Is an aftermarket intercooler really worth it for towing??

[42pilot]

I used to build early turbo Porsche motors (air cooled), including EFI conversions and designing intercoolers to match turbos for each HP application. HP/TQ numbers were 525/520 up to 675/640 on 3.3L up to 3.6L, 2500 lb cars.

With this in mind, I am trying to decide whether it really makes sense to upgrade the IC as the OEM is really not bad. The end tanks seem fine as they are molded plastic focusing on flow and the core seems fine in stock application. I don't give comments like, "it feels faster" or "better throttle response" or "engine is definitely smoother" (all actual comments on this forum) any credit as you cannot measure pressure, volume or temp through your butt. So, I bought an OBD II reader and started logging data.

Here are my parameters:

1. I own my 2020 Expedition, so longevity and reliability are paramount.
2. I tow a 6200 lb travel trailer A LOT and want to improve performance, keeping #1 above at the forefront.
3. I will NOT be buying a tune.
4. Any IC will have to be bolt-on.
5. I rarely exceed 64 mph while driving. It is the sweet spot for economy. BUT, I limit the transmission to 7th gear to eliminate constant shifting. It is also the sweet spot for torque (according to published dyno runs for stock 3.5 motors).
6. East of the Rockies, I use 87 octane fuel. Above 5,000 ft, I use 91 octane.

During my 2 hour logging today, on relatively flat, light traffic, 64 mph cruising pulling tandem axle, 6200 lb trailer, I learned the following:

1. Calculated engine load value - 27.84% (nice)
2. Engine RPM - 2546
3. Ambient Air Temp - 66.2 F
4. Air intake 1 (pre-turbos) - 78.8 F
5. Air intake 2 temp at manifold - 111.2 F (IC adding no value given ambient vs IAT 2)
6. Throttle position - 25.1%
7. Timing advance - 20 degrees (obviously no boost, so that's great - under boost, timing will be nearly 0)
8. Catalytic converter 1 temp - 1474.88 degrees (cat 2 is nearly identical)
9. Absolute load value - 66.3% (clearly no boost as that will begin at 100%)
10. Calculated boost - 0.13 bar (technically, the turbos are producing 1.9 lbs of boost)

Overall, this motor is impressive pulling a 6200lb camper. It is really not working at all at ~28%. For my application, this is the perfect platform as an everyday driver, and a vacation tow vehicle.

So, what is happening under boost? I did not log all the above parameters, but I did screen shot the live data (see attached):

1. IAT temp 1 pre-turbo is steady 82.4 degrees during the nearly 15 second pull.
2. IAT temp 2 at the manifold increases sharply under load and likely increases more over time.
3. Boost approx .76 bar (~ 11psi).

My main problem, and the primary reason I am considering an aftermarket IC is this - why in the hell does Ford have louvers blocking air to the IC that only open under load? Why not have them open all the time? Why close them at all? On air to air ICs, the holy grail was lowering the charge temp to ambient - it never happened or happens now to my knowledge. But blocking cooling air until its needed makes no sense. By the time they open, its too late.

So, I am going to lock the louvers open and see if the attached graph improves. If it does not, then I will buy an aftermarket IC AND remove the louvers.

Cooling the charge air temp will reduce the possibility of detonation (longevity and reliability), produce more torque (HP is overrated as it is simply a measurement of work over time - no need for a tune with the possible exception to lock the transmission sooner), and provide a more efficient (absolute load value) engine. Maybe, even a bit more MPG.

More later...

 

[Expy Gator]

Pilot sounds like you are educated and have done your homework - if it were me and I had that data I would do exactly what you are contemplating - open up the air flow to the IC. If you are not going to tune and increase boost - based upon your load values I dont see much advantage in a new IC. And too many people dont research new IC's they just buy them - I have found you get what you pay for - need to see how efficient the new IC is - what is the pressure differential between inlet and outlet. Some look good but definitely don't perform.

