On the driver’s side, I could not get the rear clips to reengage. I think the openings in the panel got deformed when the high-pressure water spray popped out the scoop as the panel is made of a relatively soft plastic. Hence, more screws.
That ACH run caused a whole lot of rock chips on the rocker panel before the rear tire. I used touch-up paint to cover these up. I don’t remember this area getting hit much with tire rubber during my prior track days. I remember the tire rubber mostly behind the rear tires on the rear bumper.
On the bottom side of the rocker panels, this area got hammered. What’s interesting is I checked the pictures during the install of the turning vanes and these locations looked unscathed after 3k miles and three track days. Check out the picture on page 2 showing the vanes and brake duct and you can see this section of rocker panel is unscathed. So, maybe the rocker panel getting hammered here is an indicator the turning vanes are working? Or ACH was just incredibly dirty. Or both.
Edit: I found this artist representation on the Porsche website of the airflow underneath the GT4RS due to the turning vanes. It does show air getting directed towards this area of the rocker panels.
My masking tape job is not pretty, but it’ll do.
Well, my attempt at masking tape didn’t hold up well after two more trips up ACH.
Thank goodness for the Radiator Grill Store grills!
7 comments
Khiem-
I have admired your many articles, and enjoy reading and rereading them. The title of this one sounded interesting, and the explanations, pictures, etc. were keeping me engaged, and then you casually drop that “a certain Mr. Coleman” drove your car. With you along for the thrilling ride, I assume. I’ve been onboard with Mr. Coleman’s writing, storytelling, and engineering prowess since I picked up my first issue of Sport Compact Car in late 1998. Yes, a 200-plus-page tangible magazine; remember those? I’m currently shopping for a car (a tree fell on the current ride), and that same certain Mr. Coleman is a major factor in considering the Mazda3 that I’ve been eyeing. Sorry to hijack the comments, Khiem, but I really wanted to give a shoutout to him. I hope that was alright. Thanks again for the always enjoyable and educating articles. Enjoy the drive!
I loved reading all things Dave Coleman as well! I wrote a question into SCC when I was in college and he answered it! I love Mazdas; I have a base model 2016 CX-5 that just turned 90k miles. I recently took it on a road trip with one of my dogs hitting up some of the best roads in California and it was still fun. I had to put the auto transmission in Sport mode on some sections and the transmission shift strategy was great for the twisty roads. Of course in manual mode, it has the proper sequential shifter orientation of downshift forward, upshift rearward. Lifetime average of 27mpg driving around LA. I literally just had a brand new Mazda3 sedan for a rental car and got almost 39mpg over 350 miles of mostly two-lane cruising. A lot of new cars have lane keep assist which is very annoying. Dave helped make the system be as minimally annoying as possible. The only thing that’s not optimal is the brake pad compound which doesn’t have a ton of initial bite. Though it is an improvement over a CX-30 I drove a couple years ago, but not as good as my 2016. Seems to be a bean counter change. Dave can’t fix everything. I’ll recommend anything in the Mazda lineup if you’re looking for a driver’s car.
Doing some research suggests these vanes improve front downforce and don’t do much for the rear diffuser.
https://images.squarespace-cdn.com/content/v1/5d7cfd7b13f6f06e8b55ed5c/1609096469910-BUNFCV10FN32JTZGA418/graphs.jpg
I’d found that before too. I do think it is vehicle/overall package dependent. The only thing I know for certain is that they direct air from the middle of the car outwards. I vaguely remember reading somewhere they also interact with the air swirl coming off the front tires which helps clean up the underbody airflow. I think acting as an air curtain to prevent the dirty air off the front tires from going under the rear.
This link is to an artist representation of the airflow under the GT4RS with the more extensive turning vanes array underneath the car. It does show the vanes redirecting the air outward right into where my rocker panels got hammered. Huh.
https://press.porsche.com/prod/presse_pag/PressResources.nsf/Content?ReadForm&languageversionid=1289808&hl=modelle-cayman-718_cayman_gt4_rs
My 718’s rocker panels aren’t as peppered with rocks like your is. But the under panel definitely is.
Never understood why my 718S water pump started leaking at 20,000 miles and 3 years. Makes sense. Thanks for your 718 articles, they’ve been great reading! PS I have the APR tune and wish I tried the AP…
If the car is bone stock, I think APR is a best option. It’s when you start modifying things where the pro-tune has benefits.