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lets end the egr delete/low boost issue once and for all!

93K views 49 replies 11 participants last post by  ECM_WIZZARD 
#1 ·
Ok, Ive done the research, Ive heard a few "theories" & have checked for leaks...Im sorry I cannot buy into "the boost is supposed to be lower after EGR delete" as I personally know & have researched several dozen cases where the boost did NOT change after the EGR delete. You just cant argue with that! Now to be perfectly honest I have not pressure or smoke tested for leaks as I dont have the tools or knowledge to do this properly. This is a move I am willing to do and plan to do in the very near future. I can say there are no signs of carbon anywhere around the ehaust side connections & that I personally pulled and inspected every boot after the turbo.
A note to think about: on the factory turbo, in almost all cases the boost reads 27-28 psi of boost. Everyone who is complaining about "low boost after EGR delete" is reporting 20-21 psi of boost. Is it possible we all have the same exact leak? dont you think that at a 6-7 psi loss of boost somewhere you would here the leak? Are we ALL deaf to the leak sound..I doubt it...so what is the problem? What procedure is skipped or missed that causes the same exact loss of boost on dozens of 6.0l's after the teardown of the topend? I cant believe that somone has had this problem, fixed it and not reported the fix somewhere! I also cant believe that almost all with this problem just say "oh well" and ignore it.....Im hoping we can put our heads together and finally put an end to this irritating senario!
 
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#2 ·
I'll try to explain as best I can. After an egr delete, you no longer are diluting your intake and cylinders with an inert gas...inert gas is a gas thats depleted of oxygen...just like exhaust gasses are. You now have just pure boosted air filling the intake and cylinders, without any exhaust gasses as a filler being mixed in. Therefore you don't need as much boost pressure to make the same power or even more power. You can however achieve high boost levels again with high performance custom tuning, but also need the fuel delivery to match it. My Powermax turbo with it's current tuning only has around 22-24psi, but is capable of more power than my stock turbo did with 32lbs of boost. I can also have 35+lbs of boost out of my Powermax with a different tune loaded. You should have plenty of power at 20-22 psi with an egr delete and the right tuning.

Harry
 
#5 · (Edited)
Hey Harry, as always I greatly appreciate your input! I have run across your explained theory while researching this in other threads on this situation but just have trouble justifying it as too many others were posting same boost pressures pre and post EGR deletion. Would the aftermarket up pipe as opposed to the factory welded/blocked up pipe have any realtion in how the boost is effected? If I just havent heard numerous claims to having the same boost pressure after deletion I would accept the fact that your explanation is exactly why Im seeing lower boost.....

Thank you greatly for chiming in an helping me get a better grip on exactly whats going on here!
 
#3 ·
Perfect explanation Harry.
No inert gas = more room for air from compressor
More room= less psi at given range of compressor.
 
#6 · (Edited)
I totally understand this theory as I have proven it in the past on previous force inducted vehicles ive owned. I know that installing a larger intercooler & larger intercooler piping resulted in lower boost but were talking a couple psi, not 6-7 psi. that would have to be a really large volume of area to reduce this much boost, much larger than the aftermarket parts I have installed in the past....mabey Im just not seeing the big picture yet as Im so set on finding a different, unheard of explanation that just makes me say "of course, thats why!"
 
#8 ·
Ok after letting the above comments sink in alittle better I wanted to ask again in a better way my intial question after the above theory was posted:
If the elimination of inert gasses in the intake result in 6-7 psi of boost loss why isnt everyone seeing this loss after an EGR delete? If the boost numbers on the stock turbos in question, after EGR delete were scattered results then it would be easier to accept as there would be too many variables to justify boost numbers all over the place. But were talking 27psi (+/- 1psi) before & 21psi (+/- 1psi) after reported by dozens of 6.0l owners. Then were talking 27psi (+/- 1psi) before & the same (27psi +/-) after also reported by dozens of 6.0l owners. Basically its one or the other and that is where I need the explanation.....
 
#9 ·
Raceyf7, you and another member of another forum are bringing up the same exact points and it is really starting to make sense. almost as how inducing the size of your intake (less/no exhaust/inert gas) would lower your boost....inducing the ehaust to the turbo would lessen the exhaust pressure between the exh manifold and turbo.....I hope somone chimes in to elaborate on this!
 
#11 · (Edited)
ooops
 
#14 ·
I posted in regards to what we were talking about & decided against what I was thinking, heheh.....beating myself up over this
 
#15 ·
too tired to ponder anymore tonight but on the EP sensor, dont you think we would get a code if it were sensing lower pressures? there no way it just defaults to 20psi & everyone is left to figure out why, a code would have to be thrown right? Ill sleep on that one.....
 
#17 ·
could be irreverseable unless a tuner can figure out how could trick the EP sensor as some of the pressure may have also been from the EGR cooler as well!....youll never get that back! ok....off to sleep.....lol
 
#18 ·
Hey guy's, no need to beat yourself up in circles over this. But in a nutshell, the mapping of the engine controls and the reaction to sensor data inputs and outputs is thrown into a tizzy when the egr is deleted. This can all be corrected with custom tuning. But 20-22 psi is still plenty good, as there is no longer exhaust gas dilution of the intake system.

