Can a person feel 3-5 hp?
02-07-2007 | 07:19 PM
#1
Thread Starter
The Professor
Joined: Aug 2004
Posts: 3,479
Likes: 6
From: Omaha, NE
Can a person feel 3-5 hp?
Like the title says.
What do you think?
personally I think that a person can feel a difference of 3-5 horsepower. I have explained it before in response to the naysayers.
Just think of this. when you are driving during the day and its 100 degrees outside. How does your car feel? Now, when you are driving around during the night and lets say that it dropped to 60 degrees outside. Is your car going to feel faster? Have you noticed it having a bit more pep?
Well, from 100 degrees to 60 degrees, your car just gained about 4 horsepower!
What do you think?
personally I think that a person can feel a difference of 3-5 horsepower. I have explained it before in response to the naysayers.
Just think of this. when you are driving during the day and its 100 degrees outside. How does your car feel? Now, when you are driving around during the night and lets say that it dropped to 60 degrees outside. Is your car going to feel faster? Have you noticed it having a bit more pep?
Well, from 100 degrees to 60 degrees, your car just gained about 4 horsepower!
02-07-2007 | 07:38 PM
#3
I don't think so . I have turned off my piggyback ems several times to see if I can "feel" the difference & I just can't . Now I know from dynos that I have around 15-20 hp more in higher rev range & I also know that if I test with scanalyser that it is about 0.3 secs quicker through 3rd gear , but it is just not that noticeable to the butt dyno .
02-07-2007 | 07:51 PM
#4
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Joined: Apr 2003
Posts: 9,134
Likes: 25
From: Houston
If you had a 20 hp car, you could feel it. There is no one anywhere that can feel a 3-5 hp difference on a 200+ hp car. That's even within the margin of error for a dyno which is a calibrated measuring device.
The reason you feel a power change on a 100 degree day as opposed to a 60 degree day actually isn't just because of that 40 degree temp difference. There's more to it than that. When you are sitting still at a light your engine heat soaks. It does it much faster and much worse on a really hot day. Your intake manifold does absorb some of this heat. It does this no matter what the temperature outside. When it gets really hot outside, the engine bay heats up faster and can quickly approach 180 degrees. On a 60 degree day your engine bay will still absorb and retain heat from the engine but now it might only get up to 120 degrees or so. However because it doesn't get as hot and doesn't do it as quickly, your engine's intake system doesn't absorb as much heat as it does on a hotter day with a hotter engine bay. Remember that heat travels to cold and there is air flowing through the manifold. It absorbs the heat in the manifold and takes it into the engine. It is also still doing this somewhat after the temperature sensor which means the greater the heat difference between the air at the sensor and that going in the engine, the more your mixture will be off from optimal and hence your power. Combine this with a much hotter less dense air and it adds up. Of course your car feels slower when it's real hot outside. Go dyno it on a 60 degree day and on a 100 degree day with no temperature correction on the dyno and with the hood closed. You will see MUCH more than a 4 horsepower difference! There's more to it than just outside temperature.
The reason you feel a power change on a 100 degree day as opposed to a 60 degree day actually isn't just because of that 40 degree temp difference. There's more to it than that. When you are sitting still at a light your engine heat soaks. It does it much faster and much worse on a really hot day. Your intake manifold does absorb some of this heat. It does this no matter what the temperature outside. When it gets really hot outside, the engine bay heats up faster and can quickly approach 180 degrees. On a 60 degree day your engine bay will still absorb and retain heat from the engine but now it might only get up to 120 degrees or so. However because it doesn't get as hot and doesn't do it as quickly, your engine's intake system doesn't absorb as much heat as it does on a hotter day with a hotter engine bay. Remember that heat travels to cold and there is air flowing through the manifold. It absorbs the heat in the manifold and takes it into the engine. It is also still doing this somewhat after the temperature sensor which means the greater the heat difference between the air at the sensor and that going in the engine, the more your mixture will be off from optimal and hence your power. Combine this with a much hotter less dense air and it adds up. Of course your car feels slower when it's real hot outside. Go dyno it on a 60 degree day and on a 100 degree day with no temperature correction on the dyno and with the hood closed. You will see MUCH more than a 4 horsepower difference! There's more to it than just outside temperature.
02-07-2007 | 08:05 PM
#5
Blue By You
Joined: Jun 2003
Posts: 8,717
Likes: 0
From: Milwaukee
Virtually impossible for any normal person to notice the difference. Anyone that adds a catback or intake to a car and thinks they can tell the difference is just fooling themselves, it's usually just the extra noise providing a placebo effect.
02-07-2007 | 08:12 PM
#7
I dont care...
