Suspension Upgrade questions for a Gen 2 ACR with Koni s

[Hssssss]

I have a Gen 2 ACR with Koni coilovers that are leaking. I've called Koni and for about $225 each, I can get them rebuilt but I am told Koni's were designed to be rebuilt every couple years which isn't going to happen with me. I'm not looking to spend 4-5k on new coilovers but something under 2k. Does anyone have any thoughts regarding Aldan American coilovers? If not, any other recommendations?

[99RT10]

I would get the Konis rebuilt, and store them. BC Coilovers seem to be what most are using.

[Martyb]

Just order the BC’s for my 98 GTS, paid $1150 shipped to my door. Installation later this week, can’t wait.

[str5010]

I do not recommend the Aldans. We had issues with them at our shop with both quality and fitment. I couldn't confirm in speaking with them directly that they had ever actually fit them to a Viper. It seemed more as though they determined through analysis that one of their existing applications would work.

[MH60M]

I do not recommend the Aldans. We had issues with them at our shop with both quality and fitment. I couldn't confirm in speaking with them directly that they had ever actually fit them to a Viper. It seemed more as though they determined through analysis that one of their existing applications would work.

Very helpful! Thanks!

[JonB ~ PartsRack]

I do not recommend the Aldans. We had issues with them at our shop with both quality and fitment. I couldn't confirm in speaking with them directly that they had ever actually fit them to a Viper. It seemed more as though they determined through analysis that one of their existing applications would work.

I have to dispute / question that for accuracy. PartsRack has done perhaps 100+ sets of Eagles

Aldans main engineer has been there for a least 17 years. The newer ownership (7 years) has done numerous Viper applications for us over 17 years. They can provide custom shock body lengths, spring choices, even show-options of polished shock bodies and-or chrome springs. Its a Menu of Viper options.

Also: The asian-made products are steel bodies..... chinese steel.

Aldan Eagles are ALUMINUM. Better for several obvious reasons, weight and no-rust to start.

Aldans Made In USA.

Aldans LIFETIME warrantee to original buyer..... if you have an issue, park the car, send to CALIF for fix or replace.


NOT THAT THEY HAVE NOT HAD A FEW SRT-10 ISSUES EARLY ON ... they did. But they care, are very responsive, and dont have warrantee disputes. Rare Issues got fixed fast

All That said, if you can get the KONIS rebuilt of $825, that is a good deal. Semi-annual rebuilds required in racing / heavy-duty use only.

[str5010]

That's interesting Jon as that wasn't our experience just a few months ago. The engineer I spoke with definitely was not there from the beginning and couldn't answer basic questions on required coil spring free length for the application, though he was very friendly. The previous shop had clearly run into an issue with the units because they attempted to install a shim pack in order to make up the difference. This was not the way to rectify the problem and didn't work. When a new set of Aldans was purchased by the customer, one of the two units leaked from the adjuster knob.

We don't have the experience of hundreds of sets from this company, but that doesn't make this single experience inaccurate or untrue.

[JonB ~ PartsRack]

I believe you ! A rare mistake can occur anywhere, including shock valves or heart valves. That shim-pack story is sad.....the free lengths are different on the different Gens of course.... I do spell out my individual orders, whereas orders placed with big wholesalers like Summit dont. [And Many owners dont-know-what-they-got.]

At least the things get fixed fast n free....

[Coloviper]

Not that I have a dog in the hunt but the MCS Stage 1 Coil Overs I put on my 96' RT/10 have been without a doubt the best system I have ever had on a Viper, any year. They cost a bit more but have been very happy with them. Have had them on for about 5 years now and zero issues. Just in case you wanted another opinion.

[dave6666]

I'll always take parts that don't break as a preference over parts that get fixed for free when they do. You never recover the time and inconvenience of sending junky parts back.

