How Do I Get Cold Air to the Engine?
09-02-2008, 07:45 PM
#1
Bud2
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How Do I Get Cold Air to the Engine?
In the future I'll need to have a higher hood. I prefer the look of the hood that get the cold air from the 'high pressure' area at the base of the windshield over traditional hood scoops. Well....
Yesterday I had to spend some time on the road, was a miserable day with varying amounts of rain. While driving at 60 mph, had time to study the drops on the windshield. On the top 1/4, the water was really pushed by the wind. The effect was decreasing as you moved down the windshield until the bottom 1/4 appeared to be netural, the drops were just sitting there. Where did the 'high pressure' go?
Has anyone ever conducted tests on the pressure at the base of the windshield compared to a scoop that sits 4 inches off the hood? (Tested on C2s)
Is one place more trubulent than the other?
If the pressure is greater at a scoop, does that mean the air density is higher, thus more HP?
Bud.
Yesterday I had to spend some time on the road, was a miserable day with varying amounts of rain. While driving at 60 mph, had time to study the drops on the windshield. On the top 1/4, the water was really pushed by the wind. The effect was decreasing as you moved down the windshield until the bottom 1/4 appeared to be netural, the drops were just sitting there. Where did the 'high pressure' go?
Has anyone ever conducted tests on the pressure at the base of the windshield compared to a scoop that sits 4 inches off the hood? (Tested on C2s)
Is one place more trubulent than the other?
If the pressure is greater at a scoop, does that mean the air density is higher, thus more HP?
Bud.
09-02-2008, 08:07 PM
#2
Race Director
Here is one way. This flows over 750 actual CFM with no pressure drop.
The cold air is denser and adds about a percent of HP. We measured about 8 HP difference between cold air from the front vs warm air from the engine compartment on a chassis dyno. There may be additional benefits from actually driving at speed and getting a small ram effect.
Doug
The cold air is denser and adds about a percent of HP. We measured about 8 HP difference between cold air from the front vs warm air from the engine compartment on a chassis dyno. There may be additional benefits from actually driving at speed and getting a small ram effect.
Doug
09-02-2008, 08:31 PM
#4
Race Director
09-02-2008, 10:39 PM
#5
In the C2, the base of the hood is a LOW pressure area, not high pressure. Why do you think that modern cars have moved their intake systems to the bottom front of the vehicle (sort of like what AZDoug is doing). That's where pressure builds up. If anything, a C2 at speed will likely blow its hood off if not for the hood catches.
Quite frankly, it not just the C2 that has this problem, virtually any cowl induction vehicle produced at the time doesn't work - and for the very same reason (so don't bother looking in that direction). Let's face it, aerodynamics in the 60s was a fledgling science that wasn't fully understood by the automobile industry.
In 1968, early pre-production big blocks mostly overheated (leading to the big controversy around poor quality for the cars) until they figured out that the front spoiler wasn't big enough to force the air past the radiator. The engineers actually thought the opposite was true until they rigged a few examples.
Quite frankly, it not just the C2 that has this problem, virtually any cowl induction vehicle produced at the time doesn't work - and for the very same reason (so don't bother looking in that direction). Let's face it, aerodynamics in the 60s was a fledgling science that wasn't fully understood by the automobile industry.
In 1968, early pre-production big blocks mostly overheated (leading to the big controversy around poor quality for the cars) until they figured out that the front spoiler wasn't big enough to force the air past the radiator. The engineers actually thought the opposite was true until they rigged a few examples.
