I'm throwing ideas to put together a coilover setup for the fc using koni inserts, and was wondering if anyone has any input on drilling the strut housing through the whole body to reduce unsprung weight. The idea comes from looking at muzzle breaks.

My main concern is failure due to bending moments but since the strut insert is reinforcing the assembly I doubt there's any issue, but if anyone has failure analysis formulas for this type of setup or which pattern may increase strength, i'd appreciate it. I only have for single slotted tubes. Stress risers would be reduced by chamfering the holes.

Also, anyone know if there'd be problems threading the tube after this slotting? Mainly, the tip going through edge after edge i'd imagine would cause a vibration on the lathe..

This slotting thing kind of seems pointless if I can just fab a thin wall chromoly housing, but if I can do both, than it's better.

 

Usually you fill the housing with coolant to help transfer heat from the cartridge to the strut housing then to the outside.

 

I´ve personally thought about this but since the airflow will be more direct this way, heat transfer should be more effective. You don´t have to tranfer heat to the glycol mix and then to the air. While you will be releasing the heat energy faster by conducting it to the coolant, you still have to transfer to the air, or it will heat soak if it reaches a certain temp. The insert itself is filled with oil, and it´s redundant to transfer heat through it´s steel casing, then to the other fluid (tranny oil, glycol) then through another metal casing, and lastly to air.

Now if the casing was closed, then it´s probably a good idea, given that you´d usually have a gap of air btwn metal casing and metal casing...

 

If you could test the amount of airflow you get in the wheel well around the strut you could get definite answers. I'm always open to new ways of doing things but I think keeping all the road gunk out of the holes to keep the air flowing would be your biggest problem. I would worry about strength with to many holes and worry about water gathering with to few.
Heat dissipation is one reason racing struts are aluminum(they are also lighter). Shocks can get very hot in racing conditions, over 120F is very common, and we test them at high temps so we know what we will have after a bunch of laps.

 

Yep. Very important.

No since in trying to save a few ounces by turning the housing into swiss cheese.

 

I question the effectiveness of the "fill" w/fluid method. Koni doesn't call for it, and it's just a medium to close a gap to and from metal casings. The volume going in there it's minimal, and as such, so it's the heat retention capacity, after which, it depends on air flow to remove that heat.

 

Drilling the housings is bad for a variety of reasons and is a lot of work just to create an inferior product. You'd save more unsprung weight with lighter lug nuts then you would drilling the housings.

 

what is this "variety" of reasons? I listed some, but I did start this thread for input...

 

It's not so much for how much heat it can hold, it's how effectively it can transfer heat from the cartridge to the strut housing.

 

Someone makes aluminum housing for the Koni inserts...
Better option?


-Ted