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Change in boost with new intercooler (TSB 08-25-1)
Anyone that's had that TSB done (new intercooler) notice a change in boost levels? The truck seems to have the same amount of power, but there is less boost. Around town where it would have 10lbs before, it now has around 4-5lbs. On cool mornings where it would easily go up to 20lbs, it now stays around 15lbs. Floored, it used to get up to around 36, but now max is around 30-32. I also notice that the sound of the turbos spooling up happens later, at a higher rpm. (I'm straight piped, so the difference in sound is obvious.)
Since the programming was not changed and the only difference is the intercooler... it makes me wonder if the new unit has more restricted airflow. (Turbos seeing more resistance, jamming air through the intercooler and requring more exhaust flow to spin up.) The sensor for reading pressure is after the intercooler, so this would make the numbers seem lower. My thinking is, in order to prevent the water from collecting at the bottom of the radiator, maybe they made the inlet more restrictive to aggravate the water, making it more of a mist if it does collect?
you have that backwards, less boost and same power = less resistance. boost is just a measure of resistance in intake/exhaust
A good example is the ford lightning. you will typically loose 1-2lbs of boost by adding long tube headers, due a lack of restriction. you can then add additional power by upping the boost to its previous level
__________________
2008 Ford F-250 CC SB
Dark Pearl Blue(complete repaint under warranty)
6" Stage II Pro Comp Lift
17x9 Pro Comp 7189
37x12.5 BFG M/T KM2's
Spartan/4" duals/AFE Try the SEARCH Button Because It's Probably already been asked
you have that backwards, less boost and same power = less resistance. boost is just a measure of resistance in intake/exhaust
A good example is the ford lightning. you will typically loose 1-2lbs of boost by adding long tube headers, due a lack of restriction. you can then add additional power by upping the boost to its previous level
While I understand your example, you are speaking of restriction on the exhaust side which may be somewhat different. I'm just trying to focus on the intake from turbo to intake manifold. Less air is less air.
I'm not so sure that the engine isn't running slightly more rich, because of the reduced amount of oxygen (less air compressed into the cylinder, to be mixed with the same predetermined amount of fuel). If I had a way to measure the richness of each burn, I'm almost sure it would be higher. Keeping an eye on my exhaust for more/darker smoke than before though.
It's like blowing air through a coffee stirrer. The pressure inside your mouth will be higher than the pressure in the area at the exit of the stirrer because of the restriction the stirrer creates. Since the sensor for boost pressure is after the intercooler, I think this is why boost levels are lower. The old IC (pre TSB) has a lower pressure differential... less restrictive.
Imagine an intercooler that is 100% blocked/restricted. The air pressure pre-IC would be the 20lbs, and the pressure after would be 0-lbs. Thats an extreme example, but its the best way I can describe it. Retriction creates a pressure differential.
Here is a crude example of the pressure zones around the intercooler. First image is a "before" example, and the second, "after" a restrictive intercooler is put into place.
you have that backwards, less boost and same power = less resistance. boost is just a measure of resistance in intake/exhaust
A good example is the ford lightning. you will typically loose 1-2lbs of boost by adding long tube headers, due a lack of restriction. you can then add additional power by upping the boost to its previous level
I agree that there would be less boost pressure if more air is flowing through the engine, but not because there is less resistance through the CAC. The boost pressure is measured at the intake manifold (after the CAC). It would only be higher because there is more pressure available, but the engine is unable to consume all of it.
So, Banks is correct when they claim that the boost pressure is higher because their CAC has less resistance (higher air volume throughput).
It is actually much more likely that the new CAC is either leaking or some other components in the charge air flow system is leaking. Maybe the dealer messed up the flexible hose connections to the CAC -- that'll be the easiest problem to fix.
Do you hear any hissing noises especially at higher boost? It might be difficult to hear even with an open window due to all the other noises. I had a problem with the flexible hose section (input of CAC) at the lower connection. The hose had a small tear right next to the clamp. It would prevent pressures from exceeding the mid 20s and occasionally make an incredibly loud squealing noise - but that was just lucky for me, making it easier to diagnose.
It is actually much more likely that the new CAC is either leaking or some other components in the charge air flow system is leaking. Maybe the dealer messed up the flexible hose connections to the CAC -- that'll be the easiest problem to fix.
