myBailey07

GT4 Track Setup Wiki – Version 3.0:

Added a section for maintenance considerations for those that track their cars and a circuits mode TPMS tip

Please note the following:

• This wiki summarizes knowledge contributed by forum members intended to help set up cars for track days for regular folks for HPDE’s, open track days etc. It is NOT intended for the folks that race their cars, or the 1% immortals. The needs of setting up for these needs are way beyond the scope of this thread and/or my knowledge.
• Setup needs are obviously also highly personal, so the info in here is NOT definitive, but rather intended to give people a solid baseline where to start from and then fine tune according to their needs.

THIS IS INTENDED TO BE A GROUP WIKI: PLEASE POST IF ANY INFO IS INCORRECT, MISLEADING OR MISSING AND I WILL UPDATE MAIN POST. PLEASE ALSO CHECK THE PRODUCT LINKS TO DOUBLE CHECK THAT I HAVE THE CORRECT PARTS.

Where I refer to Light, Moderate or Aggressive track use, I loosely defined it as follows:

Light = Mainly street cars that see occasional track use. Street use dominate.
Moderate = Dual purpose cars that see both street and track with somewhat equal importance.
Aggressive = For the track junkie. Who cares about street behavior!

***

GT4 TRACK SETUP SUMMARY:

The GT4 is a pretty good track car right out of the box; however, by adjusting a few things its track performance can be substantially improved. They key shortcoming of the GT4 for track use is that, out-of-the-box, it will exhibit understeer at the limit. Much of the setup below is intended to address this.

We all want to go fast, but let’s start with stopping the car first and make sure we can do it repeatedly and consistently.

BRAKES:

The oem pads and rotors are sufficient for light and moderate track use. They will stop you well, but wear faster than track pads.

For moderate and aggressive track use a set of dedicated track pads and specifically also a brake fluid upgrade comes into play.

Brake Fluid:

• Castrol SRF Racing Brake Fluid is the gold standard here. More expensive, but you don’t have to flush more than annually, brake bleeding in between is minimal, and it is one of the few fluids that will actually be able to come back from overheating. Most other high temperate, racing fluids will also work.

Pads: Pads available in GT4 sizes with positive forum feedback are:

• PFC11
• Ferodo DS1.11
• Endless ME20
• RT RE10

TIP: Brake pad changes on the GT4 is a PITA due to the way the caliper and the solid steel brake lines attach. For track users that frequently change pads it is recommended to install the Tarett Caliper Stud Kit and the Tarett Brake Line Bracket Stud Kit. The will ease the caliper removal/reinstall process as well as prevent you from cross threading the thread which is easy to do.

http://www.tarett.com/items/911-prod...csk-detail.htm

http://www.tarett.com/items/986-987-...bsk-detail.htm

The only set of known aftermarket brake lines that completely replace the solid steel brake lines is a set by RacingBrake:

http://www.racingbrake.com/Brake-Lin...-p/rbl-006.htm

Caliper Stud/Brake Line Stud Torque Specs:
54 lb/ft; 4-5 lb/ft

Useful Brake Discussion Links:

https://rennlist.com/forums/gt4/9303...s-for-gt4.html

ROTORS:

OEM rotors are sufficient for track use; however, they will wear faster than some of the aftermarket options. Use the oem rotors until it is time for replacement and then replace them with one of the following options. These will give you better wear performance as well as allow you to replace only the outer ring, making them more cost effective than oem rotors.

AP Racing:

http://www.apexperformance.net/AP-Po...-34_p_701.html

http://www.apexperformance.net/AP-Po...-30_p_702.html

Girodisc:

http://www.competitionmotorsport.com...categoryId=251

http://www.competitionmotorsport.com...categoryId=251

AERO SETTINGS:

Setting the car’s aero is probably the easiest, and often the first, adjustment folks make before getting to the track.

It involves two easy changes: First, remove the two front aero ducts at the bottom of the car, right in front of the front wheels. It can be done by simply unscrewing the screws with a Torx T25 bit. Second, unscrew the retaining bolts on the rear wing uprights with two Torx T30 bits and reposition the wing in the more aggressive position. You’ll notice it is a very slight adjustment, so don’t stress if it doesn’t move radically – it is not suppose to. You will have to completely remove the bolts in order to reposition the wing and not just loosen them.

Even though it can be moved back and forth between street and track use, I have yet to hear of a person that has not simply set it to track mode and left it there. Any difference is not noticable during normal street driving.

