trackcar

I am trying to decide between buying a 991.2 GT3 and an AMG GTR and I am leaning towards the GTR based on current prices which are ~20% lower for the GTR on comparable cars. Plan is to use the car mainly at the track. I have had 911s for many years (current DD is a 991.2 TTS) but frankly I am kind of sick of the dealer allocations/prices on the GT3s which is why I am considering the GTR. The GT3 is amazing BUT I have a hard time paying full MSRP for a 5 year old car. I test drove a GTR (on the street, not the track) and was pretty impressed with the steering, power, brakes. Has anyone here had both cars? In your experience, can the GTRs keep up with the GT3s at your local track? I am assuming running costs (brakes, tires) would be higher for the GTR given higher weight. Appreciate any insights. Thanks

LAsunset

Are you the one who also posted on RL earlier?

I had brought both of mine to a local track day once and drove them back to back. Factory setup. Both have Cup 2s if that matters. I would give the GT3 a slight preference just because as a whole factory package, it edges out to be a tad better on the track.

The GT R is not shabby at all. As much as I wished it has a NA V8, the hot V biturbo engine is strong on the track lap after lap. The handling and steering are spot on. Only thing I would improve on is brake cooling and slightly better brake pads. And there are good after market options.

That said, I love both cars. Different animals.

no401k

i havent owned a amg gt car, i test drove a few and is about to buy one in the coming weeks.
But honestly if you plan to do a lot of track, I would stick with the gt3 not becoz of running costs but repair costs. I have owned 997.2rs 991.1 991.2gt3 and currently a 991.2rs and very little things can go wrong even if you track a decent amount. The GTR is a great performance bargain but just browsing around forums or talk among friends, things break even tho most of them are used for street driving. The remedy seems to be that you are able to get warranty on them under the MB brand, as not many warranty companies provide affordable coverage for porsche gt products (and you can only get cpo for so long - 3 years max)
The AMG seems very over engineered to me and there's so little space in the front with you sitting right next to the gearbox, so I can imagine heat dissipation might be a potential issue. Obviously this being a MB forum i might get flamed for this wahahha but I would really love a AMG for a street weekend cruiser/, sounds great, looks great, cheaper than non gt porsches (which to be honest are getting really boring and soulness) and a perfect blend of performance and luxury. Yeah we all hate the porsche markup game

SLcruzen

not exactly the answer to your question, but I do have a 2020 GTR and a 2017 TTS... the TTS has extensive mods in the 700 range and I have drive both on track... the TTS would walk 991.2 GT3RS 's all day till hard breaking corners... the GTR not as powerful but could go deeper than the TTS. and just seems more at home on the track.... If I had to chose an open market car to track, I would find a GTR Pro, go 900 or 1,000 turbos, do a tranny upgrade, install front brake air ducts and go kick *** on the track !

trackcar

Yes, I posted on RL as well but thought I should post here as well to get both opinions. Assume you meant "NOT shabby at all?"

Which AMG are you getting and how are you planning to use it. And yes, I despise the porsche allocation/price games

Can you set-up a regular GTR to be close to a GTR Pro? The Pros are pretty scarce and therefore expensive which was the original reason why started looking at the GTRs (vs GT3s). Also, given I have a TTS helpful to know that the GTR is more track oriented in your experience.

shaladdin

Not really technical advice, and can be taken both ways, but everyone seems to be running a GT3 on the track every time I go. Kind of refreshing to have something different run with the pack. That being said, the GT3s are posting consistently fast laps session after session whereas it's obvious the turbo'd cars slow down as the day heats up. Are you in for posting best times for yourself or in relation to everyone else?

Probably worth mentioning that I only started tracking this year and have only been out 4 times so even I take what I say with a grain of salt lol

MBNRG

What specifically have you heard on those forums and gleaned from colleagues with the GT R?

Owner of GT R and also frequent most, if not all, of the GT/GT R forums.

Outside of the 2018 USA Model Year Recall for Driveshaft CF/Metal adhesive dehiscence (2019+ MYs not affected, as already equipped with updated DS), the rare Exhaust Rattle from Exhaust Valve Flap Failure (easily prevented by aftermarket EVM Module from ASR, Renntech, etc to keep Valves in permanent Open position, in addition to other fixes), or potential Brake Fade from lack of performative Brake Cooling, etc on brake-intense tracks (easily ameliorated with installation of Castrol SRF, track dedicated pads, and Ansix Auto Brake Ducts (inexpensive), or TiKT CF Brake Ducts (expensive), this is a very robust platform for track duty.

You can also add many of the aero/chassis options found on the Pro onto the Non-Pro, am currently in process of doing the same.

There are several members on here who beat the snot out of their GT/GT R on track without issue.
Another member has a modified GTS and is heavily involved in Time Attacks and Super Lap Battles.

AMG 17GT

GTR with the Tikt brake cooling and suspension parts is the way to go.

dav461

only track usage? 991.2 gt3 any day. that is not even a question tbh.
gt-r is like a "cow" on track comparing to gt3.

thebishman

This takes the prize for most stupid post of 2023 thus far

dav461

sorry, didn't want to hurt your feelings

no401k

I am sure this is one of those your mileage may vary kinda situations (just like mclarens). And my 2nd hand experience is not specific to GTR tho. So a friend's 19 GTC roadster has the top mechanism replaced thrice, it seem to get stuck halfway. A couple others (17 gts and 16 gt) have small electrical annoyances, such as blind spot monitors and radar cruise not working or airscarf not blowing. The gtc roadster also has drain hole (despite in southern california) clogged which led to moisture build up behind carpets and seats (dealer had to remove the entire cabin to dehumidify etc.). Another friend has a 18 GTC and his just had faulty fuel injectors, o2 sensors replaced together with some turbo oil leak repaired, that was a 10k expense but fortunately he had 3 months more before the warranty expired. I believe the gtr and gtc shared the same drivetrain and chasis (just from reading, not 100% positive) minus some software tuning. Yeah again none of these guys track, just canyon street driving highway pulls or some canyon carving. Good to hear you have no problems tracking the gtr. how long have you owned the car?

thebishman

trakcar, (Peter),

Welcome.

