"Wobbles the Mind" (wobblesthemind)
12/01/2016 at 13:50 • Filed to: Performance
0
5|
"Wobbles the Mind" (wobblesthemind)
12/01/2016 at 13:50 • Filed to: Performance | 0
| 5 |
I never get to experience performance the same way people do that live at sea level. I decided to make up a rough set of formulas in order to convert sea level performance to elevation performance. All math is based on my gut/butt feelings, so give them a try!
For naturally aspirated engines:
Total Horsepower Loss = (Horsepower@sealevel) * (0.03) * (Elevation/1000)
Horsepower @ Elevation = (Horsepower@sealvl) - (Total Horsepower Loss)
0-60 mph Time Increase:
1,000 ft = +10% | 2,000 ft = +20% | 5,000 ft = +50%
Example #1: Ferrari F12berlinetta
731 hp @ sealvl, 0-60 mph in 3.1 seconds @ sealvl.
687 hp @ 2,000 ft, 0-60 mph in 3.72 seconds @ 2,000 ft.
621 hp @ 5,000 ft, 0-60 mph in 4.65 seconds @ 5,000 ft.
Example #2: Camaro SS
455 hp @ sealvl, 0-60 mph in 3.9 seconds @ sealvl.
428 hp @ 2000 ft, 0-60 mph in 4.68 seconds @ 2,000 ft.
387 hp @ 5,000 ft, 0-0-60 mph in 5.85 seconds @ 5,000 ft.
For forced induction engines:
Total Horsepower Loss = (Horsepower@sealevel) * (0.015) * (Elevation/1000)
0-60 mph Time Increase:
1,000 ft = +5% | 2,000 ft = +10% | 5,000 ft = +25%
Example #1: Dodge Charger SRT Hellcat
707 hp sealvl, 0-60 mph in 3.4 seconds @sealvl.
686 hp @ 2,000 ft, 0-60 mph in 3.74 seconds @ 2,000ft.
654 hp @ 5,000 ft, 0-60 mph in 4.25 seconds @ 5,000 ft.
Example #2: BMW M4 Coupe
425 hp @ sealvl, 0-60 mph in 3.8 seconds @ sealvl.
412 hp @ 2,000 ft, 0-60 mph in 4.18 seconds @ 2,000 ft.
393 hp @ 5,000 ft, 0-60 mph in 4.75 seconds @ 5,000 ft.
*Note that I drive between 5,000 ft and 7,000 ft above sealevel everyday.
I have zero clue if these are even remotely accurate, but I like them! Go ahead and check out any cars you like, or just ask what car is fast to 60 mph at any elevation. For all of you that say horsepower doesn’t matter, ha! For others that don’t think 6 seconds from 0-60 mph is fast, I would need a 455 hp Camaro to experience 268 hp Camry/ 278 hp Accord acceleration @ sealvl. (Pretending my dataless fake math were actually cromulent, which it isn’t).
Bman76 (hates WS6 hoods, is on his phone and has 4 burners now)
> Wobbles the Mind
12/01/2016 at 13:57 |
|
We must go below sea level. FOR PERFORMANCE!!!
davesaddiction @ opposite-lock.com
> Wobbles the Mind
12/01/2016 at 14:06 |
|
I have zero clue if these are even remotely accurate, but I like them!
I’m pretty sure this is PEDJT’s position on all “facts”.
ESSSIX GmbH - Accountant/Wagon Thumper
> Wobbles the Mind
12/01/2016 at 14:10 |
|
I thought that for turbos, they just work harder since they must still reach the same given boost.
Frank Grimes
> Wobbles the Mind
12/01/2016 at 16:07 |
|
Maybe this is why suicide and depression rates are higher at higher?
V8Demon - Prefers Autos for drag racing. Fite me!
> Wobbles the Mind
12/01/2016 at 16:08 |
|
Density altitude, volumetric efficiency, and brake specific fuel consumption are the big players in this.
I’ll quote someone regarding Density Altitude:
There has to be a “Standard Reference” (SAE J2723) when determining the Rated HP of a given vehicle. And this is done by operating the vehicle in a “Standard Environmental Condition”.
Ideally, a Standard Environmental Condition (“Standard Day”), and would be:
1. Sea level
2. A barometer of 29.92” Hg.
3. An ambient air temperature of 59 degrees F (+15 C)
4. A relative humidity of 0%
This meteorological condition is the basis of determining rated SAE HP. It is also the standard condition for determining 1/4 mile acceleration performance.
Just because a track is at an elevation close to sea level, the Density Altitude (DA) of a given track may be real high due to a local environmental condition of low barometric pressure, high temperature and/or high humidity at the time … So, we can say that; Density Altitude (DA) is the actual altitude of the track adjusted for the barometric pressure and relative humidity at the time.
Then combine a high PA with a high ambient air temperature, and you get a very high Density Altitude (DA) … Density Altitude is the actual track altitude above sea level, adjusted for the barometric pressure, ambient air temperature and relative humidity.
And a high DA is what kills horsepower and results in high ETs and low trap speeds.
On the other hand, operating a vehicle on a track close to sea level, at very cold track temperature, a condition of high barometric pressure and very low humidity would result in faster 1/4 mile times than when operated at a Sea Level / Standard Day track, and would also not be an accurate measurement of the car’s rated HP.
It’s not uncommon to see negative DA numbers (i.e. below sea level equivalents) which means even better times....
Volumetric efficiency is at it’s highest in an engine when said engine is at it’s peak torque RPM. A heavily modified motor will usually have a higher VE than it’s stock counterpart. Forced induction raises the VE as well. THis is affected by DA.
Conversely; the brake specific fuel consumption is at it’s LOWEST at peak torque RPM (the lower the better for this value generally.