Powerboost Exhaust Heat Exchanger Delete

[Samson16]

I have been laboring under and spreading lies. I thought that the exhaust to coolant heat exchanger in the Powerboost is part of the low-temp battery loop and was designed to make sure that the LiFePO4 battery quickly gets above freezing temperatuure so that it can be charged (i.e. used at all) in cold weather. That interpretation was WHOLLY WRONG. As I have been informed (hat tip to HammaMan), the exhaust to coolant exchanger is actually part of the high temperature loop and as such its only function is to raise the temperature of the engine coolant more quickly.

At first glance, that distinction might seem unimportant, but in terms of removing a failure prone part that has earned its own Thread Of Shame, this means that we can realistically delete the stupid thing and be done with it. Were it part of the battery management system, removing it would require us to replace its role in warming the battery because lithium batteries hate the cold, and most importantly any effort to charge one while it is below 32F will rapidly kill it. If Ford's battery management system didn't have the right failsafes from direct battery temperature monitoring and just assumed battery temp based upon other inputs (not saying that this would be a good design.....but it's Ford), there is a real risk that removing a battery heater could kill your battery. However, if the stupid thing only makes the engine heat up a bit faster, then the worst case is slightly increased engine wear from slower oil warmup in cold weather. We know that a 3.5L Ecoboost doesn't require this part, so the engine can clearly run well with baseline auto start-stop. If wear really is an issue, then preemptive fix for faster wear is to change engine idle behavior in cold weather with a tune or simply using your app to warm the truck up before you drive anywhere (since it will automatically idle to run the heater in cold weather).

Bottom line the consequences for this mod are 1) hypothetical and 2) have solutions which are being actively engineered for and deployed on the most popular engine in the most popular truck in the world. I think that leads us to the question of: how?

The three steps are:
1) shunt the inlet coolant line to the outlet coolant line. Ideally, you have a double SS connector and leave plenty of hose attached to the exchanger so that it's easy to reuse/reinstall.
2) remove the exchanger from the exhaust path. This is simple for an exhaust shop, but they are VERY nervous about touching these things. That may make #3 easier to do first:
3) develop a spud connector with appropriate resistors which can attach to the controller wires to avoid angering the ECM. In some ways, just having the unit sitting on the truck without coolant is simpler, but that risks ruining the exhanger if the system directs exhaust through it while there is no coolant flow. That wouldn't hurt the truck (since the coolant loop is no longer involved), but it would likely kill an expensive part that you might want to restore some day or could at least sell.

My aims with all of this are twofold:
1) get a full custom exhaust
2) preemptively remove a failure point. I was driving through middle of nowhere West Texas last night, and it would've been pretty miserable to find out via an overheat message that this exchanger had distributed my coolant along 100 miles blacktop. It would need to have a pretty important job to justify that risk.....and I have learned that it provide nearly zero benefit in return for the threat of stranding us.

So what say you?

It isn’t a LiFePO4 battery module, Li-ion I think is more accurate, but that’s not important. I just don’t think it’s worth modifying a new truck for the 3.5 exhaust note. Part of the beauty of the PB is it’s stealth. I know the heat exchanger leak issue is real, but what percentage of PB’s have had it happen? I think there’s likely a good reason it’s there. If a nasty exhaust rumble was my thing, I would have went with a V8. my 2 cents

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[amschind]

It isn’t a LiFePO4 battery module, Li-ion I think is more accurate, but that’s not important. I just don’t think it’s worth modifying a new truck for the 3.5 exhaust note. Part of the beauty of the PB is it’s stealth. I know the heat exchanger leak issue is real, but what percentage of PB’s have had it happen? I think there’s likely a good reason it’s there. If a nasty exhaust rumble was my thing, I would have went with a V8. my 2 cents

I'm probably going to use a Flowmonster Dual in/dual out and have full dual 2.5" pipes with high flow cats. The biggest issue for me isn't sound, it's performance, so there was no reason to both unless I could replace the cats, do a full dual system with a H-pipe, wrap the whole thing to keep the heat off the transmission and add a high flow muffler. It is easy to make a loud exhaust, it's a lot harder to make a high performance exhaust. The specific performance benefit isn't so much extra power (if I get it tuned, I will go for VERY mild gains), but the ability to better isolate the transmission from the exhaust using turbo blankets and exhaust wrap. The thing that stops these trucks while under heavy load in hot/high/dry climates is transmission overheating. If I can reduce heat soak from the cats and exhaust pipes to the transmission enough to reduce worst case transmission temperatures, I've won.

