Repair ACR shock ?

[Dan Cragin]

The Dynamic shocks are prone to leakage. I replace many shocks on the new models(Dynamic) and find the Gen 2 ACR shocks the worst for this problem. Changing to a better shock is the answer.

Dan Cragin
DC Performance Inc
310-841-6996

 

[2000_Black_RT10]

It's common knowledge in the racing world why dampers are rebuildable. i.e. a quote from a random site..

Untitled Document

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"All of these better race shocks can be rebuilt or revalved at factory-authorized facilities. Depending upon the brand of shock and work performed, rebuilding and revalving can cost $20 to $135. Rebuildable shocks can also be freshened to like-new condition at the end of the racing season or before a major event. "Shocks should be rebuilt at least every other year to keep them tip-top," says Guy Ankeny."
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Unfortunately race style dampers are used on a street car and the routine rebuild is neglected. In the world of F1, Indy etc.. dampers are rebuilt after each race. Quick rebuild is surely cheaper than buying a new set, but if it goes too long, more damage is done.

Out of curiousity, what brand are the Gen3 shocks you have for sale in your recent Post?

Best regards,
Mike

 

[Viper X]

My .02 cents,

The two way adjustable Dynamic shocks on my 01 ACR made about 11,000 miles before leaking and failing.

I've driven and tracked the car with two way adjustable Moton Race shocks now for about 20,000 miles without any issues.

It is likely that the Motons were more costly to begin with, but they are also clearly more robust than the Dynamics.

Dan

 

[kcobean]

Are there any other indicators besides leakage that a shock is failing or has failed?

I've developed a squeak in the rear suspension on my car and I'm unsure at this point if it's a bushing or something else.

 

[AZTVR]

Are there any other indicators besides leakage that a shock is failing or has failed?

Mine had a metallic noise from the rear of the car as if tapping one solid metal object against another. This occurred when driving over small, but abrupt changes in road surface such as manhole covers. I believe that it was caused by the worn upper seal which allowed the piston shaft to move perpendicularly to its normal motion and knock went it went from one side of the gap to the other.

 

[2000_Black_RT10]

My .02 cents,

The two way adjustable Dynamic shocks on my 01 ACR made about 11,000 miles before leaking and failing.

I've driven and tracked the car with two way adjustable Moton Race shocks now for about 20,000 miles without any issues.

It is likely that the Motons were more costly to begin with, but they are also clearly more robust than the Dynamics.

Dan

That's good news.

There's a variety of Dynamic Suspension dampers, DSSV stuff can be quite expensive and beyond, and one of the few that supply F1 / Indy etc. which the others do not. The test again is not about durability regarding leakage for race shocks for street driven application with that many miles & time, it's all about performance & weight in the racing world.. Rather than defending a moot point about leakage, it would be better to discuss performance on a race track which is dominated by companies such as Dynamic Suspensions.

The ACR damper was supplied approx 7 - 8 years ago, seals deteriorate over time regardless of usage. There are also better seals / durometers / compounds today.

If you need any support, I'm just hanging out here to offer it as a friendly gesture.. just let me know.

I guess an anology could be aircraft design.. I worked with guys who came from Boeing in the past, having an automotive background I was surprised and intrigued that they spend absolutely no time regarding crash testing.. and focus less on lengthy component durability in exchange for weight & performance when designing an aircraft.. it's all about performance and light weight, maintenance is a given with these parameters.

kcobean - a squeak would most likely be in the suspension and not in the damper, yet a squeak can come from a spring also, in such that when you compress a coil spring it twists like twisting a wet rag in your hands (one end relative to another along the center axis, the coil spring rotates within itself when being compressed comparing the upper and lower seats) and may cause a squeak on the spring seat. Try a couple drips of oil on the spring seat, the upper & lower seats and threads. It's similar to coil valve / rocker springs, while the valve spring compresses one spring face must rotate (otherwise causing a much higher fatigue rate), and you'll see high end racing engine applications use a bearing face on one end of the valve spring to minimize friction and increase performance / spring reaction time. It may be a control arm bushing too, just babbling a bit to help out..

