[aswinrprasad]

Hi folks,

Finally made an account in Team-BHP, This is my first post and I'm hoping to get some advice.
I've had a Cross Polo 1.5 TDI since a year and a few months now. I've always been interested in modifying the car and have done a few mods after buying it.

Modifications it currently has:
1. Code6 Stage 1 Tune
2. BMC performance air filter
3. ATE Big Brake Kit
4. Cobra Lowering Springs. (30mm drop)
5. Lenso Jager Dyna - Yokohoma 195/55 R16
6. Some exterior and interior cosmetic mods.



I've been really happy with these mods, but have one concern with the suspension set up. No doubt that the cobra lowering springs have improved on the body roll and cornering speeds, but with the stock shocks the car is running on now, it tends to bounce around like a spring in undulated roads(Not talking about the regular stiffness with lowering, which I'm completely fine with). Even though it's for a few seconds, it's like sitting on a trampoline bouncing around and almost losing control a few times.

I've done my own research and googled around and found that this may be due to the OE shocks which are longer as well as less stiffer and not designed to be paired with lowering springs. On further research I've found Bilstein B8's are a good option and are specifically designed for lowering springs.

I've seen a lot of posts on this forum talking about Bilstein B6's which are OE length(and stiffer than OE shocks) but are not really designed for lowering springs, as well as people talking about Bilstein B12's(which uses B8 shocks paired with Eibach lowering Springs), but none which talked about B8 shocks in particular with cobra lowering springs.

One interesting article I've read up on while doing my research(along with the countless YouTube videos):
Bilstein B6 vs B8

Would anyone be able to advice on the same? And I'm hoping that someone has already paired cobra lowering springs with Bilstein B8's before and could give me some feedback on it. If not, that's fine and any thoughts on this will be appreciated.

[deathwalkr]

Nice mods. Have you checked with the code6 team for advice?

[dhanushs]

I think your shocks are bottoming out, and not really damping. You will need to change the shocks to match the springs.

[Jaggu]

Originally Posted by deathwalkr

Nice mods. Have you checked with the code6 team for advice?

+1 if you have changed springs to a different ride height, it is logical you need to have shock that works with that. Speak to them and get a set of shock for the kind of ride you prefer.

[Jeroen]

As other mentioned you have changed the springs the shocks need to be changed too. Also, you have altered the brake callipers, which is likely to alter the unstrung weight, so another reason to change the shocks.

In theory the shocks could be worn of course and might need replacing. But due to the above mentioned factors I think you need different shocks all together.

Without proper shocks none of your other mods will work properly either.

I can’t give any advice on what shocks. It is a science in itself. One of the reasons I would never change anything in the suspension set up.

Good luck

Jeroen

[SS-Traveller]

Originally Posted by aswinrprasad

...with the stock shocks the car is running on now, it tends to bounce around like a spring in undulated roads...

Shock absorbers are designed to produce the best damping through a particular range of suspension travel, relative to the ride height. Dropping (or raising) the suspension (in your case, by a substantial 1.2") means you need shorter shock absorbers - the OE ones won't do the job. As to which ones would be compatible, I have no idea - but anything from Bilstein to Monroe to Gabriel would work fine if they are of the right specification.

[aswinrprasad]

Originally Posted by deathwalkr

Nice mods. Have you checked with the code6 team for advice?

Originally Posted by Jaggu

+1 if you have changed springs to a different ride height, it is logical you need to have shock that works with that. Speak to them and get a set of shock for the kind of ride you prefer.

Thanks for this, I haven't reached code6 for advice yet, but I will do that soon and keep this thread posted.

Originally Posted by dhanushs

I think your shocks are bottoming out, and not really damping. You will need to change the shocks to match the springs.

Originally Posted by Jeroen

As other mentioned you have changed the springs the shocks need to be changed too. Also, you have altered the brake callipers, which is likely to alter the unstrung weight, so another reason to change the shocks.

In theory the shocks could be worn of course and might need replacing. But due to the above mentioned factors I think you need different shocks all together.

Without proper shocks none of your other mods will work properly either.

I can’t give any advice on what shocks. It is a science in itself. One of the reasons I would never change anything in the suspension set up.

Good luck

Jeroen

Originally Posted by SS-Traveller

Shock absorbers are designed to produce the best damping through a particular range of suspension travel, relative to the ride height. Dropping (or raising) the suspension (in your case, by a substantial 1.2") means you need shorter shock absorbers - the OE ones won't do the job. As to which ones would be compatible, I have no idea - but anything from Bilstein to Monroe to Gabriel would work fine if they are of the right specification.

Apologies for being late ion the replies, was caught up with work over the last week. Thanks for all these feedbacks. Sounds like the common factor here that everyone's pointing out is the spring rates not matching/compatible with shocks.