 

[2020FordRaptor]

I used to build early turbo Porsche motors (air cooled), including EFI conversions and designing intercoolers to match turbos for each HP application. HP/TQ numbers were 525/520 up to 675/640 on 3.3L up to 3.6L, 2500 lb cars.

With this in mind, I am trying to decide whether it really makes sense to upgrade the IC as the OEM is really not bad. The end tanks seem fine as they are molded plastic focusing on flow and the core seems fine in stock application. I don't give comments like, "it feels faster" or "better throttle response" or "engine is definitely smoother" (all actual comments on this forum) any credit as you cannot measure pressure, volume or temp through your butt. So, I bought an OBD II reader and started logging data.

Here are my parameters:

1. I own my 2020 Expedition, so longevity and reliability are paramount.
2. I tow a 6200 lb travel trailer A LOT and want to improve performance, keeping #1 above at the forefront.
3. I will NOT be buying a tune.
4. Any IC will have to be bolt-on.
5. I rarely exceed 64 mph while driving. It is the sweet spot for economy. BUT, I limit the transmission to 7th gear to eliminate constant shifting. It is also the sweet spot for torque (according to published dyno runs for stock 3.5 motors).
6. East of the Rockies, I use 87 octane fuel. Above 5,000 ft, I use 91 octane.

During my 2 hour logging today, on relatively flat, light traffic, 64 mph cruising pulling tandem axle, 6200 lb trailer, I learned the following:

1. Calculated engine load value - 27.84% (nice)
2. Engine RPM - 2546
3. Ambient Air Temp - 66.2 F
4. Air intake 1 (pre-turbos) - 78.8 F
5. Air intake 2 temp at manifold - 111.2 F (IC adding no value given ambient vs IAT 2)
6. Throttle position - 25.1%
7. Timing advance - 20 degrees (obviously no boost, so that's great - under boost, timing will be nearly 0)
8. Catalytic converter 1 temp - 1474.88 degrees (cat 2 is nearly identical)
9. Absolute load value - 66.3% (clearly no boost as that will begin at 100%)
10. Calculated boost - 0.13 bar (technically, the turbos are producing 1.9 lbs of boost)

Overall, this motor is impressive pulling a 6200lb camper. It is really not working at all at ~28%. For my application, this is the perfect platform as an everyday driver, and a vacation tow vehicle.

So, what is happening under boost? I did not log all the above parameters, but I did screen shot the live data (see attached):

1. IAT temp 1 pre-turbo is steady 82.4 degrees during the nearly 15 second pull.
2. IAT temp 2 at the manifold increases sharply under load and likely increases more over time.
3. Boost approx .76 bar (~ 11psi).

My main problem, and the primary reason I am considering an aftermarket IC is this - why in the hell does Ford have louvers blocking air to the IC that only open under load? Why not have them open all the time? Why close them at all? On air to air ICs, the holy grail was lowering the charge temp to ambient - it never happened or happens now to my knowledge. But blocking cooling air until its needed makes no sense. By the time they open, its too late.

So, I am going to lock the louvers open and see if the attached graph improves. If it does not, then I will buy an aftermarket IC AND remove the louvers.

Cooling the charge air temp will reduce the possibility of detonation (longevity and reliability), produce more torque (HP is overrated as it is simply a measurement of work over time - no need for a tune with the possible exception to lock the transmission sooner), and provide a more efficient (absolute load value) engine. Maybe, even a bit more MPG.

More later...

Man your knowledge is amazing. All I can say is with all the towing you'll be doing I don't think it will hurt, and I agree on no tune.

 

[JasonH]

If I had to guess, the louvers are for aerodynamics. Many EVs use them to reduce turbulence from air flowing in the front motor compartment. I think you answered your own question re: closure. The additional air flow isn't needed. The only time you're likely to demand full power while towing is while accelerating to highway speeds, or while passing. Like you, I limit my speeds to 65 mph +/- 2 depending on traffic conditions. For that use case, the stock setup works fine. That's not to say an upgraded intercooler would not improve performance. But most of the time we're not demanding peak horsepower while towing. The only other area it might provide some benefits is at high altitude towing in hot weather, since air is thinner and will cool less. Fords manual actually reduces max towing limits at high altitude to compensate for lower air density. I've contemplated upgrading intercoolers, radiators, gearing (mine is 2017 EL w/ 3.31). But really, my 4x2 does very well towing my 7K camper and any upgrades are me being a hobbyist, not due to necessity.

