Everything You Always Wanted to Know About Your Suspension But Were Afraid to Ask!!!

[JusticePete]

The LX platform has an elegant architecture as it should being derived from Mercedes Benz engineering. To reach production with price points suited to the Dodge and Chrysler brands some components were compromised by accounting and marketing. Most all brands and manufacturers face the same challenges and those challenges results in similar compromises. With the LX, when driven at anything but the post speed limits you will experience:

Rear End Step Out
Dramatic Bumpsteer
Bush Induced Body Lean and Roll
Damper Induce Body Lean and Roll
Coil Induced Body Lean and Roll
Significant Dive on Hard Braking

Adding sway bars, coil overs, springs and dampers actually make the foundational instabilities of the platform worse. By making one element of the suspension stronger, all other components become comparatively weaker. Take a look at these pictures. They are from a series of vehicles that we have Pedderised. We have been around for 59 years in AU and three years here in the USA. In our collective experience we have never seen bush failure this dramatic. The failures are the results of RWHP, awesome BREMBO brakes and what most OE manufacturers would describe as owner abuse. If you drive your car at the posted speed limits you will not see tears and wear like this. If you are like me and live for a twisty road, an autocross or a track day your car will have similar wear and tear. It will not be a warranty claim unless the Service Director is a family member.













These are not isolated instances of worn / failed bushes. These are from SRT 8s and RT driven as you or I would drive a vehicle with a HEMI. These bushes can be inspected with the car on a life. All we need to do is remove the front plastic undercar cover. Inspecting these bushes is part of the Pedders 28 Point LX specific inspection. So how does this apply to the handling issues of the LX platforms?

Rearend Step Out is directly related to the control surfaces of the sub-frame bushes. The OE bushes ride on a very small raised ares of ridges or bumps. You can clearly see in these pictures how much movement there is with the OE bushes.





Some of the noises that you are chasing on your LX come directly from sub-frame contact to the monocoque as the sub-frame squirms around under acceleration and turning loads. The harder you drive, the more they squirm. The stronger the grip is from larger / stickier tires, dampers, coils or all of these -- the sub-frame twists more and the car becomes more unstable at the handling limits. There is only one solution available for the LX platform to eliminate rear-end step out. Pedders EP1172 Sub-Frame Bush Kit.






The factory installed sub-frame bushes have a control surface of approximately 4284 Square MM. Pedders EP1172 Cradle Bushes provide 26,580 Square MM of control surface. The voids in the bushes deliver NVH standards thisclose to OE, but with vastly improved control. Your suspension is no different than your home. If your foundation is robust you can build with great confidence. Your LX foundation begins with Pedders EP1172 sub-frame bushes. Before you add RWHP, before you add a cool exhaust, before you upgrade your tires and wheels, before you take delivery of your LX -- start with a robust foundation -- Pedders EP1172.

Bumpsteer measure 9mm by our testing. The range of change in the front suspension geometry on the LX driven aggressively is quite large. Combine bumpsteer with rearend step out and you have a vehicle that wants to swap ends when pushed hard. This is critically important for emergency maneuvers on the street and mission critical for those of you who autocross or track you cars. Pedders EP2113 changes the position of your steering rack and reduces bumpsteer to 3mm.



By lowering the mounting hole with an eccentric on the steering rack, we raise the rack in relation to the wheels. The difference in control of your LX with robust sub-frame connectors and an EP2113 Bumpsteer Correction Kit is the difference between a clapped out K car and you brand new SRT 8. It is huge.


Bush induce body lean and roll is directly related to the bush durometer and material. The upper front control arms have very soft OE bush material. This video illustration is not a certified test. It is an illustration of the range of motion created by placing an OE control arm with OE bushes in a vice and wiggling it with Brandon's little finger.

YOU TUBE BUSH VIDEO LINK

Anyone can create a set of rock hard bushes for an platform. Rock hard doesn't translate into superior handling. Most production vehicles are under-tired. The tires are too small for the BHP, RWHP and Dynamic loads created when turning. Your LX weighs about the same as 2 1/2 Formula One cars. Using the rear tire width on a F1 and projecting that out to a similar width based on the weight of an LX your rear tires would each be about 30" wide. Making your LX as tight as a F1 car will just eat tires unless the tire width is brought to a similar level. That means we have to retain compliance in your LX suspension while we increase control. The result is that the ride quality is retained while handling is vastly improved. These diagrams illustrate where the range of Pedders bits fit.









