how to get 20rwhp extra for free!
08-04-2006, 11:39 PM
#11
4th Gear Member
Join Date: Apr 2006
Location:
Posts: 1,313
RE: how to get 20rwhp extra for free!
No surprise here. The rough rule I believe is 1 hp gain for every 1 degree cooler air. This usually holds true for temps from like 70+ in the summer.
But, as shown above, there are better ways of figuring it out.
More heat and humidity=less oxygen rich air= computer pulls fuel to maintain mixture= less HP
But, as shown above, there are better ways of figuring it out.
More heat and humidity=less oxygen rich air= computer pulls fuel to maintain mixture= less HP
08-05-2006, 01:04 AM
#13
2nd Gear Member
Join Date: Nov 2005
Location:
Posts: 334
RE: how to get 20rwhp extra for free!
I guess you could “technically†say that hot and/or humid weather will “de-tune†the motor but that’s not really what is happening, or I should say the computer is not “de-tuning†because of heat and/or humidity but just running its normal program.
The computer does have sensors for temperature and it has a means of determining how humid it is as well, kind of…
The reason for the temperature sensor is for the computer to determine, within reason, how much oxygen the incoming air contains. The cooler the air the more oxygen molecules it has and that is how Nitrous Oxide works.
Since cooler air contains more oxygen the computer will command more fuel to be delivered to the cylinders and hence MORE horsepower. When the air is warmer or hot it contains less oxygen molecules so less fuel to the cylinders and thus less performance. So, it’s not that the computer is “de-tuning†itself because it has no reason to it is simply following the standard program for fuel tables based on oxygen content determined by the air temperature sensors.
I mentioned there was “kind of†a way for the computer to determine humidity. Just because the air is cooler does not mean it is dryer. Dryer cooler air has higher oxygen molecules then does cooler air that is humid.
Humidity crowds out oxygen. So the way the computer “kind of†corrects for humidity since it don’t actually have a humidity sensor is by using both the air temperature sensor reading AND the oxygen sensor output.
If the oxygen sensor output does not see as much oxygen as it should, due to the air temperature sensor it sends a signal of how much oxygen is actually present after the combustion. If there is less oxygen then the computer thought there was is makes another adjustment and reduces fuel deliver to the cylinders.
Long story short:
The computer does not detune itself because of heat or humidity it simply relies on how much oxygen molecules are coming into the motor and then with its standard program increases or decreases the fuel delivered to the cylinders.
Cold dry days = the highest possible horsepower output of ANY motor…
The computer does have sensors for temperature and it has a means of determining how humid it is as well, kind of…
The reason for the temperature sensor is for the computer to determine, within reason, how much oxygen the incoming air contains. The cooler the air the more oxygen molecules it has and that is how Nitrous Oxide works.
Since cooler air contains more oxygen the computer will command more fuel to be delivered to the cylinders and hence MORE horsepower. When the air is warmer or hot it contains less oxygen molecules so less fuel to the cylinders and thus less performance. So, it’s not that the computer is “de-tuning†itself because it has no reason to it is simply following the standard program for fuel tables based on oxygen content determined by the air temperature sensors.
I mentioned there was “kind of†a way for the computer to determine humidity. Just because the air is cooler does not mean it is dryer. Dryer cooler air has higher oxygen molecules then does cooler air that is humid.
Humidity crowds out oxygen. So the way the computer “kind of†corrects for humidity since it don’t actually have a humidity sensor is by using both the air temperature sensor reading AND the oxygen sensor output.
If the oxygen sensor output does not see as much oxygen as it should, due to the air temperature sensor it sends a signal of how much oxygen is actually present after the combustion. If there is less oxygen then the computer thought there was is makes another adjustment and reduces fuel deliver to the cylinders.
Long story short:
The computer does not detune itself because of heat or humidity it simply relies on how much oxygen molecules are coming into the motor and then with its standard program increases or decreases the fuel delivered to the cylinders.
Cold dry days = the highest possible horsepower output of ANY motor…
08-05-2006, 01:13 AM
#14
1st Gear Member
Join Date: May 2006
Location: the bilge of a boat!
Posts: 63
RE: how to get 20rwhp extra for free!
Were you serious... lol.
This heat wave is pissing me off, my stang feels so weak.