[mjorgensen]

Not that I have a dog in the hunt but the MCS Stage 1 Coil Overs I put on my 96' RT/10 have been without a doubt the best system I have ever had on a Viper, any year. They cost a bit more but have been very happy with them. Have had them on for about 5 years now and zero issues. Just in case you wanted another opinion.

I of course second this, I sold 90+ sets of the MCS single when they were announced and they have been a huge hit for the street guys that occasionally take their car to the track. Another benefit of buying the MCS is if you ever wanted to sell them or sell the car without them they have a MUCH better resale value so in the end do not cost any more than cheap shocks in our experience.

[Boosted Motorsports]

Just get the BC Racing Coilovers. I removed my leaking/blown Koni coilovers from my 2000 ACR and someone was willing to buy them (in a known blown condition) for $1500 on ebay. Paid for my BC Racing and then some. 3 years later still happy with the BC racing after multiple track events and street driving.

[Bluesnake]

Ive had my KW's on my car for over ten years and 30K + miles. Not a single problem. I have ridden in cars with both BC and the MCS. Both of them seem that that rebound is not as adjustable as the KW's as the ride was bouncy. Both owners that rode in my car commented about the ride difference. Even on the road course you could see the valving difference on turn in and powering out of the corners.

I know about the cost difference but I thought I would add my 3 cents.

[Dan Cragin]

I have had really good luck with the MCS system. They work great on the track and the street. I found they are a excellent ACR replacement shock.

I have found other systems like BC and Aldan not suitable for street and track. KW is a good product, but developed in Europe where tracks are smoother, spring rates are a bit harsh. Product support can be time consuming.

MCS dampers do a great job of masking heavier springs, making them feel quite a bit softer than they actually are. This is a direct result of having a proper force curve and forces to effectively control the spring. The benefit is that you can spring the car quite a bit heavier to reduce pitch and roll movements while still retaining the pliability one would seek for road use.

Standard valving for these damper's accommodates a wide range of spring control, so a wide range of spring rates can be used without re-valving. Remote systems
Nitrogen can be adjusted as well, with a 8lb increase in spring force per 10psi change.

Contrary to what many think, these shocks are made and assembled in the USA, with select parts made in Europe. The product support is really great also, a shock repair or setup problem can be resolved right away.

This has been my experience, yours may differ.

[MH60M]

That's interesting Jon as that wasn't our experience just a few months ago. The engineer I spoke with definitely was not there from the beginning and couldn't answer basic questions on required coil spring free length for the application, though he was very friendly. The previous shop had clearly run into an issue with the units because they attempted to install a shim pack in order to make up the difference. This was not the way to rectify the problem and didn't work. When a new set of Aldans was purchased by the customer, one of the two units leaked from the adjuster knob.

We don't have the experience of hundreds of sets from this company, but that doesn't make this single experience inaccurate or untrue.

This isn't an isolated incident either......I've done lots of internet sleuthing on 3 different Viper forums and the Aldan's have Leaked/Blown & had bouncy/rough ride for 10 years. I'm all about "American Made", but maybe they just don't work well on Vipers. Jeg's/Summit has tons of great reviews from other platforms.

[nrs1]

I have had really good luck with the MCS system. They work great on the track and the street. I found they are a excellent ACR replacement shock.

I have found other systems like BC and Aldan not suitable for street and track. KW is a good product, but developed in Europe where tracks are smoother, spring rates are a bit harsh. Product support can be time consuming.

MCS dampers do a great job of masking heavier springs, making them feel quite a bit softer than they actually are. This is a direct result of having a proper force curve and forces to effectively control the spring. The benefit is that you can spring the car quite a bit heavier to reduce pitch and roll movements while still retaining the pliability one would seek for road use.

Standard valving for these damper's accommodates a wide range of spring control, so a wide range of spring rates can be used without re-valving. Remote systems
Nitrogen can be adjusted as well, with a 8lb increase in spring force per 10psi change.

Contrary to what many think, these shocks are made and assembled in the USA, with select parts made in Europe. The product support is really great also, a shock repair or setup problem can be resolved right away.

