View Full Version : Glass Packs

04-21-2007, 02:59 PM
Hello, I was wondering if anyone has put glass packs on there ride? I have a 99' Cobra, what are the pros and cons? Thank you for your time!:thumbsup:

04-26-2007, 06:24 AM
The design (Cherry bomb) is similar to that of the resonator (SLP, Aero Turbine) muffler with the exception that the resonating cavity is packed with fiber glass material (the actual design is a bit more complex than stated). Both designs offer a single straight through pass with no internal baffles other than the resonating chamber. Exhaust tones will be different depending on the shape and size of the resonating cavity.

04-26-2007, 08:50 AM
from what I have read, glass packs produce an extremely obnoxious tone in the Cobras. I have never heard any, but that is what I have read.

04-27-2007, 12:16 AM
Thanks for the info! I am still waiting for her to be shipped here. I am in the Netherlands for the time being. I will let you know what she sounds like! If it turns out to be a bad idea, do you have any recommendations? I am looking for a very, very deep sound.

04-27-2007, 06:29 AM
I guess the tones depend on the resonance of the complete system. The smaller diameter pips 2.25 " to 2.5" would favor the mid tones and higher frequencies. Deeper tones can be created with 3" and a moderately sized H pipe. Smaller crossover diameters on the H pipe will give the exhaust a bit more bite (not necessarily lower tone) a wider cross over on the H pipe will mellow it out. Follow that through with single or dual chamber high flow mufflers and you will have a deep tone (along with the associated drone that comes with it).
I have the factory H pipe hooked up to SLP loudmouth catback. After I got through the ear piercing open header sound during the seasoning of the exaust it mellowed out. I have heard some really nice tones from others drving by. Have no idea what mine soundes like from behind the car when driving. I had a friend tell me their whole car shook and vibrated when I pulled out of a parking lot with them following.

04-30-2007, 02:39 PM
Thanks! For what you have told me, your sound is what I am looking for. I will let you kow what happens. Thanks for the help!

05-01-2007, 06:12 AM
There are many other options to SLP. Bassani and Borla make some good exhausts as well as killer sound. One of the best ways is to locate a local car club sponsored cruise night (if sponsored by a mustang club even better). If you get there early, you have the opporunity to hear most of the cars roll in. If you hear a mustang with an aftermarket exhaust pull up, just walk over to the owner and ask what exhaust he or she has on the car. One thing I have noticed with the SLP is the difference in tones from a natrually asptirated 2001 Cobra to that of the supercharged terminator.

05-01-2007, 05:52 PM
Good news, I found a local Mustang club, 1200 members. There is a get together in June. RIGHT ON! Anyway, where did you buy your cat back system? I think I am going to go with the SLP Loudmouth. Again, thank you for your help!

05-02-2007, 06:28 AM
I ordered direct from street legal performance (SLP). Did it twice actually once for the 2001 Cobra and again for the 2004 . What I wanted to do was remove the exhaust from the 01 and install it on the 04 but when I went to the ford dealer to check out the 04's, I got a deal I could not refuse so I had to become a repeat buyer for the Loudmouth cat-back. It cost me a bit more the second time around (more than what I could have bought it for from another source, first time was a good price at $410 inculding shipping, second time cost $540.) Both kits I bought were the same with welded in resonators and did not have the modular design they have now. I installed the SLP loudmouth within the first 800 miles on the 04 Cobra since it was too quiet for a muscle car. Never had an issue with it on either car, actually improved fuel milage on the 04 when compared to the factory cat-back. Once you install it, expect the exhaust to be as loud as an open header for a few weaks (close to deafening) but it will quiet down. If you have a convertable, you may want a different exhaust since this will be a bit on the high side when it comes to volume at WOT. Also, it may be illegal in some areas that have strict noise ordanance in place on motor vehicles.

Check to see if the dealer or company can ship to your location before you order it. Some places may include shipping in the price and others will add it.

05-05-2007, 01:58 PM
Thanks again for the help.

05-07-2007, 06:29 AM
Since you have a 99, and as long as you still have the IRS, the cat-back install will be simple. Since SLP does not make the M31003 kit (resonators are welded in as one piece) it will take a little extra time to get it all toghether on the car. The are making the kits modular so you can swap out the muffler section for different options like strait pipes, and or insulated mufflers. The type of clamps in the kit are of good quality and will hold every thing together almost as if it was one piece. Bassani and Borla use the same clamps. Those are also good quality products as well.

05-09-2007, 02:08 PM
I have been looking at a bunch of different kinds of cat back systems. I went to a wesite called www.mustangexhaust.com (http://www.mustangexhaust.com) and was able to listen to differnt combinations. I liked the SLP Loudmouth the best. A lot of the others sounded pingy to me.

05-10-2007, 06:48 AM
I have been there too many times. The issue with exhaust sound clips is that they typically do not represent the natural experience with the exhaust. What impares the sound quality is how it was recorded (i.e. video camera is probably the most common method since the sound track can easliy be removed as a sound clip). Also where the recording device was located (in the car vrs being stationary) along with many other things. What also impacts what you hear on that web site is when the sound was recorded in relationship to the exhaust seasoning period. Tones, loudness, ect will change during the seasoning period then all of a sudden become quiet and evenutally will increase gradually to where it will reamain. Duration of the seasoning period can vary.

One thing I did notice with exhaust sounds is that it is affected by barometric pressure, humidity and temperature. There are days that I do not even hear the exhaust and there are times where it is much louder than normal. I like the SLP Loudmouths, but I have heard other mustangs with different exhaust that I thought sounded better. I just have not heard my own car without being inside of it. What sounds great on the outside may not always be a pleasure on the inside especially in terms of drone. At low rpm on the highway just cruising at 55-80 mph in the top gear I do not have very much drone to complain about and could listen to the radio without having to blast it. The same applied with the 01 Cobra but had a bit more drone at the same crusing speed. (this only applies to after the exhaust has seasoned in, before that, all you will hear is the exhaust including at idle which will be loud, and if you have a convertable it may be intolerable.)

05-10-2007, 08:06 AM
I love the LP Loudmouth II's that I have; however the Loudmouth I were a little extreme. The II's are loud without being droney, and they have a deeper sound than the I's, which to me sounded raspy. Take into account, at that point I had an OR x-pipe on also. Even with the x-pipe the II's sound much better. And now that I have an h-pipe, part of the turbos, it sounds so much better, at least to me.:thumbsup:

05-14-2007, 02:03 PM
Ya'll are awsome. Thanks for the information. I am not worried about the drone sound. I used to drive a 79 ford F-150/ranger that had only the manifolds. That was loud, but I like it. I dont know why, I will be deaf soon if I keep it up...ha