C8 Air Deflectors

dyoung said:
Eray is great. #19 since the 60's...Live in Sidney near Victoria where your car came from.
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Great. I thought BC. I use to work in Victoria quite a bit. Stayed at Westin Bear Mt. hotel. I am on no. 6 corvette. I am an old guy now - LOL :heavycar:
 
Gilles27 said:
Part # are 85580654 ( $189 USD ) and 85580653 ( $186 USD ) if someone can get CDN pricing, I tried Kipp Scott and Tubman online and doesn't come up
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Inquire them through Tuberman a few days back. Not available in Canada. Ordered 654 through Amazon.com for around $72 CDN and Amazon.ca had them for the same price. May not be oem but look the same. 653 is not available except through GM US or else where.

It seems easy enough for me to make a 653 once I get the 654 as a template.
 
Gilles27 said:
Way overpriced but if they really do work somebody will 3D print these for cheap

GM actually does install these cooling deflectors on the European-market C8s (Stingray, Z06, E-Ray), but not on U.S. cars. The reason isn’t safety or cost — it comes down to U.S. emissions and acoustic certification. Forcing air up into the engine bay changes how heat escapes after shutdown, which affects EPA hot-soak evaporative emissions. It also slightly increases mechanical noise escaping upward (injectors, valvetrain), which means GM would’ve had to recertify the entire U.S. noise and emissions package. To avoid that million-dollar recertification process, they simply omitted the part here, even though the cars physically support it.In Europe the regulations are different, so GM ships them with the extra underbody ducting to help meet their heat-management requirements.Performance impact: The only “downside” is a tiny change in rear aero balance — we’re talking a fraction of a percent of rear downforce at high speed. On normal road use it’s completely irrelevant, and even on track you’d have to be driving at the absolute limit to notice anything.Benefits: Real-world testing already shows huge gains:– 10–60°F cooler engine bay temps (Depending on ambient temps, driving style, and heat soak, people are seeing anywhere from about 10°F to as much as 60°F cooler readings in key areas).– Cooler transmission, headers, intake, and trunk electronics– Faster cooldown after parking– Less heat soak overall– Zero downside for normal drivingThese are OEM GM parts, they bolt right on using the factory holes, and U.S. dealers can order them by part number. For the temperature drop they deliver, they’re absolutely worth installing.


Part # are 85580654 ( $189 USD ) and 85580653 ( $186 USD ) if someone can get CDN pricing, I tried Kipp Scott and Tubman online and doesn't come up
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Question…..

I have a ‘25 HTC which means the engine is covered from view.
Will these air deflectors work as well as they appear to on coupes where the engine is exposed and can vent the heat thru the trunk vents.

🤔
 
Ben Malik said:
Am I wrong, but I’m sure the full package came with my 2025 C8. Uninstalled and were in the frunk when I picked up my car…
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No, those are the brake ducts that came with your C8. Not the same thing.

These were developed for an installed on European cars because those cars (in some countries) come with particulate exhaust filters, and those filters run REALLY hot. On the autobahn they were melting plastic parts in the rear of the car. These deflectors exist for that reason, and that's why they're not installed on North American market cars. It has nothing to do with EPA or noise regulations.
 
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meyerweb said:
No, those are the brake ducts that came with your C8. Not the same thing.

These were developed for an installed on European cars because those cars (in some countries) come with particulate exhaust filters, and those filters run REALLY hot. On the autobahn they were melting plastic parts in the rear of the car. These deflectors exist for that reason, and that's why they're not installed on North American market cars. It has nothing to do with EPA or noise regulations.
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I've read three different edits in 3 minutes lol...
 
I have recently installed a set of the aftermarket stainless steel ones and they look great. Unable to test / use them at this point due to winter but I think they will help with engine bay heat for sure.
 
2025Z06 said:
I have recently installed a set of the aftermarket stainless steel ones and they look great. Unable to test / use them at this point due to winter but I think they will help with engine bay heat for sure.
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For sure it will help as demonstrated in HPO video.
I had my home made one base on the GM design. I have to install the passenger side next.

20251224_163425.webp
 
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