fizxman Posted September 2, 2007 Share Posted September 2, 2007 It's not comfy here in the low desert this week - we hit 110 degrees with about 75-80% humidity this afternoon. Took the family out to the movies, and noticed that my Spec.B didn't seem to like the weather any better than I did! Anyone know what kind of performance drop off this kind of awful weather creates in terms of WHP or acceleration? Just curious. By the time movie and dinner were done, things had cooled off nicely... only 104 on the way home around 6:45PM. Car accelerated much better around town and on the freeway. Link to comment Share on other sites More sharing options...
wukindada Posted September 2, 2007 Share Posted September 2, 2007 Hasn't been that hot here but it has been in the mid-high 90's with humidity always in the 80% and up...... As far as power loss goes while sitting in traffic I'd be willing to say a stock car that puts down 195-200whp would be more in the area of 165-170 with those kind of temp's. I have no doubt my losses are 50whp or better even with a FMIC:( 2 more months to go though...... Toyota 6EATS .........SUCK!!!!!! Link to comment Share on other sites More sharing options...
fonts Posted September 2, 2007 Share Posted September 2, 2007 We certainly don't see that combination of humidity and temperature very often in the great white north but can definitely relate to the performance changes due to weather. The turbo certainly doesn't like that hot air...... Does that mean better performance for me when the wife isn't in the car?????? :lol: Link to comment Share on other sites More sharing options...
NewLegGT67 Posted September 2, 2007 Share Posted September 2, 2007 Let's not forget the AC sucking power on top of that. I didn't know this when I first got my car last June (first turbo car) until I joined this site. I just got use to the power during the summer months. I remember when I took the car out on the first cool Saturday late September '06. It was like I went Stg1. I'm probably the only person that has Wu-Tang Clan and Paul McCartney on their mp3. Link to comment Share on other sites More sharing options...
jagcars26 Posted September 2, 2007 Share Posted September 2, 2007 You go full throttle,the AC kicks off.And most people have said they see no diff in mpg with the AC on or off. Link to comment Share on other sites More sharing options...
gt_ltd Posted September 2, 2007 Share Posted September 2, 2007 does hot weather affect NA cars as much? This Space For Rent Link to comment Share on other sites More sharing options...
Vimy101 Posted September 2, 2007 Share Posted September 2, 2007 does hot weather affect NA cars as much? All cars will be affected by high temps and humidity. Forced induction cars slightly less so. Link to comment Share on other sites More sharing options...
MyWifezLEGi Posted September 2, 2007 Share Posted September 2, 2007 damn heat is irratating me! it was 115 @ 2pm Link to comment Share on other sites More sharing options...
NewLegGT67 Posted September 3, 2007 Share Posted September 3, 2007 You go full throttle,the AC kicks off.And most people have said they see no diff in mpg with the AC on or off. Really, I didn't know that but I do notice (1 or 2) less MPG with the A/C blasting. I'm probably the only person that has Wu-Tang Clan and Paul McCartney on their mp3. Link to comment Share on other sites More sharing options...
Vimy101 Posted September 3, 2007 Share Posted September 3, 2007 AC draws power but does increase torque. AS soon as I hit the AC, I can see the instaneous mpg gauge on the info system dip but overall mpg doesn't seem to suffer much. Link to comment Share on other sites More sharing options...
rao Posted September 3, 2007 Share Posted September 3, 2007 All cars will be affected by high temps and humidity. Forced induction cars slightly less so. huh??? Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
rao Posted September 3, 2007 Share Posted September 3, 2007 AC draws power but does increase torque. AS soon as I hit the AC, I can see the instaneous mpg gauge on the info system dip but overall mpg doesn't seem to suffer much. Increases torque?? How does that work. Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
Vimy101 Posted September 3, 2007 Share Posted September 3, 2007 ^ More rotational momentum. An object in motion tends to stay in motion. Link to comment Share on other sites More sharing options...
rao Posted September 3, 2007 Share Posted September 3, 2007 ^ More rotational momentum. An object in motion tends to stay in motion. Wow. Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
ncretter Posted September 3, 2007 Share Posted September 3, 2007 High Temp=low density High humidity=low density low density=sad engine (less air to burn, so less fuel able to burn, so worse engine performance) Link to comment Share on other sites More sharing options...
