LOST JEEPS :: View topic - 3 inch line, no cat no muffler !

First, if you don’t like drone, don’t get a flowmaster muffler.

Second, a 3 inch open straight pipe exhaust isn’t gonna be noticeably louder than a 2.5 inch. Which is what you have now.
I really don’t see the point of a 3” exhaust on this little engine. It’d be a lotta extra work for little benefit.

Mine is a 2.5” straight pipe.
Turn down is right underneath the front passenger seat.
I’ve been told by passerby’s that it’s kinda loud. Not as loud as some of the Harley’s driven around here but definitely very loud for a Jeep Liberty.
But for me, in the cab, windows up, AC on, and music on at a comfortable level, it’s not bad at all. Heck, my wife doesn’t even complain about it when she rides with me.

I’ve driven very long distances like this.
But it’s already been said, noise is subjective.
And I have mild hearing loss in my right ear. So take that for what it’s worth.

As I have the only diamond eye 3 in Martel bent turbo back 3 inch made I can tell you it sounds cool at first but is annoying as hell, put a diesel glass pack on it like I later did to get rid of the drinking and put a cat on it to get rid of the stink... when this corona thing is over diamond eye is coming out with a 3 in turbo back with a cat... just a heads up

Sent from my iPhone using Tapatalk

I can tell you that with the 3 in madrel bent turbo back and no cat there is boost creep when you keep your foot into it like the VW guys get so you have to tune around it

Sent from my iPhone using Tapatalk

I don’t see how “boost creep” can happen with a computer controlled VNT turbo.
Unless there’s a problem with the MAP sensor.

Both Jeeps have no problems but if you pin the throttle for more than 20 seconds it will over boost and it doesn’t happen with the stock exhaust with the muffler delete, just the 3 in mandrel bent turbo back... if you want I can video it and the same on the other Jeep and put it on my wife’s also to prove it out... boost creep is when it is higher than the desired

I think I will go ahead with a 3" line with a cheap aftermarket cat , I don't believe cat are much restrictive unless they are getting plugged.

I just did a 3" with no cat and a free flow muffler coming out of before the rear wheel on a 4.0l Jeep XJ and it sound really nice !

Author:	PZKW108 [ Wed Sep 02, 2020 4:50 pm ]
Post subject:	3 inch line, no cat no muffler !
I know it's a pretty subjective question but how loud is the CRD with 3 inch line and cat and muffler delete ? I have a muffler delete only right now and don't found it loud at all to give you an idea ! thanks

Author:	WWDiesel [ Wed Sep 02, 2020 11:51 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
To keep the exhaust drone down low, best to delete the CAT and install a free flowing flow through muffler like a Flowmaster and run tailpipe out to rear of vehicle. If you do this, you will never be bothered by noise and in most cases won't even hear it unless you standing behind it or have windows down while giving it plenty of GO petal at lower speeds.

Author:	flash7210 [ Thu Sep 03, 2020 4:50 am ]
Post subject:	Re: 3 inch line, no cat no muffler !
First, if you don’t like drone, don’t get a flowmaster muffler. Second, a 3 inch open straight pipe exhaust isn’t gonna be noticeably louder than a 2.5 inch. Which is what you have now. I really don’t see the point of a 3” exhaust on this little engine. It’d be a lotta extra work for little benefit. Mine is a 2.5” straight pipe. Turn down is right underneath the front passenger seat. I’ve been told by passerby’s that it’s kinda loud. Not as loud as some of the Harley’s driven around here but definitely very loud for a Jeep Liberty. But for me, in the cab, windows up, AC on, and music on at a comfortable level, it’s not bad at all. Heck, my wife doesn’t even complain about it when she rides with me. I’ve driven very long distances like this. But it’s already been said, noise is subjective. And I have mild hearing loss in my right ear. So take that for what it’s worth.

Author:	My66dodge [ Thu Sep 03, 2020 4:07 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
As I have the only diamond eye 3 in Martel bent turbo back 3 inch made I can tell you it sounds cool at first but is annoying as hell, put a diesel glass pack on it like I later did to get rid of the drinking and put a cat on it to get rid of the stink... when this corona thing is over diamond eye is coming out with a 3 in turbo back with a cat... just a heads up Sent from my iPhone using Tapatalk

Author:	PZKW108 [ Thu Sep 03, 2020 7:20 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
flash7210 wrote: First, if you don’t like drone, don’t get a flowmaster muffler. Second, a 3 inch open straight pipe exhaust isn’t gonna be noticeably louder than a 2.5 inch. Which is what you have now. I really don’t see the point of a 3” exhaust on this little engine. It’d be a lotta extra work for little benefit. Mine is a 2.5” straight pipe. Turn down is right underneath the front passenger seat. I’ve been told by passerby’s that it’s kinda loud. Not as loud as some of the Harley’s driven around here but definitely very loud for a Jeep Liberty. But for me, in the cab, windows up, AC on, and music on at a comfortable level, it’s not bad at all. Heck, my wife doesn’t even complain about it when she rides with me. I’ve driven very long distances like this. But it’s already been said, noise is subjective. And I have mild hearing loss in my right ear. So take that for what it’s worth. Actually I still have the cat but my 2.5" line use for the muffler delete is rusted thru. I also found a nice piece of stainless steel 3' line from a ford truck. It already have a 2.5 to 3" flexible in it and have an offset right where the crossmember of the transfer case ! I was also thinking about coming out just before the rear wheel !

LOST JEEPS http://www.lostjeeps.com/forum/phpBB3/

3 inch line, no cat no muffler ! http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=91662	Page 1 of 2

Author:	PZKW108 [ Thu Sep 03, 2020 7:22 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
My66dodge wrote: As I have the only diamond eye 3 in Martel bent turbo back 3 inch made I can tell you it sounds cool at first but is annoying as hell, put a diesel glass pack on it like I later did to get rid of the drinking and put a cat on it to get rid of the stink... when this corona thing is over diamond eye is coming out with a 3 in turbo back with a cat... just a heads up Sent from my iPhone using Tapatalk I forgot about the smell........ Thanks for the heads up 66 ! I will source a cheap 3" cat to ad to the line !!

Author:	My66dodge [ Thu Sep 03, 2020 9:49 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
As a professional I remind everyone about that... as an avid outdoorsman there is nothing like loading the vehicle early in the am and while it is warming up the lovely eye burning of a non cat vehicle... I put one on all my older cars too... if they can run a cat on a dodge daemon and make that kind of power then it’s not the restriction most people think it is Sent from my iPad using Tapatalk

Author:	Jett [ Thu Sep 03, 2020 11:52 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
Yes my lib came with a drilled out cat and a Flowmaster and it doesn’t drone at all, it sure is smelly though. I thought it was the DPF’s that killed the smell, I guess I’ve never had a cat only diesel. Good to know, I may put one back on at some point.

Author:	My66dodge [ Fri Sep 04, 2020 9:22 am ]
Post subject:	3 inch line, no cat no muffler !
The modern diesel has three components to the exhaust system the DPF or diesel particulate filter kills the soot the SCR is where that urea injection happens if it has DEF otherwise the SCR is a fancy catalytic converter that takes care of NOx and if it has DEF the SCR still takes care of NOx but with less precious metals that’s why they went to the DEF system to the exhaust costs a quarter of what it used to to make the cat is strictly there for unburnt hydrocarbons which is what on a gasoline engine burns your eyes when it’s running. The order of these components changes depending on manufacturer Sent from my iPhone using Tapatalk

Author:	WWDiesel [ Fri Sep 04, 2020 1:34 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
Don't take my word for it, there are plenty of Abstracts, studies, and write ups available online for reading concerning the: Effects of Exhaust Back Pressure on the Performance of a Turbocharged Diesel Engine Most turbocharged Diesel engines have no throttle valve, so there’s very little if any restriction on air coming into the engine. So why should there ever be a restriction on the exhaust gases leaving the turbo? That is why Diesels tend to perform better with larger free flowing exhaust systems. Any exhaust system backpressure on a turbocharged diesel engine affects the flow rate of exhaust gases passing through the exhaust system at the optimum rate. As a result of any restriction, back pressure and exhaust gas temperatures (EGT’s) increases within the turbine housing. Increased combustion chamber outlet exhaust gas temperatures due to increased back pressure affects the turbocharger in a number of negative ways and causes inefficiencies which can include problems with, oil leaks, carbonization of oil within the turbo bearing area, turbo response times and performance across its entire operating range. With increases in exhaust back pressure, engine volumetric efficiency decreases. Volumetric efficiency, fuel economy and combustion efficiency can be improved by simply decreasing exhaust back pressure. So simply getting rid of the EGR system and getting rid of the restrictive CAT and installing a free-flowing muffler can improve turbo efficiency, engine performance, and longevity. Backpressure is never “necessary” for the operation of a diesel engine! If you are concerned about NOx, then install a water-MeOH fogging system, and you take care of the NOx and have the side effect of cleaning your combustion chambers and lowering EGT’s. The more air you can flow into a diesel engine and the faster and less restricted you can get the exhaust gases out, the better the performance and longevity your diesel engine and turbo will provide.