Here are some useful links with pictures and more information:

https://rennlist.com/forums/gt4/gt4/...l#post12638622
https://rennlist.com/forums/gt4/gt4/...l#post12738843
https://rennlist.com/forums/gt4/gt4/...l#post12754587


SWAY BAR SETTINGS:

Front and rear sway bars have three setting: Soft, Medium and Hard. Start out with a setting that sets the front bar softer than the rear such as Soft in the front and Medium in the rear, or Medium in the Front and Hard in the rear, and adjust from there based on your handling preferences. This is an easy setting and will help with understeer. Some folks go directly to Soft front and Hard rear.

It seems most folks are Medium Front and Hard rear.

Since it is an easy setting to change, even track side, it is easy to experiment to find your preference.

Sway bars can be adjusted track side using a a torx key (30) and a 16mm open spanner or a ratcheting box end wrench. Make sure there is no load on the bar (both wheels on the ground, or both wheels in the air). There is little risk of being too tight if you can’t use torque wrench track side due to limited space, simply apply about as much pressure as you can manage. If your sway bar loosens up you'll eventually know it either by the change in the car's handling or clunking sounds.

TIP: It is advisable to occassionally check the nuts after/between track sessions to make sure they don’t come loose as many folks have reported that they do. Torque specs are 30lb.ft. Some technicians have reported that these bolts are single use; however, most have found that properly tightening them, checking them periodically, or using a bit of locktite works.

Useful Sway Bar Discussion Links:

https://rennlist.com/forums/gt4/9298...r-setting.html

ALIGNMENT:

Alignment, combined with the sway bars, are the most important things in order to manage the understeer tendencies of the car.

Alignment settings are very personal, so it is hard to define a “standard” that works perfectly for everyone. That said, I will summarize what I deem to be good starting points based on folks’ experience on here. Use these to start from and then fine tune for your needs.

Light Track Use:

We have learned that there is quite a bit of variance in how much adjustability folks are getting out of the oem equipment between different cars.

Align for the maximum of the range that the oem equipment on your car allows:

Front: Camber -1.6 to – 2.0; Toe zero, or slightly toe in
Rear: Camber -1.4 to -1.6; Toe in.

Caster: Whatever the oem setup falls onto based on the above should work and not present any issues.

TIP: On the oem equipment toe adjustability will become the limitation for adding camber, especially in the rear. Add as much camber as you can within toe limitations, leaving around -0.5 difference between front and rear camber. (You might be limited with what your car's oem hardware allows you)

Moderate Track Use:

Recommended settings are:

Front: Camber -2.5 to – 2.75; Toe zero, (or maybe very slightly toe out)
Rear: Camber -2.0 to -2.25; Toe in.

Caster: Center the front wheels in the well in order to minimize potential rubbing. For most this will be around a caster of about 9. Rear caster should not be a problem at these settings.

Notes:

In order to overcome the oem limitation for adding camber while maintaining appropriate toe and caster settings, aftermarket parts will need to be installed.
You will need shims to add camber, rear toe links to adjust rear toe and either front caster bushings, or adjustable thrust arms, to adjust front caster.

These parts are available either from Tarett Engineering or RSS Performance Components for Porsche.

Shim Kit:

http://rss.rpmware.com/rss/rss-align...i-1890057.aspx

Rear Toe Links:

http://rss.rpmware.com/rss/rss-adjus...i-2243823.aspx

http://www.tarett.com/items/986-987-...lnk-detail.htm

Caster Bushings OR Adjustable Thrust Arms:

http://www.tarett.com/items/986-987-...a01-detail.htm
http://www.tarett.com/items/986-987-...010-detail.htm

TIP: On the GT4 the rear toe settings seems to slip easily. It is recommended that if you install the above aftermarket parts it is also wise to install toe lockout kits from either Tarett or RSS.

http://rss.rpmware.com/rss/rss-adjus.../i-541194.aspx

http://www.tarett.com/items/986-987-...t01-detail.htm

Aggressive Track Use:

At this level of track use, I am assuming that you are most likely using dedicated track wheels (probably 19”) and probably semi slicks like Hoosier R7’s, therefore these settings are informed by that assumption:

Front: Camber -3.0 to -3.5; Slight toe out
Rear: Camber -2.5 to -3.0; Toe in.

Caster: At this level, both the front and rear caster will have to be adjusted in order to center the wheels in the wells in order to minimize potential rubbing.

