2005 STI bouncy/bumpy ride
 

This weekend I did a 450 mile trip with my girlfriend and she complained a lot about the STI ride on smooth motorways, when I looked at her I could see that she was constantly jumping up and down on the seat, and I could feel it too, the car feels very bumpy on a motorway cruise, even simples things like changing the radio stations is hard, something which I never felt in many many sports car I drove in the past.

I searched a lot in this forum, but cannot find a definite solution for this problem, some say harder springs will fix it, some say it makes it even worse.

I think the suspension in my car is in good shape, my car is a 2005 Subaru STI widetrack with only 28 000 miles, it handles very well and is stable, the only issue is this constant bounciness that really annoys the passengers and I understand why.

Is there a definite solution for this?

Thanks in advance.

Either your current suspension has worn parts (it is 14 years old) or you have non-standard parts fitted.

Does it feel like a sudden jolt, as if the shock absorbers are too stiff or is it more of a sensation that the car is not settling quickly enough and the car is bouncing on "waves"?

It feels very stiff, it doesn't feel like the car is bouncing on waves at all, feels stiff and bumpy. The suspension is stock, was checked before and also the ride is pretty high, I believe this is characteristic of the stock suspension.

Is this a new (to you) car?

Yes, I have it since the beginning of this year, everything feels great, except when cruising on the motorway, very uncomfortable.

https://cimg0.ibsrv.net/gimg/www.sco...334ebffed.jpeg

Firstly, the motorways cannot be that smooth if they are unsettling the car..... ;)

Difficult to diagnose as what you may think of bouncy, someone else may think of as smooth. Have you been in any other Imprezas to be able to compare? The ride will always be stiffer than most other cars, so there maybe nothing wrong with it, simply stiffer than what you are used to. However, any competent mechanic should be able to diagnose worn suspension components once up on a lift. Shock absorbers are the most likely culprit if everything is stock.

I thought they were very smooth untiltrying them on the STI :lol1:, and I'm very used to stiff cars.

There are very few Imprezas in my country so I have never been in other, I will have a mechanic check the suspension, but I think everything it is ok. I was thinking that maybe there was a mod to help this "problem".

Thank you very much for that information, I will definitely check the height of the car.

To me it looks stock height, but maybe it is lowered.

https://cimg7.ibsrv.net/gimg/www.sco...d5b97bf91.jpeg

I don't have a photo of the engine bay on my car but looks like this one :

https://cimg0.ibsrv.net/gimg/www.sco...cb2cebce4a.jpg

I measured the height of the car, and from the center cap until the wheel arch on the front I measured 37,5 cm, on the back 35,5 cm, with a empty tank of fuel, so unfortunately it is lowered, and that's why it rides so unbelievably bad, I will leave it on the mechanic this weekend. Since the coil overs look stock, something must not be right with the springs.

Thanks very much for the information regarding the stock height for the STI, otherwise I wouldn't have known, my car was in a Subaru specialist for some time when I bought it, and he also never noticed it.

I don't think it's lowering springs - the front would be much lower.

Low rear ride height - strut low gas pressure or the 03-07 rear top mounts are prone to compress, a lot or spring sag.

It is possible that one of the last owners messed with the stock springs, if the car had good quality lowering springs it wouldn't be as uncomfortable as my car is. Yesterday I had the chance to try a stock 2005 STI and the difference to my car in comfort was night and day. My car feels like it has no suspension, very very stiff.

What colour are the springs? Could you take a picture of them?
The stock springs are black with two coloured paint dots on them.

Replace springs/shocks/top mounts with new OEM. If they are original, they are 14 years old now, regardless of mileage.

Sure, I will try to take some photos Saturday when I leave the car at the shop, The car was completely stock so maybe it has the stock springs compressed or something.

How much would that cost? I really don't want to spend much more money on this car.

Suspension is a consumable; it wears out over time/usage and compromises performance. The same as brakes, clutch, oils, filters, plugs etc. If you want the car to drive like new, then you have to maintain all the components. As I said earlier, any decent mechanic should be able to inspect the suspension once on a lift. It maybe a simple case of lowered springs as mentioned but if it's all stock, then it's juts tired/worn and will need replacing. I don't know what labour/parts cost are where you are I'm afraid. I would have thought that the parts would be ~£1k in the UK.

Here the labour cost is around 21 pounds/hour, and in the UK?

I understand that it is a consumable but with only 28 000 miles on the clock I don't think the full suspension will need replacing even being 15 years old, and they are quite expensive at ~1k. I just want to fix what is wrong, clearly something is.

Saturday hopefully I will have some news and I will report back.

I agree that it will probably be spring sag and damper wear rather than a lowered vehicle. Regardless of the usage the car has been sat on that suspension for 14 or so years now and as it's done very little mileage it's obviously been sat for long periods of time unused. Not using a car can damage things due to condensation, moisture ingress and corrosion faster than if a car were regularly used and warmed up.

If it were me, I'd change the springs and struts to something like pedders or KYB as good OEM replacements.

https://cimg8.ibsrv.net/gimg/www.sco...b9d0af1fb1.jpg
https://cimg9.ibsrv.net/gimg/www.sco...2ed47d7a4a.jpg
https://cimg0.ibsrv.net/gimg/www.sco...4bb822196f.jpg

Just took these photos, the car has eibach lowering springs, I didn't notice it before. How do these look? Coil overs are stock, correct? Thanks

There's a good chance that the car never had a geometry alignment when those springs were put on, or a roll centre correction kit. When you lower the car, the roll centre is made higher, so it will handle worse, not better. Someone like 2Pot will explain this better than me, but it could be a cheaper fix than replacing all the shocks, giving you time to save for them

Blobs are always bouncy. My theory is the solid rear subframe bushes are the culprit since changing from stock shocks to HSDs didn't change the bouncy thing at all on my old one.

Back on stock springs :-)

https://cimg1.ibsrv.net/gimg/www.sco...5017c3f32.jpeg

How does it ride?

Definitely better, in the motorway it's more noticeable, because of this bumpiness that the lowering springs caused.

Still isn't what I would call comfortable though.

What did you do with the ebaich springs 😬