 

[LazSlate]

Lots of you tube videos on this for the F150 (some on the expys) They seems to add some value as the aftermarket are bigger and require cutting of the shroud. On the stealth and Timberline those come with intercooler fans which could make a big difference giving flow all the time when needed. IDK.

 

[42pilot]

On the stealth and Timberline those come with intercooler fans which could make a big difference giving flow all the time when needed. IDK.

That's interesting. Just proves that airflow - and supplementing airflow - matters. I built a motor years ago, and to prove my point in how important cold air was, I put dry ice all over the IC (the IC sat on top of the motor in the old air cooled motors). I then dyno'd the motor with the ice cold cooler and found it added 20 tq and 25 hp. Interesting experiment.

Getting electric fans of nearly any size is easy. I wonder if using the louver plug could be used to turn on an electric fan. Delete the louvers, but use the plug to trip a relay to provide amps to a high speed fan. This could be fun to try. Thanks for the heads up.

 

[42pilot]

If I had to guess, the louvers are for aerodynamics. Many EVs use them to reduce turbulence from air flowing in the front motor compartment. I think you answered your own question re: closure. The additional air flow isn't needed. The only time you're likely to demand full power while towing is while accelerating to highway speeds, or while passing. Like you, I limit my speeds to 65 mph +/- 2 depending on traffic conditions. For that use case, the stock setup works fine. That's not to say an upgraded intercooler would not improve performance. But most of the time we're not demanding peak horsepower while towing. The only other area it might provide some benefits is at high altitude towing in hot weather, since air is thinner and will cool less. Fords manual actually reduces max towing limits at high altitude to compensate for lower air density. I've contemplated upgrading intercoolers, radiators, gearing (mine is 2017 EL w/ 3.31). But really, my 4x2 does very well towing my 7K camper and any upgrades are me being a hobbyist, not due to necessity.

Any time you introduce cooler air, you increase the density of air, and therefore oxygen. This means, the lower the temp, the more O2 is available, and less fuel needed to do the same amount of work. Therefore, your fuel economy should improve. Why would Ford impede that? It might have something to do with emissions.

I looked for the comment you made that Ford reduces max towing at altitude to compensate for lower air density in the manual. However, this makes no sense to me when we are talking about forced air induction systems. The whole idea of adding turbos or supercharges is to compress air, and therefore "force" a lower oxygen-rich density altitude. Its the same principle of flying in an airplane. They cruise at +30,000 feet, but pressurize the cabin to simulate an altitude of 7,000 ft. The reason I really like the 3.5L ecoboost is what it does above 5,000 ft. It leaves naturally aspirated motors (even in larger displacements) in the dust because it does not care the altitude (within reason). My F450 6.7L diesel pulled just as hard at 8,000 ft as it did at sea level and so does the 3.5L.

I completely agree with you about the majority of our driving, as 95% is near-naturally aspirated. However, the turbos as still there, compressing a certain amount of air, and therefore heating the intake. I still think it makes sense to cool as much of the air as possible, whether at low cruise rpm, or while towing (under load), to improve overall efficiency.

 

[LazSlate]

That's interesting. Just proves that airflow - and supplementing airflow - matters. I built a motor years ago, and to prove my point in how important cold air was, I put dry ice all over the IC (the IC sat on top of the motor in the old air cooled motors). I then dyno'd the motor with the ice cold cooler and found it added 20 tq and 25 hp. Interesting experiment.

Getting electric fans of nearly any size is easy. I wonder if using the louver plug could be used to turn on an electric fan. Delete the louvers, but use the plug to trip a relay to provide amps to a high speed fan. This could be fun to try. Thanks for the heads up.

