orthojoe

Sweet! Perfect reference point!

orthodx2000

Great summary, thank you!
My GT4 is dual purpose, she has 17,000 miles since I got her in August. I have the 2 way seats which work well since it is rare I change any seat setting except to get in and out of the car.
I tracked it stock at Eagles Canyon and COTA and experienced a lot of understeer as everyone else has.
I went with 2.5/2.0 camber changes which did require shims and tie rod changes as mentioned earlier. I used my 19" wheels with RE71's, changed my turn in technique which eliminated the understeer with the added benefit of increased midcorner and exit speed. Ran the PCA Mayfast event at Hallet last weekend and was extremely pleased. Only issue was higher horse power having to lift to let me by which was reluctantly done in some cases. LOL


Next mods are a BBI harness bar and a racing seat with 5 point harness I can install for track days. The 2 ways are livable otherwise.

katmeho

May want to add that the only real way to get any data off the car is via the Sport Chrono option with wifi connected app or from tapping the CAN bus directly into your data tool. OBD2 data is severely limited and practically useless.

American cars don't have mounting plates for drop in half roll cages as ROW / Clubsport cars have. American aftermarket harness bars are available from GMG, BBI, BGB, Cantrell, RSS and maybe a couple I have missed. All are bolt on and require some interior modification, varying in degree.

Harness angles are an issue with many of these bars, the seat options and placement are the determining factor. You can mount the harnesses into the firewall as is done in the Clubsport.

katmeho

Aftermarket Seats

It still seems impossible to get the LWBs as a part for replacements. Some GT4 owners had stop orders on the LWB option when ordering their cars. This happened twice in the first year of orders.

The following seats are confirmed to fit in the GT4:
Racetech
RT4009
RT4009W
RT9009

Sparco
EVO II US
Pro-ADV

Recaro
Profi SPG
Pro Racer SPG
Pro Racer SPG XL

Mounting options confirmed to fit:
GMG Seat Base

Porsche Motorsports says the only way to clear the light is via PIWIS while the existing seats and sensors are connected. You can disable all alerts for all airbags. Which is how they manage it on the club sports. Loss of thorax airbags from factory seat removal does not impact any of the other airbags, how or when they will activate in the event of a crash.

ShakeNBake

Seats/Seat mods, harnesses, rollbars and harness-bars, and Canbus interface would be a good add to this wiki.

Knolow

Thank you. Great info/explanation in one location

electron mike

Do you have a source for the firewall mounts where we could get them? I'd like to go this route to allow for a better harness angle and maintain my seat travel when choosing a bar.

katmeho

There is no part number per se, its a plate that has a welded in nut that allows for the eyelets that you can them clip into. Ill try to take a picture of the spare that I grabbed soon.

ShakeNBake

Is that body area aluminum?

katmeho

Honestly, Im not entirely sure. I didn't do the work myself. I should have gotten pictures before the carpet was put back in. Its likely mounted to the same point where they exist in the Clubsport. My shop runs a CS in PDC and the mirrored the setup.

paradocs98

Another addition for the suspension section: need aftermarket drop links from Tarett or others if you want to do true corner balancing. Just learned that this week from my local race shop.

Inrev

Excellent read! Thank you so much!

Why is this thread not pinned already?

GT4VR

This is a phenomenal resource. Excellent initiative and execution. Well done OP.

Would be great to have a few other mini-wikis too, like how to properly store the car for winter or tire selection for various environments etc.

cmosman

Suggesting to add a note to put the car in SPORT mode when driving on track. Apart from the advertised Auto-blip (which is nice, but optional IMHO), the thermostat control valving map is changed to achieve lower engine running temperature under heavy load. That makes SPORT a must on track.

jphughan

While it's true that the Sport button drops water temperature 15-20 F, I don't think that makes it a must on track simply because I can't imagine that Porsche designed a system that would allow the engine to overheat unless the driver pushed a button; the more aggressive map is obviously forced on with Sport engaged, but that doesn't mean it wouldn't be triggered anyway based on running conditions if a need arose. Then again, I can't fathom why they decided to tie a thermostat map to an auto-blip function either. Even if this is a programming vestige from the non-GT 981 Sport button that controlled many more functions, I don't see why even those functions would call for a more aggressive cooling map. Why should the driver be given control of the thermostat at all?