There's more to the 2009 Dodge Challenger than a retro body and a 5.7-liter Hemi V8. It's got a modern suspension inside those full-figured wheelwells, and there are a couple of surprises.
Here we can see coil-over suspension (white), a high-mount upper control arm (green) and a forward-mounted steering rack (black). Other than the fact that it's all steel, it's the same basic layout and the 370Z and the Infiniti FX50. But the Challenger has something extra that those two don't have.
Down below, the front suspension has a dual pivot arrangement (yellow) like we've seen before. But our Challenger is the first car we've looked at in the Walkaround series that pairs this design with the high-mount upper control arm. It's a desireable combination: The high-mount upper arm provides a better camber curve than a strut, and the dual pivot arrangement and it's zero scrub radius makes for more stable and kickback-resistant steering in bumpy corners.
The Challenger R/T has two-piston sliding front brake calipers (orange) and ventilated brake rotors.
The stabilizer bar (white) connects to the coil-over shock unit in such a way that makes it appear as a direct-acting mount with a 1:1 motion ratio (yellow). But that's not the case because the coil-over in turn attaches to the lower link (green) at a point inboard of the ball joint. As a result the spring, damper and stabilizer bar share the same motion ratio of approximately 0.72:1 or so.
Modern catalytic converters (white) are mounted as close as possible to the exhaust headers so they "light-off" quickly to reduce emissions as quickly as possible after a cold engine start. Here that puts them close to the stabilizer bar bushings, which are made of rubber. A heat shield (yellow) surrounds and protects each one.
One of the advantages of forward-mounted steering racks (those mounted ahead of the front wheels instead of behind them) is that their relative distance away from the driver allows the pinion to be reclined to point more-or-less directly at the driver, thereby producing small universal joint angles in the steering shaft. Smaller U-joint angles allow for smoother and more direct steering feel.
As we've come to expect, the upper arm geometery includes a healthy dose of anti-dive.
Moving to the rear, we see the Challenger has a straightforward 5-link multilink independent suspension. The two upper links (yellow) sit more-or-less above the two lower ones (green). As we've seen before, one of the the lower links is spread wide to carry the spring. The fifth link (black) is a toe-control link. The rear stabilizer bar (white) loops in from the top to keep clear of the upper links.
The rear brake rotors are ventilated, and the calipers are single-piston sliders.
Even though it doesn't seem like much at first glance, this is probably the most unexpected and interesting aspects of the our Challenger R/T's suspension. And the only reason our Challenger R/T has it is because it has the 6-speed manual transmission.
Let me explain.
Those humungous shock absorbers are not ordinary shocks. In fact they are self-levelling units called Nivomats by the company that makes them, Sachs. These are typically found at the back end of minivans, wagons and SUVs -- vehicles that see a lot of rear axle load when all the people pile in or when a trailer is latched on.
Nivomats a very high pressure monotube dampers, but they also function as adjustable rate springs that have internal ports that vary the amount of support they give based on how far the suspension is compressed. If you add load and compress the suspension, the motions associated with driving "pump" them up using pressure stored in an internal accumulator. Unloading the trunk of a car with "pumped" Nivomats will result in an overly-raised "ass-up" attitude, but that simply exposes a second internal port that drains fluid back into the accumulator until equilibrium is restored.
Sound complicated? It is. All you have to know is that Nivomat load leveling shocks are self contained, with no compressor or external connections of any kind.
In a typical Nivomat installation, only 65 to 75% of the rear spring duties are carried out by the actual coil springs (yellow); the remainder is carried-out by the Nivomat unit (red) itself. What that means is that you can't simply toss-on any aftermarket shock in an attempt to tune your suspension because this Nivomat is an essential part of the spring force that supports the rear of the car. It has to stay here at all costs unless you put on new springs that can go it alone without Nivomats.
All of this begs the question: What is a pair of load-levelling shocks doing on the back of a 2009 Dodge Challenger R/T? And why do they only appear on the manaul transmission version?
I had to talk with Dodge engineers to figure that one out, because I'd never seen them used this way before. Turns out that Nivomats are very good at combatting axle hop during hard drag-style launches. They help put the power down when you drop the clutch. They're not necessary on automatic-equipped R/Ts because torque delivery is muted through a slushbox -- they don't launch as violently as a manual.
So that's a second reason why you want to leave these babies alone if you throw aftermarket "upgrade" parts at your suspension. And when it's time for new shocks on an unmodified car, you'll need to buy new Nivomats.
There is a bit of aluminum (orange) in the rear suspension, and it's found in the form af an aluminum rear hub carrier (aka knuckle).
The toe link (geen) has an eccentric for adjustment on its inner end, back under the car where we can't see it here. And the stabilizer bar attaches directly to the knuckle via a long slender link (yellow) that gives it a 1:1 motion ratio.
