Jnosol

Hello GT4'ers,

I would like to introduce myself on this forum. I'm Jimmy, this is my 3rd Porsche (991.1 GTS was my first) and came from (still have one) 13 BMWs. I recently sold my 991.2 GT3 and just picked up a GT4, which is new to me at 5,600mi (a GT3 is a better car all around, but it's not $80k better if you catch my drift). I wanted to share my notes and experience on owning the GT4. Hope to keep this thread open for my DIYs and conversations.

The GT4 I picked up had ERP links and track alignment done. Front under aero been removed and wing angle adjusted.

I did the following to prep for the first track event last weekend:

Oil Change - Mobil 0w40 (7qt exact), new filter, and new crush washer
The last owner changed it at 1,200mi, the oil seems very clean at 5,600mi

New Air Filter - OEM
I used Shark Werks 981 Air Filter Removal Tool (trust me, you'll want this tool)
Notes: The Cayman air filter placement allows a lot of junk into the box. You need to change or service it every 5-8k miles based on my discovery. This is at 5,600mi, it's disgusting. I would consider using BMC next after learning how quickly I have to service the filters.




New Brakes - OEM
The last owner did 2 track events and hard driving, the brakes had 35% left and already touch the brake sensor. I don't track enough to use full blown track pads. I did notice the OEM rotors had hairline cracks, will replace them with Brembo Type III when they're fried.
Notes: I tied the brake sensors away, I think it trips prematurely and unnecessary expense when the sensor is shorted. GT4 and 991 GT3 share the same part numbers.
Regrets: I should've replaced the brake lines with Spiegler 6-line system for easy brake job. Should've replace the caliper bolts with Tarett ARP studs - 62mm front and 85mm rear + brake bracket studs for easier brake change in the future.

Brake Fluid Flush - Castrol SRF
After all the research, Castrol React SRF seems to be the best. It has the highest wet boiling point, which is important for longevity.
To flush, the shop used a computer to open up the PSM to flush the entire system.



AWE Tuning Wind Foiler / Diffuser
This significantly reduces wind noise when the windows are down (track use). No more "booming" wind noise.



AutoQuest Seat Angle Adjuster for LWB
I hated the OEM seat angle. It's horrible on my back. The AutoQuest Seat Angle Adjustment changes the angle of the seat slightly, but enough to give my back some comfort. If you have LWB, I highly recommend it.

Notes: It's about 1/4" too long IMHO. Makes it harder to climb into the seat and raise my legs up higher than I wanted (I'm height challenged, if you're tall then you'll be fine).

Signature Fully Forged Monoblock SV104
20x9 front and 20x11.5 rear (yes, 11.5 rear to run 255/305 setup next)
Weight Savings over stock = 14.44LB

Notes: I'm affiliated with Signature. Please don't ask me for pricing, we have a commercial account on RL so please message that account. I personally configured the offset on this, it's perfect and no rubbing. You can ask me about the fitment and I'm happy to share.

Front Wheel: GT4 OEM vs Signature
23.92LB OEM / 20.76LB Signature SV104




Rear Wheel: GT4 OEM vs Signature
26.92LB OEM / 22.86LB Signature SV104




My impression on the GT4 platform compared to the 991.1 GTS and the 991.2 GT3 that I've owned?
Looks: I like the wide body 911 look better, but the GT4 is aggressive in its own rights. I got a few people sticking their phone out while driving to try and take photos. So I would give it an 8 out of 10, 991 GTS being an 8, 991 GT3 being a 9 and GT3 RS being a 10.
Handling: The GT4 handles like nothing I've driven before. It doesn't require a lot of effort to go around corners. Very light, nimble, and predictable. It's ridiculously fun to drive and be on the track, it's almost go-kart like. I do notice you can feel exactly what the car is doing, there's no surprises when something bad is about to happen. The steering feedback and feel is very good.
Transmission: This is the smoothest manual transmission car I've ever owned. Porsche nailed this, other than the whole 3rd gear failure thing. Very positive, precise, and good clutch engagement.
Braking: The GT4 has enough brakes to stop a rotating planet. However, it is a parts bin special borrowing brakes from the GT3 (a rear engine car). During hard braking, the rear end is very squirmy. Seems like the solution is TPC links along with DSC V3 module. Cheaper fix maybe is use more aggressive compound front and less aggressive rear.
Exhaust sound at WOT: Stock sound of the GT4 actually beats the 991.2 GT3. The GT4 has more piping allowing the flat 6 sound to open up gracefully. It sounded amazing on the track and I gotten a lot of compliments.

