PONY XPRESS

Can't find the post, maybe someone can verify. Someone posted that they did a muffler change & they ran the car without the mufflers & there was not much of a difference in the DB sound. He concluded that the cats must be fairly restrictive.

I'm thinking of having a muffler shop copy my mufflers by using straight pipes. It could be done in stainless with a flare at the end, or even regular pipe painted black. Shouldn't cost much, may be too loud but fun at the strip.

Your thoughts?

2005RedGT

That was me who said that. I had them of so I could drive to a shop and remove the cat-back pipes. Ys the Cat are VERY restrictive. Now remember, just becuase the mufflers are gone, does not mean it will run well. Engines require certain back pressures (and balanace of) to run property. You may get the 'sound' but loose power/torque.

We have an exhaust experts in here ?

PONY XPRESS

Thanks Bryan for responding.

When you drove to the shop without the mufflers could you feel any difference in performance?

How could you best describe the exhaust note?

I think with NA engines the diameter & length are the deciding factor for torque & HP. I would assume if I kept the length the same while freeing up the exhaust I should see some positive results.


Thanks for your input.

2005RedGT

I did not feel any difference in performance? I jsut putted over there not to make too much noise - since it was late at night. The note was just like the stock, jsut very amplified. There are some crackles and pops.

Let use here the results if you so choose to do this

PONY XPRESS

Bryan

Did you disconnect the mufflers only or was it from the cat back?

Wouldn't want any back off pops.

Thx

2005RedGT

Muffler only

PONY XPRESS

Saw a muffler shop today. He will put 4" stainless tips & axle pipes on my car for $200. The 4" pipe really fills up the hole in the valance nicely. He had a big choice of tips & ordered the ones I liked. They are 12" long with an inlet of 2.5 & end at 4" with a polished lip on the inside

He seems to feel as far as performance gains & loses, when the mufflers are this far back they are more for sound control then back pressure. That makes sense as most of the after market exhaust are only claiming small Hp & torque gains.

Having done next week, will post pics & maybe try to get a sound clip.

Stinky Old Fart

The idea that the catalytic converter sliences the exhaust sufficeintly to eliminate most of the noise is intriguing. Pony Express, you mentioned that you might do a sound clip. If you could rev the engine a few times then bring it up to a fixed engine speed, say 4,000 RPM, for a few seconds, and record the clip, before and after installation of the straight pipes would be intresting.

This request may be asking a lot, but Radio Shack sells an inexpensive sound pressure meter. A few before and after readings at idle, and again at 4,000 RPM would be informative. Be sure to stand the same distance away in all the measurements.

I think you are on to somthing. You may put the 2005 Mustang aftermarket muffer industry out of business!

adrenalin

I did the same thing on my 1997 GT. I removed the mufflers and replaced them with a straight pipe, keeping the factory tips installed. Sounded great and tons of people asked what mufflers I had on the car, which I smiled and said "none". I didn't notice any lose in power, but I didn't have the car dyno'd before or after.

PONY XPRESS

I'm a capitalist & I would hate to be responsible for the down fall of a complete industry.

I have been a racer most of my life & have always seen & built exhaust with as little restriction as possible. Over the last few years mufflers have been needed to meet noise regulations at certain tracks & events, Needless to say when we have to ad a race muffler we do feel a decrease in power.

That being said the new cars do have certain technologies that have to be addressed, but the IC engine always responds well to making the car breath & exhaust well.