C5 Ram Air Hood for 150+ mph Check My Math / Thoughts - Anyone made one? -
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C5 Ram Air Hood for 150+ mph Check My Math / Thoughts - Anyone made one? -
Ran 190+ at Mojave Mile in April, and going back in Oct. Car i think has the stones to touch 200, but its going to be close. I'm thinking about getting a second hood to cut up - this wont be too pretty, but it will work well, esp at 150+.
I'm thinking something like this RX7 has in this video:
Basically imagine a line that runs straight forward of the TB, cut a hole in the hood and open in up to go to the TB. Now take jigsaw and REALLY open it up about 8" wide and 4 tall or so to 'funnel' the air in.
At WOT normally an engine has a few psi going into it, just atmospheric pressure minus engine vac = the pressure pushing air into cylinders.
With my idea is that the intake will be wide at the hood (4 x 8 oval roughly) and funnel down to the TB/MAF (might change to speed density tune for it, idk yet). The dynamic pressure formula for this is as follows: q = 1/2 * rho * Vtb^2 where Vtb = Vin * Ain/Atb. Rho is the air density, Vtb is the velocity at TB, Vin is the velocity of the air coming into the funnel/scoop = speed of the car, Ain is the area of the intake at the hood = area of a 4x8 oval ~25in^2, and the Atb is the area of a 90mm TB.
100mph = 1.14psi
150mph = 2.58psi
200mph = 4.58psi
This obviously there are a lot of assumptions here like no fiction, all the air coming straight at the intake will enter and not be pushed/deflected by the air over the nose etc. So, to be safe lets say 50% of this will actually happen (realistically closer to 75-85% of this is true, but we will use conservative numbers). This means that at 100mph it should have about 0.50psi, 150mph = 1.25psi, 200mph = 2.25psi. There should be no difference in this and a turbo (supercharger takes hp to run). From a lot of research it seems that 0-5psi there is a lot more hp/psi gain then diminishes after. From said research it seems that 15whp is very conservative seeing how research showed 20whp to 30whp upto about 6-8psi, then slowly dropped off. Then this should mean that: 100mph = 7whp, 150mph = 25whp, and then 200mph = 45whp.
I'm thinking something like this RX7 has in this video:
Basically imagine a line that runs straight forward of the TB, cut a hole in the hood and open in up to go to the TB. Now take jigsaw and REALLY open it up about 8" wide and 4 tall or so to 'funnel' the air in.
At WOT normally an engine has a few psi going into it, just atmospheric pressure minus engine vac = the pressure pushing air into cylinders.
With my idea is that the intake will be wide at the hood (4 x 8 oval roughly) and funnel down to the TB/MAF (might change to speed density tune for it, idk yet). The dynamic pressure formula for this is as follows: q = 1/2 * rho * Vtb^2 where Vtb = Vin * Ain/Atb. Rho is the air density, Vtb is the velocity at TB, Vin is the velocity of the air coming into the funnel/scoop = speed of the car, Ain is the area of the intake at the hood = area of a 4x8 oval ~25in^2, and the Atb is the area of a 90mm TB.
100mph = 1.14psi
150mph = 2.58psi
200mph = 4.58psi
This obviously there are a lot of assumptions here like no fiction, all the air coming straight at the intake will enter and not be pushed/deflected by the air over the nose etc. So, to be safe lets say 50% of this will actually happen (realistically closer to 75-85% of this is true, but we will use conservative numbers). This means that at 100mph it should have about 0.50psi, 150mph = 1.25psi, 200mph = 2.25psi. There should be no difference in this and a turbo (supercharger takes hp to run). From a lot of research it seems that 0-5psi there is a lot more hp/psi gain then diminishes after. From said research it seems that 15whp is very conservative seeing how research showed 20whp to 30whp upto about 6-8psi, then slowly dropped off. Then this should mean that: 100mph = 7whp, 150mph = 25whp, and then 200mph = 45whp.
#2
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The size of the scoop opening goes down as speed increases
Ideally, the scoop cross-sectional area expands after the entrance to slow down the air and trade speed for pressure, and the TB is (almost) in still air.
Read this: http://tinyurl.com/hv6xupm
Ideally, the scoop cross-sectional area expands after the entrance to slow down the air and trade speed for pressure, and the TB is (almost) in still air.
Read this: http://tinyurl.com/hv6xupm
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The size of the scoop opening goes down as speed increases
Ideally, the scoop cross-sectional area expands after the entrance to slow down the air and trade speed for pressure, and the TB is (almost) in still air.
Read this: http://tinyurl.com/hv6xupm
Ideally, the scoop cross-sectional area expands after the entrance to slow down the air and trade speed for pressure, and the TB is (almost) in still air.
Read this: http://tinyurl.com/hv6xupm
So do you think that my idea wouldn't work as I'm wanting at all or...?
I was thinking the area in my fast 102 would basically be the diffuser to slow everything down before going into cylinders and thus pressure would increase?
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Ok I understand. I first did it with a 6x12 scoop, but that was far too much (37+ psi) and would be like a big brake, so I reduced it down to what would get me 3-5psi @ 200mph. Basically all I need is a little more umph!
SD tuning for this will be fun if I cannot shove a maf in there...
Might look into a varvaram intake maybe...
Running without a filter makes me nervous, but I think it would be fine since its for 3 runs and will be a total of 5-6 miles without anyone in front of me to kick anything up... Anything 'floating' in the air (pollen, Cotten, etc) will be fine through the motor - a rock...not so much
SD tuning for this will be fun if I cannot shove a maf in there...
Might look into a varvaram intake maybe...
Running without a filter makes me nervous, but I think it would be fine since its for 3 runs and will be a total of 5-6 miles without anyone in front of me to kick anything up... Anything 'floating' in the air (pollen, Cotten, etc) will be fine through the motor - a rock...not so much