Ordered the Boss 302 quad exhaust (H-pipe with side outlets) from BuyFordRacing.com for $699 (with free shipping)... Of course, I installed it without the restrictor plates. The hardest part (for me) was getting the new H-pipe installed at the back end (just a tip, install the clamps on the pipes going back to the mufflers, use a jack to lift those pipes up a bit, then install the new H-pipe). Another tip- I've read numerous installs where people claim one of the side pipes didn't line up with the mounting hole. I think the key is to just put the side pipes on the studs of the H-pipe and install the end bolt to the side pipe first. The pipe has quite a bit of flexibility built into the design, so I can't imagine there should be any problem lining it up.

First the observations- "Holy Freaking Mother of Goodness!" (Sorry, that's about the only way to put it !) I know the car isn't any faster- but it feels faster- or at least you can feel the engine. Its like you've put a microphone in your exhaust and directed it right at your seat! I mean, geesh- at idle the car sounds like you really shouldn't be standing near it or it might bite you. When you hit the accelerator, its like "Release the hounds!" When you downshift its like NASCAR. Suffice it to say, if you've even thought about installing this option, just do it!

Another observation would be, if you have 3.73 gears there is going to be a little bit of drone at 65+mph. No problem at 55-60, but at any decent speed the RPMs top 2k- and from there on up you are going to get a steady tone in the cabin.

Now the questions:
1.) Do the QTP electronic cutouts allow you to partially open the cutouts- or is it totally open or closed only? I can tell there are times when I'm going to be a bit more quiet (like when going through the neighborhood, driving through the DFW parking garages, or when starting in my garage in the early a.m.). Most of the time, I think I'd like to run them half open.
2.) Anyone actually using the restrictor plates? I imagine I could install them and just drill out until I get the exact level of awesomeness I want, but it would be helpful to know if someone has figured out a good hole size (the stock hole size seems miniscule).

Anyway, I already had GT500 axle-backs installed, and I guess they are still making some noise (can't hear them a bit over the side exhaust).

 

Congrats Pete. I enjoy that "awesomeness" everyday with my corsas

As for the questions, I'll let someone with boss side exhausts chime in. I think the qtp cutouts can go to any size opening. As for drilling, there's a few threads on it with different sized openings. All depends on you. I think 1" was common.

 

1) You can adjust the QTP cutouts to any position you want.

2) I run 3/4" plates in my side exhaust. To me, that's the best size to get a good sound without being too loud. You can get different size plates from a guy on BossMustangOnline: http://bossmustangsonline.com/index.php?topic=3663.0. There are some videos for the various sizes.

I have no drone...

 

Congrats on a great mod!!

I have been running the quads with no baffles for a couple years now.

I would just leave it alone. One thing to keep in mind is that the sound is bouncing back up into your ear and straight up so it may no be as loud to bystanders as you suspect.

Just enjoy...I firmly believe that it's the perfect sound quality and noise level for optimal driving pleasure. They did an awesome job with the Boss exhaust.

 

I have QTP cut outs on mine, you can run them from 0 to 100% or any place in between. Most of the time I run mine all the way open, on a long road trip I may close them.

Before the cut outs I drilled my baffles to 5/8 which was pretty good sound.

 

Thanks for the input and recommendations! Either I'm getting used to the sound, or the sound is mellowing out slightly. By the time I got to work, it seemed even better. This weekend, I'll try the plates at 5/8", and work my way up to 1" if necessary. I'm 99% sure I'll eventually order the QTPs.

I've always downshifted into stops and turns- the sound these guys produce during engine braking will encourage that habit even further!

 

I have 3/4" plates in currently, will eventually go the qtp route as I've heard only great things about that. I'd prefer to run them wide open but I don't want to always be that loud so 3/4 works well...

congrats, best sound mod I've done is the boss quad.

 

You lost me at "Drone" after having MAC ab's on my 08
I want no part of any drone ever again.

 

They don't drone...at least not on my car.

 

+1. Been running the Boss side pipes from day one with no baffles. Sound is just awesome. I get a lot of compliments on the sound of the car. I also added the roush axlebacks. Sounds like a racecar at WOT.

 

Perhaps I am not understanding what "drone" is... When I get above 60mph, I can constantly hear the thrumming of the exhaust. Not a bad sound, but its definitely constantly audible.

I have a feeling if I didn't have the 3.73 gear in the back, I would probably be fine up to around 70mph or so, but once you hit north of 2k rpms the exhaust is definitely there in the cabin (again, not a bad thing- so far).

It would be nice to be able to gear it back for long trips (I occasionally drive up to Fayetteville from Dallas for work)- I'll have to see if putting the restrictors back in (with the hole enlarged somewhat) produce a good balance of sound.

I've made about 4 trips out to the car to give "demos" (took a coworker to lunch, and now every half hour someone comes up and says "Xxxxx told me I just have to hear your car..."). Lots of smiles and several "My wife would never let me have something like this..." type comments.

 

Congrats on Side Exhaust. I think they are the best mod you can do to the Mustang, it is all about the sound when it comes to a Muscle Car.

I ran about a week baffle free before putting the 3/4" plates in, an hour drive on freeway would give headaches. Also, it becomes harder to hear/notice other stuff (like Engine), or be able to talk or awareness of surroundings...etc But who cares, we drive Mustangs! Hahaha.

Have you deleted resonators for your GT500 Mufflers yet? I've been curious about the result but nervous about the drone. Will you hear the difference, now that we have sides?

 

I recently installed the side exhaust and had my resonators cut out at the same time. I have the GT500 Quad tips mufflers and it sounds incredible, the Quad tips have a deeper tone to them now. I also installed the Ford Racing Track Cal and the lopey idle without restrictor plates is sick. It rocks the car and I get allot of compliment and looks when sitting at traffic lights.

 

Either things are mellowing out or I'm getting used to the exhaust, but after a few days of driving it doesn't seem as loud or harsh. The note on start-up is just amazing (whuff-whuff-whuff...). Seeing a lot of appreciative head nods around me in traffic.

If I have time after installing my gauge pod this weekend, I might try tinkering with the restrictor plates- but I'm pretty happy as is.

This will be a stupid question, but I've read a lot about people "having the resonators removed." Where are the resonators (are they the section right in front of the axle-back section)?

 

Yes, and if you get any other OTA pioes they'll have the resonators removed. You could do OEM 11-14 GT500 OTA pioes and keep it Ford...other than that Borla and Lethal both offer replacement OTA pipes, sans resonators.

 

Here is the photo showing bottom of my car. I believe these two pipes (one of them is dented) are the resonators.

 

They're both dented. The dent you can't see, is on the top of the pipe.

 

Oh! it did seem a little strange to have only one side restricted, it all makes sense now lol. Any update on P-51 theme yet?

 

I had replaced the stock baffles with 3/4 plates, ran those for a year. Then this winter I pulled the plates out and have been happy with the sound. If I want it quieter, I run the silver key. When I want loud, Trackey. I also run GT500 ABs, and to me its the perfect combo. I really like the chrome tips, perfect fit and finish.

 

3/4 in. plates, gt500 axle backs, just right for me