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Discussion Starter · #1 ·
Most aftermarket springs are advertised as "lowering springs" . While I'd like to lower my '09 Pursuit to improve its stance, my main goal is to improve road course/autocross handling. Its hard to compare spring rates with stock springs because many aftermarket springs are "variable rate". Looking at pics you can tell each end is wound differently. I'm assuming this is to give you a cushier ride on the street. I would think during quick transitions the softer portion of the spring would compress quickly, increasing body roll. If I've got this wrong, please help me out.
Any suggestions for a spring that wouldn't be softer than the stock ones but would lower the car some.
Currently the car has about 6-1/2" between the rocker panel and the ground at the forward jack point, with stock tires.
 

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Great conclusion over there 👌
 

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Many thanks Tony, btw I mentioned stage 1 because of (Preston 67) in post # 26 seems happy with Mopar Stage 1 on his 300C , I guess he lowered it without compromising the ride quality/comfort.
 

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Discussion Starter · #5 ·
Thanks for your extensive write up of your experiences. I hadn't considered ride quality as this car isn't currently a daily driver. I've got some experience with my 3/4 ton Ram on rough roads, and it's not pleasant! Appreciate the comments!
 

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Just adding a note, Get rid of the Load leveling shocks if you may any major suspension changes.
 

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There's only one outfit that offers a system that was / is truly worthy of a road course; Eibach.

After installing and testing (on a road course...street means absolutely nothing) what was available, (including K&W), it wasn't until I installed the Multi-Pro R2 system, did things start to really gel. The entire unsprung suspension assembly articulates on high density durometer polyurethane bushings (if they were not available I machined them).

Eibach offers many coil springs with different rates that fit the R2 (I can supply their chart). Four iterations later, I had to step back to the 3rd highest rate version because I drive it on the street; more compliance was needed to ensure a degree of safety. The R2 system is the only only one that has adjustable isolated gas / jounce / rebound (and adjustments are extremely effective).

Along with a front (hollow) / rear bar with heim joints (any rubber-based end links are a waste of money - bars are the very first thing anyone should change actually), urethane throughout, custom 3pc wheels with 295/35 P Zeros, functional rear spoiler / diffuser and lowered as much as I dare for best CoG and still negotiate sh!tty roads...there's little else I can do outside of removing more interior.

Useless / ineffective performance handling parts include: front / rear shock tower braces of any kind, bump steer devices (you need to understand the platform is 68+% Mercedes / E211 hydro-formed chassis supporting unsprung componentry) underbody braces (an oxymoron by definition) devices that claim to
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improve bump steer.

Finally; any of what I mentioned is going to significantly(!) alter ride quality. However...the tradeoff is a 4300lb (-107lb 445ci aluminum block + interior mods) tank that puts a serious hurt on six figure sports cars right where it counts...acceleration, braking (6-piston BEAR monoblocks / 420mm Coleman rotors) and close-to-neutral handling (depending on pad material) characteristics :^)
 
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You could throw the Mopar Stage 1 lowering springs on but why not try to match the spring and shock combo? Like by swapping on pre-2011 Bilsteins from SRT8s! (Beware that there was a suspension geometry redesign in '11 that at least changed the front shock's width between the mounting ears - plus those electronic Bilsteins - so avoid those later versions.)

Or you could drop a few grand on some top tier adjustable coilovers. Eibach did away with the R2 years ago but Ridetech TQ, Ultimate Performance-JRi, Wesley-Bilstein and Penske have you covered!

To make it perform on the circuit/autox (at least you already have the SRT8 Severe Duty II radiator and oil cooler!), definitely do swaybars as already mentioned (still love my 38mm hollow front bar from Hotchkis), quality 200 treadwear summer tires (Grassroots Motorsports usually has great reviews/comparisons on those competitive in class), and filling the empty diff via a Getrag LSD swap (unless it's an AWD Pursuit).

Further down the rabbit hole you'd look at the poor man's brake kit (hi-temp fluid, track pads, ss braided lines), even the 2014 Pursuit BR9 front calipers with 14.5" rotors, or dealing with the weak pump on the fully hydraulic power steering system (Holley has an adapter kit for the Saginaw TC/GM Type II pump which is bulletproof coming from Turn One, KRC, Flaming River...).
 

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Following up on Simon's reply:
If Eibach springs were any good, why I can't take a sip of coffee in my car?
As I've mentioned in my topic, handling/ lowering/the look were all perfect, but turning it into a mechanical bull?
Spring rating or not, that's no good. To be fair, your reply got me thinking: did I get the wrong spring rating?
In fact, Einbach website/US won't show any springs for chrysler 2013/300/3.6 it comes up with the charger only.
This is it :
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So, in your opinion, did I get the wrong (stiffer) springs?
I thought Chargers/300 are identical. You may remember I got the Eibach front swaybar as well.
All in all, nasty springs over stock shocks on 20" tires, one would think they might play nicer after 6 months, but....

Regards
Bill
 

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Hi Bill,

As a whole, end-users traditionally have not considered spring rate, by-far its been about ride eight changes. Also, manufacturers traditionally have not offered actual spring rate values as a result. They are reluctant to offer any information when pressed. Eibach's R2 system is considered a racing system where the expectation is the end-user would be also be turning spring rate as well as valving changes. In this case, the many spring offerings was relatively easy to offer / supply as the spring perches / retainers were deliberately the same across all their offerings. Different makes of vehicles, their mass and actual end-use made for lots of different spring rates (note there are actually two springs per strut or shock assembly to deal with differing OEM spring lengths and provide some ride comfort over a very short amount of travel.

A spring meant for a Charger will fit your 300 because our platform's suspension has physically changed very(!) little over the years. Also, offering a / any spring with a lower ride height will be produced with a different progressive coil (it will get stiffer sooner) and / or a higher spring rate (aggregate stiffness) to compensate for less travel before bottoming out. In simple terms the ride quality with most all lowered springs swill invariably be more harsh / stiffer. There might be springs out there that are similar to OEM, but with the resulting propensity to bottom that much quicker.

Finally, properly manufactured springs (during manufacture) have a very long service life. As long as they not operated near coil-bind, they will outlast the vehicle's service life. So don't expect a measurable change in firmness. They will take a set (height) very shortly after being placed into service that will be consistent for a very(!) long period of time...
 

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Apology for the OP, I don't mean to hijack! Thanks Simon, as usual, you do make parfect sense.
Eibach all about ride hights, and the one million miles gaurantees.
For the purpose of this topic, I tend to lean more towards Mopar stage1 for a simple fact: springs are car specific.
If I had to do it again? I may consider RT springs upgrade which may achieve proper hight / decent comfort.

All the best, and OP good luck.
Bill
 

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Discussion Starter · #12 ·
No apologies needed, happy for all input. I’d like to optimize what the factory provides. Next time you’re in the area measure your pinch weld near jack notch to the ground.
 

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Discussion Starter · #14 ·
Gotta admit, the stance is great!
Thanks for your numbers. A co-workers R/T has similar weld to ground numbers as yours wiith 245/45-20 tires. I wonder if she knows what springs are on her Charger. I dont think most of our roads are as bad as yours. Were your dampers specified for a lowered car?
 

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Perfect stance/excellent handling when the mechanical bull calms down :giggle: on highways which btw are excellent, but local roads are horrible !
No, dampers are stock except trimming about 1-1.5 inch out of the rear bump stops (the yellow foamy thingy)
and yes, same 245/45-20 tires.
 
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