Harry
 
#19 ·
I'm willing to bet that the ECM strategy also plays a role in this guys. With the '05-07 trucks requiring programming to turn off the CEL, and '03-04 trucks seemingly ok with it, and countless strategy changes like inferred EBP and all, it would be interesting to poll the class to draw some useful conclusions and do a bit less guessing.

It would also be relevant to collect the EGR delete kit/method relative to the above, as well as the air intake type, down pipe size, converter present or not, and aftermarket tune info if applicable.

The data needs to be collected and a trend can be identified. Once the trend is identified, then the reason for the boost loss will become clear. If it is a tuning item, then the people who have the affected strategies can know in advance and perhaps a tuner can identify the why.
 
#20 ·
Just saw this post and have something to add. The exhaust that drives our turbo is (just a guess) is seeing pressures of about 30 PSI. When this comes thru the EGR and mixes with turbo pressures of 23PSI it will raise the intake pressure to an average of 27PSI. Shut the exhaust(higher pressures) from coming in and you will have only what the compressor is putting out(23 PSI). Does this make sense to anyone else?
 
#26 · (Edited)
BRILLIANT REASONING!

I also wonder about the boost pressure, I just noticed (recently got gauges) that my boost stops at 20 psi as well on my '04. But on my truck, I also removed the throttle plate on my throttle body, that is used to reduce pressure in the intake to help with EGR flow. I too have noticed NO DIFFERENCE in performance from before to after delete.
 
#21 ·
Lenzhotrod, makes perfect sense, but as I keep asking, why do some with full EGR delete just as I have still see the same exact boost as pre EGR delete? within the same model years at that! all these senarios keep getting brought up trying to justify the lower boost wich would be perfectly understandable if everyone saw a boost drop!

Idahof350 I agree with you 100%, untill that point theres naturally going to be alot of speculation.....appearently this problem isnt large enough that a deffinate solution had been found and posted on the internet somewhere.....
 
#25 ·
Hey folks,
There’s no magic regarding changes in manifold pressure when the EGR is disabled, its simple physics and programming.
The ECM is set to maintain about 270kpa or 40 psi of EBP during most operating conditions. This variable is one of the first parameters in the logic sequence, so if TPS (throttle position) is greater than X, the ECM is looking to open the EGR whenever possible to meet EPA regs. Based on TPS and several other inputs, the EGR will open to some position, with 40 psi EG (exhaust gas) flowing into the cylinders. The pressurized EG represents a resistance for the turbo’s compressor along with cam profile, crank position, etc. All these variables equate to the manifold pressure we see during stock OEM operations.
Now, we delete, block, or disable the EGR function and the manifold conditions change. These differences result in a lower resistance on the turbo’s compressor (remember the EBP was not changed)by modifying the EGR function. The ECM has a range or allowable error of boost for any TPS input, so although the psi input may be lower, the ECM is looking at over 100 inputs to determine if engine power is correct for conditions. The ECM is doing this a few hundred times per second.
To answer the OP’s question, there is not at absolute answer because weather conditions, location, ECM strategy, and drive habits all effect manifold pressure. If no pressure leaks, fault codes, or turbo issues are found, the engine is operating ok. The EPA will likely disagree with ok, but that’s a different topic!

Wekiwa

:txflag
 
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#28 ·
lenzhotrod, I have an SCT tuner, the boost is the same stock, cutom stock w/ EGR del option or custom tune (Innovative). I never threw a CEL as I had the sensor left in the intake & connection to wire harness. Never once had any codes.....

raceyf7, that part seems like trouble, Id have to research that item a bit, good looking out though! I DO understanmd there are numerous variables that effect manifold pressure but if I lost boost w/ leaks do to the explanation above than so should have everyone. 1 day I have 27psi, 3 days later I have 20 psi, no major weather changes, same location, etc (EGR delete)......yet alot are claming absolutely no change in boost pressure after EGR delete, this is where the expanations dont make sense. Regardless if Im here in condition A and somone else is over there in condition B, yes there may be a difference between A & B but the before and after boost were different at A and and the before and after boost were the same at B.....see what Im saying?
Now there is the point of the Strategy, mabey Ford had made a change that effects this boost loss and those seeing the loss have the same Strategy, and those who dont see the boost loss have another strategy......this is the missing link that would help answer my question & allow me to accept and move on!

wekiwa, your explanations are right on with previous mentioned theories, just in a bit more detail. I honestly respect that explanation and it makes perfect sense.
 
#29 ·
Yet my argument is: sure there may be many variables that effect manifold pressure, mostly between 2 locations. but wouldnt either location result in a similar change from before to after deletion? OR, I should just accept that leak free I lost 6-7 psi and leak free others Lost 0 psi? Doesnt the above explanation apply to them as well? I would agree more to the Strategy differences and if that is the case Id like to have that proved somehow..... a poll with a large bit of information would be needed...
 
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