Damper and coil induced lean and roll are the direct result of tuning to the critical damping scale. Think of this scale as a thermometer. At one end is complete control. At the other end is complete comfort. It is a zero sum game. Engineers attempt to balance the needs of the market with control. Audi’s RS series is an extreme example of tuning for performance and control. Even by German Autobahn stands an Audi RS is a very tight vehicle that most Americans and Germans find harsh. A Peddrised LX is more AMG than it is Audi RS. It will be taut, but with no drama.

The OE setup is clearly softer and has more drama over bumps and turns because of excessive motion. I like to take a Pedderised LX out with four passengers. Every bush in the car has been replaced with urethane, every coil with higher riates, every damper higher on the critical damping scale, larger front & rear sways and LOWERED over parking lot speed bumps. All speed bumps are not created equal, but those I have taken LX owners over at 5, 10 and 15 MPH would have been a major drama with OE bit and one person. With five people in the car Pedderised and LOWERED there is no drama. Their jaws drop.

By teaking everything from bushes to dampers to coils to sways we gat control of the LX without harshness. The anti-dive results in more energy being applied to stopping and stopping from 60 MPH to ZERO with a full load is reduced by 7” according to our G-Meter. Visually it appears that braking induced dive has been eliminated. That is not the case, but it has been dramatically reduced.

You can find more information on Pedders LX Packages and Bits at: PEDDERS LX Packages & Bits

No for the bottom line – belive nothing but your own backside firmly planetd in the seat of a fully Pedderised LX. Conact your local Pedder Dealer to arrange a test ride or come out and visit us at the track. Every upgrade and modification sounds good on the internet. The test is you butt in the seat first hand where there is NO BULL.

[3Shizzle]

good writeup!!

[joey]

Originally Posted by JusticePete

Adding sway bars, coil overs, springs and dampers actually make the foundational instabilities of the platform worse. By making one element of the suspension stronger, all other components become comparatively weaker.

What is your opinion of strut bars for the LX cars?

[diegochrysler]

Great write up! I didn't have time to finish it, but will be back to finish it later tonight or tomorrow. You should post this on the other forums.

[JusticePete]

Originally Posted by joey

What is your opinion of strut bars for the LX cars?

The LX generates substatial torsional loads with BHP, RWHP and weight. A good strut tower bar would appear to be of benefit. Our R & D people are looking at designs and results for an LX strut tower brace.

[JusticePete]

Originally Posted by diegochrysler

Great write up! I didn't have time to finish it, but will be back to finish it later tonight or tomorrow. You should post this on the other forums.

I type too much

[JusticePete]

We invite you to come out to the track and see for yourself what a Pedderised LX can do.







Event Highlights

Autocross

Boxing

Car Show

Chrysler / G.A.M.E. / Pedders Hot Shoe Shoot Out

Drag Strip

Fun Runs on the Track for Special Children

Music

Road Course

You can register by sending a PM or Email to JusticeDeb or ar@PeddersUSA.com

Rock'n Box'n
Rock'n Rac'n
Rock'n Rock'n

A portion of the event proceeds goes to charity. A number of Pedders Dealers will be on hand to answer your question and turn a few wrenches as required for your track activities. If you have never drag raced -- come on out, we will have instructors for your first pass. If you have never autocrossed before -- do it her with an instructor. If you have never run a road course -- we'll take you out for a modest hot-lap -- if you don't soil yourself or the car on lap one, we'll do real lap on number two.

[vvv90]

Well, this is actually quite depressing to learn.

I'm glad you have a solution for us but I have....er, HAD no interest in swapping out suspension components.

I'd be interested in getting a an inspection just to be sure.

Where are you guys at in the USA?

[xlr8r]

Hey Pete, us Canadian folk are looking for some love! Any update on install options for Vancouver BC?

[JusticePete]

Originally Posted by vvv90

Well, this is actually quite depressing to learn.

I'm glad you have a solution for us but I have....er, HAD no interest in swapping out suspension components.

I'd be interested in getting a an inspection just to be sure.

Where are you guys at in the USA?

Once you drive a Pedderised 300C your interests may change

Pedders has number of Certified Shops around the USA and we are actively looking for more -- INCLUDING Canada. The primary criteria for a Pedders shop is soft. It is the dedication and commitment of the shop to customer service. We can teach bits and alignment, but don't have time to teach customer service culture.

You can find the Pedders Shop Nearest you at our Dealer Locator.