Notes:

In addition to the parts mention for Moderate Use it is recommended that for this level you add front camber plates in order to pull the top of the wheels in and achieve the camber using less shims. This will also provide more space for running 265 tires up front. You will also need to install front tie rod ends as well as caster bushings in the rear in order to center the rear wheel and prevent potential rubbing.

You will likely also need to consider installing Cup monoball ends for heavy track use. Please make sure you order the Cup version, otherwise you will be camber limited.


Camber Plates:

http://www.tarett.com/items/986-987-...smt-detail.htm

Front Tie Rod Ends:

http://www.tarett.com/items/986-987-...bmp-detail.htm

http://rss.rpmware.com/rss/rss-suspe.../i-525890.aspx

Cup Monoballs:
http://www.tarett.com/items/986-987-...996-detail.htm

For details on the Cup monoballs please refer to Orthojoe’s track thread as his “ramblings” are a gold mine of information

https://rennlist.com/forums/gt4/9263...mblings-2.html

Note – Corner Balancing:

It has been noted by various folks that in order to do a proper corner balancing on the car, you will need to install aftermarket drop links from Tarett or someone else.

Front Drop Links:
http://www.tarett.com/items/986-987-...lnk-detail.htm

Rear Drop Links:
http://www.tarett.com/items/986-987-...lnk-detail.htm

RSS also sells droplinks; however, I have not been able to find the links on their website.

WHEELS/TIRES:

Wheels and tires are so dependent on personal preferences that it is impossible to list a definitive “Standard”. Rather, here are some workable options that some of our members have identified.

Due to the oem caliper size, unless you want to switch out calipers, the only available options are to use either 20” or 19” wheels for track use.

20” Wheels:

The oem wheel specs are:
Front: 8.5x20 ETA 61mm
Rear: 11x20 ETA 50mm
Wheel Bolt Torque Spec = 118b/ft

For rear wheels in 20” the oem size and offset is pretty much ideal and hard to improve upon.
In the front, there is some space to add offset for a bit wider track. 8.5x20 ETA 55mm has proven to be a great size for aftermarket wheels that will give you a bit wider track, rubbing free, on oem tire sizes. You can push up to ETA of around 50; however, some have started seeing a bit of rubbing at this point at high compression tracks and it will be track/alignment depending. ETA 55 is safe.
20” Tires:

In 20” track tires are very limited and we are at this point pretty much limited to the oem sizes and Cup2’s, Dunlop Sport Maxx Race and Trofeo R’s, probably in that order of performance (per forum members). RE71R’s might become available later in the year.
19” Wheels/Tires:

With 19” wheels the options are improved from 20”. For a more affordable approach a safe choice is to run OZ Leggera HLT or BBS CHR wheels from Tirerack.

OZ Leggera HLT:
Front: 19x8.5ET53
Rear:19x10ET40

OR:

BBS CH-R:
Front: 19x8.5ET51
Rear:19x10ET38

There are a number of tire options available for these wheels with two favored options being:

Bridgestone RE-71R in 245/40ZR19; 285/35ZR19 UPDATE: Folks now report that running a combo of 265/35ZR19 and 295/35ZR19 is the preferred option. It fits well and dials out any remaining understeer if you combine wit with a proper alignment)
Hoosier R7 in 235/35ZR19; 295/30ZR19

Forum folks have tested the above options and confirmed that they work.

For an aggressive track solution, using custom wheels, the following solution has been confirmed to work.

Front: 19x9ET50
Rear:19x11ET47 or 19X10.5ET44-46
Tires: Hoosier R7: 265/35ZR19;295/30ZR19

TIP: In order to make the aggressive setup work you will need an alignment that is closer in line with the aggressive setup discussed above to eliminate/minimize rubbing. A 10.5 wheel in the rear will provide a bit more clearance for the rear toe link and will easily fit a 295 tire, although a number of folks have confirmed that a 11 inch rear wheel works.

TIP: Ride Height:

When you run non-oem tires sizes be aware and consider the impact that changes in the car's rake, due to variances in front/rear tire heights from the oem one’s will have on the car’s handling. Increasing the front height relative to the rear will increase understeer and opposite, reducing the front height, relative to the rear, will reduce understeer.

