power loss on dyno in hot weather
08-01-2006, 08:44 PM
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power loss on dyno in hot weather Just got my car dyno'd it was 100 degrees in the shop and very humid. Does anyone know how much horsepower might be lost in that heat
08-02-2006, 08:18 AM
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Seems like this subject of corrections should have been kicked to death by now, but I'll state my opinion again. If the proper dyno proceedures were followed the atmospheric conditions should have a neglagible affect on your final readings due to the SAE J1349 weather corrections. If not followed, you just wasted your time and money.
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08-03-2006, 08:34 AM
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Originally Posted by Trust
Why would you dyno a car in that heat? Intake Temps would be in the 250+ range.
EDIT: 250 IAT would be with the hood closed, but still, hot under there.
EDIT: 250 IAT would be with the hood closed, but still, hot under there.
I can think of one good reason, seems like everytime dam time there is that big, important event during the summer months here in the midwest, it's one of the hottest days of the year, so why not be tuned for it?
"250+ range", I thought everyone has cold air induction by now.
08-04-2006, 04:12 PM
#10
Originally Posted by dynocar
I can think of one good reason, seems like everytime dam time there is that big, important event during the summer months here in the midwest, it's one of the hottest days of the year, so why not be tuned for it?
"250+ range", I thought everyone has cold air induction by now.
"250+ range", I thought everyone has cold air induction by now.
08-04-2006, 08:14 PM
#11
Originally Posted by 00 black ram air
just looking to see if anyone had their car dyno'd in extreme conditions and then when it was better conditions. Just to see how much it would actually vary
Remember that it isn't what your car dynos, but what it runs at the track.
Just my $.02.
08-05-2006, 12:43 AM
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Originally Posted by Denom
I had my car dynoed in a shop that was over 100 degrees (To say I was sweating was an understatement). Typically the dyno operator will adjust for the conditions, though his numbers may be off.
Remember that it isn't what your car dynos, but what it runs at the track.
Just my $.02.
Remember that it isn't what your car dynos, but what it runs at the track.
Just my $.02.
08-05-2006, 10:50 AM
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it makes a huge difference.
When I dyno'd in the 100 degree hot weather and compared it with my old chart the program said "you cannot compare these results because of the big difference in IAT's" Thats enough for me to say just wait for the cooler weather!
When I dyno'd in the 100 degree hot weather and compared it with my old chart the program said "you cannot compare these results because of the big difference in IAT's" Thats enough for me to say just wait for the cooler weather!
08-05-2006, 10:30 PM
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I believe that the correction factors help some, but the difference between it being about 70 and like 9% humidity in the shop, and about 93 and about 28% humidity was about 25rwhp or so. The shop got this down to 10rwhp loss after descreening the MAF and playing with the tune a little more. But it was still a 10rwhp loss. These were done with SAE correction.
08-06-2006, 01:36 AM
#15
Originally Posted by 67Ranger
I believe that the correction factors help some, but the difference between it being about 70 and like 9% humidity in the shop, and about 93 and about 28% humidity was about 25rwhp or so. The shop got this down to 10rwhp loss after descreening the MAF and playing with the tune a little more. But it was still a 10rwhp loss. These were done with SAE correction.
08-06-2006, 02:36 PM
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Yea i'm really curious to see what i would have done in some cooler weather, i got a buddy who works at orange county corvette and he dynoed 355 in the hot summer sun. Let it sit for a little, then dynoed it again when it was cooler outside and it gained 14 whp.
Justin
Justin
08-06-2006, 08:12 PM
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there is a very simple way to figure out what you lost.
For every 10 degree increase/decrease in inlet tempature you will see a 1% loss/gain in power.
If in 100* heat if the inlet temps were in say the high 100's then yes you lost some power. Now say the same run but the inlet temps from to 80* then you just gained 2% in horse power.
For every 10 degree increase/decrease in inlet tempature you will see a 1% loss/gain in power.
If in 100* heat if the inlet temps were in say the high 100's then yes you lost some power. Now say the same run but the inlet temps from to 80* then you just gained 2% in horse power.
08-09-2006, 05:47 PM
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Originally Posted by Trust
In extreme heat, everything runs hotter, tranny, rear, motor. Running a car in 100* over and over is careless. My car was tuned in 85* weather, and still feels like a dog now. You can run your car in 100+* weather all you want, but its a bad idea. And I dont quite understand your last statement about cold air induction? Do you mean like an FTRA, FRA, or something else? A lid wouldnt really be considered 'cold air'. And on a Dyno... your not moving, and that fan they put there is nothing like the wind, its just not a the best time to dyno in a shop that isn't ac controlled with heat that high and expect good numbers, thats all.
By "cold air induction", that means any induction system that draws in outside ambient temp air rather then under hood hot air.
As far as "on a dyno" goes, if the "heat is that high" and it is a legitimate dyno shop, the SAE 1349 correction factors correct those numbers, so it does'nt make that much difference to the numbers.
