Ford Power Stroke Nation banner

1 - 20 of 32 Posts

·
Registered
Joined
·
176 Posts
Discussion Starter #1
I know this filter flows more air but being a open element under the hood it takes the hot air from under the hood. I was towing this weekend and it was 80 deg out side temp the air intake sensor was reading 96deg and it traffic it was over 110deg. Is this killing power because the intake charge is hot air. I know my gas truck suffered when the intake air got to hot. In the winter months this is not a big deal but summer its getting pretty hot.

What do you think?
 

·
All done now
Joined
·
22,486 Posts
Not hurting it at all.
 

·
Hoosier daddy!
Joined
·
1,700 Posts
To help promote more cool(ambient) air flow directed right at the filter you can do the zoodad mod(I think it's called that) and use the tube from the stock airbox to shoot outside air right at the filter while you're driving. I think that gains will be minimal though and as Andy stated, the temps you are seeing are not hurting anything at all.
 

·
Bigfoot is an OBS
Joined
·
3,462 Posts
I know this filter flows more air but being a open element under the hood it takes the hot air from under the hood. I was towing this weekend and it was 80 deg out side temp the air intake sensor was reading 96deg and it traffic it was over 110deg. Is this killing power because the intake charge is hot air. I know my gas truck suffered when the intake air got to hot. In the winter months this is not a big deal but summer its getting pretty hot.

What do you think?
Just watch your EGTs. If the IAT is too high, EGTs will follow.

Part of the reason the gas vehicle suffered from less power is that when the air heated up, it expanded. So less mass for the same volume. But, carburetors and FI systems meter the fuel according to air mass, not air volume. So, less air mass, less fuel.
In the diesel, the FI system meters the fuel in accordance to the pedal, and the air is just along for the ride, so to speak. when the air gets thinner, the turbo will partially make up for that by itself because it will spin faster, pushing a higher volume of air into the engine, attempting to reach the necessary air mass flow rate. Since the turbo is driven by exhaust gasses, the higher the amount of fuel, the more gas is available to the turbo. So, while fuel efficiency would go down, power really is not affected as much.
But for 20-30 degrees, you're not going to notice the difference in fuel efficiency.
 

·
Headwind Magnet
Joined
·
626 Posts
Excellent explanation Dan!
Best,
Jim
 

·
Bigfoot is an OBS
Joined
·
3,462 Posts
well at least it made sense to someone. I had to rewrite it three times before I thought it was reasonably clear.
 

·
All done now
Joined
·
22,486 Posts
My explanation was the Cliff Notes version. But I agree, nice job.
 

·
Registered
Joined
·
176 Posts
Discussion Starter #8
Allright it makes sense now thanks for the input. I still think I will do the zoodad mod to help with intake temps.
 

·
Registered
Joined
·
845 Posts
Just watch your EGTs. If the IAT is too high, EGTs will follow.

Part of the reason the gas vehicle suffered from less power is that when the air heated up, it expanded. So less mass for the same volume. But, carburetors and FI systems meter the fuel according to air mass, not air volume. So, less air mass, less fuel.
In the diesel, the FI system meters the fuel in accordance to the pedal, and the air is just along for the ride, so to speak. when the air gets thinner, the turbo will partially make up for that by itself because it will spin faster, pushing a higher volume of air into the engine, attempting to reach the necessary air mass flow rate. Since the turbo is driven by exhaust gasses, the higher the amount of fuel, the more gas is available to the turbo. So, while fuel efficiency would go down, power really is not affected as much.
But for 20-30 degrees, you're not going to notice the difference in fuel efficiency.
Wouldn't the trip through the CAC cool it some?:shrug:
 

·
Bigfoot is an OBS
Joined
·
3,462 Posts
Wouldn't the trip through the CAC cool it some?:shrug:
It would cool it some. But, you never are able to remove as much heat as you put in. So if IAT pre-turbo goes up 20 degrees, the post turbo, pre-cac will go up a little more than 20 degrees (little like 20.005), and the post-cac will go up less than 20 degrees. The post-cac would go up something around 5-15 degrees, depending on air flow in the cac, and outside the cac. The more (mass) airflow you have IN the cac (going into the engine), the more (mass) airflow you need on the OUTSIDE of the cac to maintain close to the same cac outlet temp.
 

