Rear Coil Over Shocks

[Twin_Turbo]

Here's how I modified a pair of stock trailing arms for coil over shocks.

The biggest issue I noticed was that the shock mount would introduce a torsional load on the trailing arm, something which the semi free hing bolt of the leaf spring does not do. I needed to find a way to make the arm more torsional stable without having to cut up the entire arm. There was no need for offset arms and such. Xander (V-Twin) came up with the idea of cutting holes and welding in tubes. That should make it considerably stiffer without adding a lot of weight.



This is the complete arm, ready to be installed.



The length of the mounting bracket depends on what length shock you are using. If you are using an 11" collapsed length shock, they need to be longer than this.

 

[Yellow73SB]

Heres some pics from the place in Europe

They didn't do anything to strengthen the T-arm though

 

[Twin_Turbo]

Yeah, those Germans and their crummy engineering huh

 

[phantomjock]

A few questions

Here's how I modified a pair of stock trailing arms for coil over shocks.

This is the complete arm, ready to be installed.



The length of the mounting bracket depends on what length shock you are using. If you are using an 11" collapsed length shock, they need to be longer than this.

Sorry to "Revive" this thread --- but as a Newbie here on this forum I have been pouring over the wealth of info here. THANKS all!

Twin_Turbo -- many thanks to you especially for sharing your CAD files and experience too. You have saved me a ton of hours -- as you'd well know.

BUT a few questions, if I may, on this coil-over design:
1. Has the new owner enjoyed it?
2. Would you do it again this way?
3. Or would you try and reduce unsprung weight and move the shocks and coils inboard?
4. Can you describe the relationship between "collapsed"shock length and the length of the bracket? They look very similar in length -- Are they?

Many thanks again.
Cheers - Jim

 

[Twin_Turbo]

The car doesn't have Dutch tags yet, soon it will...no road testing yet
Sure I would do it like this again.

what do you mean, reduce unsprung weight? The shocks and springs are only partially unsprung but moving them hardly makes a difference. There is no way to move them inboard, moving them if at all possible would also reduce shock and spring efficiency as the wheels vs. shock/spring rate changes dramatically.

As for collapsed length, the extended length is most important and depending on what extended length shock you use (you should use the shortest that you can find, in the 11" and shorter range) determines where the shock mounts so you can still set a proper ride height. The pics w/ the Konis are from a German company.

 

[mrvette]

Here's how I modified a pair of stock trailing arms for coil over shocks.

This is the complete arm, ready to be installed.



The length of the mounting bracket depends on what length shock you are using. If you are using an 11" collapsed length shock, they need to be longer than this.

Sorry to "Revive" this thread --- but as a Newbie here on this forum I have been pouring over the wealth of info here. THANKS all!

Twin_Turbo -- many thanks to you especially for sharing your CAD files and experience too. You have saved me a ton of hours -- as you'd well know.

BUT a few questions, if I may, on this coil-over design:
1. Has the new owner enjoyed it?
2. Would you do it again this way?
3. Or would you try and reduce unsprung weight and move the shocks and coils inboard?
4. Can you describe the relationship between "collapsed"shock length and the length of the bracket? They look very similar in length -- Are they?

Many thanks again.
Cheers - Jim

Welcome to the motley crew of the Flying Dutchmen....

another Florida type I see, ....lots of vettes down here...

:yahoo:

 

[phantomjock]

Glad you'd do it again-- I'm encouraged to build one too!

First - Thanks for the speedy reply - must be close to bedtime in Holland by now.

what do you mean, reduce unsprung weight? The shocks and springs are only partially unsprung but moving them hardly makes a difference. There is no way to move them inboard, moving them if at all possible would also reduce shock and spring efficiency as the wheels vs. shock/spring rate changes dramatically.

The weight/mass of the wheel/hub/tire/components react to road irregularities. The speed at which they rebound is often only attributed to the spring/shock and weight of the components. But, if you can reduce that weight, the system reacts quicker with less delay - less chassis twist -- some say, etc. Thats why we see (with a lot of trial and error no doubt) F1 and GT cars now sporting shock/coil setups using linkages with struts etc, moving the components inboard. A 'vette example aftermarket option - SHARKBiTES.
http://www.speeddirect.com/index.aspx?nodeID=132
I've considered other options - all cost interior space though.