A few recent updates:
We have replaced the steering rack and strut mounts. Shocks seems fine and has not reached its end of life yet luckily. The wheel alignment has been off. When we went to the alignment mechanic, they said camber has a negative offset(I guess a slight negative offset is expected when the car is lowered and is good when cornering) and they cannot seem to sort it. But the offset here was above -4.5 on both front wheels. Some research said that this can be sorted with either adjustable control arms or coilovers which allows to adjust the camber as well. And If I do go with coilovers, I suppose it should sort both my issues(Since it's a complete package). Thoughts on this ?

Will keep everyone posted on the latest.

[aswinrprasad]

I made a mistake in my last post. The camber value wasn't below -4.5, got it mixed up with the castor values. My bad.

Attaching the camber and caster(highlighted for front wheels) result values for the alignment done below.

Note: This was the second time that the alignment was done, so you may not see huge differences between initial and final values.

Even after we replaced steering rack and strut/shock mounts and after multiple trials at alignment, we still have this alignment issue. Wondering if this is normal for a lowered car or if something is seriously wrong(initially went in for alignment after noticing the uneven tyre wear on the inside). If someone can think of a reason why this might happen, Do let me know your thoughts on this?

Cheers,
Aswin

[corvus corax]

If someone can think of a reason why this might happen, Do let me know your thoughts on this?

Not an expert, but if the car's subframe has been refitted, say for an engine job or if the car has been in an accident, then I guess it would result in this? Please go through the following thread, especially post #23 by bhpian 'vedirah' for more insights. https://www.team-bhp.com/forum/techn...ml#post5454320 (VW Virtus: Stubborn left pull from the steering)

[aayushnair]

Originally Posted by aswinrprasad

Hi folks,

Finally made an account in Team-BHP, This is my first post and I'm hoping to get some advice.

It tends to bounce around like a spring in undulated roads(Not talking about the regular stiffness with lowering, which I'm completely fine with). Even though it's for a few seconds, it's like sitting on a trampoline bouncing around and almost losing control a few times.

Hello and welcome!

I've also got a lowered Skoda Fabia (technically very similar cars) running on an Eibach setup (30mm) with OEM shocks (Monroe versions) as I couldn't get TRW ones.

I had the same issue with them, when I first lowered her and after a lot of reading and understanding this, found the bump stops are too long. This literally doesn't provide enough dampening to the shocks due to which they hit the bump stops almost on every small bump which creates the feeling you have described (and at the time mine too).

Have been running these for over 4-5 years now, with cut bump stops (had checked a lot then and couldn't find the shorter versions for our cars here). Instead i just used a blade and cut about 2-3 inches on the rear and about 1 inch from the front ones. I don't exactly recall the figure now, been over 4-5 years since.

This can be done without actually removing the shocks and using a blade to cut the bump stops after careful measurements on each side, going for a ride and understanding if this works. Once you've got the measure, you can replace with new bump stops, by cutting the same amounts or just continue using them.

Things to be mindful of:
1. Bump stops are very important so they need to be there, else the shocks will completely bottom out
2. Cut equal measure from each side (front need lesser cuts)
3. They get stiffer closer to the top (so remove in 2/3 and 1/3 proportions from bottom to top)
4. Test with luggage or someone sitting in the back ,this way you wont cut too much off
5. Will reduce the life of the shocks for sure, as they aren't designed to remain so compressed always
6. Your other steering components (not rack) will also need periodic checks (tie-rods and other bushes mainly) and replacement when worn - these wear out faster as the geometry of the car has changed.

After all of the above,
1. My car handles absolutely like a go-cart
2. Is comfortable over bad roads and doesn't bottom out
3. Is still on the same front suspensions,
4. Rear suspensions got replaced in 2.5 years as they got weaker
5. Tie-rods have been replaced in 2 years and are demanding another now (number of miles on her are slowing down) - she's going to be 13 in Apr'24

Cheers and best wishes.

Aayush

[shibujp]

Originally Posted by aswinrprasad

Hi folks,

Finally made an account in Team-BHP, This is my first post and I'm hoping to get some advice.

I had the same issue with Cobra springs and stock damperson my Baleno RS. The best solution is to get a matched spring +damper setup. I got a Blitz suspension kit for my Baleno that came with the feature to adjust damping stiffness.

I did discuss this with Achintya of AM motors and he also offered to make my stock shocks stiffer by removing the current oil and fill it with a more viscous oil. You can perhaps check whether he does the same for the Polo as well.

Drive on,
Shibu

[VwRabbit]

I run a code 6 stage 2 tune on my GT TSI and had used Eibach lowering springs and had a small bouncy issue on some roads when it was new but somehow gradually became normal over time. The downsides were that the ride was stiff and suspension noise will increase over time however the tyre size that i used were 205/60 R16 and that provided a somewhat better ride because of the tyre profile.