That time of year again....

335i Pal · 12-01-2011, 09:56 AM

With the recent influx of cold air over here in Ohio, Mid to low 30's F, it has made a huge difference on my car. I know the compressed colder air helps, but was wondering how much it helps.

Has anyone ever ran a dyno of their car in the cold or track times. I just have a JB3 (map5) and a BMS DCI, but my butt dyno tells me there is an even bigger increase than when it is running 60+ degree weather, just wasnt sure how much though.

Aces · 12-01-2011, 10:16 AM

I am very interested in this as well.

Air at -30f is 17% denser than air at 70f. However, you're also starting 100 degrees rankine cooler in your V1*P1/T1=V2*P2/T2 calculations. This should help prevent knock with the denser air meaning that even with the increased mass of air the heat of compression will have a much lower starting temperature.

If anyone here can confirm or deny this I would love to read it.

onevrsix · 12-01-2011, 10:50 AM

Mustang dyno @ 81 degrees summer 2010 , 265hp, 305 ft/lbs
Same dyno winder 2010 @ 39 degrees 269hp, 318ft/lbs

no mods between; but during winter tires become the biggest issue, snow tires, shit traction, summers under 32degrees...game over

be1ieve1111 · 12-01-2011, 11:52 AM

I thought mid 50's is perfect turbo weather.

Eric335 · 12-01-2011, 12:08 PM

Quote:

Originally Posted by be1ieve1111

I thought mid 50's is perfect turbo weather.

normally, i have about 1000* weather. recently in the 65* weather ive felt HUGE improvement in torque!

335i Pal · 12-01-2011, 09:10 PM

Quote:

Originally Posted by onevrsix

Mustang dyno @ 81 degrees summer 2010 , 265hp, 305 ft/lbs
Same dyno winder 2010 @ 39 degrees 269hp, 318ft/lbs

no mods between; but during winter tires become the biggest issue, snow tires, shit traction, summers under 32degrees...game over

Wow no that much of a change, my butt dyno felt at least a 100hp increase

ryan970 · 12-01-2011, 09:23 PM

haha ive never felt that change, i live in CO high elavtion, low temp.

ludlow · 12-01-2011, 11:23 PM

All dyno's give corrected horsepower numbers. They take air temperature, pressure etc. readings and use a formula to calculate horsepower at sea level and a standard temperature. Your car actually making more power in cooler weather though just as it makes less at higher altitudes. Also turbo's benefit from the cool air.

12-01-2011, 09:56 AM	#1
335i Pal Second Lieutenant 19 Rep 284 Posts Drives: 335i Sedan Join Date: Oct 2010 Location: Ohio iTrader: (1)	That time of year again.... With the recent influx of cold air over here in Ohio, Mid to low 30's F, it has made a huge difference on my car. I know the compressed colder air helps, but was wondering how much it helps. Has anyone ever ran a dyno of their car in the cold or track times. I just have a JB3 (map5) and a BMS DCI, but my butt dyno tells me there is an even bigger increase than when it is running 60+ degree weather, just wasnt sure how much though. __________________ 335i E90 \| BMS DCI \| Black Matte Grill \| JB4 \| Logic 7 \| Sport \| Premium \| Cold \|
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12-01-2011, 10:16 AM	#2
Aces Enlisted Member 1 Rep 44 Posts Drives: 2006 330xi 6 Speed Join Date: Nov 2011 Location: Minneapolis, MN iTrader: (0)	I am very interested in this as well. Air at -30f is 17% denser than air at 70f. However, you're also starting 100 degrees rankine cooler in your V1P1/T1=V2P2/T2 calculations. This should help prevent knock with the denser air meaning that even with the increased mass of air the heat of compression will have a much lower starting temperature. If anyone here can confirm or deny this I would love to read it.
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12-01-2011, 10:50 AM	#3
onevrsix New Member 0 Rep 15 Posts Drives: RIP 330xi Join Date: Sep 2011 Location: illadelphia iTrader: (0)	Mustang dyno @ 81 degrees summer 2010 , 265hp, 305 ft/lbs Same dyno winder 2010 @ 39 degrees 269hp, 318ft/lbs no mods between; but during winter tires become the biggest issue, snow tires, shit traction, summers under 32degrees...game over
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12-01-2011, 11:52 AM	#4
be1ieve1111 Thread Killer 20 Rep 930 Posts Drives: 2014 EB M235i Join Date: May 2010 Location: Indiana iTrader: (9)	I thought mid 50's is perfect turbo weather.
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12-01-2011, 09:23 PM	#7
ryan970 Major 164 Rep 1,304 Posts Drives: Tiag 328i,DGM F10 550 Join Date: Oct 2010 Location: Colorado iTrader: (0)	haha ive never felt that change, i live in CO high elavtion, low temp. __________________ 08 TIAG 328i 13 DGM 550 x drive
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12-01-2011, 11:23 PM	#8
ludlow New Member 0 Rep 26 Posts Drives: 2011 335i 6M MSport RWD Join Date: Nov 2011 Location: Canada iTrader: (0)	All dyno's give corrected horsepower numbers. They take air temperature, pressure etc. readings and use a formula to calculate horsepower at sea level and a standard temperature. Your car actually making more power in cooler weather though just as it makes less at higher altitudes. Also turbo's benefit from the cool air.
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