The Challenger has a lot more suspension going for it then you might think, on paper at least. But our R/T doesn't exactly inspire everyone in the office with its legendary handling. Steady? Yep. Secure? You bet. Predictable? Of course. But the killer instinct isn't quite there. There's probably a few reasons for that.
First, the Challenger isn't exactly svelte. This one weighs over 4,050 lbs. It's a sizeable car.
And I have to think the tires are playing a huge role, too. It's not that they weigh 54.5 lbs apiece when mounted on their 18 x 7.5" wheels -- those numbers aren't terribly problematic.
The problem stems instead from the tires themselves, a mid-line Michelin HX MXM4. Their 235 mm width isn't terribly inspiring for a 2-ton car, either.
And whenever you see "green" on a tire, you can bet that high performance wasn't at the top of the development priority list. Between the narrow width and the low rolling resistance design, it seems likely that Dodge was trying to make sure they got the best fuel economy rating they could from the R/T to make sure they didn't run afoul of CAFE regulations.
And don't forget that the R/T isn't the model Dodge is marketing as the high-performance model. They probably want to maintain a meaningful performance gap between this and the SRT8.
I figure that a set of focused high-perforamnce tires might make a bigger-than-usual difference on this car. And if I can talk Scott into it, we might just test my theory ourselves.
Dan Edmunds, Director of Vehicle Testing @ 4,695 miles
chavis10 says:
06:23 AM, 05/16/09
Good write-up. I believe the CTS uses Nivomat shocks in the rear (or at least the first generation car). Did this chassis have aluminum intensive pieces when installed in the previous E class?
drinkduff77 says:
06:45 AM, 05/16/09
Thanks again for another excellent suspension walk around.
Is it just me or doesn't that seem like A LOT of rust on some parts for a car with less than 5000 miles. Especially in pic #3.
chuckg says:
07:12 AM, 05/16/09
Two or three guys that I know of have reported a clicking sound under the front suspension on the passenger side of their Challengers when going over bumps. I'm sure these cars had under 10,000 miles on them. One of the cars was an SRT8 and I don't remember what the other cars were.
The fix was to soak the passenger side sway bar bushing with WD-40 (that's all they had around) which eliminated the noise until they could get it repaired. One person reported the bushing was cracked.
Sway bar bushings on Chrysler products is one of the major causes of "thumps" in their front suspensions. My wife's '05 Grand Caravan had thumping noises under the front suspension of her vehicle. We got the van up on a lift and started pulling on parts. There was a clicking noise coming from the tie rod ends and we replaced both of them (Clicking noises on suspension parts usually translates into a "thump" when driving over bumps). Noise was much improved but still there. We then replaced the sway bar bushings and the "thumps" were completely gone. The van now drives like a new vehicle.
Nice job on the write up. It looks like you did this out in your driveway?
badblackrt says:
08:02 AM, 05/16/09
Wow! As an R/T owner I really appreciate that review. That is the kinda stuff people want to know about cars. Giving an understanding of how things are designed.
This kind of data is not easily had by the average car owner.
Thank you
mopar424 says:
10:33 AM, 05/16/09
Yes, tires definitly, and I might even support some aftermarket rims (lighter, but must still look cool), as the std 18s are a bit on the boring side.. Great walkaround- im glad to see that Chryslers engineers are still on top of things.
cwc1 says:
12:03 PM, 05/16/09
It doesn't take long at all for surface rust to form on a car's undercarriage, once it's exposed to the weather - probably started happening en-route from the factory to the dealer, and then while it was sitting on the lot.
Doesn't the design of this suspension go back to Mercedes' last generation E-class?
clay92 says:
01:38 PM, 05/16/09
Nivomats. They're horrible things, aren't they? The old Volvo 760, 940 SE, and 960 had Nivos. Once they go, they're GONE.
cruiserhead1 says:
03:02 PM, 05/16/09
that suspension looks cheap! I don't that uca looks wimpy and the diameters of all the joints look unimpressive.
is the bushing on the lower strut link a split bushing? really?
not impressive.
surface rust is nothing to be concerned about. it would be nice if they plated all the parts but that's expensive.
billt9 says:
05:26 PM, 05/16/09
how long does it take for surface rust to turn into structural rust?
So does the rusting translate into shortened vehicle life or not?