As for the battery chemistry, thanks. I had assumed that after Tesla switched to LFP chemistry that everyone else did. In fact, I didn't realize that the other chemistries were so common in hybrid batteries. Do you know which chemistry the PB battery uses?

 

[HammaMan]

I'm probably going to use a Flowmonster Dual in/dual out and have full dual 2.5" pipes with high flow cats. The biggest issue for me isn't sound, it's performance, so there was no reason to both unless I could replace the cats, do a full dual system with a H-pipe, wrap the whole thing to keep the heat off the transmission and add a high flow muffler. It is easy to make a loud exhaust, it's a lot harder to make a high performance exhaust. The specific performance benefit isn't so much extra power (if I get it tuned, I will go for VERY mild gains), but the ability to better isolate the transmission from the exhaust using turbo blankets and exhaust wrap. The thing that stops these trucks while under heavy load in hot/high/dry climates is transmission overheating. If I can reduce heat soak from the cats and exhaust pipes to the transmission enough to reduce worst case transmission temperatures, I've won.

As for the battery chemistry, thanks. I had assumed that after Tesla switched to LFP chemistry that everyone else did. In fact, I didn't realize that the other chemistries were so common in hybrid batteries. Do you know which chemistry the PB battery uses?

The powerboost has additional things regarding trans cooling due to the motor in it. I don't have the WSM, only the wiring. Might pay the $20 or so for a 3 day run at it amschind
It has different fan controls, an additional cooling loop that it can chill w/ the AC, an additional trans cooling pump. Quite a few things going on w/ it.

 

[Samson16]

I don’t know for sure yet, I purchased a new 22 in January, and I have a lot to learn, but its small size and extremely fast charge/discharge response point towards Lithium ion.

Impressive full on exhaust system rework you have planned. It’s possible the exhaust heat exchanger benefits the engine most in generator mode. The Pro-Power capability is no small part of the design considerations imo.

I watched the tfl trucks episode where Andres’ PB goes into protection mode, and Mr. Truck never checks his gauges while needing to floor it which normally would have speed limited the truck even while towing uphill. Slowing down and increasing RPM on the rare occasion I’m towing 10,000 lbs over the Vale pass is fine by me lol. In other words I don't think overheating is some looming boogey man out there. Tow smart. Watch your gauges. Know what they're telling you. That's my plan anyway and I'm new to towing.

 

[amschind]

I don’t know for sure yet, I purchased a new 22 in January, and I have a lot to learn, but its small size and extremely fast charge/discharge response point towards Lithium ion.

Impressive full on exhaust system rework you have planned. It’s possible the exhaust heat exchanger benefits the engine most in generator mode. The Pro-Power capability is no small part of the design considerations imo.

I watched the tfl trucks episode where Andres’ PB goes into protection mode, and Mr. Truck never checks his gauges while needing to floor it which normally would have speed limited the truck even while towing uphill. Slowing down and increasing RPM on the rare occasion I’m towing 10,000 lbs over the Vale pass is fine by me lol. In other words I don't think overheating is some looming boogey man out there. Tow smart. Watch your gauges. Know what they're telling you. That's my plan anyway and I'm new to towing.

