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Discussion Starter #1
Anyone tried a performance spring kit from H&R for the SRT8?

How low does the car get?

Still fit 22x9.5 rims?
 

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I was thinking the same thing. Also what about the Eibach springs for the SRT-8? Do you think these are specific to the SRT-8 or are they the same ones as the 300c? Do they sell shocks that match up with springs?
 

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Discussion Starter #3
The H&R springs are specific to the SRT8 since it is already lowered from the base vehicles.

The stock SRT8 shocks are Bilstein already. Hard to improve unless a custom valving is required.

Mopar Performance Parts is developing a coil-over kit in combination with KW. But this is competition only- very harsh.
 

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How can any advantage be gained in changing out a stock suspension component on the SRT8?

By their very nature and purpose, springs and shocks are tuned carefully to each other on all high performance machines. This engineering also extends to caster, camber and toe-in settings, as well as sway bar design.

The integrity of the entire package is really put to the test when you corner or brake at speeds in excess of 125 mph.
 

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I would like to share a discussion about this very subject LB44 and I shared as a PM last night. As it is a Private Message it is reproduced with LB44's permission.

Quote: Originally Posted by LB44

Zilla,
You mentioned that the rear shocks on a 300c were not compatible with the eibach kit. Am I ok with the h&r's on the srt8? Do I need different shocks? Everything seems to be ok. Thanks in advance.
LB44



LB44
The Nivomat rears have part of the "spring function" built into the shock.

To keep all working correctly a lighter than "normal" car spring is used the Nivomat to give the correct overall spring rate, and ride height for the stock car.

Some Jaguars and Volvos used Nivomats on the rear and to replace them with a non-load levelling shock we had sell a shock/spring package with increased rate springs (stiffer) or the car would drag it's ass.

The fact that SRT division has engineered everything correctly is proved in the handling figures that show in all the magazine tests as greatly increased lateral G force, and no major criticism of the ride quality.

That your H & Rs work may be a result of good engineering, or a happy co-incidence - overall if they work for you with good handling, no bottoming out of rear suspension, and acceptable ride height then that's all that matters.

Remember my forum answers related to 300c Eibachs and SRT8 Nivomats a combination that all my experience says will not be the best.

John



This is taken from Sachs Nivomat web info - note the emphasis on a spring/damper (shock absorber) system:

A simple idea – a tremendous impact

A spring and damper system that automatically adjusts to any payload without requiring an external energy source.


The basis for developing the Nivomat was the idea of an ride-height control system that automatically adjusts a car to its ideal ride-height without requiring an external energy source. Such an automatic self-levelling suspension system should be easy mounted and retrofittable.

Starting with this idea, Sachs developed the Nivomat.

The Nivomat is a unique, fully automatic self-leveling suspension system.
All elements for controlling right-height, such as pump, oil reservoir, high-pressure chamber, and height sensor, are combined into a small, compact unit. The time and effort for installation corresponds to that of a traditional shock absorber.
 

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SRT800 said:
Anyone tried a performance spring kit from H&R for the SRT8?

How low does the car get?


Still fit 22x9.5 rims?
Let me see if I can help. When I got my car the h&r springs for the srt8 were not available. I ofcourse had to have it lowered right away, so I got a set of the h&r springs for a 300c/magnum. My good friend assured me that they would be fine, so he put them on for me. when he put them on, the front was perfect. Dropped it about 2". The back, however, raised the car a little. He had to cut a coil out of the springs in the back, which lowered it perfectly. Everything has been great so far. I have about 1000 miles on the springs and they have settled a little bit more. Perfect height. I have to be careful when going up or down driveways but that is about it. The Wheels I have are 22x9 all the way around. The wheel did not come staggered which was what I wanted so I put the 295/30 on the back anyway just to give it that appearance. Works for me. The ride is great on the car, but I will probably get the correct springs when they come out, just to be right. Let me know if I didn't cover anything.
LB44
 

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Discussion Starter #7
I was lead to believe that the 300C SRT8 used Bilstein shocks, not shitty SACHS. SACHS were used on the base cars.

