Comfort oriented lowering springs

[himanshu_j]

True, but the dampers in the 77tsi will not be matched to the springs, softer dampers with unmatched stiffer springs will result in dampers not being able to keep up with the springs. kaanage can correct if wrong here but the damper needs to be able to accelerate / decelerate as fast as the spring, otherwise things get uncomfortable.

yes, lowering springs increase the springrate but this is generally to stop bottoming out. And that is maximum axle load for the weight, the engine in the 77tsi vs the engine in the GTI is approx 50-60 kgs lighter. So, unmatched dampers + higher unmatched spring rate + stiffer springs = crap ride.

Trust me, I learned this the hard way on my Mk4 golf, hence why i bought fully adjustable dampers to match the springs because with the lowering springs alone, the ride was horrible. I think you will find the spring rates of the 77tsi sport pack will differ from the gti/66 tdi springs even though they are both lowering springs.

Ahh, now I get it. So would it be better if I went in for the suspension, shocks and springs from a stock GTI? or would that be even worse?
I am having a hard time sourcing the technical data for mine as its sold only in 3 countries!

[gavs]

I would get onto websites from south Africa to start with, then search for "Polo
6R suspension" in google, then look at results from Europe.

It might just work out easier for you to get something like weitec coilovers because they are not up to the same stiffness levels as others.

[kaanage]

Ahh, now I get it. So would it be better if I went in for the suspension, shocks and springs from a stock GTI? or would that be even worse?
I am having a hard time sourcing the technical data for mine as its sold only in 3 countries!

The full suspension from a GTi would be far better than the springs alone as the damping would match the spring rates. With stiffer spring alone, the insufficient damping gives a softer initial compression response (since there is less compression damping to oppose the force compressing the spring) but the spring will compress more and then it will rebound with more stored energy which will further overwhelm the rebound damping leading to overshoot in the response. With a little help from succesive compressive loadings and unloadings (bumps) this overshoot will feed in sync to further increase suspension movement making the system oscillate. You then get a firm, yet bouncy and jarring (jouncy) ride which also reduces grip in bumping corners as the tyre loading is inconsistent.

The down side of the GTi suspension is that the stiffer front response will reduce the compliance so tyre grip will decrease a bit which leads to more understeer. Stiffer rear suspension or a rear anti-roll bar will be needed to maintain the current handling balance.
The higher spring rate with the lighter engine will also result in the springs extending more than in the GTi so the front will ride higher than in a GTi (though almost certainly still lower than stock).

gavs, who knows his stuff far better than most, suggestion is the best one - get a suspension kit (coilovers or cup kit) designed for your model of car (or one designed for the 6R with the most similar front axle weight to yours).

[Diesel_vert]

... I recently upsized to 16"ers with 205/50 rubber from earlier 185/60 R15s...

Fitting such big tyres probably increased the ride height by 6 mm or thereabouts.

Rather than altering the suspension, fitting 195/55 R15, 195/50 R16 or 215/45 R16 tyres would minimise any gain in height in the first place.

195/55 R15 would lower the ride height by a few cm, if that option appeals to you (or if you still have the wheels).

[himanshu_j]

I would get onto websites from south Africa to start with, then search for "Polo
6R suspension" in google, then look at results from Europe.

It might just work out easier for you to get something like weitec coilovers because they are not up to the same stiffness levels as others.

The full suspension from a GTi would be far better than the springs alone as the damping would match the spring rates. With stiffer spring alone, the insufficient damping gives a softer initial compression response (since there is less compression damping to oppose the force compressing the spring) but the spring will compress more and then it will rebound with more stored energy which will further overwhelm the rebound damping leading to overshoot in the response. With a little help from succesive compressive loadings and unloadings (bumps) this overshoot will feed in sync to further increase suspension movement making the system oscillate. You then get a firm, yet bouncy and jarring (jouncy) ride which also reduces grip in bumping corners as the tyre loading is inconsistent.

The down side of the GTi suspension is that the stiffer front response will reduce the compliance so tyre grip will decrease a bit which leads to more understeer. Stiffer rear suspension or a rear anti-roll bar will be needed to maintain the current handling balance.
The higher spring rate with the lighter engine will also result in the springs extending more than in the GTi so the front will ride higher than in a GTi (though almost certainly still lower than stock).

gavs, who knows his stuff far better than most, suggestion is the best one - get a suspension kit (coilovers or cup kit) designed for your model of car (or one designed for the 6R with the most similar front axle weight to yours).

Thank you so much for enlightening me. I really am uninformed when it comes to the technical side. I have written to VW India to let me know on the front axle load so I can take a call.

Bilstein coilovers are available here but the cost is prohibitive and would totally kill the ride. This puts the GTI suspension out of consideration altogether.

Fitting such big tyres probably increased the ride height by 6 mm or thereabouts.

Rather than altering the suspension, fitting 195/55 R15, 195/50 R16 or 215/45 R16 tyres would minimise any gain in height in the first place.

195/55 R15 would lower the ride height by a few cm, if that option appeals to you (or if you still have the wheels).

