A lot of this can be related to driver preference as some people use different techniques entering and exiting corners. There is usually more than one way to skin a Cat.

That being said, Mike has a lot of experience and I am confident that there is a great deal of validity to what he is saying. Stiffening front bar can make initial turn in better but cause more understeer at steady state.

As for stiffer front springs, I think they are saying stiffer front than stock front, but not stiffer than rear. The secret would be to drive standard car and then modified one and see which you like better.

 

According to guys in my club who have had this done, TPC put stiffer front springs than rear springs, not just stiffer than stock.

 

Every car is different Larry. Mike works closely with the people to go to the lengths that Dr. John has to make the ideal setting for them and their driving style... not to mention the fact that the Dr's car is highly modified in the suspension dept. If you would like to talk about a possible set up for your car, give Mike or Tom a call here at the shop.

Casey

 

Casey, on a 2007 RS, would it make sense just to change the springs ?. I already have the Rear tow arms and also installed a GT2 rear sway bar because of the understeer that seems to be inherant with the type I RS. My home track is Sebring, as you know about as rough and bouncy as it gets, and the hard setting on PASM is actually about a second slower then the soft setting.

 

What were your times before you changed out the rear bar... Honestly, a proper set up and the bars that came on the car are what we consider to be the best solution before splitting bars up. Drop me an email, would be happy to discuss.

 

Springs, shocks and a 3.9 might do the trick..
From just one day in the 2010 I suggest do whatever Porsche did.

Are the sway bars different on the 2010RS?

Erik ran a 2:21 flat at Sebring on a cold day, he is fast.
We will see this weekend what he can do in hot weather with new gearing, diff and engine mounts...

 

Normal best times are around 2:23-24's on RA1's. Record time was 21's but it was very cold. GT2 sway bar did not make a huge difference but it did feel like some of the understeer left. My driving style likes understeer over oversteer anyway.
Gotta do something to catch the cheater above with the new RS

Here's video of my fastest lap at Sebring, just to show my lousy driving style

http://www.youtube.com/watch?v=3dBVCQ6EfzI

 

Erik, it depends on a number of different factors. I would recommend putting your factory sway back on the car. Would like to talk with you about options, feel free to email me or to call the shop, ask for Tom when you call.

Casey

 

From what I gathered, the stock springs on a MK1 GT3/RS are 60mm ID x 8.5"ish in length, so you should simply be able to buy a set of linear H&R ID Race springs (60mm ID, 8-8.5" length) for front and/or rear.

There are plenty of suppliers for the H&R Race ID springs. Then use the factory bars to tune from there, or add the TPC bars.

No offense, but the whole "secret" spring rate thing is at complete odds with the whole "go to the track" notion. As a customer and driver, I want to know exactly what rate I'm using so that I can know which direction to tune to meet my driving style and car setup tastes. I don't go buy a new suspension every time I want less understeer, I swap springs and make bar adjustments.

For example, the stock 2010 GT3RS that will be raced in the 24hr Ring race is using completely stock shocks, but they have swapped it with stiffer race springs. There is not some secret spring being used, they are just using some off-the-shelf H&R Race ID spring with stiffer rates.

I've always been suprised why more GT3 tuners don't offer linear race springs. TPC is atleast the only place offering this, but I think offering a range of rates front and rear would allow more of the track focused people to tailor the setup more to their style and taste. There is no one perfect setup.

 

Mvez, you are absolutely correct.

When I first started working at TPC i walked up to Mike working on a GT3 on the rack... We had a long string of GT3s coming in and I figured Mike just had a pre programmed guide on the alignment rack that he put the car within... Boy was I wrong!...

he launched into a huge rant regarding how every tub is different and therefore there was no go to exact alignment or go to spec... Needless to say, I learned a lot that day and it gave me a new respect for my boss. Now, there is a ball park, but the ideal setup is not a ball park number... it is fairly exact! I guess i should trust him... he wears that rolex every day at the shop.

We convert to a 2.25ID spring as they are readily available and we have rates at the shop. The stock camber plates are also noisy so we couple the system with a JRZ plate which is a nicer piece.

Before making a spring rate swap we often consult with the client to learn about how they drive, their preferences and what they want out of the car.

We do have a go to rate for the .1 chassis and the .2 chassis. I understand that you would like to know it as well, but we consider that intellectual property, it is something that we invested in to make the car work better, that is how we make a living. If you wanted to know what our "magic rates" are we would be happy to tell them to you after you made the purchase.

We also do this same thing when selling the Damptronic shocks, get rid of the horrible progressive spring upfront, convert it to run 2.25 and then reprogram the PASM module...

 

I don't know enough about chassis setup, so I won't get into that discussion, I just drive whatever is in front of me and make the best of it.

Your comment about the noisy camber plates is interesting. Can you elaborate on the noise it makes? I think I have an odd noise that comes from the front over cobblestone surfaces and it sure sounds like the camber plate bearings, but haven't investigated further. Your insight would be appreciated.

Thanks!

 

Casey,

I totally understand your need to profit on the investment made in making the GT3 better. I would have no problem paying for your expertise, fair enough. Just nice to see a tuner offering sensible modification options to "track focused" enthusiasts who may have outgrown the stock setup, or are looking to make changes beyond what the current spring and bar settings can give. Until now, I think the majority of owners thought their options were either GMG bars or a whole new coilover setup, and nothing in between, which is crazy.

Nice work, you guys clearly know what you are doing. I'll be calling you when I get my .1

 

[quote=Josh@TPCRACING;2836078]Stiffer front springs will allow more advance drivers to brake later into corners without upsetting the chassis./quote]

I'm confused...which is it? Do the springs control weight transfer during breaking, or just up and down wheel motion?? I've always understood it to be the former, while the struts control the up and down motion of the wheels (hence the rebound and dampening controls).

 

Springs and sway bars together control lateral weight transfer (side to side), and springs alone control fore and aft weight transfer.

That being said, it's pretty rare that one brakes in exactly a straight line, and waits to open the throttle until the steering input is complete straight.

The more weight transfer, the more grip that respective side/corner has.

So with a softer front spring, you get more weight transfer to the front axle under braking and more front grip = more over steer tendency.

Likewise, a softer rear spring means more rear weight transfer under throttle which means more rear grip = more under steer tendency.

 

Informative video. I will be looking into your package when I pick up (god willing ) my GT3 RS in the next 3-4 weeks.