Confirm/deny?
 

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LB44, you said you "had to lower it".

Was this for appearance purposes?

Since the major lowering, have you done any performance driving with your SRT8? If so, how is the high speed tracking; handling; transition behavior and braking stability since the mod?
 

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SRT800 said:
I was lead to believe that the 300C SRT8 used Bilstein shocks, not shitty SACHS. SACHS were used on the base cars.

Confirm/deny?

SRT800

Who has been feeding you this disinformation and poor opinions?

SRT has Bilstein front and Sachs Nivomat rear

The Nivomats area a premium product - way different from base dampers

Zilla
 

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Discussion Starter #10
SACHS Nivomats are horrible shocks for a performance car- especially one with huge weight transfer like the SRT8.

A properly valved high pressure gas shock would be three- no four times better than the oversized hydraullic lifter Nivomats. Why would I buy a performance car if all I cared about was it sitting level with a trunkload of suitcases.

I thought the guys at MPP were nuts when I heard they were going to replace the Bilsteins with KW coilovers, but now I think they're pretty smart.

Hopefully Bilstein will make a replacement shock for the base car that I can but on an SRT8.
 

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SRT800 said:
SACHS Nivomats are horrible shocks for a performance car- especially one with huge weight transfer like the SRT8.

A properly valved high pressure gas shock would be three- no four times better than the oversized hydraullic lifter Nivomats. Why would I buy a performance car if all I cared about was it sitting level with a trunkload of suitcases.

I thought the guys at MPP were nuts when I heard they were going to replace the Bilsteins with KW coilovers, but now I think they're pretty smart.

Hopefully Bilstein will make a replacement shock for the base car that I can but on an SRT8.
The self-levelling feature is just what is so beneficial in weight transfer.

Because I don't want to get in a big and stupidly time consuming debate I repeat

"Who has been feeding you this disinformation and poor opinions?

SRT has Bilstein front and Sachs Nivomat rear

The Nivomats area a premium product - way different from base dampers"

make your statement if you like, but my opinion is based on the fact that nearly my whole working life, was spent as owner of high performance tire/suspension accessory/accessory stores. End of discussion for me.
 

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Northern Rider said:
LB44, you said you "had to lower it".

Was this for appearance purposes?

Since the major lowering, have you done any performance driving with your SRT8? If so, how is the high speed tracking; handling; transition behavior and braking stability since the mod?
NR,
I am more of an appearance guy, so I did it for that reason. I'm not really a performance driver other than an occaisonal WOT when somone gets cute. I had a BMW E46 M3 conv. prior to this car and was ready for a change. My friend told me about this car so I went and looked at it. Bought it that night. Like I said before I have to be careful on driveways so I don't rip my front fenders off, but all the fenders have been rolled so in all honesty I am a little more careful than I need to be. Brakes still work great, but probably changing those out for bigger brembos and cross-drilled rotors. They look better, you know!
 

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LB44 said:
NR,
I am more of an appearance guy, so I did it for that reason. I'm not really a performance driver other than an occaisonal WOT when somone gets cute. I had a BMW E46 M3 conv. prior to this car and was ready for a change. My friend told me about this car so I went and looked at it. Bought it that night. Like I said before I have to be careful on driveways so I don't rip my front fenders off, but all the fenders have been rolled so in all honesty I am a little more careful than I need to be. Brakes still work great, but probably changing those out for bigger brembos and cross-drilled rotors. They look better, you know!
Got ya, LB. Enjoy!
 

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How does the factory ride height of the 300C SRT-8 compare to the Magnum SRT-8? If I lowered the front of my MSRT-8 2" like you mention, it would have the tops of the tires in the front wheel wells. This would be terrible for getting around and it wouldn't come close to what your pictures show for your 300C SRT-8.