Trying to combine replies to the two preceding posts:
1) The PB does have extra cooling, but since the system is a black box even to very experienced Ford techs and basically all other mechanics, I can't really go off of more than subjective experience. samson brought up the exact story from TFL that I was going to mention, namely that the PB went into limp mode due to a transmission overheat condition: whatever extra cooling the PB features, it didn't seem to help there. Adding transmission coolers is beyond the level that I want to broach, even if it would be the most effective solution. That leads me to....
2) The proximal exhaust system coils around the transmission like a pair of pythons that just ate two catalytic converters each. REMOVING more heat from the transmission involves complex rejiggering of a poorly understood and newly designed system, but KEEPING heat out only requires some exhaust wrap and ideally new pipes. Maybe I'm overestimating the effect, but my guess is that continuous boost under load is putting a LOT of exhaust heat into the transmission. Ford put (marginal) heat shields around some parts of those pipes, but I think I can do much better.
3) Great point about the ProPower utility of the exhaust heater. My specific use cases are running a welder and charging a 15 kWh travel trailer battery, both of which are amenable to just letting the truck idle while it's powering XXX. I can easily envision it being a wear issue with constant start/stop as the 0.6 kWh capacity is charged and discharged on a job site powering saws and air compressors. I'm not there yet, but when that sort of work becomes a priority, I'll need to choose between buying a 3-5 kWh standalone battery+inverter or maybe an upgraded battery for the truck itself.

 

[HammaMan]

Trying to combine replies to the two preceding posts:
1) The PB does have extra cooling, but since the system is a black box even to very experienced Ford techs and basically all other mechanics, I can't really go off of more than subjective experience. samson brought up the exact story from TFL that I was going to mention, namely that the PB went into limp mode due to a transmission overheat condition: whatever extra cooling the PB features, it didn't seem to help there. Adding transmission coolers is beyond the level that I want to broach, even if it would be the most effective solution. That leads me to....
2) The proximal exhaust system coils around the transmission like a pair of pythons that just ate two catalytic converters each. REMOVING more heat from the transmission involves complex rejiggering of a poorly understood and newly designed system, but KEEPING heat out only requires some exhaust wrap and ideally new pipes. Maybe I'm overestimating the effect, but my guess is that continuous boost under load is putting a LOT of exhaust heat into the transmission. Ford put (marginal) heat shields around some parts of those pipes, but I think I can do much better.
3) Great point about the ProPower utility of the exhaust heater. My specific use cases are running a welder and charging a 15 kWh travel trailer battery, both of which are amenable to just letting the truck idle while it's powering XXX. I can easily envision it being a wear issue with constant start/stop as the 0.6 kWh capacity is charged and discharged on a job site powering saws and air compressors. I'm not there yet, but when that sort of work becomes a priority, I'll need to choose between buying a 3-5 kWh standalone battery+inverter or maybe an upgraded battery for the truck itself.

Are you towing 10klbs up the rocky mountains at 10kft altitude throughout the summer continually? Might want a different vehicle entirely. The engine in that run was hotter than the trans. Anytime you see one of their 'tests', which aren't really, they just randomly drive vehicles up on any given day. It's usually much colder, but on that day it was 81 degrees up there on the climb itself. (they have responses from ford in later vids)

As for the exhaust, just get it ceramic coated if you're worried. You're chasing a problem that doesn't exist. Heat shields block IR radiation -- they serve their purpose. Your 'idling' use cases have nothing to do with the trans though, it's not used. Hybrids are designed for start stop and deleting the exhaust heat exchanger designed to keep things warm won't serve any positive purpose. I've run the truck for 90 minutes at 7.5x kWh of power charging an EV and the results were unremarkable. The aux trans pump keeps fluid flowing even with the ICE off when required. The oil pressure system also has a valve that keeps it pressurized when off so that there's no lubrication lag on start / stop (even the high pressure fuel rail stays up there). It's a moot point for the most part as the film is still present on those parts. It's not like a cold start where there's no oil and tolerances are 'off' due to temp.

