The bumps were playing havoc on the aero as well, the car was slamming through the travel and our classified under-car aero was getting damaged. To mitigate this, we adjusted the shocks high-speed compression damping and raised the ride height by 10mm. This helped a lot. Dai didn’t like how the compression adjustment made the car turn in super sharply so I dialed it back a little. By our last run, the car was still not great over the bumps but much better. A car built for downforce is never going to be super good over bumps and the bumps were so bad it was bumpy in a stock rental car. This is how good our KW motorsports shocks are, stiff with good pitch control for aero stability yet capable of handling pretty big bumps at a low ride height.
This was Dai’s first time up this part of the mountain at speed as it was closed due to snow during prerunning the week before.
This part of the course is a mixture of fast sweepers and a few tight hairpin switchbacks.
So for our first day, we were reasonably fast in the top third of the cars but were a little disappointed with our speed. In the real event, our tires would be much warmer from the run-up to this point though and Kelvin was continually refining our traction control to suit the corse. The tuning of the traction control was pretty critical and very helpful for the management of the rear tires. Kelvin got it so the car would kind of surf the traction control limit and Dai could modulate the throttle to hold it there and not affect the balance of the car.
So we returned to the house and prepped the car, the big thing was repairing the undercar aero devices. Dai was disappointed at his time so he wanted to take a support vehicle and make some recon runs to figure out some new lines to miss the bigger bumps. I wanted to go to measure the pavement temps so I would get a better idea what the surface might be like on race day.
The rest of the crew wanted to go to the summit too to see what it is like. So we all piled into our support vehicles and did some sightseeing. This is the climb from the midpoint to the devil’s playground. Look how high it is! Look how far down you fly if you mess up!
7 comments
Really cool article Mike, it made me think of a few questions though.
Does the aero noticeably get weaker as the car climbs? if so, would having driver/automatic tuneable suspension make a difference?
The car seem to have small endplates, are those rules limited as well? I would think gigantic endplates would be the default for a course like Pikes Peak.
About the turbo, does it spool up quicker and reach higher RPM in thinner air? So you would get better response but less overall power the higher you go? Unless it’s not limited by the friction on the compressor wheel…
Anyways TIL about racing with oxygen bottles on Pikes Peak.
The aero gets weaker as the car climbs higher, also the turns get tighter and for the most part lower speed. Having driver-adjustable suspension is not that useful because the driver is pretty busy on this course because very little of it is straight and if your chassis guy knows what he is doing the car is balanced high and low-speed aero load or not. A big endplate doesn’t mean much. It gives more room for sponsor logos. The end plates main job is to prevent spillover on the ends of the wing elements or front diffuser for that matter. The ones on our front diffuser also serve as vortex generators so they can only be around a certain size. That is what the weird looking shape is for. At high altitudes, compressor Overspeed and surge are for sure a thing and sometimes you have to reduce boost as the car climbs. Watching that situation is something that is a headache that kicks a lot of people’s ass.
Oh, I thought endplates had a big effect on yaw control, like the shark fins on WEC cars, but if they have a big effect on the budget aren’t they even more useful!? hahaha.
Good to know about boost control at altitude, I just realized that pikes peak is even higher than the Andros Trophy in the french alps. The mexico GP is only half that and they have trouble.
The shark fins don’t do anything in CFD and wind tunnel, at least when they were first tested. They did give more advertising space.
Mike! Do you have any kind of fan setup behind the radiator? Or do you get enough air flow from how fast the car is going up the track?
Yes a pretty large fan, I think its a Spal.
Great article, I love the prep perspective to go with the technical articles.
It seems like you were prepping at Pikes Peak for about a week?