ACR OWNER ALERT LETS BAND TOGETHER

[Vipergtsbob]

As the owner of an ACR "rattler" with the defective rear shocks, and after several othe ACR owners have shared thier experiences with me, I have decided to sample the ACR community to determine if there is interest in making a mass appeal to Dodge and/or D/C to seek a replacement with the new ACR shock package that has been installed as OEM at CAAP since approximately May of 00. I believe many have experienced being told to accept the noise and vibration as "...it is a race car after all" When pressed the next level of response is to offer a replacement with standard GTS shocks and in a showing of "good faith" they will hand you your old "rattlers" so you can use them "on the track". I don't know how many of us routinely change our rear shocks every weekend (if you have this kind of time I am jealous!!) but this is not an acceptable remedy. All we want is the replacement with improved/remedied ACR shocks which will provide the level of performance befitting the extra $$ that we shelled out to get the ACR.
I am willing to author a strong letter on behalf of all of us affected by this problem. It clearly would be a stronger submission if we can get all of us to include our names, addresses and dealerships. It would also be prudent to seek the support of VCA National and VCA Regional Clubs in support of our cause. If you wish to participate in this effort, E mail me a [email protected] and comment and/or leave the requested information. I will post the actual letter we will submit after getting a sense of the interest in doing so. If I do not get a suffucient showing of interest I will likewise post this result
Strength in numbers....
Thanks,
Bob Carroll
NJVCA

 

[Jeff-00-ACR]

Wish I could help, but my ACR shocks do not rattle.

Jeff

 

[Fred(DrivingSchool)Kinder]

I have a 99 ACR and I do not have any problem with the shock rattle. To me the 5 point seat belt fasteners make more noise neither of which is a problem. Squeaky brakes, NRG, Shock rattle, etc. The Viper is among the fastest street cars in the world and close to being a road race car. The ACR comes a more race specific suspension components, which has a stiffer ride. I do not feel the performance related sound complaints are valid. Why do owners put on cat back exhaust, that can be a noisy modification. I can not relate to these complaints. Sorry just my feelings and $.02.

 

[ACR Joe]

Bob:

I'm with you 100%! The ACR shock rattle is driving me totally nuts and I've heard all the same stuff as you. GTS shocks are totally unacceptable; replacement of only the rear shocks may be as well.

Jeff - Glad to hear your shocks don't rattle.

Fred - Your rationale is representative of your personal opinion which I happen to vehemently disagree with.

My car rattles like a bucket o' bolts and I find the noise to be distracting and annoying. It belies the many quality attributes of this otherwise fine car. The "race car with license plates" approach just won't sell here.

With that said, I am willing to support this initiative in any way possible. I was close to trading my car in for an 01 ACR this week to remedy the situation but couldn't make the finances work. It's troubling to think that I would need to trade a 1.5 year old car to eliminate this annoyance. Dodge knows perfectly well what the problem is and should act reasonably and responsibly and take assertive corrective action without further delay. I have fooled around with this issue since September 1999 and have made virtually no progress. The Dealership has acted nonchalantly which hasn't helped.

I am sure you will receive many posts in support of banding together to resolve this matter.

This is an ACR shock rattle issue, not a viper issue as evidenced by my attempt to transition to an 01 ACR.

Love the car ---- hate the rattle.

 

[Jeff-00-ACR]

Actually I do have one complaint. The little button on my parking brake rattles/buzzes at certain RPM. I can put my thumb on it and it stops. I think I might be able to just put an o ring around it or something to stop it.

Anyone else notice this and have a fix for it?

Thanks
Jeff

 

[John ACR]

Bob and other ACR owners,
Count me in for one.
I am presently making an attempt via a different Dodge dealer and Viper Tech instead of where I bought my car to get a esolution. The "We will replace ONLY the rears" is NOT acceptable. In my book that is like wearing a nike on one foot and a converse on the other. Have any other owners had either the rears or all 4 replaced? Please post your experiences.
Thanks.

 

[JonB]

Rattle Revisited: (You bought a "Rattle Snake")

Philosophy aside, here is what you can do CHEAPLY to mitigate shock noise and save your sanity:

Realise that TWO complaints may be involved. Personally, I have never heard the "valve operation" noise. Just the spring rattle. Models affected: 1999 ACR, '00 Production thru approximately June 00 of '00 ACRs.

2) The stiffer, shorter ACR springs do NOT unload the full length of the shock tube. So this primary rattle complaint can be solved in two ways: Small Soft Rubber bumber inserts top/bottom of the springs. I believe Dan Cragin has solved quite a few this way. The rubber is NOT a factor in compression. It acts as a noise damper only.

