The rear rotors were about 350C and the rear calipers at 96C were a bit warmer than I got them to at PECLA. I was more comfortable in the car at this point. Granted, I was using different tools for temperature measurement, so there’s some uncertainty introduced.
I modified my driving style which seemed to work in getting the tires more even in temperature front to rear. The temperature split was less than 10C compared to the 28C I experienced at PECLA. Basically, I late apexed the corners more which meant scrubbing off more speed in the braking zone, getting the car turned quickly, straightening out the wheel, and putting the hammer down. I was definitely driving in a more point and shoot style.
I set the tire pressures to 2.4 bar the night before going to the track. As also shown by the tire temperatures, the front tires are at a bit higher pressure than the rears. Another observation is the dynamic range estimator which is showing 68 miles left with half a tank of gas. I was averaging about 10 mpg on track which is better than I thought it would do. The stock tune does run an air:fuel ratio of lambda = 1.0 through much of the engine operating range. Back to the dynamic range estimator, it shows a warning to refuel when the range drops below 50 miles which was at around a third of a tank left. That’s annoying because I lost the temperature gauges.
With only 300hp, 55% of the weight on the rear due to the mid-engine layout, 265 wide rear tires, and limited slip differential, the T puts down the power very well powering out of turns. I could feel the LSD doing its thing with the rear tires clawing for traction. This is my first track car with traction control and I used the PSM Sport setting which gives a bit more freedom to get loose. I honestly never got anywhere near those limits and I would typically drive with traction and stability control off, but I really like the auto rev matching of the downshifts for track use. I just mash the brake, shift the gears, and push the clutch in and out. On the street, I do turn PSM all the way off and do my own rev matching. In other observations, the T is the first car I’ve felt the need to get driving gloves due to the Race Tex material on the steering wheel. My skin tends to be pretty dry out here in the desert, so the steering wheel is too slippery otherwise. Oh, one other thing, the wind buffeting gets pretty bad at 100mph with the windows down.
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Check out the AWE Tuning “Foiler” wind diffusers—they make high-speed, window-down driving a much better experience.
Yup, I learned about those about five years ago. I’m typically a function over form type of guy, but I don’t particularly care for how the foiler looks. And it only comes into play during track days. Functionally, I do wonder if it would affect the airflow into the side scoops. On a 911 Carrera, not an issue as they don’t have the side scoops. Maybe come into play on the 911 Turbo and GT cars.
Jaguar’s also have reversed threads on the tow hook for no good reason. I learned this during a snow storm on a busy street while trying to get my wife’s car unstuck. Not the best place to spend 10 minutes trying to figure out why the hook won’t thread in.
LH threads on the tow hook are to prevent it from being easily used in some other manner, separate from the car, for which it is not rated… such as bolted to a hoist and used for vertical lifting.
Huh… learn something new everyday. So now the question is…. how many people tried using the tow hook not for its intended purpose and got hurt.
I was taught the LH thread is necessary so that when the tow cable is pulled taut, the direction of the cable winding would not start loosening the tow hook.
Most VW/Audi cars as far as I know are like that.
Not sure about Porches though, I remember the 964 having a RH threaded tow hook.
Excellent write up! I’m looking forward to seeing what you do to make it a better street and track car. I’m always baffled at how Porsches can pull over 1G with inferior suspension like McStruts and ~0 degree front camber alignment. It seems to defy the law of physics, but it’s probably more like it’s taking advantage of the laws of physics. Your knowledge and findings are very appreciated in the 718 community.
I love coming back here for the Cayman T updates. Thank you for the detailed write ups!
Are the front struts double bolted to the hub? I dial in some negative front camber by switching out the top bolt with one with a slightly smaller diameter one and pushing in the hub. Seems to get an east 2-3 degrees. It’s amazing how much better the front feels with such a simple mod. I make sure to use a high grade bolt. I also lighten my cars significantly from stock.
I’ll have to look at the strut design. What the Cayman and 911 chassis’ do have are slotted mounting holes for the upper strut mounts. I’ll have the details in the next article, but that allowed me to dial in about -1.5 deg of camber up front. Options for getting more camber are adjust camber plates and GT3 lower control arms to get up to the -3 or more range. On my old Evo8, going from whatever the stock camber was to -3 with adjustable camber plates made a world of difference. On Project S2000, I was running -2.8.
Yeah, looks like you will need some new hardware:
“You need minimum -2 degrees all around for the track. The outside wear is from a lack of negative camber. I run -2.5 to -3 in my Cayman. You’re likely going to need a method for adjusting camber in the front. The OE slotted top mounts are very limited in adjustment range. The GT3 LCAs work well for a dual purpose car. For cars that see a good bit of track time and aren’t driven in the winter we lean towards SPL. Given you’re on stock suspension I’d suggest GT3 LCAs.”
Yup, absolutely need new hardware to get to -3deg camber. I made a full build list of parts before I even got the car 🙂 The rate I’m destroying the shoulders of the tires and the fact the stock thermal system is good enough for the stock 300hp in moderate weather has shifted my parts purchase order a bit. I was originally going to attack the engine thermal system first but now I’ll get suspension bits next.
I love all the data you’re gathering before doing any mods.
Also “late apex point and shoot”? That’s how you drive the grey MotoIQ Project Mustang, too. 😀
How did you deactivate PTV on your 718 Cayman?
Using the Launch X431, it’s hidden somewhere under Porsche Stability Management which I think is under DCM. I had to actually use the search bar using the term ‘PTV’ to find it.
The picture of the screen is in Part 1, page 5. https://motoiq.com/project-cayman-t-part-1-intro-and-must-do-mods/5/