Enjoy these photos:





Thanks,
Jimmy

PCarOMFS

ExMB

I'm calling BS.

If those pics were from last weekend why did it have 2 different #s on the side: 307 & 317? What track are those pics from?

I also question that you only had to use 7 qts on an oil change. Either you didn't drain it completely or you didn't tell us about filling it up after the low oil message; especially on track.

needmoregarage

cmosman

Reiterating what PCarOMFS already indicated - dial in a little more toe-in in the rear and squirmy will disappear + turns more readily.
Welcome to the team!

Jnosol

Flat Out Classic June 2nd and June 3rd, Heartland Park Raceway. The first number represents run group, mine was run group 3. Second 2 numbers represent instructor ID, my assigned instructor after day 1 got sick so I had a different instructor on day 2. And why the hell would I lie about tracking my car? (confused)

https://www.nfimage.com/Flat-Out-Cla...t-Classic-2018

I don't drain the oil all the way, don't have the patient. Takes 7qt (using 2 Walmart jugs) so measurement was pretty close. I got it to 1 line before the "full" mark, which is where you want to be. I think I know how to change the oil. It's a pain to take measurement on the GT4, every time you open the hatch the car thinks you add oil so moving gears from the trunk to load into the garage reset the oil every time. But the car did need 1/4 quart for the weekend, not bad.

Wow, not sure what your problem is. You need to chill.

Jnosol

Thanks so much for the feedback.

Yargk

In addition to a little toe-in in the rear, stiffer springs in the front help with the squirm under braking.

The Tarett 448/560 springs work well, but so do 394/560 springs or 336/504 springs. I have the last option now and can still tell that there is less weight transfer under braking, but 336/504 seems to match the damping better than when I had 394/560, but that's personal preference. (stock is 257/457 btw).

Jnosol

I do love the mid-engine feel for sure and how much lighter the GT4 is. Don't get the impression that I'm bashing in any way, I enjoy the GT4 otherwise I wouldn't have bought it.

Thanks so much. I'll work on my driving skills (which is pretty weak) first, then I'll start messing with the car with more mods.

Jnosol

Thanks so much, I'll have to add this to my "to-dos" for next season. I'd rather take notes from someone who tried it all like yourself then trying to learn it the hard way.
This summer I'm trust trying to learn the car. The last owner had it setup pretty perfect, temp probs was used on the tires and temp variation was only 5% across.

GT TREE

Seems to be the norm with this guy from what others claim and the little I've seen.
There's always one....

Jnosol

He might be trolling me, lol.

PCarOMFS

Five12Free

Jnosol

Good to know. How's the stiffer spring for the street? Since the strut isn't valved for the stiffer rate, wouldn't that make it bouncy and unstable?

Oh no, I didn't say the GT4 is better than a 991.2 GT3 at all. The 9k RPM bespoke motor, wide body, and crazy torque - C'mon LOL. What I said what the stock GT4 sounds better than a stock GT3, exhaust sound and not engine valve train sound. I said the GT3 is better than the GT4 in my opinion, but it's not $80k better.

I like manual and PDK equally.

Also, it's disappointing the Porsche didn't put stronger 3rd gear on the GT4. After 78 reported cases on RL alone, you would think they'll recall the issue and replace it with stronger parts.