redpriest

Yes, I distinctly remember reading this in my 991 manuals; but everything had to be beefed up to handle the higher G force loads the new RS is capable of generating because of the downforce. Not to mention which the Cup 2R, even though they are terrible at lasting any longer than a session, would be capable of generating the same slick peak loads over the course of a few laps.

GrantG

If you look in your owners manual, you’ll see the warranty disclaimer info about using slicks. I’m not going to get into the possibility (or not) of enforcement - just wanted people to be aware of the general landscape before making a choice.

7382929296

Do Hoosier R7 void warranty?

GrantG

I don’t think DOT rated tires are a problem

zedcat

The warranty exclusion for "racing tires (e.g. slicks)" has been around for Porsche sports cars a long time. My 987.2 had such language in the manual and stated the supply of oil to the engine could be jeopardized. I noted that by the 991.1 GT3 which of course is dry sump, the language referred to suspension components not being designed for the loads slicks could generate. For Porsche race cars (Cups, Clubsports) many parts including axles, subframes, control arms etc, etc. time out due to the loads.

ipse dixit

I am pretty sure that the GT department knows exactly the maximum G-force tolerances for a GT3 RS using even the most aggressive DOT tires.

Component failures (or premature component compromises) and/or oil starvation due to lateral G's that can only be mechanically achieved with "racing slicks" will be an easy tell-tale sign for their forensic engineers to conclude that "slicks" were being used.

Now, that doesn't mean that simply using slicks will void or affect one's warranty. Because, after all, even with slicks a person may not have the ***** or the know-how, or both, to push the car to the limits of what the slicks can provide.

mthreat

I was just thinking about this... what is the G limit for the oil system to keep flowing? Does anyone know?

I have no plans to run slicks on my GT3 RS, but I can't wait to see others do it!

sechsgang

So...what ARE the best DOT approved tires? Id Imagine an R7 hoosier if fitted would still be faster/hold better than a cup 2 r or?

GrantG

That info is not published, but the RS engine was modified beyond the GT3 engine in a few ways. One of those ways was to make the oiling more resilient and able to resist higher g forces than the GT3.

Interestingly, the GT3 engine is shared with the Cup (which comes with slicks), but the RS probably has the ability for more g's than the Cup (when using equal tires), due to even more extreme aero.

My guess is that one would tend to break things other than the engine before breaking the RS engine itself when using slicks. But if one has to buy an engine out of pocket, it's probably close to 6-figures...

RossP

Yes the R7 is faster than a cup2.

CX_GT3

I love your videos on YouTube, may I ask how your experiences are like with the Goodyear vs Pirelli vs Michelin Cup2's? The Cup2Rs are on a national backorder, and I don't see myself purchasing a set of 19s. It's time for a new set of "street" tires for track use, and any suggestions would be greatly appreciated!

redpriest

I think in order of ranking I would list:
1. Goodyear Supersport R - seems as fast as the other two, maybe even better peak. More consistent, falls off slowly, very usable and fast up until they cord/chunk. I can get almost 4 full days out of them, or 16 sessions of 5-10 hard qualifying laps. Cheaper than the other 3! My favorite of the 3 "Normal" tires
2. Pirelli PZero Corsa - I had one set, which were the ones that came with the car. Seems ok. They're much more pricey than the Goodyears, and they delaminated on me after about 3-4 days. They fell off pretty hard.
3. Michelin Pilot Sport Cup 2 - I have never liked Cup2s on any car. They perform great for exactly one day and the fall off is dramatic. I think I got 3 days of life out of them; but I will say that right before they chunked on me they were 'faster' than the Pirellis.

The wildcard factor here is the Cup 2R which I finally managed to get a set of - though I thought it was nearly impossible. I had planned to run 265 in the front instead of 275 but Alekshop found a set somewhere for me.

Traditionally, I have never liked the Cup2R because they were a one session only qualifying lap tire. Great for manufacturers trying to set lap records, but horrible for amateurs like us just trying to have some fun. I had a set on my 991.2 GT3RS. I hadn't been to Laguna in a couple years, and I was rusty. Also had never done Laguna in the 991.2 RS, so many variables and driver rust at play here. My first session was a sloppy mess, but ironically was the best time out of 3 days! No matter how much better I got, how much braver I got, the lap times fell off. This was on a pre-repave surface.

However, Serge of Serge Track Days fame here in California had been running them on his 991.2 and since the repave on Laguna has been able to nurse several sessions out of them. I think on low degradation surfaces they may be the best of the lot, but we'll see! I did set my 1:38.338 PB Sonoma Lap on the 4th session of use, so already that shows that they clearly lasted beyond just one lap.

I plan on heading to Thermal this coming weekend to test them again; so we'll see. I have a set of Goodyear Supersport R waiting to replace, and also, will be doing Chuckwalla on Monday.

ipse dixit

FWIW, I've had my best lap times at Thermal with Cup2s, not that I keep track of lap times, but the data is the data.

CX_GT3

Thank you so much for the detailed explanation. I will do my best to source the CUP2R; in the meantime, I will get my hands on a set of Goodyear R.

I will keep this thread updated.

npalacio

Why in particular are you looking to run slicks?