Track oriented suspension

[seangti]

Howdy,

I'm about embark on a track oriented polo gti. Brakes, power and chassis is otherwise more than tweaked and up to the task. Some will know the car, but until it's in my garage I'll refrain from pointing it out.

Bracing, shim's, bushes, etc are all ready done, so just the spring/strut is what I'm seeking input on.

In my current polo I run bilstein struts with H&R springs, some bracing, rear sway bar on hard, standard front swaybar, which I am very happy with. I really like the balance of the car, very nuetral, works all tyres well and lets go controllably when I exceed the limit. There is occasionally over steer, though it suits my driving style and gives me a laugh. I'm seeking input from those with experience in tracking powerful FWD cars, what suspension have you ran, and any opinion?

What I'm considering: - Put in the same gear as my polo has, the balance is predictable and suits my driving style.
- custom springs suited to the balance of the car with some good, matched struts.
- Coilovers like a KW Clubsport at the upper end of the price range. Any other recommendations? I don't yet have good knowledge of how compression/rebound adjustments truly impact vehicle cornering feel, so by having it will it add an unnecessary level of complexity.

I'd be happy to retain the balance I currently have in my polo, but as I'm seeking lap times, will a coilover and more money expended provide a return?

I'm considering spending up to / around $3k to do suspension and potentially adding limited slip diff thereafter to handle the power level.

Open to thoughts.

Sean

[fred27]

Sean, you have a good set up that up that you are happy with. The Bilsteins are top notch and you will not go wrong with the high end KW's if you decide to go that way.
Dependant on how you structure your budget you could revalve the Bilsteins and fit the LSD-(money well spent), then it's lots of seat time. Another additional piece of euipment could be a traqmate, and keeping a record of suspension settings and lap times. IMHO soften the rear sway a bit and see how you go from there.
As you mentioned the high end KW's have adjustable rebound and compression, and you are right about the issue of adjsutability but they are a major factor in chasing lap times, maybe you can consider fitting them sometime down the track (no pun intended) Good luck with the lap times.

[seangti]

Hi Fred, thanks for the input. I'll look into the revalving idea to match the springs. I'll get it corner weight and balanced accordingly as it's a much lighter weapon than a standard polo.

I run a gtech fanatic gps for datalogging, gopro's for video and can overlay in racerender when the desire arises.

[Sharkie]

Sean, go and have a chat to Guy at APR. They used to race their 9N3 Polo around the country in a lot of Targa etc events. He'd be able to give you some decent feedback and advice.

[Stuwey]

Suspension is science, not magic.

Spring holds weight. Spring bounces. Damper controls. This MUST match.

With the budget you're suggesting, go MCA!

Personally I'd go for the slippy diff first though.

[seangti]

Thanks guys. I'll try do some research in APR's old polo to see what it ran.

Stuwey, cheers for MCA, I'll certainly follow up on that. I've also made contact with Accurate Suspension on Brisbanes southside, they're renowned for race car prep too. I'll have to wait till receipt of the car, though I don't believe the current suspension will suffice. It'll at least be some tweaking as I have driven it on the track, with better rubber than I had ran on mine at the time, it was understeering much earlier, corner speed and g's were down in comparison.

[jamesatfish]

APR's old Polo ran Bilstein PSS9 coilovers - I bought them off Guy when he returned the car to stock to be sold.

I ran the PSS9s with an adjustable sway bar at the rear (set to hard which dialled out understeer but gave a lift-off oversteer characteristic instead). I looked at a camber plate for the front struts but found we were getting enough negative camber without that mod.

I had a reputable suspension shop set up the spring rates and alignment to suit the type of driving I was doing and that was well worth the cost.

[seangti]

Anyone have experience with H&R Monotube coil overs? I'm currently sourcing a price locally, along with PSS9's. I've also been checking a lot of the UK sites for the H&R's, PSS9's and KW V3. I have reservations about chasing compression and rebound adjustability as it adds complexity.

I spoke with Guy Harding yesterday about LSD's and suspension, he was very helpful, really appreciated his input and time. For the LSD to do it properly with a plate style locker, assuming the gears are in good condition I'm looking around $4k. Add some more if there's wear on the gears, which I would expect given the power and mileage. From the reseach I've done, there's little point doing a torsion or clutch style locker, still costs a lot, so for a little more might as well do it properly.

Also spoke with Murray at MCA. Custom is the only option. Got some invaluable insight. For a FWD to really handle on the track, the rear needs to be oversprung, with strut valving to match, which means ride is going to be terrible. Any of the above mentioned coilovers whilst are "performance" oriented, is street tuned, springs and valving. Though the car will be oriented to track, custom isn't realistic, plus I want to keep the car streetable and roadworthy.

Anyhow, I'll focus on suspension and my driving first. Will pull some power if that's what's required to get traction.

Opinions on H&R monotubes??