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 The Effects of Ambient Temp on Acceleration

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AA
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Name : Aaron
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PostSubject: The Effects of Ambient Temp on Acceleration   Wed Oct 03, 2007 12:00 pm

Last week I did a WOT at 85บF ambient temp. This week I did a near identical run at 75บF. Same location, same mods (3.4" SC pulley), same tune, same fuel (94 oct). Here are the results:



The 75บF (yellow) curve does spin out a tad at the launch, but notice it stays ahead of the 85บF (orange) curve the whole time, and starts to gain slightly up top. KR (not shown) was minimal for both runs. I plan to do more tests for 65บF and lower temps to show the effects of colder air on our engines. Also will compare 3.3", 3.2", and maybe 3.1" SC pulley if possible.

_________________
'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180บ t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'05 GTO • 85k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26
Because fun


'70 Olds Ninety-Eight Holiday Coupe • 116k miles • 455 Rocket V8
Because cool


'95 Celica • 152k miles • 0-60: yes
Because free
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Mr.Riviera
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Name : Matthew
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PostSubject: Re: The Effects of Ambient Temp on Acceleration   Thu Oct 04, 2007 4:53 pm

was IAT the same?
it will be nice to prove how air temps change our engines dramaticly...nobody believes me when i say it feels so slow when its 90* outside.

_________________
1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black -daily
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PostSubject: Re: The Effects of Ambient Temp on Acceleration   Thu Oct 04, 2007 6:08 pm

quote: "was IAT the same?"

No, IAT was of course higher on the 85บF day. This is the reason for the performance increase.

Below is the same graph, but including IAT curves for the 85บF (red) and 75บF (green) ambient temps. My IAT sensor typically reads close to true ambient immediately after a WOT run, and according to the numbers, my 85บF day was actually 88บF. My 75บF day was actually 72บF. I try to take the car out when it's exactly the right temperature, but sometimes things can change by the time I get to "the track".


_________________
'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180บ t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'05 GTO • 85k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26
Because fun


'70 Olds Ninety-Eight Holiday Coupe • 116k miles • 455 Rocket V8
Because cool


'95 Celica • 152k miles • 0-60: yes
Because free
Back to top Go down
http://www.cardomain.com/ride/657082/4
AA
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Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18327
Merit : 240

PostSubject: Re: The Effects of Ambient Temp on Acceleration   Sat Oct 13, 2007 4:26 pm

Here's a new graph with a 55บF run added:



The 55บF run is using a slightly different tune, but I think the results would be the same as it's close to the old tune at this point. I'm seeing the lower temps are making less of a difference now. Time to drop pulley size...

_________________
'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180บ t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'05 GTO • 85k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26
Because fun


'70 Olds Ninety-Eight Holiday Coupe • 116k miles • 455 Rocket V8
Because cool


'95 Celica • 152k miles • 0-60: yes
Because free
Back to top Go down
http://www.cardomain.com/ride/657082/4
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18327
Merit : 240

PostSubject: Re: The Effects of Ambient Temp on Acceleration   Thu Oct 25, 2007 6:38 pm

Today I did another WOT run at 60F with the 3.3" SC pulley. Interestingly, the result was EXACTLY the same as my run at 55F with the 3.4" pulley (green line above). I was very surprised at how close they were.

Just shows how much ambient temps can affect your times... just 5บF can make as much impact as a pulley swap!

_________________
'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180บ t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'05 GTO • 85k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26
Because fun


'70 Olds Ninety-Eight Holiday Coupe • 116k miles • 455 Rocket V8
Because cool


'95 Celica • 152k miles • 0-60: yes
Because free
Back to top Go down
http://www.cardomain.com/ride/657082/4
 
The Effects of Ambient Temp on Acceleration
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