[nissanite]

Hi Guys,
Please dont yell about search. I have read most of the suspension post about shock. They have been great & informative but have just missed my mark. I just bought a BMW 330i with the ZHP performance package. The shocks are 60% stiffer on bump & 30% rebound. I love the feel. Makes my 968 feel like a Buick.
I would love to install a coil over set up but funds are now limited. I am looking at the Koni Sports as an alternative to stock replacement. I know they have rebound adjustment but is the bounce stiffer to start with? Ground Control valves their coil over shocks stiffer because you can use a 600 lb spring.
We now have a dedicated F class race car & will not be tracking my car. It has the 993 style 17s with Bridgestone RE-11 all around. The odo says 105K & the stock shocks are whipped & galled at the top from coming close to bottoming. [img]style_emoticons/<#EMO_DIR#>/unsure.gif[/img]

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[flash]

you cannot relate shocks and struts in terms of "stiffness" - whoever told you that either had no idea what they were talking about, or were trying to relate things in terms of common layman misnomering

shocks and struts are dampeners only (they are actually called dampers overseas) - you can quantify them in terms of dampening rate, which is measured in terms of speed relative to the spring frequency, but they do not stiffen anything - that is done by the springs

further, you really cannot compare the stock stuff, which is hydraulic, to the koni yellows, as first they are adjustable, and second they are gas - apples and oranges - they behave totally differently

the koni yellows give a firmer "feeling" ride, but much of this is due to the preload from the gas charge,and is misleading - they are indeed only rebound adjustable, with a fixed compression rate - they are adjusted though based on the spring rate you choose, so how much more they dampen the spring frequency is based on that spring rate

properly tuned, the feel in a bump is not all that different regardless of spring rate - it is just less travel with stiffer springs, and more controlled as the shocks and struts are tuned up to match them

if you think your car "rides like a buick", what you are probably feeling is the extension and compression of soft springs, and you may ultimately want to increase spring rate, as well as then the dampening forces provided by your shocks and struts

as for the ground control shocks (rear) like almost every package out there, they are missing a vital component that will result in the rear of the car being jacked up in installed as is, due to the nature of torsion bars - if yo ukeep them in there, you would have to add preload to the coil spring to prevent it from falling loose in wheel drop - this results in raising the rear end - you would need to add a tender spring and coupler to alleviate that - tack on an extra $175 to the price of the shocks

600# springs are REALLY stiff - i had those in the rear with torsions removed, and 400 up front, on dual adjustable hydraulic struts and shocks, and yanked them as too stiff for street - i am now at 300 up front and 500 rear - it is still far stiffer than most would like for daily use, but my car is purely a toy - were i to set it up for daily use, and were to keep the torsion bars, i would run a 250 up front and a 90 helper in the rear

but you can read a lot more about that in the suspension section of REV IT UP, to where this thread has now been moved

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[nissanite]

If you use a high rate spring with a shock that was valved for a stock, lighter rate it will compress diferently The car sits on the springs. When in motion the shocks take over. They control both compression & rebound. The BMW I have has springs found on other models that have the same ride height but substantialy different caracteristics. The compression & rebound rates are higher.
I have put high rate springs on another car that used koni spts but the compression settings were too light.
I am not trying to re-engineer the 968. I love the car & am just trying to get it closer to the feel of a M030 car. Is the M030 option with gas shocks?

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[flash]

the only thing shocks do is slow down the rate of spring compression and extension - the springs are doing all the work of holding the car up

shocks that are set for light springs will not work with heavy ones, and shocks set for heavy springs will not work with light ones

M030 is gas, however, the springs are different than standard - the front is a progressive spring and the rear has a helper

to get close to the M030 feel, you will need to increase the spring rates - the closest thing would in fact be the koni yellows up front - the setting of those would be dependent on the spring rate you choose - the rears however will be entirely different - the koni yellow shocks will not accommodate helper springs - you could change your torsion bars though to larger ones - or you could install a coilover shock and include tender springs and couplers - again adjustment of this shock would be dependent upon your spring rate

keep in mind that koni yellow struts will not work well with a spring over 350, and hit the ceiling at 400

call pete at rs barn - he can fill you in on all of the different options for struts and shocks, and what each one will act and feel like

one thing you can do to help things is balance the car and set the ride height correctly - this is very critical on these cars - there is such a thing as too low - front to rear balance is very important too - it's hard to tell what's going on for sure, but it looks like the rear of the car in the pic above has its butt dragging on the ground - this would transfer too much weight to the rear, effectively softening the spring rate

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[nissanite]

the pic is of the track car at Sebring under full throttle with 750 rear springs. I am looking for shocks for my street car.(avitar) Thank you for your replies. I would like to change springs but will just go for shocks now I think. I have been buying from Pete already & RS Barn is great!

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