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  #11  
Old 09-10-2009, 05:25 PM
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69427 69427 is offline
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Walk up to your car and pull up on one of the front fenders. It doesn't take much of a pull to lift the front end up 1". The air that comes into the front of the car, thru the grills or thru the bottom openings in front of the spoiler has a lot of area to come into the engine compartment, but only the side vents to go out. The rest is forced to the bottom of the engine compartment and out the back under the chassis, where our also infamous rear bumper parachute catches air again. The high pressure under the hood is what makes the front end lift at speed and give that light non-steerable feeling. My red Italian car does 171mph easy with only 300hp. But when you look at the bottom of the car, it's flat. Any intake for air, water cooling, and oil cooling, is more than matched with outlet vents. My entire engine cover is vents and in between the rear lights are more vents. Look at the C6R, that hood has more vents than I've ever seen on a stock based car since the Grand Sport Vettes of the 60s.
Bee Jay
Good looking car! Is it a front radiator? If so, what does the inlet/outlet look like?
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  #12  
Old 09-10-2009, 06:01 PM
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Originally Posted by Bee Jay View Post
Walk up to your car and pull up on one of the front fenders. It doesn't take much of a pull to lift the front end up 1". The air that comes into the front of the car, thru the grills or thru the bottom openings in front of the spoiler has a lot of area to come into the engine compartment, but only the side vents to go out. The rest is forced to the bottom of the engine compartment and out the back under the chassis, where our also infamous rear bumper parachute catches air again. The high pressure under the hood is what makes the front end lift at speed and give that light non-steerable feeling. My red Italian car does 171mph easy with only 300hp. But when you look at the bottom of the car, it's flat. Any intake for air, water cooling, and oil cooling, is more than matched with outlet vents. My entire engine cover is vents and in between the rear lights are more vents. Look at the C6R, that hood has more vents than I've ever seen on a stock based car since the Grand Sport Vettes of the 60s.
Bee Jay
Good looking car! Is it a front radiator? If so, what does the inlet/outlet look like?
No. The oil and water radiators are just behind the doors. The side strakes guide air to those radiators. The engine lid has tons of vents to let air out of the engine compartment. There is a vent between the tailights also.
Bee Jay
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  #13  
Old 09-10-2009, 06:36 PM
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Quote:
Originally Posted by Bee Jay View Post
Walk up to your car and pull up on one of the front fenders. It doesn't take much of a pull to lift the front end up 1". The air that comes into the front of the car, thru the grills or thru the bottom openings in front of the spoiler has a lot of area to come into the engine compartment, but only the side vents to go out. The rest is forced to the bottom of the engine compartment and out the back under the chassis, where our also infamous rear bumper parachute catches air again. The high pressure under the hood is what makes the front end lift at speed and give that light non-steerable feeling. My red Italian car does 171mph easy with only 300hp. But when you look at the bottom of the car, it's flat. Any intake for air, water cooling, and oil cooling, is more than matched with outlet vents. My entire engine cover is vents and in between the rear lights are more vents. Look at the C6R, that hood has more vents than I've ever seen on a stock based car since the Grand Sport Vettes of the 60s.
Bee Jay
Still no upward pressure on the vast majority of our hoods, it would have to come out that back section opening if it was much, instead it's flowing into/on top of the engine....and not by much....

I been thinking of doing holes in the back plane, ala' GS racers...but had no confidence I could pull it off, enough with the body work already....

I think it's because our rads are angled back so much that the air is forced downward in front of the engine....

Those flat panels are a funny item as in my wife's '99 Escort had them under neath refered to as 'fairing'....by some guys in the past....anyway, leaving it off has not affected fuel economy one bit....so there can't be much windage reasons for it to be there on THAT car anyway....