(see this thread https://www.f150gen14.com/forum/thr...-to-the-test-max-sustained-draw-output.13166/)

 

[amschind]

Are you towing 10klbs up the rocky mountains at 10kft altitude throughout the summer continually? Might want a different vehicle entirely. The engine in that run was hotter than the trans. Anytime you see one of their 'tests', which aren't really, they just randomly drive vehicles up on any given day. It's usually much colder, but on that day it was 81 degrees up there on the climb itself. (they have responses from ford in later vids)

As for the exhaust, just get it ceramic coated if you're worried. You're chasing a problem that doesn't exist. Heat shields block IR radiation -- they serve their purpose. Your 'idling' use cases have nothing to do with the trans though, it's not used. Hybrids are designed for start stop and deleting the exhaust heat exchanger designed to keep things warm won't serve any positive purpose. I've run the truck for 90 minutes at 7.5x kWh of power charging an EV and the results were unremarkable. The aux trans pump keeps fluid flowing even with the ICE off when required. The oil pressure system also has a valve that keeps it pressurized when off so that there's no lubrication lag on start / stop (even the high pressure fuel rail stays up there). It's a moot point for the most part as the film is still present on those parts. It's not like a cold start where there's no oil and tolerances are 'off' due to temp.

(see this thread https://www.f150gen14.com/forum/thr...-to-the-test-max-sustained-draw-output.13166/)

I think that we're mixing use cases, so let's try to separate them to avoid confusion:
1) Towing: I can't think of a situation where I'd tow heavy under hot/high/dry circumstances. I live in East Texas, where we are low, wet and temperate, and any towing close to max capacity would be there. Worst cases are West Texas with a stock trailer to grab cows to finish (which is still a hypothetical at this point, I could easily have a Superduty by then). What I DO worry about is a travel trailer up high: it's a 25' Airstream that weighs 2600# right now, but will be closer to 5000# when finished and loaded. The mountains are pretty, and I could easily see myself bringing that up there to hunt elk (scouting is a summer activity, so not necessarily just winter) or visit.

To your point about ceramic coating: Yes. I'm just using ceramic in the form of a wrap secures with stainless steel vs pulling parts and having them spray coated because it's cheaper, easier, and works better as long as you use stainless instead of aluminized pipe (the ceramic coating isn't gonna trap water). Bear in mind that I live in an area where they CAN'T apply road salt even if they wanted to do so because they have no salt and no trucks.

2) Idling for power: I agree with you, I'm just thinking through "worst case" rather than "most likely" scenarios. To be clear, I have ZERO concern about trans temp while idling; my worry was that the super frequent stop/start behavior while charging and discharging the battery for ProPower would not allow the engine coolant and therefore oil to get up to temp, which would be somewhat mitigated by faster coolant warmup from the exhaust exchanger. This is a 200k mile problem, and I think that there are behavioral solutions to it.

More broadly, if I leave the exchanger in line with one of the two 2.5" pipes and just have less exhaust flow through it, I get all of the advantages EXCEPT excluding a failure prone part. That may be the best solution, but during the planning stage it makes sense to consider all of the various cost/benefit options. At this point, it's extremely tough for me to see how the risks posed by the heat exchanger are matched by the nebulous and relatively minor benefits, so I'm exploring ways to be rid of it without causing more issues.

 

[HammaMan]

I think that we're mixing use cases, so let's try to separate them to avoid confusion:
1) Towing: I can't think of a situation where I'd tow heavy under hot/high/dry circumstances. I live in East Texas, where we are low, wet and temperate, and any towing close to max capacity would be there. Worst cases are West Texas with a stock trailer to grab cows to finish (which is still a hypothetical at this point, I could easily have a Superduty by then). What I DO worry about is a travel trailer up high: it's a 25' Airstream that weighs 2600# right now, but will be closer to 5000# when finished and loaded. The mountains are pretty, and I could easily see myself bringing that up there to hunt elk (scouting is a summer activity, so not necessarily just winter) or visit.

To your point about ceramic coating: Yes. I'm just using ceramic in the form of a wrap secures with stainless steel vs pulling parts and having them spray coated because it's cheaper, easier, and works better as long as you use stainless instead of aluminized pipe (the ceramic coating isn't gonna trap water). Bear in mind that I live in an area where they CAN'T apply road salt even if they wanted to do so because they have no salt and no trucks.