Best regards,
Mike

 

[AZTVR]

just babbling a bit to help out.

Please babble whenever you want !!!
It's great to get experienced insight into the details of design issues involved with items many of us don't know too much about.

 

[kcobean]

Please babble whenever you want !!!
It's great to get experienced insight into the details of design issues involved with items many of us don't know too much about.

Absolutely! If anyone is qualified to "babble" about the DS shocks, it's Mike, so thanks Mike, I will try what you suggested and put a few drops of oil on the spring seat and see if that helps.

Kelly

 

[2000_Black_RT10]

It's a tough situation to defend, old ACR shocks to what is supplied today in comparison.. with a bit of research on-line, others will find who our customers are in comparision to the others today.. Thanks for the support, honestly, if any need support, just shoot me a PM and I'll help you out with any DS related products.

i.e.
2007 Newman/Haas/Lanigan Racing // Team: Carl Haas

Tested: 2008 Dodge Viper SRT10 Coupe and Convertible - Suspension and Performance - Car and Driver - September 2007

Just Google Multimatic or Dynamic Suspensions (same company) if interested.. there are too many on-line links / articles to Post here..

As a fellow Viper enthusiast, if you want a rebuild for your ACR dampers including a dyno report, I will take care of this myself personally at work, as a friendly gesture to save on higher cost otherwise / elsewhere.

 

[01ACR/VIPER]

I you need help since you notice a difference, let me know, you know where we're at and the shop rate, feel free to call again if needed.

I did ask about changing the rear springs, your drop to 800 lbs, the significant issue is the change in front to rear distribution, regarding vehicle dynamics, during dive, braking, etc. If you want the dampers retuned internally for the lighter springs and less harsh of a ride, it can be done. Rule of thumb is a change in 30% spring rate requires damper adjustment internally. It's not the wear & tear being an issue, it's changing the overall vehicle dynamics since the front and rear dampers are designed for that spring rate. Our facility sets up top race cars, so whether to take this advice as being extreme for street use is up to the Viper owner, but our damper expert just replied with a simple answer (regarding changing the springs only) - "I wouldn't do it".

Mike

I will have to get with you about getting the rear pair rebuilt.Jon at partsrack explained to me that the 1100lb was way to much spring for a car that does not have a wing on the back causing down force.without the added down force what would be the purpose of that high a spring rate?On everyday street driving,that rear suspension probably moves none at all with the 1100lb springs(at least it sure felt like there was no give)the 800lb springs seem a "little"softer,but not that noticable until you hit a bump.but at any rate,i will be getting with you Mike sometime after the holidays.what do you think is a time frame for the rebuild?

 

[2000_Black_RT10]

what do you think is a time frame for the rebuild?

That's cool, I'd just check stock on any misc parts / seals prior to you sending, if all looked ok, it'd be done within the week of receiving. They can be modified to suit the new springs and dyno tuned as a match set.
Mike

Here's another online doc with our dampers, neat to find this stuff so I can share it publicly.. see Suspension for the RB3.
RedBullRacing.com | Official Red Bull Racing F1 site | Coulthard . Webber . Doornbos

 

[01ACR/VIPER]

That's cool, I'd just check stock on any misc parts / seals prior to you sending, if all looked ok, it'd be done within the week of receiving. They can be modified to suit the new springs and dyno tuned as a match set.
Mike

Here's another online doc with our dampers, neat to find this stuff so I can share it publicly.. see Suspension for the RB3.
RedBullRacing.com | Official Red Bull Racing F1 site | Coulthard . Webber . Doornbos

sound good Mike. have a great holiday.

 

[blownrunner]

Found this post and I have an interesting discovery to all the Dynamic Suspension ACR owners. I got my 02 ACR in Oct 2015. I did a complete detail on it to include pulling the wheels and doing a disassembly on the suspension. I also got the 2002 service manual which states that the shocks must be kept clean. I noticed initially that there was a lot of stuck on dirt that I cleaned off and the shocks stopped leaking. They have been leak free for 9 months now, they don't even leak a little.