NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > Modified Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

Modified Tech Discussion Forum for Tech related discussion for Modified XJ's and MJ's.

Reply
 
Thread Tools Display Modes
  #31  
Old February 6th, 2019, 09:35
Rockwood Rockwood is offline
NAXJA Forum User
 
Join Date: Sep 2011
Location: San Diego
Posts: 139
Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by tech1001 View Post
No that's not loud most people can talk at about 50db and they check it 20 inches from the end of the exhaust at 3000 to 5000 rpm . It would be loud if they checked it at 50 yards or so .
You should check out J1169. At one time, it was 75% of rated peak HP RPM, but my understanding is that has since been amended back to idle (or some other relatively low RPM) because many cars did not allow the engine to rev that high when stationary. The test on stationary vehicles is done at 3M, up to 45* offset from the exhaust outlet. Even if you were to still be required to rev to 75% of the HP peak's RPM, that's 3400 on a Jeep, which is about where it shifts when I'm driving around at normal acceleration. Since it's stationary, there is no load on the engine, so 3400rpm during this test will be quieter than when you're driving.

The decibel scale is logarithmic and doubles every 3dB. 95dB has 30 times the sound intensity/energy that a measurement of 50dB does. 95dB has twice the sound intensity my no muffler/no cat/divorced wastegate racecar did at 5000-ish RPM racing at Laguna Seca. 95dB is four times as loud as a lawnmower at full tilt and about the same volume of a leadblower strapped to your back (which requires hearing protection for any operator doing it for work).

Why you'd want to drive around with an exhaust that loud just cruising around is beyond me. No excuse to exceed those sound levels in any vehicle cruising around, let alone on a Jeep 4.0 with it's teensy tiny cam and tractor-like maximum RPM.
Reply With Quote
  #32  
Old February 6th, 2019, 13:27
tech1001 tech1001 is offline
NAXJA Forum User
 
Join Date: Oct 2016
Location: Los Angeles
Posts: 107
Re: Best Sounding Exhaust For The 4.0L?

I was just saying that you mite want to stay on the quiet side because they are starting to go after loud cars , and some cars with OE exhaust systems that won't pass the test the California bar does , they have there own test that California came up with and most newer cars with a auto trans will not free rev over 2500 to 3000 rpm but that's California .
Reply With Quote
  #33  
Old February 7th, 2019, 22:38
4x4JeePmaNthINg's Avatar
4x4JeePmaNthINg 4x4JeePmaNthINg is offline
NAXJA Forum User
 
Join Date: Nov 2008
Location: colorado, severance
Posts: 1,003
Re: Best Sounding Exhaust For The 4.0L?

Straight pipe, no muffler
Reply With Quote
  #34  
Old February 8th, 2019, 07:31
Rockwood Rockwood is offline
NAXJA Forum User
 
Join Date: Sep 2011
Location: San Diego
Posts: 139
Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by tech1001 View Post
I was just saying that you mite want to stay on the quiet side because they are starting to go after loud cars , and some cars with OE exhaust systems that won't pass the test the California bar does , they have there own test that California came up with and most newer cars with a auto trans will not free rev over 2500 to 3000 rpm but that's California .
Per the CVC, it's J1169, which has since been modified (but can't confirm since I'm no longer an SAE member) to idle (again, I believe) due to new cars not allowing free-revving to 75% of peak HP.
Reply With Quote
  #35  
Old February 9th, 2019, 01:08
tech1001 tech1001 is offline
NAXJA Forum User
 
Join Date: Oct 2016
Location: Los Angeles
Posts: 107
Re: Best Sounding Exhaust For The 4.0L?

I don't know how they would be able to test those cars , I was just saying what they are starting to do in California .
Reply With Quote
  #36  
Old February 12th, 2019, 06:01
cherokeecrawler's Avatar
cherokeecrawler cherokeecrawler is offline
NAXJA Forum User
 
Join Date: Aug 2018
Location: Atlanta, GA
Posts: 40
Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by Rockwood View Post
Even if you were to still be required to rev to 75% of the HP peak's RPM, that's 3400 on a Jeep, which is about where it shifts when I'm driving around at normal acceleration.
You must get 5mpg! My "driving normal" shifts at about 2200-2300 RPM and i only get around 16 average...
Reply With Quote
  #37  
Old February 19th, 2019, 07:17
sixditchoffroad's Avatar
sixditchoffroad sixditchoffroad is offline
AKA Skip
 
Join Date: Apr 2005
Location: Denver, Colorado
Posts: 211
Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by 4x4JeePmaNthINg View Post
Straight pipe, no muffler
I was going to say... I'm surprised nobody said open headers yet... This is close enough... lol
Reply With Quote
  #38  
Old February 19th, 2019, 10:25
Rockwood Rockwood is offline
NAXJA Forum User
 
Join Date: Sep 2011
Location: San Diego
Posts: 139
Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by cherokeecrawler View Post
You must get 5mpg! My "driving normal" shifts at about 2200-2300 RPM and i only get around 16 average...
12-ish...

Maybe not EVERY time I accelerate it's rolling to 3400RPM, but it's not uncoming. I live in the foothills and my rollers are about 100lbs a corner...

Either way, no XJ should be over 95dB under normal operating (which includes WOT).
Reply With Quote
  #39  
Old February 19th, 2019, 10:26
Rockwood Rockwood is offline
NAXJA Forum User
 
Join Date: Sep 2011
Location: San Diego
Posts: 139
Re: Best Sounding Exhaust For The 4.0L?