Do you hear any hissing noises especially at higher boost? It might be difficult to hear even with an open window due to all the other noises. I had a problem with the flexible hose section (input of CAC) at the lower connection. The hose had a small tear right next to the clamp. It would prevent pressures from exceeding the mid 20s and occasionally make an incredibly loud squealing noise - but that was just lucky for me, making it easier to diagnose.
Oh man, hadn't thougth of a boost leak. Thanks for the suggestion. If that's it... thats going to be tough to diagnose short of taking the hoses back off to inspect them and manually pressure testing the intercooler.
There was one post, on another forum, with the same comment about boost. I was hoping to see more of a trend to rule that out as a possibility. Time to go out to the driveway.......
Ok.... just went out... both boots look fine. The material is smooth with no tearing or break in the surface along the clamps edges. Clamps seem to be on properly and in the right spot.
If there was a boost leak (instead of a high pressure area waiting to get funneled through the intercooler), wouldn't the turbo (as heard through the exhaust side) spool up much faster since there is no resistance on the intake side / wheel? I definitely notice it takes a lot more throttle to spool it up.
In my opinion, that means it is meeting more air pressure / resistance, and needs more exhaust flow to get up to speed. That pressure is not seen by the MAP in the intake manifold because of the holdup in the intercooler.
It would be interesting to have a reading between the turbo and CAC, to compare with the MAP on the intake manifold.
if you are curious about a boost leak get a shop to smoke test it for you\
and i understand your restriction example, however if there were enough of a restriction to stop that much air flow, you would notice it in throttle response and overall power level
__________________
2008 Ford F-250 CC SB
Dark Pearl Blue(complete repaint under warranty)
6" Stage II Pro Comp Lift
17x9 Pro Comp 7189
37x12.5 BFG M/T KM2's
Spartan/4" duals/AFE Try the SEARCH Button Because It's Probably already been asked
if you are curious about a boost leak get a shop to smoke test it for you\
and i understand your restriction example, however if there were enough of a restriction to stop that much air flow, you would notice it in throttle response and overall power level
I might be a bit sensitive to the slightest differences in sound and gauge readings. (Diagnosing computer hardware issues will do that to you.)
It's just that, when the turbos spool later and the gauge is clearly down in its readings, it makes you wonder what Ford is up to and how they are trying to fix things. With the dpf on, the sound wouldn't have been as noticeable. Combine that with the fact that you'd have to constantly watch the gauge to see the 4-5lbs difference.... maybe it's normal for the "new" CAC and nobody has noticed.
I'll have to look into the smoke test. Might try a soap and water test in the driveway with 1200rpm high idle. Maybe that will show something, but I'm starting to wonder if thats a possibility given the turbo characteristics.
There is also a possibility of having an exhaust leak causing a reduction of exhaust pressure to drive the turbos. If you have a way to check for codes - make sure you are clear there.
Of course, marginal sensors could be contributing to this problem as well. However, most likely you'd experience less power or a change in the amount of smoke (since you don't have a DPF). Has your mileage change a lot? That could be another indicator. At any rate, I'd check the MAP and the MAF sensors and possibly replace both of them. I would also check the exhaust pressure sensor - all, if you can not find any evidence of leaking either on the intake or exhaust side. These sensors determine how much boost is required and direct the turbo actuator to produce more or less boost.
....... My thinking is, in order to prevent the water from collecting at the bottom of the radiator, maybe they made the inlet more restrictive to aggravate the water, making it more of a mist if it does collect?
Anyone notice this?
Is the "white smoke problem" a consequence of water collecting in the CAC? Which would mean that the "white smoke" is actually water vapor? WOW - not sure how one could change the cooler design to prevent this since the water did not simply "materialize" in the cooler - rather it must be aspirated from the intake filter system....??
There is also a possibility of having an exhaust leak causing a reduction of exhaust pressure to drive the turbos. If you have a way to check for codes - make sure you are clear there.
Of course, marginal sensors could be contributing to this problem as well. However, most likely you'd experience less power or a change in the amount of smoke (since you don't have a DPF). Has your mileage change a lot? That could be another indicator. At any rate, I'd check the MAP and the MAF sensors and possibly replace both of them. I would also check the exhaust pressure sensor - all, if you can not find any evidence of leaking either on the intake or exhaust side. These sensors determine how much boost is required and direct the turbo actuator to produce more or less boost.