I had a '18 GTR and tracked it extensively in KS summer temps of mid-90's, and the car ran perfectly every time and without pulling any timing that I could appreciate. Also, all temps; Engine oil; water and transmission temps stayed well within the (high) normal zones. Even more importantly, my Son who is a damn fine driver would drive the car in the intermediate run group at our local PCA/BMW HPDE events, and then I'd immediately jump in and run it in the Advanced run group for another 20-25 minutes. The tires would be 'cooked' but the drivetrain ran great.

The car is fast on track as you can imagine, and I would routinely be (slightly) faster than a colleague of mine who has a 991.2 GT3 MT on most days.

As others have mentioned, you need to do the following: upgrade to high temp DOT 4 brake fluid; (Endless 650 and Castrol SRF worked great); if the car you purchase has the CCMs then replace the pads when they are worn 2/3rds of the way being mindful that the inner pads tend to wear faster than the outer ones and are more difficult to check; get Pagid RSC1s F and R; install Tilt brake ducts F and R; (they're stupid expensive but you'll get at least 2/3rds of your money back when you sell them when you're done with the car); there are replacement iron rotors from Girodisc and pad choices if the car you find has the iron brakes; get a track alignment which means purchasing 2 boxes of the OEM shims, and try for -2.5 camber F and R; more if you can get it; (once set, the alignment shouldn't wander iirc correctly, because it is a shim based alignment); get a set of track wheels in smaller diameter than the OEM 19s/20s so that your choice of track tires increase, but the C7 Corvette Cup 2 ZPs found on the Z07 version fit the OEM wheels as the car can be ordered that way in the ROW, and those tires cure the understeer that the car can exhibit with the OEM 'regular' Cup 2s, plus the ZPs are easily faster by 2-3 seconds/lap.

There are owners here who've installed the factory roll bar but it's not easy to source, along with better seats as the OEM seats here in the US aren't close to the Lightweight buckets in the GT3s, so advantage Porsche there. Also, if you are planing on doing Private track days with a car, the Porsche would probably be better on multiple runs greater in length than those found in your typical HPDE; (especially in FL's heat/humidity).

My '18 never had one non-routine maintenance issue despite having a harder but well cared for 'life' than most other GTRs. It's a great car.

Skilly

why would you saying something dumb hurt someone else's feelings?

G. P

Bish, thank you for the great summary above. Following this form members recommendations over the last 2 years, I did all the modification you have indicated above, and the results are fantastic. Higer speed around the corners, better grip, lower brakes temperature, much better brakes, all resulted in significant lap time reduction and higher level of safety.

I do have a question regarding your recommendation for ZP tires. It seems that CUP2 ZP is available in 335/25ZR20 only. Is this the one you referred to? if so, my concern is with the max load rating (99Y) instead of (106Y) and the smaller diameter that will make the car slower for a given RPM.

thebishman

That exact tyre can be ordered as an OEM tyre on the GTR outside of the US, so the load rating wouldn’t be any sort of concern. The rolling radius is slightly smaller, so when the car states you’re driving at say 70 mph, you’re doing around 67-68mph per GPS. However, the ESP is in no way disturbed by the difference in rolling radii between the ZP and normal Cup 2 tyres, so you’re not going to be triggering any CELs, etc. The advantage over a dedicated set of track wheels and ‘slicks’ is of course that you can drive to/from the track with them; just be careful in sub-50dF weather and if it’s wet. (Frankly I have driven on them when caught out in an afternoon thunderstorm and it’s not a lot of fun, and I wouldn’t drive on track with them if it’s wet either.

G. P

Is the ZP variance faster because it has a 25% height profile vs the 30% of the standard CUP2? which makes the sidewall stiffer and better slip angle, or there is something else in the ZP that makes it faster?
Just from the 335/25 smaller circumference it looks like it will be slower than a standard 325/30 CUP2.

I am about to get my replacement track tires so this info about the ZP variance came just in time. I do need street legal tires to drive forth and back from the track.
Do you have a link to sourcing this CUP2 ZP outside the US? someone that can ship to the US. Thanks

canucklehead

The ZP is more of a semi-slick vs the regular cup 2. Less tread.
Also the ZP has less tread depth than the regular cup 2.
Compounds are probably the same but the ZP feels sticker.

thebishman

Actually I’m fairly certain that the compound is substantially different, (read ‘stickier’) than the regular Cup 2, and of course it has far less tread, especially on the outside.

thebishman

Tirerack.com

Here you go:

https://www.tirerack.com/tires/tires...oModClar=Coupe

trackcar

Thanks - super helpful advise.

Any specific suspension parts that give you the 80 for the 20 benefit?

AMG 17GT

Email them they have parts that are constantly changing. Steering bump.

trackcar

Do you mean email TIKT? I see that they have a Bilstein set for 6k Euros. Would you also recommend all their other suspension parts (uniball, bumpsteer, etc). It adds up to ~$10k for suspension parts


https://www.tikt.de/produkt-kategori...rwerk-amg-gtr/

AMG 17GT

Yes. They constantly develop new parts. Big focus on GT platform.

trackcar

What suspension parts do you recommend for a solid track setup? All? Bilsteins+Steering bump enough?