Bilstein sports on the rear and now torn shock tower, advice please!

[madsedan]

A rust free 91 IS with only mods being a recent S50 swap. I have Bilstein sports and H&R race to install and went ahead and threw the rear shocks on with new rear shock mounts with stock springs a couple nights ago because its easy to do in a half hour.

This morning hitting a bump on the interstate it pulled the nuts for the new shock mount through the rear tower!

'

Can I repair this without welding? Using something like a top ring like the VAC tower reinforcer?

[jlevie]

If you are going to use Bilstein sport shocks you need upper mounts with reinforcement plates. The ones from Rouge engineering are good. In this case I'd say the you need the bettermounts and that you need to fab up and weld reinforcements.

[Swanny]

Any pictures of said supports?

[jeffnhiscars]

My thought is that if you swapped just the Sports & still had stock springs, that is asking for a problem.

[chance]

thats unfortunate. Possibly bolting reinforcement plates on the top and bottom you MAY be ok. I would still much prefer to weld them.

[AndrewBird]

Just to clarify what happened, your stock springs are very soft and therefore bottom out very easily. Being that Bilstein Sports are shorter then stock struts, they have less travel. So when you bottom out the strut, it basically becomes a solid shaft. The spring can still compress more though, so all the weight of the car is now sitting on the strut, not the spring, and it gets shoved through the sheet metal.

[madsedan]

Just to clarify what happened, your stock springs are very soft and therefore bottom out very easily. Being that Bilstein Sports are shorter then stock struts, they have less travel. So when you bottom out the strut, it basically becomes a solid shaft. The spring can still compress more though, so all the weight of the car is now sitting on the strut, not the spring, and it gets shoved through the sheet metal.

Thats exactly what happened, hard impact that was hardly felt up front with blow shocks was harsh on the rear.

One of my local buddies recommended a top/bottom plate with jb weld in between lol.

[reelizmpro]

Should have just installed the entire rear suspension if u went thru the trouble of installing the shocks.

[Nsquared97]

Just to clarify what happened, your stock springs are very soft and therefore bottom out very easily. Being that Bilstein Sports are shorter then stock struts, they have less travel. So when you bottom out the strut, it basically becomes a solid shaft. The spring can still compress more though, so all the weight of the car is now sitting on the strut, not the spring, and it gets shoved through the sheet metal.

Correct me if I'm wrong, but this doesn't make any sense to me. I completely agree that the Billie sports are shorter and have less travel, but this would mean they have less range all full extension, not full compression correct? And with the Billie sports being stiffer damped, it should be harder to bottom the suspension out than OEM struts correct? And if they do have less travel in compression, how do they handle lowering springs (beside the higher spring rate helping control suspension travel)? Again I may be wrong, just looking for answers. And really hoping the Koni SA's I installed a week ago don't do the same thing, espicially as they are adjusted fairly stiff right now (I'm in the same boat as OP, only have rear struts installed, mainly due to the rules of the class I autoX in).

That said, I will agree that the stiffer damping of the struts exerted more force on the shock tower, thus the failure. However, it seems pretty odd to me that just the struts would cause that to happen. Is there anything else, like maybe rust issues in that area? Doesn't really appear so from the pics, but idk.

[reelizmpro]

The theory is that a stiffer spring in combination with the bilstein would have distributed the load between each other instead if just the shock. The stock spring is going to compress a lit more than a sport spring and the shock has to deal with this compression. now typically its the shock mount that fails, saving the body from damage. Same principle as the double sway bar vs one.

Now who knows if the same thing would have happened with the race spring/bilstein combo but its less likely because now the spring is sharing much of the load and its increased rate will slow the traval of the shock.

[Nsquared97]

The theory is that a stiffer spring in combination with the bilstein would have distributed the load between each other instead if just the shock. The stock spring is going to compress a lit more than a sport spring and the shock has to deal with this compression. now typically its the shock mount that fails, saving the body from damage. Same principle as the double sway bar vs one.

Makes sense, load would be distributed to the spring mounting points as well. Care to elaborate on the double sway bar at all, or have a link?

[hooken m]

damn, this makes me want to buy an extra set of reinforcement plates. one below the tower and one above

[reelizmpro]

Makes sense, load would be distributed to the spring mounting points as well. Care to elaborate on the double sway bar at all, or have a link?

Instead of removing the stock swaybar and installing an aftermarket thicker sway bar...Metric Mechanic used to just add another stock size swaybar to different points which is effectively acting like a single large swaybar except the load is distributed to 4 points (2 bars) instead of 2 points (1 bar).

[Quinthirty]

If you are going to use Bilstein sport shocks you need upper mounts with reinforcement plates. The ones from Rouge engineering are good. In this case I'd say the you need the bettermounts and that you need to fab up and weld reinforcements.

I suppose this is true for both front and rear shocks?

[Quinthirty]

The theory is that a stiffer spring in combination with the bilstein would have distributed the load between each other instead if just the shock. The stock spring is going to compress a lit more than a sport spring and the shock has to deal with this compression. now typically its the shock mount that fails, saving the body from damage. Same principle as the double sway bar vs one.

Now who knows if the same thing would have happened with the race spring/bilstein combo but its less likely because now the spring is sharing much of the load and its increased rate will slow the traval of the shock.

I have the Bilstein sports and stock spring combo with new shock mounts in front. The car came with a huge front stabilizer bar (seats on top of the strut mounts).

Will this combo not last as long as well? Would you still recommend going for harder springs? I don't want to have a hard riding car.

Would appreciate your advice. Thanks!