I notice Edelbrock makes a shock for the C5 which has an "inertia valve" variable rate dampening system. I just put in a similar valve made by Racetech in my Harley front forks with outstanding results, and this form of dampening is used on most sport bikes. Form what I have found; for compression dampening, on high velocity bumps (sharp bumps and potholes) little dampening is desired. For low velocity situations, ie curves on a smooth road or braking, a much higher level of dampening is desired. The "inertia valve" works by having the dampening oil push againt a washer which is spring loaded. The higher the force, the more the washer opens, and the greater the rate of oil flow. Thus high velocity bumps have less dampening than low velocity bumps. On the Harley, I obtained a much more compliant ride over bumps, but still (for a Harley) decent handling. How does the velocity sensitive dampening (and ride quality) of the Edelbrock compare to that obtained by Bilstein or OEM. Does anyone have direct experience with Edelbrock shocks? Cost are around $475. Note: rebound dampening is not as velocity sensitive, so the quality of the ride is based more on the compression dampening.

 

I heard of some others here using them.

Seems that the pricing could be closer to Bilsteins though. :confused:
Which can be had for $279 (a set of 4) from Mid-America which is cheaper than the GP in the Corvetteforum Mall. :confused:

 

Frank- VettesRule just put them on his '01 Z06 and loves them. You might try paging him so he can give you the full scoop on them (he used to be an engineer at Edelbrock for over 10yrs....) so he should know. I have heard nothing but raves!!!

VettesRule are you listening? Give us the full scoop!! :jester

 

I briefly had them on my previous GT Mustang. A Long story, but I shouldn't have taken them off. They work as advertised and do ride better over bumps giving great handling with the benefit of not being too stiff. Truely, the best of both worlds. The Edelbrocks eliminated the floatness of the standard shock. I'd expect similar results on the vet and I'd buy a set in a heartbeat. I replaced them with a set of Tokico 5-way adjustables and there was no comparison at all. I'd say buy them. I know they are expensive, but I believe they are worth the money for a daily driver.

 

I have been thinking about getting these myself. I was waiting to see if someone had good or bad experience with them :chevy

 

For the record:

High velocity bumps require exactly the same amount of damping as do low velocity bumps (compression). What happens in a typical shock is that the orifice that regulates the flow of oil from one side of the shock piston to the toher has a pressure transfer charateristic that increases resistance to flow as the pressure get higher. What the high performance motorcycle shocks do is to incorporate an oil valve that has the characteristic of of constant resistance to flow with increasing pressure. These shocks can use a washer that bends as the pressure increases to open up more of the orifice and maintin a flow proportional to the pressure difference accross the piston. In low velocity situations, this washer is unbent, and little oil flows. {In an alternate system instead of a bending washer (or stack of washers) a spring and (unbending) washer provide the constant resistance.

Since these shocks have constant resistance to bump velocity, the low speed damping can be decreased for better ride without sacrificing the high speed damping required to control body movements in the face of large bumps of smaller bumps at higher car velocities.

Rebound damping is not velocity (as) sensitive because its the spring thats pushing the tire back towards the road. The tire is constant in mass (minus some weight loss as it wears), and the spring is constant in force per compressed inch. So the rebound damping is less sensitive to velocity because the spring and tire are constants in this situation, wereas the compression situation is a tire reacting to a bump.

Non car related: all real motorcycles have used these shocks since the mid 1990's

 

Do they help control wheel hop on acceleration without sacrificing handling?

 

I sent an email to VettesRule, hopefully he can enlighten us :cheers:

 

Did I hear someone calling me???

Yes, I have the Edelbrock shocks on my 2001 Z06. And yes I am very happy with them. I put them on for increased handling in an autocross situation without killing me on the street. They do just that and they have a side benifit of looking very nice.

The inertia valve really works! It can distinguish either wheel or chassis movement. Over a bump or pothole the shock moves to softer circuit and in a corner it stays on the firm circuit and provides better handling. Bottom line, it is a smoother ride with no compromise in performance.

What I was looking for specifically was a decrease in rear compression loads in low frequency events (2-12 inches per second). I think the OE shocks are too stiff with an end result of snap oversteer and the Edelbrock shocks do that. Now I am not saying that for a full race setup these shocks are equivalent to say Penskes, but, for a car driven on the street and the track, they are excellent.

Now I don't know if you guys want to start a very technical conversation, so I'll just stop there.

Bottom line, Edelbrock shock are great shocks that deliver a good ride and excellent performance.

 

Vettesrule where did you get yours? I looked at Jegs and Summit and they both have the same price.

 

I heard the best price was through 4 wheel parts and wholesalers or Jegs.

I got mine direct from Edelbrock. I am a former employee.

 

Hmmm… I think most things have been touched upon in this very interesting thread (I love reading about all things to do with setup), but I’m not sure I agree with Mitch’s opening statement:

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High velocity bumps require exactly the same amount of damping as do low velocity bumps
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Most decent shock absorbers these days have two compression damping circuits; one for high speed, and one for low speed, just to cater for differing degrees of severity of bump. Really expensive shocks allow you to adjust high and low speed damping individually, for example, some of the motor cycle racing Penskes. How this manifests itself in the real world, is that if a car is cornered hard over a series of ‘stutter’ bumps, which has overly stiff high speed compression damping, then the car will just skip over the road surface as the wheel fails to follow the road as the suspension has effectively hydraulically locked. I tried all kinds of tricks to get rid of this on my stock vette but the only real solution was to fit a decent set of shock absorbers (Penske) which has now cured the problem (well at least raised the bar a lot).

Many performance bike shops offer replacement valves for front forks which work using the washer stack mechanism discussed above, (both bikes and vettes) but if you look at what the world superbike guys are running, all the teams have high and low speed circuits on their forks which are individually adjustable, and if it works for them… it works for me! Just for info. $5K should get you four entry-level Penske’s for a vette. $25K should get you a pair of factory Ohlins WSB forks – ahem…

 

Will the edelbrocks work well on alowered vehicle and are these the Performer IAS shocks?

If they are I saw them at ultraperformance.com for $319.96 with free shipping. :)

 

I still have a couple of questions:

1. Do they help control wheel hop?
2. Could I just put them on the rear wheels?

Thanks,

 

Guys,

The Edelbrock Performer IAS shocks look really good in the advertisements and the tech data, but in real world conditions, we found that they failed very easily under light load driving.

We used to carry them until they caused us nothing but problems.

Most of the sets we sold came back as defective.

We tested them on a vehicle and within 1 month and 3,000 miles after installing them, all four shocks went bad. They started leaking like crazy and had to be replaced.

We then replaced the Edelbrock Performer IAS shocks that were on the car with Bilstein shocks and 3 years later, the car has experienced no drop in performance and the shocks are still holding up as if they were still brand new.

The funny thing is they also costed more than the Bilstein shocks and we couldn't figure out why. They are no where near the quality of the Bilsteins.

Just thought I would give you an insight on these shocks that we tested out.

Shawn

 

louzon,

I forgot to mention that the Bilstein shocks for the C5 that are listed in the mall are sold by us.

We have them listed at: $299.95 SHIPPED FREE VIA FEDEX AIR SERVICE.

Mid-America will end up charging you an arm and a leg for ground service, so we still beat their price even at: $20.00 higher.

We also always keep them in stock so we can ship them the same day you place your order.

So far, the best bang for the buck award on shocks for the C5 goes to Bilstein for their sport version of the shock.

Shawn