·
Bigfoot is an OBS
Joined
·
3,462 Posts
Well there you go... Thanks. I think.
You can read that as:
As long as you're moving (driving) you shouldn't see any difference. In stopped traffic, you might see EGTs go up just a bit, but not much since at idle you're not using much air.
 

·
Registered
Joined
·
845 Posts
Yeah, I get the moving VS stopped intake air temp difference. I was thinking that the intercooler cooled it more than it does, I guess.
 

·
Bigfoot is an OBS
Joined
·
3,462 Posts
The numbers I gave are rough guesses.

The higher the difference between the cac inlet and the ambient temps, the greater cooling effect there will be.
You'll never get the cac to cool in compressed air to the same as ambient simply because the cac is not large enough. And a large enough cac to do that would be larger than the truck.

Now, an air to water cac with chilled (ice) water, OTOH... :evil
 

·
Registered
Joined
·
176 Posts
Discussion Starter #15
Im not to sure If I am understanding all of this. If it does not matter what the air intake temp is why have the intercooler? When the air is compressed it is heated so if you ambient temp on inlet is 20deg warmer your charge temp will be 20 deg higher? You would need temp probes in before and after inter-cooler and know what your intake air temp is. Sitting in traffic the intake air temp with air on was up to 125deg. and took a mile or two going down the road to bring it down to 20+above ambient.
 

·
Bigfoot is an OBS
Joined
·
3,462 Posts
Im not to sure If I am understanding all of this. If it does not matter what the air intake temp is why have the intercooler?
IAT at the manifold does matter, that's why you have a CAC.

When the air is compressed it is heated so if you ambient temp on inlet is 20deg warmer your charge temp will be 20 deg higher?
Actually, because the air is just a teensy bit thinner at the same temp, the air temp after the turbo (pre-cac) would then be just a little more than 20 degrees hotter. But, cac can't take all the heat out, so the post-cac is less than 20 degrees hotter.

You would need temp probes in before and after inter-cooler and know what your intake air temp is.
Yup. That's why I said those numbers are rough guesses.

Sitting in traffic the intake air temp with air on was up to 125deg. and took a mile or two going down the road to bring it down to 20+above ambient.
My point was that operating in 60 vs 80 deg weather you won't really notice anything different. By operating, I mean driving. Sitting at idle with the AC on in traffic is another story.


You asked what I thought, and I told you. Be careful asking an engineer what they think. LOL We tend to think a lot.
 

·
Registered
Joined
·
176 Posts
Discussion Starter #17
You asked what I thought, and I told you. Be careful asking an engineer what they think. LOL We tend to think a lot.
Ya I work with engineer's on a daily basis and know what kind of thinking goes on.....(I think this should work?????)LOL
 

·
OEM Moderator
Joined
·
9,381 Posts
I for one would love to see some fresh data measuring intake air temps with a tymar style intake.
 

·
Registered
Joined
·
3,940 Posts
So you are basicly saying that a truck in Oregon injesting 70* air would be the same as my truck injesting 115* air?

The air coming off the radiator & engine is way hotter than ambient air. If the intercooler can only cool X amount wouldn't it be better to injest ambient rather than heated air off the engine and rad? Now I think it would, thats why I want ambient air cause here in southern Az when it's 115+ outside the air from the engine compartment is pretty warm. The 115* air would be better than the 150+ or what ever that is in the eng compartment. Maybe I'm off base here but the cooler can only take away so much heat so the cooler intake air temps would have to help. Just my $.02
 

·
Registered
Joined
·
176 Posts
Discussion Starter #20
So you are basicly saying that a truck in Oregon injesting 70* air would be the same as my truck injesting 115* air?

The air coming off the radiator & engine is way hotter than ambient air. If the intercooler can only cool X amount wouldn't it be better to injest ambient rather than heated air off the engine and rad? Now I think it would, thats why I want ambient air cause here in southern Az when it's 115+ outside the air from the engine compartment is pretty warm. The 115* air would be better than the 150+ or what ever that is in the eng compartment. Maybe I'm off base here but the cooler can only take away so much heat so the cooler intake air temps would have to help. Just my $.02
This is my feeling too. The cooler the air going into the turbo the cooler the air will be going into the intake.
 
1 - 20 of 32 Posts
Top