running 4.7 JGC with no muffler.... - JeepForum.com
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post #1 of 18 Old 11-25-2006, 12:22 AM Thread Starter
Bliss Racing
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running 4.7 JGC with no muffler....

Just wondering if i ran the jeep with no muffler..... if id would run ok...or lose power or torque....and if it would be obnoxiously loud, or sound good??

I did this with my Grand Prix GTP and it ran great, but that was a supercharged car.

Any feedback would be appreciated!!

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post #2 of 18 Old 11-25-2006, 12:42 AM
Woody
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You will loose torque.

HP will be close if not higher.

My Trans Am made huge gains in the 1/4 mile when I added mufflers and a cat compared to an open exhaust.

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post #3 of 18 Old 11-25-2006, 12:48 AM Thread Starter
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Quote:
Originally Posted by Woody
You will loose torque.

HP will be close if not higher.

My Trans Am made huge gains in the 1/4 mile when I added mufflers and a cat compared to an open exhaust.
Yea, i'm not too worried about losing out in something like the quarter.....more or less just want to give it a more aggressive sound.

so HP gains might go up?? Do you think it would be a noticable loss in torque?

Obnoxious sounding at all??
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post #4 of 18 Old 11-25-2006, 01:06 AM Thread Starter
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Oh, and i'm too broke right now for mufflers, so that's why i ask this
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post #5 of 18 Old 11-25-2006, 01:09 AM
Woody
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Lots of torque loss, probably 15% or more. You might not even get overdrive to engage. I had a manual in the T/A and I thought there was something wrong with the 350 HO under the hood.

If you want agressive sound, drop a Flowmaster 40 series muffler in there. It'll sound great and your performance will not be degraded.

Your HP gains will probably be less than 5%.

VERY OBNOXIOUS, especially if you don't pipe it to the rear bumper. Mine was dumped by the tranny and I only lived with it for a couple of weeks before I put pipes on. I would've done it sooner, but had a motorcycle I could ride till I had the money saved to do it.

Many areas have made it city, county, or state ordinances that require noise reduction decices on a vehicle. You could be fined for running without one. Do yourself and your vehicle a favor and leave your pipes alone. If you want more noise, get a flowmaster or cherry bomb. They are inexpensive and will keep you out of trouble.

Woody
1985 1 ton K-5, Detroit diesel, 36" tires (going bigger when money permits), 4-speed manual swap, Rockwell T-case, Hybrid lift, 12.5K winch.
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post #6 of 18 Old 11-25-2006, 01:11 AM
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Quote:
Originally Posted by Bliss Racing
Oh, and i'm too broke right now for mufflers, so that's why i ask this

Don't touch your exhaust till you have money to do it right.

Woody
1985 1 ton K-5, Detroit diesel, 36" tires (going bigger when money permits), 4-speed manual swap, Rockwell T-case, Hybrid lift, 12.5K winch.
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post #7 of 18 Old 11-25-2006, 01:11 AM Thread Starter
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Quote:
Originally Posted by Woody
Lots of torque loss, probably 15% or more. You might not even get overdrive to engage. I had a manual in the T/A and I thought there was something wrong with the 350 HO under the hood.

If you want agressive sound, drop a Flowmaster 40 series muffler in there. It'll sound great and your performance will not be degraded.

Your HP gains will probably be less than 5%.

VERY OBNOXIOUS, especially if you don't pipe it to the rear bumper. Mine was dumped by the tranny and I only lived with it for a couple of weeks before I put pipes on. I would've done it sooner, but had a motorcycle I could ride till I had the money saved to do it.

Many areas have made it city, county, or state ordinances that require noise reduction decices on a vehicle. You could be fined for running without one. Do yourself and your vehicle a favor and leave your pipes alone. If you want more noise, get a flowmaster or cherry bomb. They are inexpensive and will keep you out of trouble.
I've never had trouble with exhaust and police......i've had plenty of fast, loud toys....cammin and all.....i just really miss the sound. I had a 2001 WS6 that shook houses....my neighbors hated me!!

Maybe i'll just try to find a used 40 series somewhere then...sounds like the smart thing to do.
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post #8 of 18 Old 11-25-2006, 01:13 AM Thread Starter
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sorry, damn computer is double posting......
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post #9 of 18 Old 11-25-2006, 01:15 AM Thread Starter
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yea, maybe a good idea to wait till i can atealst get a muffler
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post #10 of 18 Old 11-25-2006, 01:21 AM
FearTheDentist
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I ran my 4.7 w\o a muffler for a few weeks after I installed my long arm- VERY, VERY obnoxious.

'04 4.7 WJ 6" Clayton's, full width 60\14b, 37" Nitto mud grapplers, lots of bits and pieces
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post #11 of 18 Old 11-25-2006, 07:11 AM
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Just get a nice FM40 muffler. I have it and it is loud enough for me. When I added the FIPK it got louder.

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post #12 of 18 Old 11-25-2006, 02:43 PM
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Its really odd...with the 2 precats and the main cat, it sounds VERY quiet at idle. You touch the gas and it gets loud FAST =P. Maintaining speeds at lowish RPM's its actually a decent sound, but any throttle up...and lol.

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post #13 of 18 Old 11-25-2006, 03:42 PM
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Quote:
Originally Posted by AgitatedPancake
Its really odd...with the 2 precats and the main cat, it sounds VERY quiet at idle. You touch the gas and it gets loud FAST =P. Maintaining speeds at lowish RPM's its actually a decent sound, but any throttle up...and lol.

You have the crazy cali emmisions exuast though.

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post #14 of 18 Old 11-26-2006, 07:50 PM Thread Starter
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so even with the cats still on , with no muffler, it will get that much more louder and obnoxious???
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post #15 of 18 Old 09-20-2017, 08:55 PM
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4.7 jgc no muffler

hi i have a 1999 jeep grand cherokee now that i am going to do this with in a few days but i did this same thing to my old 2001 jeep grand cherokee 4.7 and my dodge dakota 4.7 and i did run them no muffle but i did connect the pipe so it came out where it norm would come out but it ran fine for years sounded awsome wiked loud had alot of people tell me my jeep and truck sound awsome i dident notice any loss in power or any thing they both ran for years like that till i sold them but i will be doing this to my 99 jeep but it sounds better if you connect it to the tail pipe
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