05

Nerd’s Eye View: Dale Coyne Racing IndyCar

by Khiem Dinh

 

The MotoIQ crew was roaming the IndyCar paddock during the Grand Prix of Long Beach hoping to get our eyes on some high-end race machinery. Getting up close with an IndyCar was more than we could have hoped for as it represents the highest form of open wheel racing for a US based series. Besides, it has turbos!

 

Justin Wilson’s crew at Dale Coyne Racing was gracious enough to give the MIQ crew unlimited access to the car while the crew wrenched on it. One change this year from the previous year was the mandated use of a twin-turbo system whereas last year had the option of a single turbo setup. Wilson’s car uses the Honda Performance Development power plant. As you can see, each side of the car carries unique heat exchangers with one side cooling the coolant and the other side the oil.
No thermostats are used on the car as they can be potential failure points and add complexity. Instead, simple block-off plates are used to cover parts of the heat exchangers to regulate temperatures.
The size of the openings in the side pods can also be adjusted by blocking off various amounts to adjust cooling.
Packaged very tightly behind the heat exchangers on each side are the Borg Warner EFR 7163 turbos. These IndyCar turbos use V-band flanged turbine housings and external wastegates. The Honda power plant places the turbos as far forward as possible pushing them up against the heat exchangers. Chevrolet places the turbos more rearward roughly in-line with the last cylinder. Each arrangement has their positives and negatives. Honda decided to keep the wastegate and turbine exhaust flows separate whereas Chevrolet merge the two flows back together into a single big exhaust pipe exiting the bodywork.
Extensive heat shielding covers the exhaust manifolds and turbine housings. Heat equals energy and energy makes the turbos spin. It’s also nice to not damage the very expensive carbon fiber in close proximity to the hot bits. The wiring for the O2 sensors is protected in the orange insulation as electrical wires don’t react well to extreme heat either. The oil and water lines to the turbo and practically every line near the hot parts are similarly protected from heat by insulation. The big silver line attached to the top of the wastegate connects to the air box.
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Comments
Calvin
Calvinlink
Tuesday, May 06, 2014 8:25 AM
Very cool! Love seeing how the pros build up their cars.
warmmilk
warmmilklink
Tuesday, May 06, 2014 12:35 PM
whats going on with the wastegates? why do they have a window cut in the side?
ETM
ETMlink
Tuesday, May 06, 2014 2:35 PM
Wastegate window: They are separating the actuator from the hot wastegate body. Windows cut in the side are just mass that is removed so that less heat can transfer between the two components. Air is also ducted to from the airbox to the shroud that covers the actuator.
8695Beaters
8695Beaterslink
Tuesday, May 06, 2014 8:06 PM
I got the chance to watch Chip Ganassi's team swap their Honda engine at Baltimore in September. Amazing to watch these guys work, they had the engine in and out in less than an hour! I got a peek at the intake design. Very clever, with velocity stacks (I think they were adjustable length but I was too far away to tell for sure) and the injectors pointed right down into the ports. I think I got a bit too close for comfort because after a while Honda made sure to block my view when they were looking inside.

Another benefit of shims for camber adjustment is that adjustment on the upright does not affect KPA. Adjusting on the arm itself would move the location of the arm pivot and change KPA and scrub. Though it looks as if that can be adjusted with shims on the inner brackets or the arms themselves. And a final benefit is that the shims are quick and easy to install and give repeatable changes in camber that don't require breaking out the angle finder.
ginsu
ginsulink
Wednesday, May 07, 2014 12:57 PM
Surprised they run so much pro-Ackerman geometry, seems like anti-Ackerman is all the rage in Formula 1 for many years now. You can clearly see it on the onboard videos.

Do the Indy tires not like to be run at higher slip angles? I thought race rubber needed a bit more slip angle to generate higher lateral cornering forces.
spdracerut
spdracerutlink
Sunday, May 11, 2014 7:11 PM
Ginsu, interesting observation. I imagine one variable are the tire designs with the F1 tires having larger aspect ratios. So maybe something with the dynamics of the tires. Maybe also the weight distribution; I know the F1 cars have very strict regulations on the distribution.
Anonymous User
Anonymous Userlink
Wednesday, May 06, 2015 11:09 PM
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