I do have the ability to check for codes. No CEL, but a soft code is always possible. I will keep an eye on the mileage. Haven't paid much attention to it, but it seems the same. Your suggestions on sensors make quite a bit of sense. It's just funny that it was literally a direct change in boost after leaving the dealership with the new intercooler. It definitely wasn't a gradual change. A direct before/after.
Quote:
Originally Posted by BeatMarti
Is the "white smoke problem" a consequence of water collecting in the CAC? Which would mean that the "white smoke" is actually water vapor? WOW - not sure how one could change the cooler design to prevent this since the water did not simply "materialize" in the cooler - rather it must be aspirated from the intake filter system....??
Just curious.....
Yeah, the tsb 08-25-1 was in response to actual water collecting in the intercooler. Lots of discussion on another site regarding the issue.
The situation presents itself in high humidity and/or rain. My truck was only affected by heavy rain. Some would do the same in high humidity.
You have to drive (usually in overdrive, low rpm) for 20-30min at a constant speed, relatively low boost, below 20psi. The air filter will remain DRY through all of this. What happens is, the high humidity air enters the system where it is compressed. Since compression also heats the air, the air is still able to hold its moisture but its dewpoint is significantly higher. (Pressure plays a factor in dewpoint.) Enter, the CAC. As the saturated hot/humid air is cooled, it is cooled below its new dewpoint, (which will be a warmer dewpoint temp than the outside ambient temp going across the intercooler, in this rare condition). The water slowly condenses and collects at the bottom of the intercooler. When you come to a stop, and take off again, anything over 20lbs of boost and around 2500rpm, and the water is forced up through the intercooler and into the intake where it causes major hesitation and TONS of steam from the exhaust. After a few seconds, it seems to clear up, usually with the driver backing off the gas, realizing something is wrong.
My thinking was, if they knew it was collecting but did nothing to change the core area of the radiator or the end tanks... (I measured everything and they are exactly the same externally), there must be some change in the internal flow in order to either prevent, or aerate any water that collects in the bottom so that it does not all go into the engine at once. I have yet to take off the lower CAC inlet boot to check for anything that may aggravate the air/water to prevent the water from just pooling and sitting still.
Thanks for all of your (and everyone elses) suggestions and information so far!
Thank you for the detailed explanation. It makes a lot of sense. Yes, I too wonder what Ford did to increase the absorption of moisture by the passing air even at lower boosts. I suppose it might be that they added some porous "filler" in the lower end cap to "catch" the water and let it evaporate over time. This would definitively explain why you may have more resistance through the CAC!
For me, a much simpler, totally effective solution would be to install a water drain valve at the bottom of the CAC - that, if you notice white smoke/hesitation, simply stop, open the drain valve and drive for a couple of minutes with the CAC "leaking". The boost pressure will force all the water out of the CAC. Of course, a much more sophisticated solution would be to have it controlled electrically - "simply push a button in the cab while driving" -- or better yet, have the ECM control the dumping of the moisture! :-))
Thank you for the detailed explanation. It makes a lot of sense. Yes, I too wonder what Ford did to increase the absorption of moisture by the passing air even at lower boosts. I suppose it might be that they added some porous "filler" in the lower end cap to "catch" the water and let it evaporate over time. This would definitively explain why you may have more resistance through the CAC!
For me, a much simpler, totally effective solution would be to install a water drain valve at the bottom of the CAC - that, if you notice white smoke/hesitation, simply stop, open the drain valve and drive for a couple of minutes with the CAC "leaking". The boost pressure will force all the water out of the CAC. Of course, a much more sophisticated solution would be to have it controlled electrically - "simply push a button in the cab while driving" -- or better yet, have the ECM control the dumping of the moisture! :-))
I'm not sure they did anything to "absorb" the water... I think they tried to disperse it in a way that it can go through the engine somewhat undetected. (Like, not all at once, to choke the engine out.) I think the resistance is caused by whatever part that may speed up the water to vaporize it. The only analogy I can come up with is the old hollywood "spit-take" where a person spits out the drink they just took a sip of. They probably made something in the intercooler that causes the water to rush through a small opening and become more of a mist than a gob of water.
I hear you on the drain. A little too afraid to attempt that one with the 40+psi it would have to handle though. With the CCV venting into the air intake (and oil making it to the intercooler eventually), the EPA would probably have a FIT if they had a purge for water.
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