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Discussion Starter · #1 ·
I've read on here where quite a few folks have removed the plastic/foam baffle that is in the air intake tube between the filter box and the turbo. The thinking being it removes a restriction, improves air flow and you can now hear your turbo whine. With that in mind: I was in Chicago on business last week and struck up a conversation with another guy in the bar. We got to talking and I mentioned that I had a new CTD. That caught his interest and it turns out he is an engineer working for one of the companies that supplies the air intake system components for these trucks.

So I told him that I was going to remove the baffle to get better performance, etc and he said he recommends not to. He claims that the plastic/foam baffle is built the way it is for several reasons:

1-The foam is not for noise deadening but for temperature insulation. Apparently the EGR tube is very close to the air tube plus the normal engine heat, so they insulate the baffle to try and keep the incoming air as cool as possible and not pick up any engine heat before it gets to the turbo.

2-The rest of the baffle is designed to steer the air and reduce turbulence to improve the "laminar" flow into the turbine wheel. The baffle ensures the incoming air hits the turbine vanes at the proper angle and with the least turbulence.

3-If you remove the baffle the air is slowed quite a bit by the sharp right angle bend in the intake tube just before the turbo and it creates a lot of turbulence. It is the air hitting the turbine vanes at the less than ideal angle that makes the turbo whine noticeable. He explained it as being similar to when a boats propellor cavitates in the water.

It sounds like he knows what he is talking about, but take it for what its worth. He claims if you remove the baffle you will see an increase in turbo sound, a very slight increase in EGTs, a very slight decrease in performance, and a slight increase in the amount of soot the engine creates due to the reduced performance/efficiency of the turbo and the increased temperature of the incoming air. If (IF) that is true, you may actually decrease your MPG for the reasons above, plus IMO, more soot means more frequent regens which = less MPG.

He also said the best after market CAI systems were the ones that are totally sealed (not a filter on a stick) so they only intake cold air and not engine compartment air. He recommends you use a "sock" pre-filter even with the new dry 2 micron filters. And, he recommends if you get an after market CAI that you also get a "TAG" (turbine air guide) device that smooths and steers the air into the turbo much like this baffle does. The only place I could find a TAG device was at dieselpowerproducts and the product description seems to fit his explanation.

Thoughts?
 

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Diesel Junkie
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There ave been many threads on this topic...... My opinion is , he is probably right. With that said, I don't think the difference in performance or fuel economy with this mod is substantial......at least on the 5.9.
I think most do the mod for the sound.....those doing it for mpg gains or HP gains will probably be disappointed.

Did he offer any numbers as far as HP loss or fuel economy loss?
 

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good info very informative has me kind of scratching my head thinking about the whole thing
 

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I just posted a thread (turbo shot?...) cel came on codes p2000, p2262, p2299, this is about a week after removing the air baffle. I think I'll put it back in and take it to the dealer.
 

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im glad i saw this thread. i was going to remove my baffle tom. good info. thanks:thumbsup
 

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I have mine out on my 5500. It sounds alot better to me. I still believe that the baffle is put in there for sound deading. All they brag about is quite diesel. The air is not restricted in anyway to the turbo.
 

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does anyone honestly know if there is a baffle on the 2001 cummins???
 

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I believe that the baffle is in there for insulation against heat from the EGR. I have the S&B cold air intake and realized how hot the tube gets going to the turbo.
The factory tube gets extremely hot after driving it for a while. Just pop the hood next time and feel the part where the insulation is in the intake tube. You won't hold your hand on if for long. Funny thats where the insulation is. I wish now that i would not have purchased the C.A.I. for this reason.
Yeah, don't get me wrong it sounds awesome, but what else is great but the whistle. Plus, I have to install the factory intake every time I have to go to the dealer for warranty issues. Lately, I've just left it on so the dealership won't void my warranty especially with everyone's turbo issues.
 

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Air Baffle

does anyone honestly know if there is a baffle on the 2001 cummins???
In my O1, there was not a baffle in the intake plumbing. I bought it brand new.
 

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Discussion Starter · #10 ·
Did he offer any numbers as far as HP loss or fuel economy loss?[/QUOTE]

All he said is that the hotter, more turbulent air will make the turbo respond a little bit slower. This would give you a little bit of lag or slower throttle response, a little more soot and a few pounds less of boost. Nothing huge but minor decreases in performance, certainly no gains.
 

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I ripped my cai off because of the service air filter light kept coming on, but my next complaint was the turbo lag, it was definatly noticable.

anyone want a AFE StageII SI(sealed airbox) w/ proguard 7.
 

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I have a hard time putting that together. the fins might straighten the air flow but as soon as it hits that last 90 it is going to be turbulent again. typically stuff like that is done to pass epa noise regulations. those fins looked more like sound acoustics with all the little dimples on the surface. I could be wrong and prolly am
 

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Discussion Starter · #16 ·
I have a hard time putting that together. the fins might straighten the air flow but as soon as it hits that last 90 it is going to be turbulent again. typically stuff like that is done to pass epa noise regulations. those fins looked more like sound acoustics with all the little dimples on the surface. I could be wrong and prolly am
But if you look at the baffle, the part that goes in the furthest bends towards the turbo right in the middle of the 90 degree bend, specifically to minimize the amount of turbulence created by the 90.
 

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You would think that the increase in efficiency from a after market intake would over ride the decrease from the baffle being removed. My truck spools like a old woman when the stock air filter is put back on. All you would have to do If your really worried about the heat is just wrap it for the three foot section with some 1 inch foam insulation with the thermal reflective stuff on the outside. Sould work better than the foam inside the tube.
 

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But if you look at the baffle, the part that goes in the furthest bends towards the turbo right in the middle of the 90 degree bend, specifically to minimize the amount of turbulence created by the 90.

Those are still in on mine....I just replaced the tube between the two rubber elbows with an afe tube , and removed the silencer ring....:thumbsup
 

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Mtn Trucker,
I totally agree that the baffle in is better. I've said to many people that most of the aftermarket intakes do more harm than good. I've tried a few of them. The air starts swirling all the way up the intake without the crosshair style baffle in the middle.
Picture the turbine blades trying to slice the air as it enters. It will slice less of the air if the air is turning the same direction as the turbo. I found that a large AFE or K&N with a piece of exhaust tubing at the middle of the stock intake would gain me about 1 MPG. After replacing the entire intake, I lost 1/2 of the 1MPG gain. If you want to hear the turbo, just smooth out the top of the intake and add a huge free flowing filter.
Garry
 

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I would think if cummins wanted to make it quieter they would wrapped it on the out side ,we can only guess why the did it ,they make this wonderful machine and we only add little things to it . the reason we buy new is to have the newest technology .if someone can make a better motor from scratch in there garage let me know i want one , i know it will be a lot cheaper :lol3:
 
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