At minimum, you should be aware of these changes or consider adjusting the F/R ride height of the car somewhat to get the rake of the car back closer to OEM

ShakeNBake is maintaining a spreadsheet with various tire options for the GT4 with all the information you might require in your analysis, including the above mentioned ride height impacts.

https://docs.google.com/spreadsheets...it?usp=sharing

Usefull Wheel/Tire Discussion Links:

https://rennlist.com/forums/gt4/9158...7-tires-3.html

https://rennlist.com/forums/gt4/9109...alignment.html

https://rennlist.com/forums/gt4/9132...arrived-2.html

https://rennlist.com/forums/gt4/8860...track-use.html

SPRINGS:

OEM Spring Rates:
45 N mm Front (257 lbs/ inch)
80 N mm Rear (457 lbs/ inch)

It is generally agreed upon that the car, even though a GT car, is a bit softly sprung for aggressive track use. Even though the stock springs are more than sufficient for casual, moderate track and aggressive track use, users have found that the outer edges of tires wear very fast on the track, indicating excessive roll. This edge wear, even though improved, has persisted even up to camber of -3.5.

A probably solution for this is to use stiffer springs and some users have indicated improved handling and tire wear characteristics as they make these changes.

At this point I do not sense a consensus on what the ideal springs rates are and cannot state a consensus recommendation, simply because not many folks have gone this far and reported feedback. This is an area to keep our eyes on for further development.

GENERAL TRACK SETUP TIPS AND TRICKS:

1. Zip tie your rear brake ducts together. They are made of two plastic pieces that
simply clip together and the bottom pieces tends to fall off on track, especially if you go off. It is easy to lose them.

https://rennlist.com/forums/gt4/9317...ake-ducts.html

2. Check you headlights: If you ever have your head lights removed in order to detail the car, wrap the car, or do maintenance, ensure that they are properly installed again. Especially ensure that the metal safety/release mechanism in your light housing that clips into the bottom of the headlight unit is properly latched. This is done with a special tool from the inside of your front trunk through two holes in the side of your trunk. This tool is included in the tool set that came with the car.

(I had both lights removed for a detail and they were not properly latched in and I did think to double check. This weekend at high speed they both caught wind, was ripped off the car, destroyed the headligh units and caused paint damage on the car as they bounced off the fender.)

Instructions: http://blog.schnellautosports.com/20...-your-981.html


3. TPMS On The Track Wheels, or Not? Not having TPMS will throw all kinds of annoying messages. It is also useful from a safety aspect as it can be a warning when a tire suddenly start losing pressure rather than finding out you have a flat on track the hard way. Answer: Yes, get them for your track wheels.

4. Circuits Mode/TPMS Freaking Out? Ever run into the annoying situation where you set the TPMS in circuits mode initially and then mess it up for a subsequent session, resulting in a TPMS that freaks out with repeated warnings and/or being stuck in trying to re-learn pressures without success? In your settings change the wheel type over to “winter wheels”, acknowledge the TPMS learning message and then set it back to “Summer Wheels” right away and acknowledge the learning message again. Now drive the car for about two-five minutes and it will pick up the tire pressures right away, allowing you to re-engage the circuits mode – works like a charm ☺

MAINTENANCE CONSIDERATIONS WHEN TRACKING THE GT4:

Here are some suggestions for additional maintenance when tracking the car.

Disclaimer: These are purely suggestions based on various forum member’s experience. You assume responsibility for your own maintenance and if in doubt, consult your Porsche Dealership.

(I’d like some help on this section as to see if we have some kind of consensus on some of these items, or adding ones I missed – Thx!)

Before every track day:

I am not going to describe every item to check before track days as these are well covered in most regular tech inspection forms; however, from forum feedback I have noted that, in addition to the regular inspection items, it is wise to make sure that your sway bar bolts are tight as they can work themselves loose.

It is also wise to have your suspension bolts marked after the car has been aligned. That makes it easy to inspect before a track day or track side when you for example go off.

Oil Changes:

Porsche’s Race Circuit manual recommend changing engine oil after 6000 track miles at the latest. This sounds like a lot and many folks will change their oil after every 5 – 10 track days.

The recommended oil level for track use is 3 segments/bars above the minimum mark on the oil measurement display. The difference between the minimum and maximum marks on the display is 1.8 quarts (1.7 liters). This calculates to around 0.36 quarts or 340ml per bar.

Therefore, when topping off oil, in order to be safe not too overfill, add around 200ml or ¼ of a quart at a time until you reach 3 bars.

A common Porsche approved oil used use for cars seeing track use is Mobil1 5W50.

Transmission/Diff Fluid:

On the GT4 the gearbox and differential is part of the same unit and the oil is not changed seperately.

