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Junior Member
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6 Posts
Discussion Starter #1
I realize that I should've done a nice complete 4 or 5" exhaust all the way from the downpipe, but I didn't. Kept the 3.5 all the way to the muffler or resonator, whatever it is when I deleted the DPF/DOC. I understand the hardryer sound is coming from my vented tailpipe. What are most of u guys replacing this with?
Thanks, Tom
 

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Junior Member
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Discussion Starter #3
I respectfully disagree w/ you Sir. Why would the turbos have anything to do with it @ 0-1 PSI. Just to check, I went out and wrapped some towels around the vents...and it was gone and sounded 100% better. So back to my ?, what are most people using for the 3.5" DPF back?
Thanks, Tom
 

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Senior Member
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497 Posts
ooohhh, im subscribing to this!
 

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Spartan Diesel Tech
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969 Posts
I respectfully disagree w/ you Sir. Why would the turbos have anything to do with it @ 0-1 PSI. Just to check, I went out and wrapped some towels around the vents...and it was gone and sounded 100% better. So back to my ?, what are most people using for the 3.5" DPF back?
Thanks, Tom
Tom,

How much to do you know about the turbo's on these trucks? Did you know that the sequential setup consist of an atmospheric charger and a VGT (variable geometry turbo)? Have you ever heard of a VGT duty cycle? Did you know that even when the turbo's are not spooled, the VGT duty cycle is active?

So....back to your question. A more thorough answer to your question would have been that the tubo's are the reason for the hairdryer sound and you will never fully get rid of it.

Here are your options though....

1. 4" downpipe back exhaust. It will slightly deepen the tone of your hairdryer sounding exhaust.
2. 4" turbo back exhaust. Once again, it will slightly deepen the tone of your hairdryer sounding exhaust.
3. 4" downpipe in to a 5" downpipe back exhaust. It will REALLY deepen the tone of your hairdryer sounding exhaust....but I assure you it will not rid you of it. This is the setup I have currently.
4. 4" exhaust w/muffler. It will just about make your exhaust as quiet as stock....and get rid of a good bit of the hairdryer. If your up for super quiet, go for that route.
5. 5" exhaust w/muffler. Probably the best option for dampening the hairdryer sound. It will still be there, but not as pronounced as a straight exhaust. Doing 5" with a muffler will also still give you that throaty hard throttle sound.
6. Swap your turbo's out to either a compound setup without a VGT or a single non VGT.

Hopefully this helps you out....and prevents you from wrapping a towel around your exhaust tip again. :thumbsup
 

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Member
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215 Posts
I respectfully disagree with both of you, in part.

If you are referring to the louvered exhaust vents prior to your exhaust tip. Then the sound you are hearing is the venturi effect which actual compounding the turbo sound. As the exhaust is rushing out the tip the movement of exhaust is sucking air in through these vents. The process increases your exhaust flow which in effect creates vacuum in the upstream exhaust pipe removing pressure from the backside of the turbo.

There is an increase in turbo noise due to the relief in pressure but most of the sound is from the air rushing in and then out the tip.

I actually like it. I just tell people my truck is the one that sounds like a Jet...
 

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172 Posts
If you don't believe what was said above, go buy a new exhaust tip and see if your happy with it. When it doesn't make a difference, reread the post above and pick your new exhaust. I have a for inch turbo back and don't like the hair dryer sound I have.I plan to go to a five inch with a muffler sometime soon. Just not sure which muffler yet. The time can make just as much difference as the exhaust though, my 250 time has almost no hiss while the 310 has a ton... THE 310 has more back pressure...
 

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Spartan Diesel Tech
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969 Posts
I respectfully disagree with both of you, in part.

If you are referring to the louvered exhaust vents prior to your exhaust tip. Then the sound you are hearing is the venturi effect which actual compounding the turbo sound. As the exhaust is rushing out the tip the movement of exhaust is sucking air in through these vents. The process increases your exhaust flow which in effect creates vacuum in the upstream exhaust pipe removing pressure from the backside of the turbo.

There is an increase in turbo noise due to the relief in pressure but most of the sound is from the air rushing in and then out the tip.