I was just currious if there is much [in your opinion] to be gained here --I suspect its mostly at the margins for our nearly under 3000 pound hulks! Meanwhile, I'll be looking for some shorter shock coil overs (less than 11 inches as you suggest). AND, sourcing a welder. THANKS!

Cheers - Jim

 

[phantomjock]

Thanks MRVETTE! I'm NW FL --- FWB and in the early stages of a "MAJOR." Body is off, chassis cleaned up and soon working components - ie Suspension, Engine, etc.
Cheers - Jim

 

[Twin_Turbo]

The weight/mass of the wheel/hub/tire/components react to road irregularities. The speed at which they rebound is often only attributed to the spring/shock and weight of the components. But, if you can reduce that weight, the system reacts quicker with less delay - less chassis twist -- some say, etc. Thats why we see (with a lot of trial and error no doubt) F1 and GT cars now sporting shock/coil setups using linkages with struts etc, moving the components inboard. A 'vette example aftermarket option - SHARKBiTES.
http://www.speeddirect.com/index.aspx?nodeID=132

This is grossly overstated, the shocks are only partially unsprung. The caliper, rotor and spindle make up so much moer weight, as does the wheel and tire.

The serious racers use push or pullbarsystems with rockers/cams for a different reason altogether. Their suspensions have a severely limited travel and allowing shocks/springs to do the dampening 1:1 would mean they are only used over a very short stroke, making them very inefficient and much less respinsive to small suspension movement. That's why they yse the pushrods and cams to inrease the wheel to shock/spring ratio above 1:1. It's simply scaling to improve efficiency. And the pushrod/pullrods obviously reduce unsprung weight but those cars already have the lightest wheels, brakes, spindles...yadda yadda.

As for Speed Directs system, their design is not taylored to improve shock efficiency..it's crammed in there to fit and look good. Their cams actually reduce the efficiency because of the ratios used. And when asked, they will even sort of admit it.

Check this:

http://www.vettemod.com/forum/showthread.php?t=1345&highlight=shark+bite

It's just another poser suspension..and flimsy at that.

If you're going for a coil over setup, get the Van Steel one, although I prefer the Meyer lower A arms because of theur shock mount design over the Van Steel ones (they have the mount hanging off a tube, introducing torsional stress and there's no support tube for that)

 

[Steve M.]

Reviving an old thread again.

Been contemplating switching to coil overs on my '80. That setup that Twin Turbo looks good and easy enough to fab up.
Is there enough room to fit a 2 1/2" or 3" spring in there, or did the box need to be cut? Can't tell in the pics of the German model.

Also was wondering if it would work by coming off the rear of the trailing arm.
Weld a mount on the frame, Fab up some brackets to surround and box in the arm where the original bolt goes thru and come down from there. Seems to be a lot more room.
I don't think there would be any binding issues using coilovers with heim joints.

Anyone done this?

Thoughts?

Issues?

Reason I would like to do this is, I put in a replacement 9 leaf 2 yrs. ago and it still sits to high. Have 8" bolts in there now. 10" is too long, end of the spring rubs the sidewall. Plus, it would be something different. Hate following the crowd.

Almost forgot. Would the rates on both springs be 1/2 of what the leaf spring is or, say, a 200 lb. spring on each side if the leaf is rated at 400lbs.?

 

[AJ77]

VanSteel sells a setup kit with offset trailing arms and QA-1 coilovers. I bought the one with double adjustable shocks. Pricey at $1600.00 but I love it. Art

 

[Twin_Turbo]

Get narrow body shocks w/ the smallest diameter springs, 2" or under. Then it will fit without cutting.

 

[jthompson]

Reviving again! Twin_Turbo, it looks like the pictures have been removed or the links broken. Any way you could repost them, send us a link or let me know how to find them? Thanks in advance!

 

[Twin_Turbo]

Can you see my image gallery? The pics are in there. Otherwise look at v-twins 77 pro touring build. Piics should be there