Goddardzilla,

The Nivomats are not a premium shock in terms of a handling shock. They are definately a premium shock when it comes to comfort and load ability, hence the additional spring in the shock to compensate. However, as loads increase due to cornering effort and not load issues, having an additional variable rate spring come into play can cause serious handling changes in circumstances you want a nice, predictable result. This is simply bad news in a performance aspect and I personally would remove the Nivo's immediately if I was going to autocross/road race this thing(it would be cool, a big wagon out on the course ;) ).

Todd
 

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Todd, the 300C SRT8 won first in class and 6th overall in the One Lap of America - a 6 day endurance race spread over several tracks - and the cars have to drive between venues. There were 93 entries - lots of tricked out vettes, Porsches, Ferraris, etc.

The stock suspension on the SRT8 is TRACK READY.

Unless you can out-engineer Dan Knotts and his SRT crew, changing any suspension components may downgrade performance.
 

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Northern Rider said:
Todd, the 300C SRT8 won first in class and 6th overall in the One Lap of America - a 6 day endurance race spread over several tracks - and the cars have to drive between venues. There were 93 entries - lots of tricked out vettes, Porsches, Ferraris, etc.

The stock suspension on the SRT8 is TRACK READY.

Unless you can out-engineer Dan Knotts and his SRT crew, changing any suspension components may downgrade performance.
First the disclaimers:
A) Everything is a tradeoff. I agree that changing suspension components can downgrade 'overall' performance of the entire package while improving one specific areas. e.g. ride harshness for reduced nose dive on hard braking.
B) I have no interest in arguing what is 'Track Ready', and intend to run my stock 300c SRT8 at the autocross track.
C) I am not an expert in suspension components or design.


However, with respect to the 300c SRT8 that won it's class at the One Lap of America, it is my understanding that this vehicle had some significant modifications from a stock 300c SRT8 suspension.
Per prior posts:

Suspension is 25% stiffer than on a factory SRT-8. Contrary to earlier reports, these are not necessarily the suspension parts from the upcoming Charger SRT-8, as the final decision on suspension for that car has not apparently been made. <JMatt 04-30-2005, http://www.300cforums.com/forums/showthread.phpt=5775&page=2&pp=10&highlight=america>

The car is a rescued test mule.
It was black, and has been painted Steel Blue.
I has the entire suspension from a stock Charger SRT-8, which includes 25% stiffer springs and everything that goes with it.
295/30-20 tires mounted on 20x10" custom made 3 piece BBS polished rims.
it has 40mm fiberglass fender flairs, Custom spoiler and front air dam for zero lift.
Engine is stock 6.1L w/ cleaned up heads and intake manifold. Stock exhaust manifold.
Gutted cats, stock center muffler, and the rear resonators have been removed.
Mopar CAI. Stock ECU/TCM with cat check disabled.
Stock brakes with Carbotech XP9 front pads.
Stock ABS/ESP. The ESP was partially disabled for the wet skid pad.
 

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No argument from me on your info - and I have gone over the same data, myself. Even so, as race cars go, that particular car was not heavily modified.

I caution folks about suspension mods because it is very complex. If you have the time and money to swap components in and out on a trial and error basis, by all means, go for it.

Up until recently, I was did test driving for a manufacturer who wanted to compete at the highest level of international rally racing. Much of our work was focussed on suspension modifications and durability of all components.

My job was simple: drive as fast as possible on northern Quebec logging roads, in between rock outcroppings and pine trees and try to break the car, while my buddy sat in the passenger's seat with a laptop wired into every part of the vehicle.

We also had a factory spec Evo and WRX (at $350,000 a pop) as benchmark cars. I drove those to set benchmark speeds to compare to.

I'm not an engineer, just a driver. But I can tell you this - sometimes, even just the smallest of changes can really screw up the transition qualities (moving from vertical movement; lateral movement; acceleration / decceleration in smooth predictable motions).

