EB vs GT Summertime Powerloss

[NoahsArk117]

Hey Everyone,

So I took my GT out for the year in March, we had high 40s, mid 50s weather up until this past week. It's been in the mid 80s and humid all week and the performance difference is absolutely insane. I feel like the car has taken a 30hp-40hp drop with the temp change. I had an Ecoboost before this for a few years and I don't remember the summertime power drop being this intense. I thought with a NA motor you wouldn't feel as much of a power loss compared to a turbo car? I have a CAI and tune on my GT so maybe that's the cause? Anyone have any input on this?

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[Rinzler]

A turbo car is literally forcing air into the engine so you're not going to see as much of a loss there at all.

The biggest culprit is going to be an open element CAI and IAT temps that are out of control. Since a N/A car relies on dense air at atmosphere, ambient temperature is extremely important. If you still have the stock airbox, it may be worth putting it back on for the summer if you're concerned with the losses.

 

[NoahsArk117]

A turbo car is literally forcing air into the engine so you're not going to see as much of a loss there at all.

The biggest culprit is going to be an open element CAI and IAT temps that are out of control. Since a N/A car relies on dense air at atmosphere, ambient temperature is extremely important. If you still have the stock airbox, it may be worth putting it back on for the summer if you're concerned with the losses.

That makes sense now that you say that. I always thought it was the other way around for some reason. You're 100% right about the IAT, when I come to a stop they absolutely skyrocket until I start moving again. Sort of ironic when it's called a "Cold" air intake. Thanks for the explination!

 

[boB]

Hey Everyone,

So I took my GT out for the year in March, we had high 40s, mid 50s weather up until this past week. It's been in the mid 80s and humid all week and the performance difference is absolutely insane. I feel like the car has taken a 30hp-40hp drop with the temp change. I had an Ecoboost before this for a few years and I don't remember the summertime power drop being this intense. I thought with a NA motor you wouldn't feel as much of a power loss compared to a turbo car? I have a CAI and tune on my GT so maybe that's the cause? Anyone have any input on this?

Hot and humid may cost power but hot and dry is worse, the air gets thin and planes have trouble taking off (Phoenix airport). Turbos can compensate to keep the cylinder pressure the same as with cooler air (as long as detonation is controlled).

 

[NoahsArk117]

Hot and humid may cost power but hot and dry is worse, the air gets thin and planes have trouble taking off (Phoenix airport). Turbos can compensate to keep the cylinder pressure the same as with cooler air (as long as detonation is controlled).

I live in Michigan so the hot dry weather is a rarity here, usually incredibly muggy all the time in the summer. I can't imagine the struggle in AZ though.

 

[NightmareMoon]

N/A cars can't make up for the reduced pressure density when conditions or altitude changes.

Turbo cars can literally compensate for thin air by working the turbo a little harder. They can get the same air pressure density, just with a slight reduction in efficiency.

Advantage: Turbo

 

[Balr14]

Forced induction means heat sink. That can mean big power loss.

 

[Cobra Jet]

A turbo car is literally forcing air into the engine so you're not going to see as much of a loss there at all.

The biggest culprit is going to be an open element CAI and IAT temps that are out of control. Since a N/A car relies on dense air at atmosphere, ambient temperature is extremely important. If you still have the stock airbox, it may be worth putting it back on for the summer if you're concerned with the losses.

Ding, ding, ding…. We have a winnnnnnaaaaah!

Open element CAIs are not beneficial on vehicles where they don’t see constant maintained speeds (Highway use), sit in traffic or are only driven short distances.

There’s been many facts posted about this across many auto forums, it’s nothing new. Even on this site alone it’s been proven that a closed airbox on a N/A S550 being used for daily driving in dense traffic has more benefits.

You might as well just call an open element CAI a HAI, because that’s exactly what it does… it sucks hot air building up under the hood right into the intake due to overwhelming heat soak. Heat soak is worse in spring/summer months due to higher exterior temps and far worse if the vehicle sits in stop/go traffic.

