4 Inch Exhaust Needed!!!

[notlimah]

Are the mufflers supplied with the flo not quiet enough or not flow enough air?

 

Why not just go with a 5in?

Edited August 30, 2017 by notlimah

[AH64ID]

28 minutes ago, notlimah said:

Are the mufflers supplied with the flo not quiet enough or not flow enough air?

 

Not quiet enough. They would be fine a lot of the time, but the kids are in the back seat for a lot of my towing and even with 2 mufflers now it can be loud. 

29 minutes ago, notlimah said:

 

 

Why not just go with a 5in?

Drone is more common with a 5" and I don't need that much. 4" flows plenty for a lot more hp than I make, it's just finding a quiet muffler with minimal back pressure that is more difficult. 

[Mopar1973Man]

Puzzled?  How can a straight flow through muffler be restrictive? 

 

Like even the old NAPA muffler I ran was just a straight pipe muffler 3" in and 3" out and see straight thru.

[dripley]

4 hours ago, Mopar1973Man said:

Puzzled?  How can a straight flow through muffler be restrictive? 

 

Like even the old NAPA muffler I ran was just a straight pipe muffler 3" in and 3" out and see straight thru.

Curious about that myself.

[Dieselfuture]

I don't know,  I love my 5" with see through mufler. Drone comes on around 80mph I usually don't drive over 75. Sounds great too, but this is like who likes what color and taste.

[AH64ID]

7 hours ago, Mopar1973Man said:

Puzzled?  How can a straight flow through muffler be restrictive? 

 

Like even the old NAPA muffler I ran was just a straight pipe muffler 3" in and 3" out and see straight thru.

 

Mufflers with good attenuation have baffles on their straight thru design......

 

 

There is a LOT more to a muffler than just it's overall design and size. Take a look at the Donaldson catalog, it has lots of great info. 

 

It's just like saying since the air filter fits the box, or inlet tube, then it must filter and flow enough... and we all know that's not true. 

 

15 minutes ago, Dieselfuture said:

I don't know,  I love my 5" with see through mufler. Drone comes on around 80mph I usually don't drive over 75. Sounds great too, but this is like who likes what color and taste.

 

They do sound good!  empty :-)

 

With just my see thru Donaldson 40" muffler I loved the sound until I hooked up a trailer or ran the exhaust brake. Since I do a fair amount of towing, most of which is at 19K GCW or higher, on a fair amount of steep hills I want it quiet when towing, which means it will be nearly silent when not towing but oh well. 

Edited August 30, 2017 by AH64ID

[jlbayes]

9 hours ago, AH64ID said:

 

Not quiet enough. They would be fine a lot of the time, but the kids are in the back seat for a lot of my towing and even with 2 mufflers now it can be loud. 

Drone is more common with a 5" and I don't need that much. 4" flows plenty for a lot more hp than I make, it's just finding a quiet muffler with minimal back pressure that is more difficult. 

 

I know how to fix this. Compounds. 

[Mopar1973Man]

17 minutes ago, AH64ID said:

There is a LOT more to a muffler than just it's overall design and size. Take a look at the Donaldson catalog, it has lots of great info. 

 

Still, after reviewing the Donaldson catalog it seems backward to me that using a larger ID muffler to attempt to make quieter? Explain how your theory works?  

[AH64ID]

11 minutes ago, Mopar1973Man said:

 

Still, after reviewing the Donaldson catalog it seems backward to me that using a larger ID muffler to attempt to make quieter? Explain how your theory works?  

 

It's not theory, it's published data in the catalog. Did you look at the part of their catalog that shows attenuation and flow?

 

In order to get the attenuation and flow I want I need a 5" muffler, as a 4" muffler with the proper attenuation lacks the flow required. 

 

 

 

Exhaust flow for my engine is going to be around 2000 cfm peak. I'd like a muffler that can flow at least 2000 cfm at 3" Hg of restriction. 

 

My current muffler can flow 3119 cfm at 3", so a lot more than I need and proves that a 4" muffler can do it... but it's only 8-12 db of attenuation and it wasn't nearly enough for my application which is why I had to add the OEM resonator from a MC truck. 

 

I'd like a muffler with ~20 db of attenuation. Looking at the 4" mufflers there isn't one that meets both criteria. There is a 4" in 5" out that is close but it's 15-20 db, and that just barely meets my criteria. 

 

In 5" we have the M100580. It can flow 2530 at 3" and has an attenuation rating of 19-25db. Perfect! My back-pressure should never hit 3" and I'll get great attenuation. 

Edited August 30, 2017 by AH64ID

[Killer223]

i have a flow pro on my 08. it's quiet, no drone while towing either, but it will whistle when i use the EB on the VGT turbo. i can only hear the whistle when the windows are open. i got the 4" turbo back. 5x15" tip, couldn't tell you what model. but it took me longer to get the old exhaust out than to put the new one in. it's really easy with a can of dw-50.

 

The one on my 04, no idea what muffler is. took it from my 02, it's quiet for 90% of the time, but it'll drone a little pulling 13K up a 7% grade for 17 miles. but it's not loud enough to bother anyone. radio on low makes it go away. it's a stock from turbo to muffler, then a 4" tip.

[AH64ID]

I've been using published QSB5.9 data to get exhaust flow numbers. 

 

A 425hp QSB is rated at 3000 rpms and has an exhaust flow of 1825 cfm. 

A 480hp QSB is rated at 3400 rpms and has an exhaust flow of 2174 cfm. 

 

Those are crank horsepower numbers. On my last dyno I was ~410, which translates to ~480 based on a dyno of my stock tune on that same dyno. I don't often turn over 3000 rpms, let alone 2700 towing, which is where the 2000 cfm goal for exhaust flow came from. 

 

Donaldson also publishes some exhaust flow data. A 5.9 making 275 hp at 2500 rpms and 956° EGT is moving 1673 cfm. That's crank hp, so rwhp would be ~230 and we almost all above that number. 

 

As you can see the 4" mufflers with any descent attenuation run out of flow really quickly, especially for those of us that load the truck up often. 

[Mopar1973Man]

 

Still don't understand how 5" muffler is going to work on 4" pipe. Seems rather weird. I figured you would step up ot 5" pipe keeping the flow up and then using 5" muffler. Still trying to wrap my head around what I read on Donalson catalog and what you are saying. If this flow and attenuation was an issue wouldn't more manufactures of performance exhaust being doing what you saying? 

 

So could you point out the pages and what you're doing so I can see how this works?

 

 

[AH64ID]

31 minutes ago, Mopar1973Man said:

 

Still don't understand how 5" muffler is going to work on 4" pipe. Seems rather weird. I figured you would step up ot 5" pipe keeping the flow up and then using 5" muffler. Still trying to wrap my head around what I read on Donalson catalog and what you are saying. If this flow and attenuation was an issue wouldn't more manufactures of performance exhaust being doing what you saying? 

 

So could you point out the pages and what you're doing so I can see how this works?

 

 

There are 4" to 5" adapters that can get clamped or welded onto the muffler, and then it installs the same. I don't need 5" from the turbo back since 4" flows more than enough, I also don't want to deal with the notorious 5" drone while towing, we just don't have the exhaust flow to warrant a 5" exhaust. This won't effect anything in terms of flow, at least not more than the expansion/contraction that is already occurring in the muffler. 

 

You assume that the manufactures pay attention to all the specs. Recall the fuel filter issue from 8 or so years ago? The filtered pump companies had the world believe their filtration was better than OEM, when in reality it was worse in some cases. 

 

The other factor is that we are making a lot more power, which results in higher exhaust flow, than your standard industrial 5.9. The aftermarket world for industrial applications is a lot bigger than for pickups, so pickups seem to get what fits. Also, industrial applications are the ones who favor quiet exhaust while many pickup owners like the low attenuation sound. 

 

In this catalog you can find what I am talking about. 

 

https://www.donaldson.com/content/dam/donaldson/engine-hydraulics-bulk/catalogs/Exhaust/North-America/F110028-ENG/Exhaust-Product-Guide.pdf

 

page 34 has the 4" to 5" adapters. 

 

page 67 has the style 1 muffler specs. I currently run a M085171 and will run a M100580 next. 