That little italian thing, looks likw a C4 in front/windshield, the back looks like a Fiero with Trans Am tail lights on it..... must be some lo production custom job....
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  #14  
Old 09-10-2009, 06:52 PM
Bee Jay Bee Jay is offline
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Originally Posted by mrvette View Post
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Originally Posted by Bee Jay View Post
Walk up to your car and pull up on one of the front fenders. It doesn't take much of a pull to lift the front end up 1". The air that comes into the front of the car, thru the grills or thru the bottom openings in front of the spoiler has a lot of area to come into the engine compartment, but only the side vents to go out. The rest is forced to the bottom of the engine compartment and out the back under the chassis, where our also infamous rear bumper parachute catches air again. The high pressure under the hood is what makes the front end lift at speed and give that light non-steerable feeling. My red Italian car does 171mph easy with only 300hp. But when you look at the bottom of the car, it's flat. Any intake for air, water cooling, and oil cooling, is more than matched with outlet vents. My entire engine cover is vents and in between the rear lights are more vents. Look at the C6R, that hood has more vents than I've ever seen on a stock based car since the Grand Sport Vettes of the 60s.
Bee Jay
Still no upward pressure on the vast majority of our hoods, it would have to come out that back section opening if it was much, instead it's flowing into/on top of the engine....and not by much....

I been thinking of doing holes in the back plane, ala' GS racers...but had no confidence I could pull it off, enough with the body work already....

I think it's because our rads are angled back so much that the air is forced downward in front of the engine....

Those flat panels are a funny item as in my wife's '99 Escort had them under neath refered to as 'fairing'....by some guys in the past....anyway, leaving it off has not affected fuel economy one bit....so there can't be much windage reasons for it to be there on THAT car anyway....

That little italian thing, looks likw a C4 in front/windshield, the back looks like a Fiero with Trans Am tail lights on it..... must be some lo production custom job....
The base of the windshield is a high presure area. The air flow over the hood is met by a brick wall windshield and causes higher pressure there. That is why the Vette, Camaro, and Chevelles have Cowl Induction. I have the back of my hood opened up, and it definitely does not vent the engine compartment. If it did, I'd have oil film on my windshield and occasionally some smoke from oil leaks hitting the headers. When I build my modded hood, it will have vents and a cold air cowl induction system.
Bee Jay

Last edited by Bee Jay; 09-10-2009 at 06:55 PM..
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  #15  
Old 09-10-2009, 07:24 PM
1Michel 1Michel is offline
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Dont know if these would help
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They talk about aerodynamics of the cars.
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  #16  
Old 09-12-2009, 11:49 PM
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Took a break from working on the rear suspension to take a look at the front bodywork. There's significantly less surface area in the bottom portion in front of the radiator compared to the top. If this diffuser volume is even remotely efficient (at converting air velocity into air pressure), then there's going to be a decent amount of force pushing the front bodywork upward.
This has got me curious enough to start thinking about constructing a manometer to measure this pressure.
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  #17  
Old 09-13-2009, 12:04 AM
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I sealed the three cooling holes in the lower valance and reduced my outer grill openings to about zero but the biggest improvement came from adding the little plastic factory spoiler...I could honestly feel that difference....
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  #18  
Old 09-17-2009, 01:28 AM
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I have been saying this for a while now on other forums but its like nobody believed me,i was one of the fellas that claimed he went 150 mph according to my speedo,which probably isnt right,but the fact is at that speed my hood started to pry off from the hinges,i seen it lift about an 1 to 1 1/2 inches ,then i started to slow down,plus the front end got lite .
I have a question to somebody who might know here when the 68 to what ever vettes that read 160 mph on the speedo,would the cars do 160 mph when they were new?If so ,why cant they run that fast now ?.

Last edited by Billsvette; 09-17-2009 at 06:26 PM..
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  #19  
Old 09-17-2009, 01:49 AM
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The radiator airflow/downforce on these cars worked really well.
Some of the C6R cars had this idea adapted to them.



Here are a couple pics of a front engine design, forgot what they are, don't even know if they worked, but the effort looks good.



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  #20  
Old 09-18-2009, 03:31 PM
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Bee Jay, try putting some manly springs under your frame rails and you won't be able to lift the front so easily.

My car is stable at 140mph, don't feel any lift. Now when my car was stock, I felt lift at any speed past 80mph.

The front end of a C3 is like a big spoiler, if you drop the car low enough with enough of a rake, she'll stabilize. The bottom of your oil pan might get all scraped up like mine, but it's worth it to turn your snazzy looking muscle car into a sports car. IMO.

I installed the 550 coils, with 3/4 of a coil cut and some low profile tires. I also cut out a wide opening behind the cowl on the hood.
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