I actually like it. I just tell people my truck is the one that sounds like a Jet...
You do know that the vents are there for heat reduction at the exhaust tip during regeneration.....correct?

Not sure where you heard the information that you presented above, but it is news to me.

I have a standard MBRP tip on my exhaust, no vents anywhere, and the hairdryer sound is still very much there. I assure you that the vented exhaust tip has nothing to do with the hairdryer sound. It is VGT related. Same with the newer Duramax's. The VVT turbo's that they have (similar to a VGT) cause their exhaust note to have a pronounced hiss to it, unlike the LB7 Duramax which did not use a VVT turbo. Compare the exhaust note of a 7.3 and 6.0. 7.3 does not use a VGT, the 6.0 does. Same with the 6.4. If the VGT duty cycle is active, you will have hiss.
 

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Rollin' Coal
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379 Posts
jeff stop waisting your time. haha he wont get it. let him find out the hard way.
 
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:popcorn
 

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Rollin' Coal
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379 Posts

here watch this. no tail pipe vents all 4 inch tubing. if this doesnt make a beliver out of you i give up. not that i was really trying to begin with. this thread is pointless except for a good laugh. and why you wont believe 08stroker250 whom which probably knows these truck better than 90% of the people on this forum is beyond me...
 

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Member
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215 Posts
YouTube - flo-pro 4" downpipe back on a 2008 straight piped f250

here watch this. no tail pipe vents all 4 inch tubing. if this doesnt make a beliver out of you i give up. not that i was really trying to begin with. this thread is pointless except for a good laugh. and why you wont believe 08stroker250 whom which probably knows these truck better than 90% of the people on this forum is beyond me...
First off I wasn't arguing that Jeff's data was incorrect.

And your video proves my point my truck is far louder and sounds nothing like that.

All I was saying is the louvered vents compound the noise from the turbo.
 

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CRAZY CANUCK
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4,320 Posts
You cannot say that his truck is quieter than yours unless you hear it in person, most cameras that people use to record youtube videos use the built in microphone, and they are not going to record sound in high quality, let alone i doubt you have a surround sound system hooked up to your computer

I have recored my truck idled up, and the sound on the video is no where near as loud as in person, and you can clearly tell that this is not a 6.4powerstroke, but it STILL has your hairdryer/vacuum sound, explain that one away please
 

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221 Posts
My truck has the hair dryer sound regardless of tip or exhaust. I started it up the other night with just the downpipe on and it soulded like a huge hair dryer. The 4" Flo Pro with the Twister resonator took out some of the noise but it is still there.
 

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Junior Member
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16 Posts
This is really making me laugh :haha, how can you argue with a SPARTAN DIESEL TECH? They pretty much rule over the 6.4l tuning. I think he would know better than anybody!
 

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Junior Member
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70 Posts
This is really making me laugh , how can you argue with a SPARTAN DIESEL TECH? They pretty much rule over the 6.4l tuning. I think he would know better than anybody!
I agree with 6.4lStrokin. Plus, I've been following a similar thread on the PSN, you might want to check it out, people are trying the FTE resinator to get rid of the hair dryer sound.
 

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Senior Member
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497 Posts
Jeff, got a question for u. I have the doc/dpf delete on mine already. does MBRP make a cat back or a doc back exhaust that would fit my flo pro setup? or what other brands do this? I kinda want to look for a different tip instead of the stock twin tip setup.
 

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Spartan Diesel Tech
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969 Posts
Jeff, got a question for u. I have the doc/dpf delete on mine already. does MBRP make a cat back or a doc back exhaust that would fit my flo pro setup? or what other brands do this? I kinda want to look for a different tip instead of the stock twin tip setup.
There are several companies that make DPF back exhaust systems that will work in conjunctions with a DPF/DOC delete pipe. I used an MBRP 5" DPF back exhaust with my 5" Powerstroker67 DPF/DOC delete pipe. Only thing that had to be done was cut the 5" to 3.5" reducer off of the MBRP pipe. I think Magnaflow comes with the reducer separate, but cutting was no big deal.

What size delete pipe do you have? Does is reduce down to 3.5" or did it come with a separate reducer for the stock tailpipe?
 
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