Yes a spring will definitely be needed… the weight of the car will be enough to collapse the cylinder while its in the air but you’re going to need something to get it the rest of the way once the weight is back on the suspension.
I’m thinking of fabricating a box (1/8" steel comes to mind) right in front of the rear wheel which will protrude up into the car approx 4". welded on top of the box will be cylindrical donut (same exact one used on hydro cars) that will locate the cylinder. We need to design this around the cylinder as we are going to need to weld the cylinder collar to this donut in order to keep the cylinder up inside the car. This will make the actual case and guts replaceable from inside the car should they need to be rebuilt.
inside the “box” on each side of the cylinder will be a bolt in (from inside the car) spring mount where we can just clip on a spring. The spring is going to need to have tension on it when the cylinder is fully retracted. This is going to be the worst part I think, is finding a spring that can sustain that kind of extension.
Design #2 would be a 2 way cylinder out of say a tractor or something with the ability to move both ways under power. It will require a slight bit more fabrication and plumbing but we can still use a single pump
On 12v no matter what you do this is not going to operate fast at all, in fact it’s really going to come down to cylinder size and pumphead gear / pressure to see if it even really lifts on 12v. There may be a better gear combo than a lowrider pump for this design, we are going to have to look at pumpheads and do some calculations.
Shit I just thought of something… I think it was prestolite but I can’t remember exactly … either way someone at one point was making a 6v motor for lowrider pumps. the benefit to this is that running a 6v motor on 12v is essentially the same as running a 12v motor on 24v you’re going to significantly increase the torque output of the motor and thus the pressure generated by the pump. I bet a 6v motor would do it with just a #6 Marzocchi gear.
My idea was similar for cylinder placement. However, I’m unibody :-(. I’d like to mount it to the rear subframe (in front of the wheel), than cut a hole in the floor for the cylinder to poke though.
unibody or not if you build the box area around where the lift point is the metal should be strong enough to support the weight of the car… its a lift point! May require a little bit of fabrication and bracing but it sure would be a pun project!
My idea for the bottom of the cylinder (usually cylinder itself is threaded) is just a metal plate with a stud in the center (to screw into the spring) and 2 hooks to put the other end of the springs on.
I really think this would work and be a fun ass project. The worst part of it is goign to be the springs i think.
What I do know is that the absolute cheapest way out is going to be a set of 8s, 1 pump, 1 dump, 1 slowdown, and 1 check. 2 lines. Only need one solenoid, and a single switch. This is assuming the spring idea would work to retract the cylinder. best part is you don’t need a serious pump for any of this, could even grab a used one if you could score it cheap enough.