A vehicle with an open element CAI only benefits from it when and if the vehicle is used in a track environment, on highways or open rural roads where the vehicle is constantly moving and the air is cooled due to maintained speeds.

 

[NoVaGT]

Hot and humid may cost power but hot and dry is worse, the air gets thin and planes have trouble taking off (Phoenix airport). Turbos can compensate to keep the cylinder pressure the same as with cooler air (as long as detonation is controlled).

Hot and dry is not worse for cars.

It is faaaar better than hot & humid.

 

[LxMike]

I ran some number through a density altitude calculator and humid air is worse. I ran two different simulations only thing I changed was the humidity. I used 50' above sea level, 77 degrees air temp, barometer of 30.00 and humidity 75%. In second test I changed humidity to 35%. At 75% the calc showed 1435 ft above sel level and at35% showed 1274 above sea level...

 

[Zooks527]

Hot and humid may cost power but hot and dry is worse, the air gets thin and planes have trouble taking off (Phoenix airport).

Nope.

At any given temperature and pressure pair, dry air contains a higher partial pressure of oxygen than humid air, as with humid air the water vapor in the air exerts its own partial pressure, decreasing the absolute percentage and partial pressures of all other gases.

With respect to aircraft taking off, humidity increases the density altitude notably, lowering effective lift on humid days. Therefore, it is easier for a plane to take off from any particular location on a hot / dry day than it is on a hot / humid day at the same location.

There's a calculator for showing the effect of humidity on air density and density altitude here: https://wahiduddin.net/calc/calc_da.htm

 

[Idaho2018GTPremium]

The high DA of a 80+ deg. day and humidity will cause a lot of hp loss in a 435-460 hp GT compared to a cold day. You're about right with the 40-50 hp loss compared to a cold day. Look at airdensityonline.com. That has DA for many of the tracks in the US and other countries. I look at it all the time for the track a few miles from my house. I've noticed a general rule of thumb is about 70 feet higher DA for every 1 deg it warms up during the day. You can easily see 2000-3000 feet higher DA in a late afternoon compared to a 7-8am in the same summer day. That's a huge change in hp for the same car. Humidity and natural barometric pressure fluctuate as well, changing the DA. Another rule of thumb is 3% loss of power for an NA car per 1000' of DA increase. Turbocharged and supercharged cars lose less, since they are using boost to force extra air into the engine. But they are still losing hp as DA increases, just at a lower rate (lower % loss) than NA engines.

 

[mc68386]

I've lived in Tucson, AZ for years and honestly I don't notice any performance change over temperature. I've got a GT with Ford Performance Pack 2 with the GT350 cold (read: hot) air intake. Like lots of people who have to use 91 gas, I do get more knock at low speed when it's hot, but even that doesn't seem to adversely affect my quickness off the line. Really, if I want to "go fast" I put it in Sport and that makes way more difference than anything else in my experience.
I don't drag, so I can't support my feels with numbers, just my butt dyno and we all know how reliable those are.

 

[ice445]

High desert gets the worst of both worlds, 100F days but also low air density to begin with due to elevation. You definitely get less power, but cooling is also less effective.

Turbo cars suffer less because of the intercooler, but they still get a substantial penalty.

 

[NoahsArk117]

I've lived in Tucson, AZ for years and honestly I don't notice any performance change over temperature. I've got a GT with Ford Performance Pack 2 with the GT350 cold (read: hot) air intake. Like lots of people who have to use 91 gas, I do get more knock at low speed when it's hot, but even that doesn't seem to adversely affect my quickness off the line. Really, if I want to "go fast" I put it in Sport and that makes way more difference than anything else in my experience.
I don't drag, so I can't support my feels with numbers, just my butt dyno and we all know how reliable those are.

I live in Michigan so we have insane temperature swings all year. I've noticed around Septemeber/October when it dips down into the lower 50s the car feels stupidly faster (better throttle, response, pulls way harder, more consistent power etc.)

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