Joined: Apr 2005
Posts: 574
Likes: 0
From: Pleasantville
Originally Posted by Ike
Virtually impossible for any normal person to notice the difference. Anyone that adds a catback or intake to a car and thinks they can tell the difference is just fooling themselves, it's usually just the extra noise providing a placebo effect.
02-07-2007 | 09:30 PM
#10
Banned
Joined: Oct 2005
Posts: 189
Likes: 0
From: Ely, UK
Now, this was a different class of car, but when I put an under drive pulley on my ZX2 (AT), I certainly felt a difference. Max whp gain is about 3-4, and it's on an engine that makes less than 100whp in AT form. That would be a little less than 5%, but I certainly felt it. The intake added approx. 3 whp as well, and I felt that too.
02-07-2007 | 10:16 PM
#11
RotoRocks Powered
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Originally Posted by rotarygod
If you had a 20 hp car, you could feel it. There is no one anywhere that can feel a 3-5 hp difference on a 200+ hp car. That's even within the margin of error for a dyno which is a calibrated measuring device.
The reason you feel a power change on a 100 degree day as opposed to a 60 degree day actually isn't just because of that 40 degree temp difference. There's more to it than that. When you are sitting still at a light your engine heat soaks. It does it much faster and much worse on a really hot day. Your intake manifold does absorb some of this heat. It does this no matter what the temperature outside. When it gets really hot outside, the engine bay heats up faster and can quickly approach 180 degrees. On a 60 degree day your engine bay will still absorb and retain heat from the engine but now it might only get up to 120 degrees or so. However because it doesn't get as hot and doesn't do it as quickly, your engine's intake system doesn't absorb as much heat as it does on a hotter day with a hotter engine bay. Remember that heat travels to cold and there is air flowing through the manifold. It absorbs the heat in the manifold and takes it into the engine. It is also still doing this somewhat after the temperature sensor which means the greater the heat difference between the air at the sensor and that going in the engine, the more your mixture will be off from optimal and hence your power. Combine this with a much hotter less dense air and it adds up. Of course your car feels slower when it's real hot outside. Go dyno it on a 60 degree day and on a 100 degree day with no temperature correction on the dyno and with the hood closed. You will see MUCH more than a 4 horsepower difference! There's more to it than just outside temperature.
The reason you feel a power change on a 100 degree day as opposed to a 60 degree day actually isn't just because of that 40 degree temp difference. There's more to it than that. When you are sitting still at a light your engine heat soaks. It does it much faster and much worse on a really hot day. Your intake manifold does absorb some of this heat. It does this no matter what the temperature outside. When it gets really hot outside, the engine bay heats up faster and can quickly approach 180 degrees. On a 60 degree day your engine bay will still absorb and retain heat from the engine but now it might only get up to 120 degrees or so. However because it doesn't get as hot and doesn't do it as quickly, your engine's intake system doesn't absorb as much heat as it does on a hotter day with a hotter engine bay. Remember that heat travels to cold and there is air flowing through the manifold. It absorbs the heat in the manifold and takes it into the engine. It is also still doing this somewhat after the temperature sensor which means the greater the heat difference between the air at the sensor and that going in the engine, the more your mixture will be off from optimal and hence your power. Combine this with a much hotter less dense air and it adds up. Of course your car feels slower when it's real hot outside. Go dyno it on a 60 degree day and on a 100 degree day with no temperature correction on the dyno and with the hood closed. You will see MUCH more than a 4 horsepower difference! There's more to it than just outside temperature.
02-08-2007 | 12:56 AM
#15
Registered
Joined: Apr 2003
Posts: 9,134
Likes: 25
From: Houston
Originally Posted by rotorocks
And o top of that, on the hot days if I am not mistaken, the stock ECU senses increased cooler temperature, and to get the engine to cool down it will add more fuel to the mixture and retard the ignition which makes the car feel even more sluggish.
02-08-2007 | 05:44 PM
#16
Why haven't you guys mentioned vehicle weight re: the 3-5 h.p. change being noticeable? Although I can tell you the frequency of a given tone and the actual db level with extreme accuracy just by hearing it, I cannot tell a difference of anything less than 10 h.p. while driving my car.
02-09-2007 | 02:30 AM
#24
More important than the peak power difference that occurs when the ambient air mass is higher is the overall change in the torque curve and the increase of effective Ve at lower RPMs.
That is what you feel, not a net increase in power.
That is why people think they feel a power increase when they install a part that changes the torque curve, even when they lose peak power.
That is what you feel, not a net increase in power.
That is why people think they feel a power increase when they install a part that changes the torque curve, even when they lose peak power.