Again Porsche recommends that the transaxle fluid be replaced after 6000 track miles. This, again, seems long and many folks will do it more frequently, or after around 6 track weekends (12 track days), or so.

The official oem transmission fluid is Mobil 1 Mobilube PTX 75W-90. It is available from your dealer or from SuncoastSports.com

https://www.suncoastparts.com/product/00004320420L.html

A good, safe, alternative oil to use is Mobil 1 Delvac 75W-90, it is sad fill for the Porsche Cup Cars, although you will find many arguments on which oil is best to use. You will need 4 quarts.

Useful Link:
https://rennlist.com/forums/gt4/9336...ity-diy-2.html

Spark Plugs:

As the car sees much higher rev ranges on the track than on the street I received a personal recommendation from my dealer to replace spark plugs every 15-18000 miles.

Wheel Hubs/Bearings:

Porsche recommends replacing wheel hubs and wheel bearing on rear axle after 6000 track miles and replacing wheel hubs and wheel bearings on front axle after 12000 track miles.

Coolant:

Complete flush every year/season

Wheel Bolts/Studs:

Replace every year/season for cars that see frequent track use.

WHAT AM I MISSING ON ADDITIONAL TRACK MAINTENANCE?




PLACEHOLDER – SEATS, HARNESSES, HARNESS BARS

PLACEHOLDER – CAN DATA COLLECTION

Bill Lehman

Excellent summary, Thanks for doing the work.

audipwr1

Dude well done, thanks

Posts like these make me forget about all the "value" and "appreciation of car" threads

It's also why I'm buying a GT4

konaforever

Damn. You must have lots of free time! Nice work!

paradocs98

Great job. That's a lot of work--I had been thinking about doing a similar thread for a while, so I'm glad you beat me to it.

Only thing that may need a correction is the Bridgestone RE71R front tire size suggestion--I believe the front is 245/40-19. At least that's what I saw on a car at Lime Rock over the weekend.

jphughan

Nicely done! A few corrections/recommendations though:

- For the toe links, you might want to specifically call out that the RSS version includes bump steer adjustment to explain its higher price, but that if buyers don't care about that, it may even be preferred to stick with something closer to OEM for part lifespan reasons, from what I've read from others here.
- I would also add a note strongly recommending the locking plate kit and rubber boots, the former because I've seen people having their toe fall out of alignment after as little as 1 track day, and the latter because there's no downside at all. I see you have it as a tip, but only underneath the heavy track use section; I'd put it as a note right up with the links to the rear toe links.
- The Tarett adjustable thrust arm bushing link you provided goes to the rear toe links, not the thrust arm bushings.
- The front bits should rightfully be called tie rod ends, not toe links.
- You might want to suggest the Cup monoball ends for heavy track use alignments since they include a big shim built-in, but if memory serves, I think Orthojoe found that their MINIMUM camber as a result was still pretty aggressive (-2.5?). I'm not sure whether one should do Cup monoball ends before camber plates or vice versa, though.
- For the rotors, if you have links to just the replacement friction rings as opposed to the full rotor assemblies, that would be helpful too.

audipwr1

Question on brake lines

If you buy the flexible brake hose kit does that negate the need for the brake line bracket studs? If so replacing the lines seems like an absolute no brainer

rraustin

Very helpful information. Thanks.

HRE_Jurrian

Thanks for posting that up! Great info!

jphughan

The RacingBrake lines are designed to be joined at the bracket location like OEM because other lines follow that same path and are held down by that bracket, but even if you didn't keep those under the bracket, I don't see how buying a $265 set of brake lines becomes a no-brainer to negate a $25 bracket stud kit.

myBailey07

I asked them (Racingbrake) on another thread and they stated that, yes, you no longer need the bracket. BUT, I do not have them installed and it would be helpful if someone that does have them installed can weigh in to confirm. But, you are right, if I have not already done the stud installs I would have gone this way right away.

Edit: Based in jphugan's comment above I might have misunderstood their answer. I would assume they meant that you no longer need to REMOVE the bracket every time you need to remove the caliper to change pads.

morjo02

nice posting....... many thanks

myBailey07

Thx!! Will correct later today when I get home. Always great to get your detailed feedback.

DeerHunter

Very nice write-up - thanks.

ExMB

Even if you have the bracket stud kit its still a PITA in the front due to the rear location requiring access from under the car or turning the front wheels - longer times. Do it often enough and lines will be better. We just need to get more competition in those SS replacement lines to get the price down.