My understanding is this is a typical Dodge trademark feature, and I'd like to know how it affects durability/reliability, whatever word you want to use.
mopar424 says:
05:48 PM, 05/16/09
Rust is normal. Every car rusts underneath. It actually forms a protective barrier around the structural un-rusted part.
misterfusion says:
07:17 PM, 05/16/09
Yeah, the rust is definitely not just a Mopar thing. EVERY one of these "Suspension Walkarounds" on Inside Line shows surface rust on the underbody components, no matter what the car.
majin_ssj_eric says:
08:10 PM, 05/16/09
I love these walaronds Dan. Wish you could do one on my car (08 G37S coupe). Is the 370Z suspension similar?
majin_ssj_eric says:
08:11 PM, 05/16/09
*walkarounds! Duh!
rlg86 says:
06:35 AM, 05/17/09
Dan you're sort of redeeming IL with these types of posts. Now if only you guys would drive something other than every damn BMW out there, JRiz/Bono(head) posted less and Magrath more....
First-gen & current CTS both use Nivomats. Current CTS uses them on the FE3 (Sport) suspension only. The IL CTS has FE2 suspension. Many 2004-09 SRX & 2005-09 STS models also have Nivomats; mostly the vehicles without the MR/controlled suspension.
Nivomats are also good for reducing impacts loads into the rear suspension under heavily loaded conditions. By holding the rear end up under increasing load, this allows the shocks to do a better job of dissapating (sp?) energy before the suspension hits its stops. Drive for awhile around the great Midwest and you'll see what I mean.
Nivomats may be expensive, but a cracked or busted body is more expensive and probably unsafe. Take a look at the many web pictures of busted BMW rear end body structure & you'll see what I mean.
kingkhalas says:
09:09 PM, 05/17/09
I read those comments before but it does seem very very rusty for a new car.
kingkhalas says:
09:14 PM, 05/17/09
I just looked at the suspension pics from the Pontiac G8 and Honda Fit and the Challenger has way more rust on it.
randycat99 says:
11:41 PM, 05/17/09
I've been told that the rusty joints are simply a symptom of Challengers sitting in a depot staging area in Canada, where they are manufactured.
The suspension walkaround was really cool! Kudos to you, Mr. Edmunds for these feature articles! It's great to see somebody comment on the particulars, who can really "read" sense into a suspension design which looks otherwise like a mechanical maze to the layman.
vvk says:
05:50 AM, 05/18/09
Rust is normal? On a brand new car living in salt and snow free South California?! I don't think I ever saw as much rust on any of my cars, including the ones with over 300k miles on the clock. Despite frequent salt baths...
This just looks aweful. And pathetic.
drhorrible says:
06:51 AM, 05/18/09
So where is the jack stand?
actualsize says:
07:33 AM, 05/18/09
I didn't want to make this post about rust, but since so many of you have gone there, I'll make a comment:
The amount of rust was surprising. OK, these are thick pieces that'll no doubt last, but c'mon. There's a photo of the lower front pivot area that I almost put in that'll raise an eyebrow or two.
Every arm, every link, especially up front, was peppered with brown points of corrosion, as if the thin paint was an afterthought, easily scratched by handling during assembly. Maybe the parts rattle against one another while being shipped to the plant. Whatever. Something is going on. And then there are all of those machined surfaces that look utterly unprotected. All this on a "California Car" with less than 5,000 miles on the clock.
OK, a lot of the cars we've looked at had aluminum suspension bits, so we have not seen the entire spectrum yet. Still, compare what you see above to the first one I did...
http://blogs.edmunds.com/roadtests/2009/03/2009-honda-fit-sport-suspension-walk-through.html#more
Just look at the paint on that brake drum. Even from here you can tell it's thicker, more chip resistant and didn't get banged around during assembly. All the brown specks you see in these photos are dirt, not corrosion. And this car spent time at two oceanside ports, with weeks at sea in between during shipping, before arriving at a dealer.
indy_mistert says:
08:16 AM, 05/18/09
love these technical write-ups, thanks much!
I've thought the Challenger could use a bit of a drop (for visuals and to reduce some body roll I've seen mentioned in other reviews), so it is interesting to factor that nivomat rear into things. Would love it if you guys would have a set of Eibach (or other mfgr) springs installed! Ditto headers and a nice exhaust...
but these are obviously my own daydreams ;~)
manuelc says:
05:08 PM, 05/18/09
More suspension walkarounds!! More suspension walkarounds!! More suspension walkarounds!!
Especially for the long-term Audi A4 Avant.
Monocrom says:
06:29 PM, 05/18/09
I love how the manual transmission version needs help because it produces too much torque from a standing stop.
canadaphant says:
11:02 AM, 05/19/09
Another great walkaround-thanks for looking at the tires too! I'm about to invest in some new rubber for a similar sized and powered vehicle (albeit with a very different suspension), you're encouraging me to not cheap out! Sumotomo HTR ZIIIs, here I come...
yellowmiata says:
06:40 AM, 06/19/09
Great walkaround! Thanks for this detailed view of the underbelly of the Challenger.
Cheers, Kevin