Uncommon* not sure why I typed "uncoming"
Reply With Quote
  #40  
Old February 19th, 2019, 16:39
offroadman83's Avatar
offroadman83 offroadman83 is offline
NAXJA Member
 
Join Date: Apr 2003
Location: Edinburg Texas
Posts: 871
Re: Best Sounding Exhaust For The 4.0L?

Didn't read through all of this but I am about to do my 92 xj exhaust and I have now ordered a high flow cat cheapie off ebay (Izumi) and a jones exhaust max flow muffler which was all of 40 bucks shipped off ebay. I was gonna do magnaflow as I am going for a deep but not too loud sound with no drone. Ive had flows and they drone without a doubt. My tj has a magnaflow and it just sounds great! Granted it has a turn down but the xj will go all the way out. I need it to be deep and grumbly not loud and annoying. After much research I found the jones muffler to be almost exactly like a magnaflow so I am looking forward to getting it done. If anybody wants to know how it sounds I will see about giving an update. ---------------Kyle
__________________
92 XJ stock at moment
2000 tj, superduty one tons, 3 link front, 4 link rear, Ox locked front and rear with 5.13s and 40s
Reply With Quote
  #41  
Old February 19th, 2019, 23:06
4x4JeePmaNthINg's Avatar
4x4JeePmaNthINg 4x4JeePmaNthINg is offline
NAXJA Forum User
 
Join Date: Nov 2008
Location: colorado, severance
Posts: 1,003
Question Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by sixditchoffroad View Post
I was going to say... I'm surprised nobody said open headers yet... This is close enough... lol
I've almost done that. Took it off at the cat with the intention of a clamp on cat back. Liked the sound/ feel of the engine offroad so I put pipe on and it sounds great, plus way quieter in the cab lol, not nearly as bad as you'd think.

There's a youtue vid of a guy running down the street header only, just for giggles, now that is loud.
Reply With Quote
  #42  
Old February 20th, 2019, 08:12
freerider15 freerider15 is offline
NAXJA Forum User
 
Join Date: Jan 2004
Location: FoCo, Crawlorado
Posts: 3,216
Re: Best Sounding Exhaust For The 4.0L?

I ran a Flowmaster 40 on my buggy when it was still an XJ.

Not bad, but in the long run more drone than I cared for.

Installed a Walker SS Quiet Flow on my wife's '96, and after hearing how well that one works (quiet, sounds good), I put one on my 2001 XJ.

Then again, I drove my XJ as a DD, and from CO to CA and back several times...so droning on sucks. The Flowmaster 40 was better than no muffler (ran with none for a bit), but still not quite what I cared for.
Reply With Quote
  #43  
Old February 22nd, 2019, 09:50
offroadman83's Avatar
offroadman83 offroadman83 is offline
NAXJA Member
 
Join Date: Apr 2003
Location: Edinburg Texas
Posts: 871
Re: Best Sounding Exhaust For The 4.0L?

Quote:
Originally Posted by offroadman83 View Post
Didn't read through all of this but I am about to do my 92 xj exhaust and I have now ordered a high flow cat cheapie off ebay (Izumi) and a jones exhaust max flow muffler which was all of 40 bucks shipped off ebay. I was gonna do magnaflow as I am going for a deep but not too loud sound with no drone. Ive had flows and they drone without a doubt. My tj has a magnaflow and it just sounds great! Granted it has a turn down but the xj will go all the way out. I need it to be deep and grumbly not loud and annoying. After much research I found the jones muffler to be almost exactly like a magnaflow so I am looking forward to getting it done. If anybody wants to know how it sounds I will see about giving an update. ---------------Kyle
Update..........it is installed and I like it! Its actually really quiet at idle with a very minor deep grumble when you get it on it. No drone that I can tell the one time I drove it up and down the road. I am thinking it might be way more quiet since I didn't dump it right behind the exhaust and went out all the way to the back. For the money I can't complain one bit.........
__________________
92 XJ stock at moment
2000 tj, superduty one tons, 3 link front, 4 link rear, Ox locked front and rear with 5.13s and 40s
Reply With Quote
  #44  
Old February 28th, 2019, 12:58
R6TeXJ's Avatar
R6TeXJ R6TeXJ is offline
NAXJA Forum User
 
Join Date: Dec 2005
Location: Allen, tx
Posts: 289
Re: Best Sounding Exhaust For The 4.0L?

^any video clips?
Reply With Quote
  #45  
Old March 4th, 2019, 13:43
jmg222 jmg222 is offline
NAXJA Member
 
Join Date: Jul 2015
Location: US
Posts: 440
Re: Best Sounding Exhaust For The 4.0L?

just throw a flowmaster on it


https://youtu.be/HSU1hSwK1Wg

https://youtu.be/RdRxFbUGEEE
__________________
Daily drive: 2018 Jeep Grand Cherokee TrackHawk; stock (for now)

Trail ride: 1988 XJ: Motor/plumbing/electrical: '19 ZZ6 350 sbc, 405HP/405 lb-ft; holly performer EPS, Terminator EFI, headers, novak aluminum radiator; MSD ignition
Drive train: d30 front, F8.8 rear, 4.11 gears, np242 transfer case, rusty under-armor; fully locked with detroit lockers; Chevy 700r4 tranny, 35" MT's
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
TUFF SOUNDING EXAUST blue83 Jeep Street and Performance 50 November 8th, 2010 16:08
Diesel/marble sounding 4.0 w/ 101K Ewen91 OEM Tech Discussion 14 April 5th, 2009 10:24
Is this a lifter sounding off? (with video) clunk OEM Tech Discussion 5 December 28th, 2008 12:24
Water Pump Sounding like a Banshee verrive OEM Tech Discussion 9 May 24th, 2005 22:45


All times are GMT -7. The time now is 11:29.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014