along with outer brackets that pivot ala Penultimate rear end. There will be some bind but not as much as having stationary outer points and I can use Poly bushing without too much risk of them failing. Rubber is great but has too much give and spherical bearings are kinda harsh for a street driven car.

 

My buddy and I once talked about moving it all up into the car to lower everything and keep it all in almost stock spec and we even came up with making a whole new rear crossmember but it was just too much work we just forgot about it. But, that is another idea, make a new crossmember.

 

Jesse,

 

Now thats a good idea! Using the best of all the options. It will take a little work, but the end result will be worth it. You will gain a suspension that doesn't bottom or bind and good handling and enjoyable driving will be the result. Looking forward to seeing the end result. I will post some pics of what my final mods are sometime soon

[hang_510]

Poly bushings move the CM up a little and locate it fairly solidly.

 

this providing more isolation to prevent NVH (noise, vibration,and harshness)

mines not so bad

 

I am planning to grab a set of brackets from Byron soon

i have a set(save ship $$) remind him once you make a deal.

[philcas1987]

Looks like you got it figured out bud. Go out and build it.

[draga240z]

Looks like you got it figured out bud. Go out and build it.

 

 

I agree, I would like to see this when it is done

[DISLEXICDIME]

Talk to the guys on the realm a few there have done this

[Duke]

I have my rear crossmember and differential raised as much as possible without cutting anything. I did this by taking all of the washers out of the crossmember mounts and only using the "cupped" washer, but flipped so that is pushes up on the crossmember. This will essentially solid mount the crossmember to the car. For the diff mount I used the mustache bar in the position that mounts the diff the highest (holes are offset). I also used poly bushings for the mustache bar and shortened the inner sleeve of the bushing and shortened the upper bushing so that the mustache bar is essentially solid against the bottom of the car as well.

 

This may not be the best thing for noise/comfort, but I know that the rear crossmember will not be moving around and adversely affecting handling. It also gives me the best half shaft angle for how low my car is.

[FastDat]

I've raised my rear cross-member almost 2 inches in my Solo EP car. This was for two reasons: first to improve my rear roll center and second to eliminate the extreme angles on the half-shaft u-joints. Everyone dreams of CVs, but if you get your diff in line with your hubs, then there is no difference in velocities.

 

This mod. is a lot of work (not as much as putting in twin A-arms up front, but let's not go there right now). I cut out the entire rear floor and raised it. There are tubes from the cage tying into the crossmember attachment points. You will also need to modify your tunnel as the driveshaft will hit. Also, your exhaust will need to be modified. If you are using the stock spring locations then these will need to be raised as well. Also your brake and fuel lines will take some attention. And your mustache bar mounting will need to be changed. If you still have your spare tire well, then removing the diff will require dropping the entire cross-member each time (I use a fuel cell and the trunk floor is non-existent.

 

It is definitely worth it if you are going to be competitive on the track. On the street it would be overkill. Access to a plasma torch is preferable to the sawz-all method.

 

I'm not sure where you are but I am looking to sell my frame jig for $300. I wouldn't try this sort of thing without one. The jig is 5 foot by 14 feet on large casters so it can be moved and is dead-nuts square. The main frame is 3inch by 4 inch box steel. If I remember correctly it is 3/16" thick so it won't flex. There are two cross sliders with 4 vertical posts to mount the car on. Obviously the jib would cost too much to ship.

 

I have a project tread on the Realm.

 

Good luck.

[510-GUY]

This is a really nice way to go http://www.datsport.com/adustable-rearxmember-kit.html and then just put savage washers on the crossmember after!

 

$285 for the kit and $2 bunks to make the washers!

 

The other kit is sweet on this forum but u get it all with this kit!

[DISLEXICDIME]

That is a nice kit