It's nice in the winter when you get your average bass boat with a 250 or 300 hp motor to run 90+ with 2 ppl and tournament gear, same boat in the summer will only do 85 with two people and no gear.
This heat wave is pissing me off, my stang feels so weak.
It's nice in the winter when you get your average bass boat with a 250 or 300 hp motor to run 90+ with 2 ppl and tournament gear, same boat in the summer will only do 85 with two people and no gear.
08-05-2006, 06:07 AM
#16
6th Gear Member
Join Date: Apr 2005
Location: West Los Angeles
Posts: 5,390
RE: how to get 20rwhp extra for free!
So should I predict a big run on Ziploc Freezer bags?
I've seen ricers load up their engine compartments with bags of ice but where should WE put them? Anyplace that's stable?
Pics would be nice>>>
I've seen ricers load up their engine compartments with bags of ice but where should WE put them? Anyplace that's stable?
Pics would be nice>>>
08-05-2006, 01:24 PM
#17
4th Gear Member
Join Date: Jun 2006
Location: CA
Posts: 1,700
RE: how to get 20rwhp extra for free!
toss a bag of ice right on top of the intake manifold and walk away for 30 min. good for 2-3 tenths for me. everyone told me it was a waste of time on a plastic manifold but it still worked.
08-05-2006, 05:00 PM
#18
5th Gear Member
Join Date: Nov 2005
Location:
Posts: 3,235
RE: how to get 20rwhp extra for free!
ORIGINAL: imyy4u
alright guys, i got some interesting news. if you've read any of my threads the past few days, you'll notice i've had trouble spinning my tires on my stock gt, even with TCS off. well, as you know, that's not right - this car was practically designed for burnouts. anyway, i dynoed 255whp on a dynojet just two days ago w/500 miles, with the temp at 100 not including humidity and heat index. that number was with the hood closed, A/C on low, and TCS off cause i wanted to know what i'd put out in real world driving conditions. stock everything. and no i didn't let the engine cool before the run.
so, today my car was feeling a lot faster (it was 80 today and maybe cooler), so i got it dyno'ed to see if i was imagining things. 276whp on the same dyno, only thing different was the temp and that i had a few hundred more miles. +21rwhp without me doing anything! i also dynoed this time with the hood closed and without letting the engine cool to maintain consistency. i was completely shocked; i never expected such a difference
i guess the computer pulls timing or fuel or something when the intake temps are really high. just shows you that in hot weather, you must have a CAI or you're gonna lose a lot of power. i had no idea the stock intake system was so sensitive to heat. keep in mind i also have a black on black GT, so my results may be more drastic than yours. as soon as i find a scanner i'll post up the dynos, along with my 1/4 mile time. i am so shocked at how drastic the difference was...20rwhp is a hell of a lot, that's almost a 10% change! then again, the extra miles may have had a chance to change something on the computer, or teach it better, but who knows. amazing!
alright guys, i got some interesting news. if you've read any of my threads the past few days, you'll notice i've had trouble spinning my tires on my stock gt, even with TCS off. well, as you know, that's not right - this car was practically designed for burnouts. anyway, i dynoed 255whp on a dynojet just two days ago w/500 miles, with the temp at 100 not including humidity and heat index. that number was with the hood closed, A/C on low, and TCS off cause i wanted to know what i'd put out in real world driving conditions. stock everything. and no i didn't let the engine cool before the run.
so, today my car was feeling a lot faster (it was 80 today and maybe cooler), so i got it dyno'ed to see if i was imagining things. 276whp on the same dyno, only thing different was the temp and that i had a few hundred more miles. +21rwhp without me doing anything! i also dynoed this time with the hood closed and without letting the engine cool to maintain consistency. i was completely shocked; i never expected such a difference
i guess the computer pulls timing or fuel or something when the intake temps are really high. just shows you that in hot weather, you must have a CAI or you're gonna lose a lot of power. i had no idea the stock intake system was so sensitive to heat. keep in mind i also have a black on black GT, so my results may be more drastic than yours. as soon as i find a scanner i'll post up the dynos, along with my 1/4 mile time. i am so shocked at how drastic the difference was...20rwhp is a hell of a lot, that's almost a 10% change! then again, the extra miles may have had a chance to change something on the computer, or teach it better, but who knows. amazing!
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