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Donald Trump's Landlord
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Discussion Starter · #1 ·
What is the ratio (%) between actual HP produced and the air temperature entering the chamber? It's getting to Fall up here and (despite actually feeling home much stronger the car runs) I was wondering what increase in HP a decrease in air temperature was actually making. Say there's a difference of 25 degrees (85 to 60). What would the formula suggest is the increase?
 

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Schadenfreude Connoisseur
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Im not sure if there is a formula for temp swings, but I do know that with the same SC pulley, my car picked up 25 rwhp changing from a dyno room at 100 degrees to a dyno room around room temp. If you feel a change at the seat of your pants, that ass dyno isnt lying.
 

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ass dyno
:rofl: :rofl: :rofl: :rofl: :rofl:
 

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RIP - Gone But Not Forgotten
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CitySnake said:
What is the ratio (%) between actual HP produced and the air temperature entering the chamber? It's getting to Fall up here and (despite actually feeling home much stronger the car runs) I was wondering what increase in HP a decrease in air temperature was actually making. Say there's a difference of 25 degrees (85 to 60). What would the formula suggest is the increase?
From my automotive training classes in Tech School

These are "close approximates". Not dead on but very very close.

Power Decrease per elevation Minus 3.5% per 1,000' above sea level

Power Decrease from heat Minus 1% per every 10 degree's above 60 degree's F.



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Donald Trump's Landlord
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Discussion Starter · #5 ·
OK J:

So if the inverse is accurate, then a decrease of 25 degrees would yield an increase in HP of 2.5%? That seems like too slight an increase. At 550 RWHP I would get less than 14 horses? My ass dyno is NOT that sensitive. Did I make a mistake?

PS- Your avatar is frightening me :ugh:
 

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RIP - Gone But Not Forgotten
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CitySnake said:
OK J:

So if the inverse is accurate, then a decrease of 25 degrees would yield an increase in HP of 2.5%? That seems like too slight an increase. At 550 RWHP I would get less than 14 horses? My ass dyno is NOT that sensitive. Did I make a mistake?

PS- Your avatar is frightening me :ugh:
I only have the info for 60F and above. Cooler temps have other affects on the engine for which I may not have the info for, Sorry...

Let me share some things with you. This is written by Virgil Hartman of NHRA Top Fuel fame. This guy knows his shit and this class proves the "experts" wrong almost constantly.




"........I am glad we do not run these cars by math, as the experts have been wrong since the early days when they stated we could not exceed 160 mph in the quarter mile. I have two graduate mechanical engineers on our team that are constantly proving to me with math that we cannot possible be doing the things we do almost every run..............

.........And if physics and math are so precise, why hasn't the ultimate vehicle been designed already? Why do funny car bodies keep getting changed for aerodynamics if the wind tunnel data is so great? Dyno horsepower verses on track performance, again they are only tools that get you in the ballpark."

He is talking about Fuelers but the bit on math still does apply. The best line is the last one.

Let me see if I can find my old notes etc. and see if I can dig up any more info on the subject.




Edit: Almost forgot, Rob is just by for a visit 'till I find a new babe pic I like.






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