Vimy101 Posted September 3, 2007 Share Posted September 3, 2007 Wow. Yup. That's torque for you. Link to comment Share on other sites More sharing options...
edmundu Posted September 3, 2007 Share Posted September 3, 2007 It's not comfy here in the low desert this week - we hit 110 degrees with about 75-80% humidity this afternoon. Took the family out to the movies, and noticed that my Spec.B didn't seem to like the weather any better than I did! Anyone know what kind of performance drop off this kind of awful weather creates in terms of WHP or acceleration? Just curious. By the time movie and dinner were done, things had cooled off nicely... only 104 on the way home around 6:45PM. Car accelerated much better around town and on the freeway. Some of that power loss was no doubt the heat, but the stock ROM starts yanking timing at IAT's of 104. Having 2-6 degrees pulled will make the car feel like it is down on power. And explains how in just slightly cooler air, it felt notably better.... Link to comment Share on other sites More sharing options...
rao Posted September 3, 2007 Share Posted September 3, 2007 Some of that power loss was no doubt the heat, but the stock ROM starts yanking timing at IAT's of 104. Having 4-7 degrees pulled will make the car feel like it is down on power. And explains how in just slightly cooler air, it felt notably better.... Your timing "theory" is interesting, but in hot weather I just use the Vimi method. I turn on the AC and feel the increase in torque - problem solved http://images.bimmerforums.com/smilies/rofl.gif Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
edmundu Posted September 3, 2007 Share Posted September 3, 2007 ^^^ Me, I just hit the "Easy" button:lol: Link to comment Share on other sites More sharing options...
Vimy101 Posted September 3, 2007 Share Posted September 3, 2007 Your timing "theory" is interesting, but in hot weather I just use the Vimi method. I turn on the AC and feel the increase in torque - problem solved http://images.bimmerforums.com/smilies/rofl.gif More torque but less horsepower to the drivetrain. I know it's a difficult concept for some. Link to comment Share on other sites More sharing options...
Beanboy Posted September 3, 2007 Share Posted September 3, 2007 All cars will be affected by high temps and humidity. Forced induction cars slightly less so. Maybe for Spec Bs, but most FI cars suffer (in heat)/benefit (in cold) MORE from weather issues than NA cars. With yeah if you are talking about altitude... -B http://www.standardshift.com Link to comment Share on other sites More sharing options...
gt_ltd Posted September 3, 2007 Share Posted September 3, 2007 More torque but less horsepower to the drivetrain. I know it's a difficult concept for some. see that's why i did bad in physics. different people (including some "professors") tell different stories. hmmm... dr. vimy101 vs dr. rao... ibdrjedi :lol: This Space For Rent Link to comment Share on other sites More sharing options...
Vimy101 Posted September 3, 2007 Share Posted September 3, 2007 All ICEs suffer in heat and benefit in cold. Same with humidity. Being able to force air into the motor in high temps or high altitude amounts to the same thing. Link to comment Share on other sites More sharing options...
Zed 2.0 Posted September 3, 2007 Share Posted September 3, 2007 see that's why i did bad in physics. different people (including some "professors") tell different stories. hmmm... dr. vimy101 vs dr. rao... ibdrjedi :lol: Good article discussing the same weight/torque theory, but for flywheels: http://www.uucmotorwerks.com/flywheel/there_is_no_torque_loss.htm Short story shorter, adding rotational weight (obviously) reduces torque as well as horsepower. Inertia does not equal torque. Link to comment Share on other sites More sharing options...
Vimy101 Posted September 3, 2007 Share Posted September 3, 2007 Good article discussing the same weight/torque theory, but for flywheels: http://www.uucmotorwerks.com/flywheel/there_is_no_torque_loss.htm Short story shorter, adding rotational weight (obviously) reduces torque as well as horsepower. Inertia does not equal torque. Cool. Neat explanation. From the article: "That "false torque" sensation tricks human perception into thinking the car has more power, when the torque measurement of such an engagement style shows that the "false torque" jump up is immediately followed by a sub-normal torque dip as the heavy flywheel requires more energy input to re-accelerate than the lightweight alternative." Seems like once the rotational potential energy has been realized more power is needed over time to re-energize it which is a function of hp more than straight torque. I do notice on my well known routes that when the AC is on, the instaneous fuel consumption guage does not move around as much on small elevation changes probably due to some amount of inertia. However, once your foot comes off the gas for a gear change, the engine rpms drop much more quickly (from AC compressor load). Flywheels can really affect driveability. That "false torque" comes in really handy for parallel parking. Link to comment Share on other sites More sharing options...
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