[QUOTE=MG1422;7877335]Took the car out to COTA this weekend and finally got my track wheels and tried out the michelin slicks (S9A front S9M rear).

Car was 2-2.5 seconds faster with the new tires, keeping in mind the track itself has gotten slower and slower over the years.

Great times.

Any rear end links or sway bar modification?

 

Mentioned before but will be keen to hear how the car holds up with these on especially as you clearly know what you're doing driving wise. These are worth 2-2.5 vs which tyre? I would expect a larger gain over the stock cup2.

No real desire to run my car on slicks but its great to see others are. I have 4 days on track in the PRO over the coming 4 weeks, just hoping its not too wet!

 

Nice! Very cool to know members here are corner marshals at COTA. Too bad you missed this near wipeout at T20 on Sunday.

 

[QUOTE=AMG 17GT;7877954]No modifications on car other than Tikt Brake ducts, Girodics Rotors, Cobalt Pads, Alignment, Wheels and Tires

 

Whiteblack I should've been more clear. I usually run Hoosier R7 Which are about 2 seconds faster around COTA than Cup 2. Michelin Slicks are around 2-3 seconds faster than Hoosier R7. So slick is about 5 seconds faster than cup 2

 

So I find the MPSC2 ZP tyres; (the ROW option tyre), to be at least 2-3 seconds per lap faster than the OEM SC2s..

I would easily ‘guess’ that a set of Hoosier R7s on the car would be an additional 2-3 seconds/lap faster than the ZPs.

The Michelin slicks being 2-3 seconds/lap faster than the R7s means that the Michelin’s alone are probably worth about 6-9 seconds/lap quicker than the OEM SC2s.

Bish

 

You might be right Bish. to be honest I never tracked the car with the regular cup 2s unless it was raining or wet but I've seen comparable data on a GTR at cota with regular cup 2 vs. hoosier.

 

Thanks, that's more what I would expect.

 

I'm surprised you find some much delta in the ZP. Most of the Porsche guys I know point to a 2-3Sec delta with the R compound. My understanding is that that the ZP sits somewhere between the two.

All speculation anyway, I've never driven either tyre.

 

Cant say this from experience but I've heard the ZP tire's performance falls quickly...again I just heard that DON'T SHOOT ME

 

I tested back to back brand new ZP's vs brand new Michelin slicks this weekend at http://arizonamotorsportspark.com/
The Michelin slicks were 3 seconds faster. No other variables. Same track, same car, same day, same driver, within 90 minutes apart.
The ZP's are an extremely fast street tire with a bogus treadwear rating, about the same as an R7 imo.

 

So i guess I was right above about a slick being faster than regular cup 2 by about 5-6 seconds.

 

Has somebody tested back to back new Cup 2's vs new ZP's?
To put in perspective how fast the ZP's are, when I ran the slicks Sunday I broke the longstanding Nasa TTU record by over .8 seconds. So the ZP's were withing 2.2 seconds of a nasa TTU record lap time. That's nuts.

 

Also I ran heaters to take out even more variable as the slicks take forever to heat up, the ZP's don't.
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You forgot to mention you are running the Renntech TT upgrade! LOL

 

So I have extensive experience with both the ZPs and OEM SC2s with my car. The ZPs are easily 2-3 seconds/lap faster, and cure the baseline understeer that my car suffered from; (this was also helped by a more aggressive alignment). The car is far more confidence inspiring driving it fast on a road course with the ZPs.

That being said, the ZPs do come up to temp pretty fast; (I start leaning on them the second lap in higher ambient temps), and are good for about 3-4 laps. After that they are still a much better tyre than the SC2s, but they do lose some adhesion, so best to back off a little lest the rear end try and come around on you.

It sounds as if the ZPs might be almost as quick as a set of R7s, but doubtful they’d be as ‘sticky’ for as long as the Hoosiers.

I can get about two track weekends out of a new set of ZPs, although they are getting slower by that fourth day.

So assuming your best lap time, Mario could well be correct in that the Michelin slicks are worth 5-6 seconds/lap since the ZPs might well run close to the R7s.

Bish

 

Something a bit off topic but it looks like the wing on the Pro is non adjust, mine doesn't appear to have any movement at all after loosening the bolts. Seems odd!

 

They do move, mine did. But virtually nothing compared to the regular GTR.
I think this is why they added the Gurney Flap.

On the regular GTR with the wing fully adjusted, it did cut down on the already very limited rear view.

 

Yeah, even with the 685whp, the car would actually still be a TT1 car because it's so heavy, one class DOWN from TTU where I ran it. I run a big power Viper in Nasa in TTU, but that car doesn't pass sound limit at this track, so I needed the points in my class so chose to run a class up, and it still broke the record!

 

Nice save! I do remember hearing your number come over the radio at one point, but don't remember for what. It may have been that....

 

I also got the Intercooler meshes fitted per the MB retrofit, free of charge by the dealer. It’s great they offer these free OE fixes/improvements for these cars.

 

Here is a video of James Vance, IMSA TCR driver doing a 2.19 flat at COTA.

 

Ok so that was fun............. and the 3 others i watched after lol

Funny how the GTR looked so much smoother than the GT3 video that popped up after...

 

Shows off how bad the buckets are with the 4 points perfectly!

 

I don't think he was strapped in very tight. I usually tighten the harness then move seat a bit forward and i stay planted, never have to worry about moving around the seat or holding on to steering wheel