DIY Coilovers for cheapskates

[Master Hack]

How about Coilovers for about $120 each? I decided to try my hand at 'em and the result is nothing short of amazing! They might not be much to look at but the performance is perfect. I needed coilovers for the Franken Kart project and $400 or more was not in my budget. So if you're interested follow along.


You need the following materials:
Shock (obviously)
Spring(obviously)
.1875 inch aluminum sheet
.125 inch steel sheet
a foot or two of 2 inch electrical EMT conduit
3.75 inch polyurethane or other suitable plastic rod
2 inch Plastic rod
2 inch welded ring
Tools:
3.75 inch hole saw
2 inch hole saw
Bandsaw or hacksaw
.625 inch drill bit
A couple of files
A lathe would be nice but not required.

So on to making stuff:

I bought these shocks cuz I have had excellent results with them on past projects. I chose 12 inch travel, but you will need to decide what length you need. This shock with 12 inch stroke has an overall length of almost 32 inches. (uncompressed obviously)

ES9000 Series Shock Absorber - 929507 - Pro Comp

www.procompusa.com

Springs, There are a million different lengths, rates and diameters. Here I used18 inch long 2.5 inch x 250 lbs spring rate. There is an online tool to help figure out what rate you need. There are a million variables like, shock angle, fulcrum point and more. Don't just guess. Springs are here: https://www.magnitudeperformance.com/collections/2-5-coil-over-springs

Making parts:
cut out round aluminum discs using the hole 3.75 inch hole saw:

I had some already cut so I needed to find center:
to find center of a circle:
Draw 3 (or more) chords on the circle. All chords must be equal length.
Then find center of each chord and draw a 90 degree line towards the center.

Where the lines intersect is center.

Repeat the process with steel. 2 inch diameter.
Now drill a .625 (5/8) inch hole on center of all Aluminum discs You need 2 aluminum and 2 steel for each shock. Steel discs will require a larger hole.(depending on your shock).
From Center of the aluminum discs cut out a 5/8 inch slot.


Drill 3 holes an inch or inch and a quarter from center (not critical). Drill one disc with a number 7 drill and thread 1/4 x 20. The other disc drill for 1/4 x 20 clearance.

Stay tuned for phase 2 of coilers for cheapskates!

 

[Master Hack]

OK Phase 2
Cut the EMT conduit to length. The actual length depends on your shock, spring and desired preload. I chose zero preload cuz the whole assembly gets compressed an inch or so when installed.

The 2 inch welded ring (available at Ace among others) gets welded to the top to provide a bearing surface for the plastic spring retainer.
Then cut out piece of 3.75 inch poly for the spring retainer/bushing. Cut a 2 inch hole in the center. The shock body is 2.050 diameter the hole needs to be large enough to clear the. If you used a hole saw to cut the 2 inch hole in the bushing, the plug can then be used for the top spring retainer/bushing. The purpose of all that is to keep the spring centered and not rubbing on the shock body.

Notice it has a lip on it to keep the spring centered. This is where a lathe would be handy. It can be accomplished with a dremel and/or a file.
There is a counter bore on the other side for the welded ring and conduit to rest in.



Now cut out a piece of the 2 inch plastic for the upper spring retainer. Or use the plugs cut out earlier.

Cutting the poly isn't easy cuz its soft and wiggles around. It doesn't matter if its ugly , its an unseen part. Drill and tap to match the 3 - 1/4 x 20 holes made earlier in the aluminum discs.

Next up Assembly.

 

[Master Hack]

OK, moving on to assembly.
Take the 2 inch steel discs and hack out a center hole to fit over shock where the eyelet meets the shock body.
this is really ugly buy is an unseen part also.

Now take the aluminum discs and the 2 inch poly retainer made earlier and assemble with 3 - 1/4 x 20 Socket head cap screws.
The discs hace to be clocked about 120 degrees so as to lock onto the 5/8 shock shaft.


Final assembly next.

 

[Master Hack]

Previously on coilovers for cheapskates….

Now drop the spring and EMT conduit on to the shock body.


Add the two hacked out steel discs to make a retainer for the bottom. As you can see they fit between the shock body and the mounting eyelet.


add a small tack weld to keep them where they belong and its done!


So that's how a hack would make coilovers. At the beginning I said the performance was beyond amazing.
The buggy soaks up bumps much better than I had hoped for and nothing scrapes, grinds or binds up.
If I missed any critical details please ask. This may not be a project for everyone, You need to be fearless, stupid and a hack at heart!

 

[Denny]

Wylie Coyote has nothing on you. Sheer genius. A parts list and suppliers would be helpful too! Might have to build me a set some day soon.

 

[Master Hack]

Did the links for the springs and shocks not display? The rest is just home depot stuff and somewhere you can find metal remnants. (which in my case was behind the lathe to the right, there on the rack....)

 

[Denny]

Missed it, sorry. Where did you get the urethane? And what density is it?

 

[Master Hack]

Where did you get the urethane? And what density is it?

Ebay l actually had lertovers from another job. The black is 90 the red stuff is 40 or 50 l think. They both are plenty hard for the job. I think you could use about anything. The harder stuff machines easier.