The overall radius of 205/50s is 4mm more than stock. 195/50s aren't available in India and with 215/45s the sidewall height is lesser and also the wider patch might further increase drag and decrease efficiency.

[Diesel_vert]

The overall radius of 205/50s is 4mm more than stock.

You have to consider the static radius, which takes into account the deflection under load, because a tyre is deformable and not perfectly round. The amount of deflection mostly varies depends on the aspect ratio.

... also the wider patch might further increase drag and decrease efficiency.

And yet, you fit 205/50 R16 tyres and 16" wheels?

...

There's no such thing as a free lunch.

-Fitting bigger wheels with appropriate sized tyres usually means less compliance, more unsprung weight and more fuel consumption.
-Fitting bigger tyres to compensate for reduced compliance leads to additional increases in ride height, unsprung weight and fuel consumption.
-Fitting bigger wheels and tyres that weigh the same as the original setup, or less, costs more $$$.
-Fitting suspension components that either lowers the vehicle or improves compliance also costs $$$.
-Fitting suspension components that can do both (if possible) will cost you even more $$$.
-Inconvenience is the price you pay for aesthetics, though that too can be rectified with $$$.
Etc.

As far as I can see, the most effective solution is to eliminate the cause (remove the big & heavy tyres and wheels) rather than solve all the issues it's creating.

Alternatively, just put up with the ride height and keep the compliance, or lower the vehicle and live with the ride quality. You can always do both (probably?) but that would require $$$.

[himanshu_j]

You have to consider the static radius, which takes into account the deflection under load, because a tyre is deformable and not perfectly round. The amount of deflection mostly varies depends on the aspect ratio.



And yet, you fit 205/50 R16 tyres and 16" wheels?

...

There's no such thing as a free lunch.

-Fitting bigger wheels with appropriate sized tyres usually means less compliance, more unsprung weight and more fuel consumption.
-Fitting bigger tyres to compensate for reduced compliance leads to additional increases in ride height, unsprung weight and fuel consumption.
-Fitting bigger wheels and tyres that weigh the same as the original setup, or less, costs more $$$.
-Fitting suspension components that either lowers the vehicle or improves compliance also costs $$$.
-Fitting suspension components that can do both (if possible) will cost you even more $$$.
-Inconvenience is the price you pay for aesthetics, though that too can be rectified with $$$.
Etc.

As far as I can see, the most effective solution is to eliminate the cause (remove the big & heavy tyres and wheels) rather than solve all the issues it's creating.

Alternatively, just put up with the ride height and keep the compliance, or lower the vehicle and live with the ride quality. You can always do both (probably?) but that would require $$$.

The ideal upsize would be 215/45 R16 but tires aren't available in India in that spec due to strict ISI regulations, they can be imported however but cost would be prohibitive. I am not all that hassled by the decrease in efficiency as my daily drive is hardly 10-15km and the 77kW motor can easily put up with the increased drag. If I am right, the 77kW is also sold with 215/40 R17 on Boa Vista's as an option.

Polo's sold here have ground clearance of 168mm, plenty high in my opinion and with the new tires it sits slighty higher still which is all I want to rectify. Coilovers are definitely not an option as they cost $$$ which I being a student can't afford and honestly, the impact on ride quality is unquestionable something I can't do with on Indian roads. With 205/50s I have a sidewall height of 4.03", any lesser and I risk ride quality, premature rattles and suspension wear.

Since my car weighs 1090kg which is 45kg higher than a 1.2 and 55kg lighter than a 1.2TDI, I am confused whether its safe to go for the springs from a 1.2TSI.

Also, does any one have a clue of the ground clearance of a 1.2TSI with and without sports pack? I can't seem it find it in the brochure off the VW AUS website.

[himanshu_j]

Hi again everyone,

Since my 1.6s kerb weight lies somewhere between the 1.2TSi and the 1.2TSi DSGs, would it be safe to go ahead with springs from the sports pack?

[Gusman]

Hi again everyone,

Since my 1.6s kerb weight lies somewhere between the 1.2TSi and the 1.2TSi DSGs, would it be safe to go ahead with springs from the sports pack?

THe 1.2TSI DSG here in Oz weighs 1088kg, so I think you'll be fine. I believe ground clearance for a standard 1.2TSI here is 163mm, sports pack drops it by 15mm.

[himanshu_j]

THe 1.2TSI DSG here in Oz weighs 1088kg, so I think you'll be fine. I believe ground clearance for a standard 1.2TSI here is 163mm, sports pack drops it by 15mm.

Thank you so much Gusman. My polo weighs 1095kg and since it's a petrol motor, I don't expect it to be as heavy as the 1.6TDi or the GTi. I was having a hard time finding out stock ground clearance for AUS Polos. Our Polos too have a GC of 163mm.

Just hope member JexL is willing to sell his set to me.

[kawabanga]

Just installed on my GTI the Eibach Pro Kit springs: I can say that comfort is very similar than before...

I was worried about rebound with original shock absorbers, but it's not so much evident,being the springs thought also for TDI version of the Polo, so with a lower rebound breaking
...
More reactive and fast on cornering, I like it very much!

Here's a pic with 10mm wheel spacers: