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Thread: what is the difference in suspension

  
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    what is the difference in suspension

    what is the difference in suspension between different astra models?

    regs
    Opel Astra CD 1.6 Auto

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    On MK4's all the mounting points are the same, so they are physically interchangeable in theory.

    But different models vary in both spring length/rate and shock ratings depending on Axel weights and expected loading - ie estates and van have stronger springs. Even the same spec models with different engines will have differing OE spring and shock rates, due to the weight differences

    In general...

    SRi, SXI, SRi-T and GSi are all have 20mm lower springs than lower spec hatch models.

    Early coupe turbos, SE1's and some SE2's had lower springs on the back end.

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    Doesnt the Sri-T have prodrive suspension Geoff?

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    Nope it don't - it was just a limited production run test bed for sticking the (coupe/cabby) turbo engine if it to see it would sell, before they made the decision to go to full scale production with one (ie the GSi)

    It's essentially a boggo SRi with a prodrive kit on it (and a Zlet of course),

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    Ah right, i thought it had prodrive suspension as well, i seem to remember people saying that it was better than what was on the GSi but maybe im dreaming that one up.

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    According to VXC's press release in 2002...

    Vauxhall had to look no further than the Astra Coupe for elements of the car’s underpinnings: wheels, tyres and brakes are identical to those used on its Coupe Turbo stablemate, while the springs are the same as those first used on the high performance Opel Astra OPC.


    So they were uprated using springs from a lighter car Any knowing VX's habit of penny pinching I'd assume they are on the GSi too

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    Quote Originally Posted by Ffoeg View Post
    On MK4's all the mounting points are the same, so they are physically interchangeable in theory.

    But different models vary in both spring length/rate and shock ratings depending on Axel weights and expected loading - ie estates and van have stronger springs. Even the same spec models with different engines will have differing OE spring and shock rates, due to the weight differences

    In general...

    SRi, SXI, SRi-T and GSi are all have 20mm lower springs than lower spec hatch models.

    Early coupe turbos, SE1's and some SE2's had lower springs on the back end.

    Thanks Ffoeg, I asked so because I though about installing 17 alloy wheels
    some one told me that the suspension is weak for more then 16.
    and he said that suspension became bad , the older the medel the better the suspension.

    btw Ffoeg what do you mean by "rate"?

    regs
    Opel Astra CD 1.6 Auto

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    I'm not too sure where your friend gets his information from , but as long as the wheels you are going to fit are not a great deal heavier than the ones you have on now, then there will be no bad effects.

    Fitting lighter wheels will actually take loading off the suspension and make it react quicker - All the bits on the car that are not supported by the springs: wishbones, brakes, wheels etc etc really need to be as light as possible. This is referred to as "unsprung weight", and the lighter it is the quicker the suspension can react, which is all good. However on a road car a slight increase in unsprung weight won't make a noticeable difference

    Obviously, when changing wheels the "sprung weight" of the car (IE everything supported by the springs) will not have changed.

    As for "rate" - that the distance a spring will compress for a given load - take front a spring off a GSi, and one off a 1.4 and add a certain load to them. the one off a 1.4 will compress slightly more than that off a GSi, as the GSI comes from a heavier car so needs to be stiffer. An uprated spring for a GSi will compress less than a standard one.

    I hope that explains it, across the language barrier

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    clear now , simply uprated is stronger.

    well how to measure the uprating?
    and what else improves suspension rather than shock absorbers and springs?
    Opel Astra CD 1.6 Auto

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    Simple question, with a complicated answer.

    I'm assuring you mean for handling, as that is the primary function of suspension

    The best way is to make sure you get shocks and spring matched to the weight of your car - springs are more important since once on the car you can't adjust them. You can get adjustable shocks so you can tweak them to get them perfect.

    Also lowering the car will get the roll centre (centre of gravity) nearer the ground. Ideally it should be as near to the centre-line of the axle as possible, and this will reduce body roll on corners. BUT if you go too low and you'll start to mess up the suspension/steering geometry - I'd never advise going lower than 60mm

    Fitting a rear anti-roll bar on the back end, will make a vast improvement to handling, as will uprating the front one (this means removing the fornt subframe to do the work though).

    After that there's not much you can do on an Astra without going for the custom component's, which starts to get very expensive

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