Author:	My66dodge [ Fri Sep 04, 2020 3:33 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
I can tell you that with the 3 in madrel bent turbo back and no cat there is boost creep when you keep your foot into it like the VW guys get so you have to tune around it Sent from my iPhone using Tapatalk

Author:	PZKW108 [ Sat Sep 05, 2020 1:23 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
My66dodge wrote: I can tell you that with the 3 in madrel bent turbo back and no cat there is boost creep when you keep your foot into it like the VW guys get so you have to tune around it Sent from my iPhone using Tapatalk Can you explain "boost creep" please ?

Author:	My66dodge [ Sat Sep 05, 2020 3:08 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
I like this explanation best Boost creep is defined as a condition of rising boost levels past what the predetermined level has been set at. For example, if your target boost level is 15psi, you would see the boost levels increase beyond that as RPMs increase. The short explanation for boost creep is that the wastegate is not able to flow enough air to bypass the turbocharger’s turbine housing. When the volume of air flowing through the turbine housing continues to increase, boost will also continue to increase. Boost creep is most commonly observed in areas that have very low ambient temperatures as well as high atmospheric pressure. This often encompasses those in the Pacific Northwest as well as New England and East Coast. So basically I get over boost codes that pop, I am sure it’s the exhaust cause I have swapped it from my kJ to my dads and the problem follows the exhaust and they both have the same GDE eco tune... the exhaust flowed so much it had boost creep, adding a cat fixed it... still no back pressure though Sent from my iPad using Tapatalk

Author:	flash7210 [ Sat Sep 05, 2020 3:39 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
I don’t see how “boost creep” can happen with a computer controlled VNT turbo. Unless there’s a problem with the MAP sensor.

Page 1 of 2	All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/

Author:	My66dodge [ Sat Sep 05, 2020 4:13 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
Same as the vw guys have... the turbo closes to spool up quick and opens to reduce boost, but when it is all the way open and the exhaust is free flowing enough the boost can continue to rise. I use to sell Malone tunes for the vw and bmw guys and they need to know if the exhaust is stock on the TDI platform to ensure it doesn’t have boost creep... reach out to GDE or Malone to find out more, I am a mechanic but they can give you more technical details of how it works, it is a real thing, the exhaust needs to be free flowing but on certain designs at certain times it will continue to build boost even when the VNT nozzles are opened up Sent from my iPad using Tapatalk

Author:	WWDiesel [ Sat Sep 05, 2020 4:17 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
flash7210 wrote: I don’t see how “boost creep” can happen with a computer controlled VNT turbo. Unless there’s a problem with the MAP sensor. May be true on VW's, but don't think it is an issue on these engines. Definitely has never been observed happening on mine. If it did I would know it since I have a very quick acting mechanical boost gauge that I monitor every time when accelerating hard. I can tell you for sure if you increase the boost to above the upper limit of the GM MAP sensor, it will throw it into limp mode. With the free flowing exhaust and no CAT, the little tubo will make 35 psig or more boost if I dial it up, but the MAP/ECM don't like it and will limp mode it. Have to stay below ~25 psig for everyday driving. But it still runs like a little race car even at that level and never smokes.

Author:	My66dodge [ Sat Sep 05, 2020 5:12 pm ]
Post subject:	3 inch line, no cat no muffler !
Both Jeeps have no problems but if you pin the throttle for more than 20 seconds it will over boost and it doesn’t happen with the stock exhaust with the muffler delete, just the 3 in mandrel bent turbo back... if you want I can video it and the same on the other Jeep and put it on my wife’s also to prove it out... boost creep is when it is higher than the desired Sent from my iPad using Tapatalk

Author:	WWDiesel [ Sat Sep 05, 2020 5:52 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
My66dodge wrote: Both Jeeps have no problems but if you pin the throttle for more than 20 seconds it will over boost and it doesn’t happen with the stock exhaust with the muffler delete, just the 3 in mandrel bent turbo back... if you want I can video it and the same on the other Jeep and put it on my wife’s also to prove it out... boost creep is when it is higher than the desired So what problems does it cause if any? May be a good reason to stick with the 2.5"?

Author:	PZKW108 [ Sat Sep 05, 2020 10:35 pm ]
Post subject:	Re: 3 inch line, no cat no muffler !
I think I will go ahead with a 3" line with a cheap aftermarket cat , I don't believe cat are much restrictive unless they are getting plugged. I just did a 3" with no cat and a free flow muffler coming out of before the rear wheel on a 4.0l Jeep XJ and it sound really nice !

Author:	Jett [ Sun Sep 06, 2020 2:53 am ]
Post subject:	Re: 3 inch line, no cat no muffler !
PZKW108 wrote: I think I will go ahead with a 3" line with a cheap aftermarket cat , I don't believe cat are much restrictive unless they are getting plugged. I just did a 3" with no cat and a free flow muffler coming out of before the rear wheel on a 4.0l Jeep XJ and it sound really nice ! Which cat are you thinking?