This has been my experience, yours may differ.

I bought the MCS system from Dan and they are fantastic. Everything about the experience with Dan was great. He took care of everything and did the investigation to come up with the right spring rates and settings for my application. May cost a bit more, but you won't have any regrets on the performance, quality and aesthetics of this system.
Neil

[71firebird400]

Spring Rates of various OE and aftermarket coilovers;

Gen 2 GTS/RT10
225 lb/in front
450-500 lb/in rear

Gen 2 ACR 1999 (Koni)
400 lb/in front
700 lb/in rear

Gen 2 ACR 2000-2002 (Dynamic)
500 lb/in front
1100 lb/in rear

BC Racing BR
559 lb/in front
671 lb/in rear

KW V2
515 lb/in front
685 lb/in rear

MCS Coilvers (custom springs, but these are the recommendations as quoted to me by them)
500 lb/in front
800 lb/in rear

[GTS Dean]

My EMI Penskes are set up with 600/800 split.

[Dan Cragin]

One thing I would like to add, as looking at the spring rates can be very confusing. A 250lb spring on one shock can effectively be like a 600lb spring on another shock. Shock valving, gas pressure, spring length, preload and dual rate springs all determine how the shock controls the spring.

[GTS Dean]

Very true, Dan. The valving in the shock has a lot to do with "ideal" spring rate values. They should be considered together.

[Hssssss]

Everyone, thanks for all the Comments and help. I’ve decided to go with the Aldan’s for my 99 Gen 2 ACR. I ordered them from Jon B and will install as soon as my viper mechanic can fit me in his schedule. I will update this post with a review once they are installed and I can hit the Detroit roads again.

[Gavm360]

Very interested in your Aldan Eagle feedback, Jon B's feedback is what swayed me ; Made in USA and Aluminum makes sense ; also was able to speak directly to owner (Garret) about issues in past etc and really enjoyed the access to the ownership as I'm in the manufacturing business myself.

I installed them (lowered coilovers) on my 01 GTS last year and loved the stance but ride was very bouncy ; shocks came with knobs in different positions out of the box ; set them all to the same but ride still poor. To be fair installed them at same time as new 19" wheels and tires but still it was not handling good especially at speed on highway ; Garrett has been responsive and helpful and I will be following his instructions on raising spring preload and reporting back ; at very least they do not come "out of the box ready" ; I will follow back with my adjustment success ; If I can't get it to work I will be going BC

[GTS Dean]

If you lowered the car to any serious extent, then your bump steer curves are guaranteed to be far from ideal and lead to unpredictable ride/steering. 19's have shorter sidewalls than 18" or 17" tires and will generally be much more sensitive to road imperfections. Couple this with bad bump steer curves and untried shock absorbers, you are in for some surprises.

[71firebird400]

Dean, recognizing that the way to adjust for bump steer is by shimming the steering rack or moving the inboard toe links at the rear, how do you go about measuring it? I don't see any mention of it in the FSM. Just trying to wrap my head around a feasible way to ensure that it's set properly.

[Mr. Acoustics]

Dean, recognizing that the way to adjust for bump steer is by shimming the steering rack or moving the inboard toe links at the rear, how do you go about measuring it? I don't see any mention of it in the FSM. Just trying to wrap my head around a feasible way to ensure that it's set properly.

You need a bump steer gauge or similar.
http://www.longacreracing.com/produc...ate-(No-Holes)

Here is one of their basic articles on how to do it with there unit, same principle with other brands:
http://www.longacreracing.com/instru...ge%20-%2079000

Bump steer is probably the biggest pain to measure and adjust of all the suspension adjustments, but at least with the viper it is adjustable. You are correct that you shim the rack and slide the rear toe links up or down. This will help with any darty-ness or strange steering that happens during acceleration, braking, or any real suspension movement. It won't really help with ride quality or bounciness that some have described earlier in the thread, but it still is a very important setting to look at when lowering the car.