3) In addition (or instead of) you could do what many race car drivers do: Zip-tie the springs at 3 points in the UP position.

Those that demand a retro-fit and are successful, MAY affect the OE 'collectibility' down the road....so save the OEM equip!

HEY: A Viper is SUPPOSED to be a "Rattler" ain't it? ANOTHER ACR option to brag about !!!

 

[GTS Dean]

Just some objective thoughts for you guys to consider.....

(I edited this message after a couple of hours because my damping logic was backwards the first time.)

If I remember correctly, the OEM mounting bolts have a larger diameter under the hex end than at the threaded end. The upper shock mount ears on the frame have holes that are slightly larger than the 1/2" dia. bolts that fit thru the upper shock rod ends, or at least that's the case on my Penskes. When I first installed them, I used airframe bolts which did rattle a little bit. So, I tightened them up some more with weight on the suspension (not easy if the tires are on) and the rattling was GONE.

The new ACR shocks are supplied by Dynamic Suspension, largely because they are a bigtime supplier in Europe and currently provide the dampers for Oreca's Vipers. Obviously, there is a lot of engineering data available to Chrysler from Oreca on the new shocks, just like there was when Koni supplied dampers for the GTS-Rs.

I really can't imagine the spring/retainer rattle being possible except under extreme unloading of the suspension (read: catching air). Every corner of the car has between 750# and 1000# of weight on it and the springs simply have no way to rattle. The Dynamic units have 1100#/inch rear springs, whereas the Konis have something like 600#/in springs. Perhaps when the rebound is set near the low end of the adjustment range, the springs overpower the rebound valving inside, which normally helps keep the springs firmly against the perches under all situations. This would make them act like the spring on a pogo stick. You could try notching up on the rebound a click at a time to see if it helps.

 

[Fred(DrivingSchool)Kinder]

I drove my 99 ACR to VOI 5 in Las Vegas from the S.F. Bay Area and the shock noise was not noticeable at freeway speeds. My ACR is lowered a little perhaps that is why I am not sensitive to excessive noise from the suspension, just a thought. American Club Racer (ACR) why did we but this car? Perhaps some ACR owners would be happier if they purchased a Viper GTS. I for one do not encourage people to buy an ACR unless they want to have the ability to tune the suspension for track events. I think is is pretty nice that Dodge offers to change to the stock shocks and allow the ACR owners to hang the KONI shocks on their garage wall. As technology improves so will these performance items that is normal evolution. Intel comes out with faster chip that has better cooling less fan noise do they upgrade the old cpu's fan under warranty?

My 96RT10 has no exterior door handles, canvas for side curtains and plenty of wind sound and I love it. I buy Vipers because of their high performance, that keeps a grin on my face as well as those who see the car. It is fun to drive on short and long trips. My Viper ownership has introduced me to the VCA which has allowed me to meet many wonderful people from all over the world. I have never been to an event track, VCA social or VOI where anyone has complained about the ACR suspension noise or brake noise.

Most High performance brakes can be noisy when cold, the brakes on my 2001 S500 are a little noisy but it is harder to hear because of the heavy insulation. But is stops on a dime. It seems to me that recently there are more complaints about sounds and less appreciation for the net performance that is provided by the Viper. In my opinion the Viper is not for everyone and some owners may want to sell their cars and buy something that has better insulation and fewer performance enhancements that come with sounds of performance.

The 2003 Viper has most of the changes that we owners have requested Team Viper to provide. To see all the complaints is pretty interesting. Team Viper gives us what we want and people complain! What is wrong with this picture. Where were the complainers when Team Viper asked what you wanted in the next Gen? Or were those who complain to busy to offer suggestions for the next generation. I wanted Bigger Brakes, Better Brakes, ABS, more HP, what do you want! I want the Viper to continue to be King of the Hill! And I for one do not care if there is a bit of NGR, brake noise, etc. as long as the other high performance rides from Europe, Japan, or GM are in my rear view mirror!

Perhaps the reduced Winter Sun light is making people more negative.

Team Viper should be congratulated for making the best sports car in the world, winning Le Mans, FIA, ALMS, Rolex 24 hour at Daytona and on the streets and at local track events! And at the same time giving life to the VCA! We came together for the love of the car and end up loving the relationships from the VCA!

VIVA La Viper!

 

[Tenney]

Jeez, put down the D-C Kool-Aid, D. School! Seems most of these owners like their ACRs. They just wish the shocks didn't rattle. Fact is, as **** and track-worthy as they may be - current ACRs seem to be rattle-free. A factory supported swap of these items doesn't seem to be out of line on an 80+K car, IMO.

