Mounting Coilover Shocks Upside Down

daloff · 02-15-2006, 02:07 PM

Anyone know who sells the kit to mount your rear shocks upside down. I have a 1971 tub so must do this with coilovers.

Thanks
David

JoeMag · 02-15-2006, 02:21 PM

Racers Group and I'm sure there's many others...

daloff · 02-15-2006, 02:49 PM

WHo else ?

jluetjen · jluetjen's Garage

Smart Racing?

hesaputz · 02-15-2006, 05:16 PM

Dart.

Jeff Alton · 02-15-2006, 09:51 PM

You can mount them right side up with in your early tub if you use the SRP upper hats. Otherwise I recommend using the TRG parts. Your shock needs eyelets on both ends to mount upside down. I have used both types before and both are good solutions. The TRG one uses a solid upper mounts, no rubber, if that matters to you.

Cheers

Porsche Doc · Porsche Doc's Garage

Hey Guys!
A note here.
If you invert shocks that are set up for a normal mounting.
The bump and rebound also invert. That will screw things up.
So if your gona invert the shocks they need to be set up like wise.

jluetjen · jluetjen's Garage

Don. Huh????

Isn't compression still compression, and extension still extension no matter which way the shock is mounted?????

TimT · 02-16-2006, 08:22 AM

Coilovers in an early tub can be tricky. There is very little room in the crossmember for the spring.

I got clevises from Kelly Moss to mount my shocks upside down

Here you can see that the spring doesnt fit up in the crossmember

To get around this problem, I got a shorter spring, and made a spacer up

Porsche Doc · Porsche Doc's Garage

Quote:

Originally posted by jluetjen
Don. Huh????

Isn't compression still compression, and extension still extension no matter which way the shock is mounted?????

No! not the same bump turns into rebound and rebound turns into bump. When inverted!

So get them set up right!

jluetjen · jluetjen's Garage

Compression = bump
Extension = rebound

Turn it over....
Compression = bump
Extension = rebound

Or are you suggesting that by flipping the shock the internal valve shim stack settles in the other direction and thus "reverses" the flow dampening??? This is certainly not the case with orifices since I can't imagine them caring one way or the other which way they are facing. If I picture shim-stacks (for one-way dampening and "blow-off" capability) I still don't understand how it makes a difference.

The only time it would seem to make a difference is if it were a shock which was gas pressurized with the gas directly in contact with the fluid. In that case I could picture the fluid settling to the other end of the shock and the the gas doing likewise. If the valves become exposed as a result I can understand the issue. Otherwise, as long as the valves are always immersed in fluid -- what's it matter???

cstreit · cstreit's Garage

David,

As you see above with a 71 chassis the coil-overs must be mounted upside down.

IMPORTANT!: When you use the clevis kit (available from TRG, SRP, etc..) and have the eyelet on the bottom (was top) you lose a LOT of suspension travel and will be into the bump-stops with a standard length shock. These "KITS" don't include this, nor do the people that sell them know much about building these custom shocks. I found this out the hard way and ultimately went to Jae Lee for the answer.

WHen I did this on my racecar I had to have a custom length set made up. Jae Lee at Mirage helped me sizing the custom shock and valving along with Bilstein...

The front is much easier. I have a kit that I worked with Ground-Control on that works with standard strut-bodies and 2.5" coil's.

David I think you have my phone number, if not it's on my website, please feel free to call me if you want to chat about it, I went through a lot of blood-sweat-and tears two years ago when I did this, but in the end it's simple, just needs to be done right.

TimT · 02-16-2006, 02:14 PM

Quote:

you lose a LOT of suspension travel and will be into the bump-stops with a standard length shock

correctamundo, I forgot to mention that tidbit in my post.
I forgot the shaft length and body length of my shocks. Its on the build sheet stashed away somewhere.

Truechoice set up the shocks based on measurements I supplied.

cstreit · cstreit's Garage

Ah yes, I believe I pestered Tim quite a bit back then didn't I?

daloff · 02-17-2006, 06:40 PM

Thanks Chris and All, I'll talk to you soon.

APKhaos · 02-21-2006, 09:40 PM

Also be very careful to check with your shock vendor to confirm that the specific model you are using can be installed inverted. Some can, some can't. Don't assume that a given Bilstein can be inverted because you have seem another Bilstein inverted setup. Motons can be installed inverted, as can SOME Koni models and SOME Bilstein models.