Modifying shock absorbers - softer please!

[BigIrish]

The ride on my new vintage racer is brutal. The shocks are way too stiff for cruising around the terrible H-town streets. I just have the standard speedway short shocks on the front and basic Carrera coilovers on the back. Both are too stiff, esp the front. The car is too light!

I've got to figure a way to soften them. I'm thinking drill a small hole in the top of the shock body and drain out some oil, weld up hole. Been reading some similar posts on motorcycle forums. Most bikes have drains in the forks so you can change out the oil. Apparently by reducing the oil level it softens them. Makes sense as well when you think of a worn-out leaking shock, its softer than should be. I think this should work for me. Anyone ever mess with this?

I know they are gas shocks under pressure, so will have to plan accordingly to avoid getting oil sprayed in my face.

 

[sneakysnake]

A typical shocks movement is to collapse easy and be restrictive on the way out. It sounds like your springs are to stiff for your ride limiting travel.With a coilover you need a rated spring for the body weight. You might try adjusting the spring tension on the shocks and see if it makes a difference in the ride,Otherwise I think your looking at swapping out for a softer spring.

 

[donsrods]

I don't think it is the shocks. I have used the same short Speedway shocks 3 or 4 times and they are pretty well balanced to a light hot rod. I have them on my 27 right now and just drove it today, rides like a new car.

Take the shocks off and go for a ride and see what, if anything, changes. I think it is something else, like your spring not working well or having too many leaves. Let's see some pictures of your front end, that would help.

Don

 

[donsrods]

Ok, I just found your build thread and think I see the problem. Everything on your front end is actually done very well...........pretty standard hot rod stuff. But, you put the lower shock mounts on the axle on the wrong sides. The shock should sit outboard more and be on more of an angle. That will soften the ride and act as an antisway bar sort of.

Here is how you have yours:

And here is how I have mine:

Swap them side to side and I bet it rides a lot better.

Don

Oh, drop your air pressure to 26-28 in the front and about 24 in the back. That will soften the ride and is a good starting point to fine tune the air pressure. Also, do you have slider buttons in those holes on the ends of the springs.......you should have those in place too.

 

[King Herald]

Everything Don says.

Your shocks will rise smoother if they are angled over that few more degrees.

If it is still too harsh at the front, take a leaf out of your spring.

As for the back, you may have too stiff springs, rather than too stiff damping. Get softer springs.

Or you could angle them over too if you have a way to do it without major reconstruction.

I put three top mounting holes in my chassis, for just such situations. You can just see the holes for the mounting tubes I welded in in the top of this pic:

Draining the oil from shocks will simply make your car bounce around, and will foam the remains of the oil, removing all damping action.

Same with tire pressures, you don't need much more than 25psi in them with a light car like that.

 

[donsrods]

My artwork failed, I'll try later.

Don

 

[BigIrish]

Swap them side to side and I bet it rides a lot better.

Don
.

Brilliant!! I can't believe I didn't think of that. Whew - that will make a big difference for sure. Thanks.

I have the teflon buttons in the spring. I took the shocks off and bounced the front end - spring flexes easily and smoothly so I think its about the right firmness.

I have the lightest springs they sell for those coilovers. The only way to soften them up is to angle them I guess but that would involve modifying my frame. I'll just air the tires down ...and of course I have no seat right now so that will help when I'm not sitting on plywood

 

[Torch]

right shocks?

Did you buy normal everyday shocks or did they specify 60/40 or 50/50?
On the street you don't want 50/50 those are for racing.

on the street you want a 60/40 or 70/30.
what that means is the shock is easy to compress and difficult to extend.
The purpose of a shock is not to stiffen the suspension.
The purpose of a shock is to slow the recoil from bumps and dampen rebound.
when you hit a bump you want the wheel to rise over the bump asap but then stop going up when the bump stops pushing it up.

You want that tire to ease down the other side of the bump.
The energy from the bump is gong to travel up and down the spring after the wheel stops going up and down until the molecules in the spring absorb that energy through internal friction and dissipate it as heat

The shock absorbs THAT energy so it doesn't make the wheel move when it is not supposed to be moving.

leaf springs add into the scheme of things with friction between the springs that dissipates extra energy as heat.

A normal leaf sprung suspension needs less shock to control bounce than a coil spring or air bag suspension.

Valve springs in an engine will get very hot if there is no oil to cool them.
Valve springs are arranged in nested sets to rub and cancel out oscillations.

In short the shock isn't supposed to be preventing the suspension from compressing. It's supposed to be stopping it from compressing beyond what's necessary..
And It's supposed to be slowing or damping the return of the suspension to it's normal position so it doesn't ocillate.

Another thing the shock does is when you drive into a pothole or off a high onto a lower surface it prevents the wheel from hitting the bottom as fast and hard as it would without a shock.

It's not stopping Tysons arm from cocking, it's just pulling the punch.

I don't know why 50/50 shocks work better on the track can't answer to that but they aren't for use on the street.

as a set of shocks breaks in they will soften up. the oil in them is pretty thin but it does get thinner as the molecules shear. A new shock is stiffer for about 20% of it's service life. That's if you consider them leaking out or not working anymore as the end of their life.

With My semi I would get 20k to 30k out of a set of new shocks before they would start to feel loose but they'd last for 200k miles or more before they'd wear out or start leaking.
I like the feel of them when they are new before they break in. I always thought it would be neat to just change the oil in the shock when the oil broke down. someone invented rebuildable shocks for big rigs. It costs about $700 for a set of 6 but they won't sell you a kit they require you send them in every 150k miles. I see that as a fail. I'd just throw on a new set of disposables every 200k.

 

[BigIrish]

I swapped the shock mounts and it did help a little, but the ride is still way too hard. If I lean out of the car and watch the front axle, it barely moves even over a big bump.

So I took the shocks off entirely and now it soaks up the bumps like a caddy. Axle bounces a little too much on the really big bumps but overall its much, much better.

So i guess I'll just leave them off for cruising at low speeds and put them back on for any highway travel.