BTW - Haven't heard one complaint regarding the specs of the Gen III. Good job, Dodge! On the other hand, not too many people are doing back-flips over the styling. Personally, even though it lacks some of the drama of the original, I like the new design and imagine I'll like it even better in coupe-form. Regardless, those that don't care for the new shape (seems like the majority) should definitely make their feelings known. While it may not be the response Dodge was pulling for, it should be deemed valuable information from their existing customer base, IMO.

 

[Bob Woodhouse]

Shock Rattle: hmm, before we demand all new shocks, (which if it sounds unjustified your fate has already been decided) lets identify the actual noise. I have read through the posts but it still eludes us I think. The shock itself and internal components do not appear to be involved. Do remember, these pieces run approximately $1800 each, not the kind of part to toss on the garage wall to feed one's frustrations. The noise is as pointed out, likely to be in the spring, the perches, or the heim/type ends. All reasonably easy corrections. Anyone out there with some touch and feel experience to contribute?

 

[John Moore]

I just recently had built and installed some Koni 3012 racing shocks and in the process discovered many easy to over look fitment challenges. One of which is the bolt sizing, the shock-eye inside diameter, the hole diameters in the shock support ears, and finally the odd shape of the OEM bolts as they are larger on each end and narrower in the middle of the bolt. After having taken this arrangement apart and put it back together a dozen times I have found all kinds of potential rattlers. The noisiest source of the rattles I've found were from the upper rear shock mount area. As Jon B pointed out in an earlier post this is the one mounting point in the interior "sound envelope". When working on this mount I found:
1) The shockeye bearing can rattle on the bolt
2) The spacers and bearing can rattle between the support
ears
3) The bolt can rattle in the holes of the support ears
4) The spring can rattle against the spring perch
5) The spring perch itself can rattle against the bottom of
the shockeye
On my set up the actual source of the noise was the bolt rattling in the holes of the support ears. It was cured by making sure the bolt was properly torqued while the suspension was loaded like Dean Word described. Now I only occasionally get a single rattle if I pass over some particularly rough roads. I guess that'd be a "rat"

You must be registered for see images

 

[ACR Joe]

Thanks to everyone that took the time to post a reply and offer suggestions and/or opinions. It's obvious that many of us are deeply passionate about this issue, as we are about most every aspect of our Vipers.

The above posts offer a number of possible solutions; just one of which will hopefully be the key to resolving this issue. For the record, I am totally and objectively committed to finding the cure. At this point, I believe it may be prudent to roll the shirt sleeves up and have a look for myself.

I believe most ACRers are not interested in either the mix n' match or the stock GTS replacement alternatives. The former is disconcerting; the latter is plain silly. As DC's response has failed to produce a timely and acceptable solution, let's pool our collective knowledge and resources and determine appropriate corrective action procedures. I'm still on board with the "pursue DC as a group for a technical solution" scenario, but cannot sit on the sidelines any longer.

Those of you interested in more direct communication, please send an e-mail so we can form a group to facilitate a more effective exchange of technical information during the R&D stage; of course final results will be posted on the board. Per John B's suggestion, we can call ourselves "Rattle Snakes". I intend to initiate some "physical" efforts this afternoon so (much) more to follow shortly.

Stay tuned and thanks again for all of your responses!

 

[ACR Joe]

OK ...... I lied; well sort of. I really had intended to dedicate some time and effort this afternoon to this "Rattle Snake" business. So guess what? The weather here in Philadelphia is just spectacular; mid 40's, sunny, dry; just a "feels great to be alive" kinda day.

Well, I took one look at my Viper sitting there idle and thought "I'm outta here". Wow, what a wonderful, fabulous, thrilling car to own. I feel very blessed and fortunate that I can actually call this car mine.

As far as my investigative efforts are concerned ...... Domani! I'm sure you understand.

Caio ....

 

[Vipergtsbob]

I wish to extend my sincere appreciation for all the respone to my venting on the ACR rattle issue. The technical advice has been fantastic. Be assured I intend on following through on my offer to author our collective complaint letter. I intend on including everyones name who has (and will??) E mailed me at [email protected]. BTW I wish to make a couple of background comments:
1. No one loves their Viper more than me!!
2. No one respects Team Viper for their fantastic product and their guts it getting it to us.
3.Never before has an American car company supported a small group of its customers with such zeal and sincerity that we all feel a part of "team viper" in a small way.
4. I am neiteher a whiner nor opportunist who is seeking to get the latest technological improvement by asserting a defect in a prior iteration of a product!!
5.I have a great relationship with my dealer and know he is trying to help (Warnock Ryan Dodge, East Hanover, N.J.)