You may want to see if there is a plug for the fans in the harness. They may not have a separate harness for the Timberline and the plug is just tucked away. This way you can get the factory fans from the TImberline and install them relatively easy.

 

[JasonH]

Any time you introduce cooler air, you increase the density of air, and therefore oxygen. This means, the lower the temp, the more O2 is available, and less fuel needed to do the same amount of work. Therefore, your fuel economy should improve. Why would Ford impede that? It might have something to do with emissions.

I looked for the comment you made that Ford reduces max towing at altitude to compensate for lower air density in the manual. However, this makes no sense to me when we are talking about forced air induction systems. The whole idea of adding turbos or supercharges is to compress air, and therefore "force" a lower oxygen-rich density altitude. Its the same principle of flying in an airplane. They cruise at +30,000 feet, but pressurize the cabin to simulate an altitude of 7,000 ft. The reason I really like the 3.5L ecoboost is what it does above 5,000 ft. It leaves naturally aspirated motors (even in larger displacements) in the dust because it does not care the altitude (within reason). My F450 6.7L diesel pulled just as hard at 8,000 ft as it did at sea level and so does the 3.5L.

I completely agree with you about the majority of our driving, as 95% is near-naturally aspirated. However, the turbos as still there, compressing a certain amount of air, and therefore heating the intake. I still think it makes sense to cool as much of the air as possible, whether at low cruise rpm, or while towing (under load), to improve overall efficiency.

Cooler air does increase the density, but ICE have a narrow stoichiometric range for combustion, so more oxgyen = more fuel. By your criteria, efficiency would be improved by increasing boost since more boost = more oxygen. That's not quite how it works since additional fuel is needed to ensure a suitable stoichiometric mix.

Here is an article from Edmunds on how the active shutters work:

Active Grille Shutters Are Latest Way To Improve Fuel Efficiency | Edmunds

Active grille shutters, which are designed to boost fuel efficiency, are popping up on a number of new models, including the 2015 Ford Mustang.

www.edmunds.com

The reduced towing capacity is straight from the manual. You may have seen comments online about Ecoboost engines overheating while towing. Part of the reason why is that the air is thinner at high elevations, so the engines can't exchange heat as quickly. Here's a link to the 4th gen manual regarding towing at altitude. It says reduce gross weight by 2% for every 1,000 foot increase in elevation.

https://www.fordservicecontent.com/Ford_Content/vdirsnet/OwnerManual/Home/Content?countryCode=USA&languageCode=EN&Uid=G2097969&ProcUid=G2097970&div=f&variantid=7543&vFilteringEnabled=False&userMarket=USA&buildtype=web

 

[5280tunage]

@JasonH That's an interesting last sentence, on reducing gross weight. That number seems very similar to one we've used for years when talking about tuning, even carbureted engines. We always went by 2-3% loss in oxygen per 1K feet elevation gain. But then again, I'm not sure on the loss of cooling, as generally gaining altitude reduces ambient temperatures. To me it's kind of a wash.

@42pilot One of the very first things I did was put in a good IC. I have built and tuned other Turbo engines (mainly high RPM 4 CYL's) and I've always liked better IC's with larger volume, more efficient heat transfer. I like to think (no real proof to this) that anything you can do to help reduce turbo temps can help them last longer. Realistically I also wonder about the charge pipes, etc. Reducing turbulence and improving flow would be great. I actually wish some of these companies could make them using a concentric design, to help reduce the engine heat raising air temps on the cold side. Of course the pipe kits are already stupid expensive, that would make them only worse. Also, you're note about the dry ice, that's awesome, we used to do a lot of tinkering with cold water injection systems, and even using dry ice blankets on NOS bottles.

the louvers are interesting, they've been talked about quite a bit on here. Many cars have them these days, regardless of aspiration design, and yes, the primary reason is to improve aerodynamics. My understanding is that they are supposed to closed during engine warmup and generally at highway speeds depending on engine temps. what's kind of interesting is it kind of shows how good these engines are at keeping a pretty consistent temp at normal output, if you can effectively cut off airflow to the radiator too.