2) Idling for power: I agree with you, I'm just thinking through "worst case" rather than "most likely" scenarios. To be clear, I have ZERO concern about trans temp while idling; my worry was that the super frequent stop/start behavior while charging and discharging the battery for ProPower would not allow the engine coolant and therefore oil to get up to temp, which would be somewhat mitigated by faster coolant warmup from the exhaust exchanger. This is a 200k mile problem, and I think that there are behavioral solutions to it.

More broadly, if I leave the exchanger in line with one of the two 2.5" pipes and just have less exhaust flow through it, I get all of the advantages EXCEPT excluding a failure prone part. That may be the best solution, but during the planning stage it makes sense to consider all of the various cost/benefit options. At this point, it's extremely tough for me to see how the risks posed by the heat exchanger are matched by the nebulous and relatively minor benefits, so I'm exploring ways to be rid of it without causing more issues.

Here's ai's response to the question at hand...

"At 10,000 ft elevation, the cooling efficiency of the radiator decreases due to lower air density, while the heat generated by the engine increases due to higher energy consumption for uphill towing. Conversely, at 1,000 ft elevation, the cooling efficiency of the radiator is better, and less heat is generated due to improved MPG.

Approximate heat generated at 1,000 ft elevation: 3.73 MJ/mile (9 MPG)
Approximate heat generated at 10,000 ft elevation: 9.88 MJ/mile (3.4 MPG)

The radiator's ability to dissipate heat is reduced by approximately 25% at 10,000 ft elevation compared to 1,000 ft elevation. This means that the engine at 10,000 ft not only generates more heat but also faces a reduced cooling capacity, making it more challenging to maintain optimal engine temperature."

As for the coolant leak issue reported on some trucks, the solution is to just have the little pieces of plastic on hand to replace it. It takes 5 minutes or so with the tool in-hand.

 

[amschind]

Here's ai's response to the question at hand...

"At 10,000 ft elevation, the cooling efficiency of the radiator decreases due to lower air density, while the heat generated by the engine increases due to higher energy consumption for uphill towing. Conversely, at 1,000 ft elevation, the cooling efficiency of the radiator is better, and less heat is generated due to improved MPG.

Approximate heat generated at 1,000 ft elevation: 3.73 MJ/mile (9 MPG)
Approximate heat generated at 10,000 ft elevation: 9.88 MJ/mile (3.4 MPG)

The radiator's ability to dissipate heat is reduced by approximately 25% at 10,000 ft elevation compared to 1,000 ft elevation. This means that the engine at 10,000 ft not only generates more heat but also faces a reduced cooling capacity, making it more challenging to maintain optimal engine temperature."

As for the coolant leak issue reported on some trucks, the solution is to just have the little pieces of plastic on hand to replace it. It takes 5 minutes or so with the tool in-hand.

TFL Powerboost Overheat

That response is very good: let me build upon it: 30-50% of that heat is in the exhaust. If I can push more of that heat straight out the tailpipe, less of it soaks into the engine and transmission. Turbo blankets and an exhaust wrap are pretty much the only solution that we can practically add.

As for the tube connector, I just bought 3 of them. Sadly, they are NOT the only source of leaks, but I'm gonna spend some time perusing the Heat Exchanger Failure thread and the compiled list to get a vague idea of the percentages. If 90% of the failures are that one part, then the $18 I spent on 3 spares is almost certainly a better solution than a full delete. My first glance says that's not the case, but I'll report back on this thread with better numbers.

 

[HammaMan]

TFL Powerboost Overheat

That response is very good: let me build upon it: 30-50% of that heat is in the exhaust. If I can push more of that heat straight out the tailpipe, less of it soaks into the engine and transmission. Turbo blankets and an exhaust wrap are pretty much the only solution that we can practically add.

As for the tube connector, I just bought 3 of them. Sadly, they are NOT the only source of leaks, but I'm gonna spend some time perusing the Heat Exchanger Failure thread and the compiled list to get a vague idea of the percentages. If 90% of the failures are that one part, then the $18 I spent on 3 spares is almost certainly a better solution than a full delete. My first glance says that's not the case, but I'll report back on this thread with better numbers.