My motivation for my rant in the seminal post on this topic related only to my frustration in trying to get a solution to what is clearly a defect in a production item which has already been remedied by Dodge!! This is not a dealer issue but clearly a manufacturer issue.
I only hope that Someone in Dodge has seen the number of passionate posts on this topic and maybe that will stimulate some internal discussion to enable an acceptable remedy.
For my part I will get my letter done and submit same. I will also copy the VCA with the hope that they can assist in getting our issue to the right "desk".
In any event My sincere thanks for all the great info. I intend on giving copies of these posts to my viper tech.
Thanks again.
Bob Carroll

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[ACR Joe]

The shocks on my ACR rattle regardless of the firmness settings. It's most noticeable at speeds below 40 mph when driving over even the slightest road imperfection. The dealer claimed to have tried a different spring setting but said that that only worsened the problem.

I am certain that the problem does not relate to the suspension unloading to the point that the spring disengages from the perch. You'd need to catch some pretty big air for that to happen; it just isn't so.

If DC is actually reading these posts, I sincerely hope that they realize that a considerable number of Viper Disciples are less than satisfied with their response to date, and that they decide to take assertive corrective action. It bears repeating that neither replacement with stock GTS units nor the mix n' match scenarios are acceptable.

 

[JonB]

1) I can assure you that SVE-Team Viper is aware of the complaint and our grass-roots attempts to fix, and even THIS particular thread!

2) I agree 100% do NOT accept a mix/match shock fix! Although safe, it is like making Carl Lewis run in combat boots, just to stop his squeeky running shoes.........

Rattle Snakes Rule ! {American Club Rattler! )

 

[ACR Joe]

As promised, I removed and disassembled the right side shock/spring assembly. While I haven't arrived at any final conclusions just yet, my best guess at this time is that the upper shock mounting bolt may be at fault. Again, this is very preliminary.

To further advance this initiative, I need help in two areas:

1) Does anyone have a supplement to either the owner's manual or service manual covering the ACR? There are no ACR references in the literature I have.

2) The lower shock mount is a "U" shaped yolk that is a asymmetrical. I failed to record its orientation when I removed it. Does the curved side of the yolk face the front or the rear of the car. I suppose I could inspect the left side and orient the assembly accordingly.

More to follow.

Sincerely ...... Determined!

 

[GTS Dean]

Joe,

Can you check the diameter of the frame ear holes? I think you will find that they are about 9/16" dia. Also, measure the ID of the spherical rod ends - probably going to be 1/2". That means that the 1/2" dia. bolt that has to go thru the top shock eye bearing will have a 1/16" clearance.

Check out http://www.koni.com/800/racing/2812dia.html

Notice the factory specifies a 7/16" diameter thru bolt size in the bearings. This will lead to a full 1/8" of slop in the holes unless Dodge specifically addressed this issue with special machining.

The standard Viper shocks have a tube with knurled ends thru the center of the rubber bushing that bites the inside of the frame ears. When you torque the bolt, this 1/16" tolerance is insignificant because the bolt mainly provides clamping force and the tube tranfers the load to the frame, with sound damped by the rubber bushing.

The conical aluminum spacers on the ACR shocks may have slick sides (no knurling) which, when combined with the bolt/hole diameter mismatch and insufficient clamping force, give you the bolt rattle nearest your ears. Take a look at the inside of the frame ears and the mating surface of the spacers to see if there is any fretting between the two metals from relative motion.

Pictures later....

 

[ACR Joe]

Can't ID obvious fretting on any of the upper shock mount mating surfaces. I inspected every component very carefully expecting to find some definitive evidence but no such luck. However, I am more confident than ever that the problem lies in the upper shock mount.

A few possibilities:

1) The conical bushing that sits on the threads of the mounting bolt may be the problem. The bolt should have been designed with an extended and stepped shoulder to provide higher and closer tolerance contact surface area while accepting the two different bushings ID's. Better yet, the bushings should both be the same ID with the shoulder simply extended so that neither rests on the threads of the mounting bolt. It is clearly a looser fit vis-a-vis the bushing that sits on the shoulder of the mounting bolt. One answer, therefore, may be have new mounting bolts and possibly bushings fabricated.

2) The fit between the upper shock mounting bolt and the eye bearing on the shock could be a bit tighter (.0005 perhaps). Here again, a custom bolt may be the answer.

I am trying to design a temporary fix to allow me to confirm that I'm on the right track. If I can can confirm, it's off to the machine shop with drawings in hand.

Anyone know where I can obtain cooper shim stock - range .002 to .0005?