Edelbrock IAS shocks

[2rods]

Anyone tried these on their rod? How are they for ride? From what they say they are the best but they'll say anything to sell them.

[Bob Paulin]

I own a shock absorber dynamometer, and I have dynoed a goodly number of stock and racing shocks over the last several years.

I haven't had the opportunity to dyno any Edelbrock IAS shocks yet, I would be interested in dynoing some and disassembling one to study it....but, I'm too cheap to buy a new one for that purpose.

I really wouldn't expect to see much difference between the Edelbrock dyno pattern and the Monroe or Gabriel dyno patterns, since they all have to be engineered to work with the same suspension systems.

In looking at their design however, all I really see that is different is the use of a shuttle valve to help control low and high speed circuits in the shock, instead of a simple coil spring blowoff valve as used in other designs.

Thirty-plus years ago when I attended Monroe Shock sales meetings....er... "training sessions", they were bragging about having developed the "self-adjusting" shock absorber.

Well, by definition, all shocks are "self-adjusting" due to velocity and hydraulics. Try to move a shock faster, and the hydraulics resist you more - "adjusting" themselves to the input force.

Most shocks separate the low and high-speed circuits with some sort of blowoff valve.

In the case of the Edelbrock shock, it is through the use of the shuttle (or so-called "Inertia Active System")...a somewhat larger, more complicated, but functionally similar method of allowing low-speed blowoff to bleed a metered amount of fluid past the valving, and soften low-speed hydraulic control.

There are MORE moving parts in the Edelbrock versus the standard Monroe, Gabriel or Pro, Carrera, etc. which - to me at least - translates  into more things to wear/break internally.

F.Y.I. - Many of the so-called "racing" shocks out there are manufactured under contract by either Gabriel or Monroe, and use Gabriel and Monroe components internally.

In my shop, I have a 3000 series oval-track, Carrera coilover racing shock, a 7000 series oval-track, Pro-Shock coilover racing shock, a stock Monroe shock and a stock Gabriel shock all apart.

The two racing shocks have 1-3/8" pistons and the two stock shocks have 1-3/16" pistons, but all four are of a similar twin-tube design.

If I layed the two racing shock pistons and rods side-by-side, you could not tell the difference - same with the two stock shocks.....

....and, the two racing shocks are simply larger, 1-3/8" versions of the stock 1-3/16" shocks, with identical valving design....the only differences being in the size of the coil  springs on the pistons and base valves.

So, when someone tells me that they can "feel" the difference between a Pro or a Carrera, I have to chuckle.

And, one final thing.....

When dealing with stock, over-the-counter shocks such as Monroe and Gabriel, it is actually the cheaper shocks that offer the most agressive control.

The more expensive shocks have more valving stages and pressure bleeds in order to smooth the transitions between boulevard ride and pothole-filled dirt road in poppa's Luxo-cruiser, so they tend to produce a much softer dyno graph.

This was told to me by a Monroe engineer when I managed the NAPA store so, of course, I had to prove it to myself.

I brought home the three different levels of shocks for the same application that we had on the shelf, and dynoed them.

As I progressed upward in price, the dyno graph moved downward in compression and rebound resistance in the 3-5 i.p.s. velocity range - the very range we used to tune our shocks.

I have recently picked up a number of Koni "30" series, monotube racing shocks, along with a set of Koni "stock mount" oval-track, twin-tube  racing shocks.

They are all disc-valved, and externally adjustable. The stock mounts even come apart, so I am using them as "test mules" for some shock fluid experimentation.

If I could find a set of stock-mount oval-track Konis that fit the car - that's the route I would take.  Next best would be KYB adjustable/rebuildable.

I realize that most people here would probably not be interested in disassembling and modifying shocks, but I just wanted to let everybody know some of the similarities, and differences in shock absorbers, and some of the options that are out there for your cars.

Bob Paulin

[Crosley.In.AZ]

Bob,

interesting post on the internals of a shock absorber.

[2rods]

Yes thanks.