There's a couple rad options if I recall and the PB has the largest of them. The turbos have water cooled bearings and I'm sure that's a pretty good hit for the heat. Capture any data you can. I'd be curious what an EGT gauge would show behind the mods pre-post under similar conditions, while capturing temps via OBD. Go borrow 8klbs of trailer and map out a loop to run!

 

[amschind]

There's a couple rad options if I recall and the PB has the largest of them. The turbos have water cooled bearings and I'm sure that's a pretty good hit for the heat. Capture any data you can. I'd be curious what an EGT gauge would show behind the mods pre-post under similar conditions, while capturing temps via OBD. Go borrow 8klbs of trailer and map out a loop to run!

EGT Monitor

This one is about $530+S&H. I am open to cheaper options.

 

[HammaMan]

EGT Monitor

This one is about $530+S&H. I am open to cheaper options.

There's cheap digital ones on amazon -- logging costs more $. A camera is a cheap data recorder FWIW, particularly in time lapse. For $500+ something like banks idash w/ data logging is a better option. There's no easy AIO solution. It'd be great if one could be added to the truck tapped into a bus.

The 3.0 has 4 EGTs -- those spots on the harness are used for O2 sensors. Spot 4 is open but they're different PCMs. Where's a ford engineer when ya need one.

Monitoring the rear cats won't buy you any data there either. Oh well.

 

[Snakebitten]

No way of accurately deducting the percentage of leaking heat exchangers that would have been fixed with replacing the now available tubes.
The thread just wasn't documented in a manner that would support the analysis. I've read that thread since the day Iceman posted.

I do believe that significant weight should be given to both the recent release of instructions by Ford to replace the tubes, rather than the whole pipe assembly, AND the fact that the part was made available as a standalone item. It wasn't before.

But I agree that there are other potential coolant leaks that would have nothing to do with the heat exchanger itself.
Hoses and couplers for one.

But those are still in play even if the heat exchanger was performing perfectly.

 

[HammaMan]

No way of accurately deducting the percentage of leaking heat exchangers that would have been fixed with replacing the now available tubes.
The thread just wasn't documented in a manner that would support the analysis. I've read that thread since the day Iceman posted.

I do believe that significant weight should be given to both the recent release of instructions by Ford to replace the tubes, rather than the whole pipe assembly, AND the fact that the part was made available as a standalone item. It wasn't before.

But I agree that there are other potential coolant leaks that would have nothing to do with the heat exchanger itself.
Hoses and couplers for one.

But those are still in play even if the heat exchanger was performing perfectly.

The only thing I came across regarding overheating was the valve that sends the coolant to the exhaust had a malfunction (seemed like a bad batch w/ similar build dates). That caused the truck to throw a overheat malfunction, but it was really just an issue with the heat exchanger malfunctioning causing the water to either move or not move spiking the return gauge's temp.

 

[amschind]

No way of accurately deducting the percentage of leaking heat exchangers that would have been fixed with replacing the now available tubes.
The thread just wasn't documented in a manner that would support the analysis. I've read that thread since the day Iceman posted.

I do believe that significant weight should be given to both the recent release of instructions by Ford to replace the tubes, rather than the whole pipe assembly, AND the fact that the part was made available as a standalone item. It wasn't before.

But I agree that there are other potential coolant leaks that would have nothing to do with the heat exchanger itself.
Hoses and couplers for one.

But those are still in play even if the heat exchanger was performing perfectly.

I agree, but in general hoses are relatively reliable unless injured in some way (e.g. shredded by a fan). The hoses are close to the exhaust, but could be tucked farther away if not connected. The connectors and the U-joint is my biggest concern. I think that both coolant hoses are SAE Quick Release fuel fittings, which means that a part to shunt between them could be quick release fittings on both ends. I.e. the shunt is itself a quick release part and thus easy to replace for whatever reason. If I use aluminum fittings, then the likelihood of failure drops to a very low number.

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