Sound Level - Shorty V Full-Length Headers

[18usc371]

I have a 2008 bullitt, with full length headers, no cats, X pipe, bullitt mufflers.
it is very loud

I am going to put on some high flow cats, and was wondering if changing the headers would make a difference, from full length to Shorty.

I don’t want to go back to the stock manifold.

Would Shortys make a difference? Or with the sound level remain the same? All other things being equal.

Thanks in advance,

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[Cobra Jet]

Shortys will decease the volume of the exhaust at idle - but at a WOT blast, or driving normal speeds it’s still going to be loud - especially since you deleted the cats and are running an X.

The X is equivalent to a “scream”, think Indy cars.

The H is equivalent to more of a “rumble”, think NASCAR.

When there are no cats at all regardless of H or X - the dB level is much louder not only at idle but at WOT with LT’s as opposed to shorties.

If you’re trying to tone it down, throw on (2) hi-flow cats that have the metallic spun cores. These won’t diminish your HP (if that is a concern)...

If you’re totally against cats, the only options are:
Swapping to shorties and keeping existing mufflers
Keeping LTs and swapping out mufflers for a toned down set

I have BBK LTs on my 94 Cobra, BBK 2.5” catless H and 2.5” catback - yes it’s loud, but does not bother me. It’s been that way for over 16 years now... Eh, what did ya say? LOL!!

 

[18usc371]

Thanks CJ. I appreciate the input

Let me give you the full story:

Not too long ago I bought a 2008 Bullitt with 24,000 miles. Despite being heavily modified, it is in great shape, no issues or codes, and runs like a daily driver. I want to keep it as a “grocery getter” - which it is now.

However it is heavily modified -

C&L Intake
Ford “GT500” TB
Ford Racing Intake
Ford “Hotrod” Cam’s
Borla LT headers
X-pipe w/o cats
Stock Bullitt mufflers

I had it custom timed locally, via SCT tuner, and it’s about 338 RWHP in bad air.

The car came with Ford “FR500” mufflers, and was insanely loud. Changing out to the original mufflers calm down quite a bit but is still quite loud. Of course the lopey cam also makes the car run rich and stink of exhaust. Though I love the sound of the slope at idle!

As you suggested, I am going to put on a high flow catted H pipe, to replace the un-catted X pipe. That should solve, some of the problem. I don’t want the car to be quiet, and I know it will still smell a bit rich, but it’s just needs to be dialed down a notch or two.

If, after putting the high flow catted each pipe doesn’t work, my next step would be stepping down from long tube headers to shorties. The inter-webs are divided: Some say shorties are actually louder, some say shorties are a bit quieter, some say shorties make the same volume as long tubes.

Horsepower on this vehicle is of no concern, whether I lose a few here or there. Makes no difference. I am fortunate that my other car is a GT 350 so I don’t want for power.

Again thanks for your input

 

[Cobra Jet]

Sounds like a very nice Mustang indeed with very good mod selection.

I think you notice a difference in sound level with a catted H. It will be a decease in overall sound - but just know that with the LT’s it may still be loud at WOT. Your cruising sound should be at a more manageable level once catted.

I know back in the day (original 5.0 era for some of us), LT’s with Dynomax mufflers was the choice over the common “Flowmaster 40’s”. The reason being is the Dynomax muffler had interior insulation (similar to a glasspak muffler, but they are not a tubular muffler why were still shaped like a regular muffler), but the Flowmaster was and is an open cavity muffler. Running Dynomax with LT’s gave the car a very nice rumble at idle and when at cruising speeds - but when WOTing, those Dynomax mufflers screamed, which is the effect many were after.

When at idle with LTs and F40’s, the sound is much louder, because of the fact the F40’s have an open interior cavity with no insulation. So even at idle and at cruising, the sound can be very loud and to some, over time, can just be downright annoying - especially if you’re one that likes to listen to music tunes over exhaust tunes while cruising.

I can’t find it now but there used to be images online of different cutaways of common performance mufflers and one could see how the exhaust was routed.

I think going with a catted mid-pipe you may be happy and def try it before going through the effort of swapping the headers.

 

[18usc371]

I’m going to do just what you suggest. I’m going to put on the catted H pipe and see where I’m at with the sound. Changing out the long tubes is a much bigger and expensive process, and I’d hate to swap out the sexiness of the long tubes for the basic manifolds, or even shorties. We’ll see . . .

I really enjoy this S197 Bullitt, as it is very low-key (but for the sound), and looks great.

On another note, I had a 91 LX Notch 5-speed with shorties and Flowmaster 40s. It sounded fantastic. Sadly it was stolen in Miami

 

[Cobra Jet]

I’m going to do just what you suggest. I’m going to put on the catted H pipe and see where I’m at with the sound. Changing out the long tubes is a much bigger and expensive process, and I’d hate to swap out the sexiness of the long tubes for the basic manifolds, or even shorties. We’ll see . . .

I really enjoy this S197 Bullitt, as it is very low-key (but for the sound), and looks great.

On another note, I had a 91 LX Notch 5-speed with shorties and Flowmaster 40s. It sounded fantastic. Sadly it was stolen in Miami

Good luck and hope the suggestion gives you a little less of the loudpipe syndrome!


With the power of google, if you still have the old Fox VIN, run it and see if anything surfaces.

Also for future reference, these are good tools for researching VINs if researching a potential vehicle to buy or if seeing something online that looks fishy:
https://www.nicb.org/vincheck

http://stolencar.com/Report/Search

 

[18usc371]

Good luck and hope the suggestion gives you a little less of the loudpipe syndrome!


With the power of google, if you still have the old Fox VIN, run it and see if anything surfaces.

Also for future reference, these are good tools for researching VINs if researching a potential vehicle to buy or if seeing something online that looks fishy:
https://www.nicb.org/vincheck

http://stolencar.com/Report/Search

Thanks for the links.

I'm installing the catted H pipe next week.

Here is my base line using a very non scientific, non calibrated iPhone app - 81 DBA

:

Also, here is my GT350 with stock exhaust set to "sport" - 68.5 DBA Ave

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