The 300C is not tuned for competition - yet it is easy to drive; great acceleration; good brakes and very predictable transitions. A good driver can go fast. Case in point: with a bit of work, I outlapped a Honda S2000 with a good driver behind the wheel, with my C at Mont Tremblant recently. The SRT8 is even better.
 

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Northern Rider said:
Todd, the 300C SRT8 won first in class and 6th overall in the One Lap of America - a 6 day endurance race spread over several tracks - and the cars have to drive between venues. There were 93 entries - lots of tricked out vettes, Porsches, Ferraris, etc.

The stock suspension on the SRT8 is TRACK READY.

Unless you can out-engineer Dan Knotts and his SRT crew, changing any suspension components may downgrade performance.
I can E-A-S-I-L-Y out engineer the SRT crew if you think that Stephan (the SRT Suspension Engineer) would pick the Nivomats as his perfect shock. Same holds true if you think Al picked the "groovin' baby" rotor/pad combo as the perfect set.

Sometimes you are handed a steaming pile of crap and told to mold it into DaVinci's Adam.

BTW, sometimes PR is BS.

But I love those guys, and somehow they turned a chiseled brick of a rental car into a performance machine. Hasn't been done since the original 1964 GTO.

Engineering vehicles is all about compromise. Sometimes you need to give up the ten-tenths answer to get the seven-tenths solution. When "trunk performance" is a deliverable, and the metric is "how many golf bags with oversized drivers" you can fit, is it really a balls-out performance car?! (I hear Cadillac uses "dead bodies" unofficially as their metric)
 

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I_8_U_2 said:
I can E-A-S-I-L-Y out engineer the SRT crew if you think that Stephan (the SRT Suspension Engineer) would pick the Nivomats as his perfect shock. Same holds true if you think Al picked the "groovin' baby" rotor/pad combo as the perfect set.

Sometimes you are handed a steaming pile of crap and told to mold it into DaVinci's Adam.

BTW, sometimes PR is BS.

But I love those guys, and somehow they turned a chiseled brick of a rental car into a performance machine. Hasn't been done since the original 1964 GTO.

Engineering vehicles is all about compromise. Sometimes you need to give up the ten-tenths answer to get the seven-tenths solution. When "trunk performance" is a deliverable, and the metric is "how many golf bags with oversized drivers" you can fit, is it really a balls-out performance car?! (I hear Cadillac uses "dead bodies" unofficially as their metric)
I find it odd that you are choosing to flame the SRT crew specifically and the LX platform in general. You offer no credentials to substantiate your claims.

You say you can out- engineer thes guys? How so? Can you out-engineer the entire Mercedes E-class computerized suspension/steering/brakes system on the platform?

Even the 300C (non-SRT8) is a very competent performance car at speed. This 4 door family sedan (competitor to the Buick Park Avenue) manages to get around road circuits just fine. Case in point:

NR's 300C Devastates Competition at the Track - Almost!

This experience is being repeated over and over again this summer by other drivers. And you can't argue with the results from ONE LAP OF AMERICA.

DCX has never claimed these vehicles to be all-out performance cars (like the Viper). But the results speak for themselves. The 300C SRT8 is simply the best $70,000 car that $45,000.00 will buy you on today's market.
 

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Northern Rider,

You argument applies ONLY when we are looking at duties required of a stock vehicle for sale to the public. I can gurantee you that simply swapping the shocks on this vehicle to aftermarket will improve its track readiness(I have very good friends in Auto-X and one is a repeat national champion, his Z06 Vette improved 1 second from a switch in shocks and the base shocks are very capable). I can also gurantee you that changing sway bar sizes and/or the lever arm geometry of the sway bars will improve track handling. Same goes for a host of other things, geometry, springs, alignment, ect....

You are correct in that it can take time and money to come up with the step up, but it is very easy to out do the factory for a specific purpose. You must remember the factory has much broader interests in what this suspension must be able to do. Did you know I can put just over 1400lbs in my MSRT-8? I wouldn't be able to do that if I started messing with some of this stuff ;)

Todd
 
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