 

This catalog talks about exhaust flow, and common engine exhaust flow data, as well as backpressure recommendations. 

 

http://www.asia.donaldson.com/en/exhaust/support/datalibrary/1053747.pdf

 

 

Here is the QSB 425@3000 rpm performance curve chart

https://www.sbmar.com/docs/performance-curves/QSB 5.9 [425%2C3000%2C8732%2CHO%2CMay 10%2CM-91632].pdf

 

and the 480@3400

http://www.american-nautics.ro/pdf/QSB5.9-480.pdf

 

and finally the 440@3400. 

https://www.sbmar.com/docs/performance-curves/QSB 5.9 [440,3400,1860,HO,May 10,M-92284].pdf

 

The 6.7 surprisingly doesn't require much more exhaust flow than the 5.9 at 480 hp.  480@3300 is 2161cfm. But it's a bit more air for the 550@3300 motor, up to 2450 cfm. Even the 550@3300 could use the 4" M085171 I have, if the attenuation was desirable. Even the 600@3000 8.3 is only 2830cfm. 

 

 

Edited August 30, 2017 by AH64ID

[CTcummins24V]

That's technical. Belive it or not, going from straight pipe to adding a muffler, I did notice a slight restriction. That was a bone stock truck, other than a fuel boss lift pump.

 

Going from a 4" to a 5", then adding a resonator, I couldn't tell any difference.

[Mopar1973Man]

 

Still this where I don't get it. You are claiming your HP number and comparing to these other engine specs as a guideline for exhaust flow. (around 900 cfm roughly speaking) Ok... I got that... But now when I look up the muffler you plan on running it capable flow rate 1431 to 3100 cfm (at 1-3" Hg backpressure). I just can't see you getting that attenuation out of that muffler being when you read the section on back pressure.

 

 

 

So you increase the tube size inside the muffler area backpressure will be nil. Out of the 3 types, I'm assuming the 3rd is the truest that you are going after. Because the first two types won't work because of the oversized tube inside the muffler. But as you see the second picture showing higher back pressure give better attenuation but in your case there is going be very little if any. So this is where my confusion is.  

Edited August 30, 2017 by Mopar1973Man

[AH64ID]

I'm not sure what spec's you're looking at. I am looking for 2000 cfm of exhaust (not 900) and the muffler I'm looking at is rated for 1565-2530 (1-3 inHg). 

 

The size of the exhaust pipe before or after the muffler will have minimal impact on the attenuation capabilities of the muffler, so minimal that it's probably noticeable in a laboratory setting. The flow thru the muffler will be the same as thru the exhaust pipe. Backpressure is based on flow, of which I have plenty. 

 

I'm looking at nearly 2000 CFM of exhaust flow on my motor if I rev it up under full load. The M100580 will be giving just under 2 inHg restriction at that flow which should put it in the middle of it's attenuation rating at peak exhaust flow/volume. That's exactly what I am looking for. The attention can be much lower at cruise exhaust flow/volume as the actual volume is down. Even at moderate exhaust flow the attenuation of the M100580 is higher than my current muffler is peak. It should work quite well. 

 

 

The M090544 would also be a good muffler but I am not sure than 13-18db is enough attenuation for what I want. 

Edited August 30, 2017 by AH64ID

[Mopar1973Man]

My bad I was looking at air flow. 

[notlimah]

On 8/30/2017 at 8:36 AM, Killer223 said:

i have a flow pro on my 08. it's quiet, no drone while towing either, but it will whistle when i use the EB on the VGT turbo. i can only hear the whistle when the windows are open. i got the 4" turbo back. 5x15" tip, couldn't tell you what model. but it took me longer to get the old exhaust out than to put the new one in. it's really easy with a can of dw-50.

 

The one on my 04, no idea what muffler is. took it from my 02, it's quiet for 90% of the time, but it'll drone a little pulling 13K up a 7% grade for 17 miles. but it's not loud enough to bother anyone. radio on low makes it go away. it's a stock from turbo to muffler, then a 4" tip.

 

What's the exhaust angle like on that setup? Muffler or no?

[Killer223]

i do have a muffler.

 

[notlimah]

That sounds pretty nice! That's with the muffler provided by flo pro?