red454

Time to play Dr. Frankenstein...

I like the look of the stock mufflers, but want some more sound. So I opened a set up to see what there was to work with... I purchased a spare set from Terry at Fang Performance to be the Guinea Pigs.

After some debate, I decided to open a hole from the reverb chamber directly into the exit pipe. It is double walled and packed with fiber glass. I then fabricated some stainless covers and siliconed them over the access openings.

After the silicone is set up, I will install and see how they sound. If it sounds good, I will weld the covers to the body. If not, they can be removed for some more experimentation.

Here is what the inside looks like with no modifications.

(See post #26 for the first sound comparison)

red454

Here is the rectangular cut into the exit pipe. A plasma cutter was used for all cutting.

red454

Here is the cover we made...

red454

And here we are laying the bead of silicone...

Boomer

kinda cool

Keep us updated..and get sound clips if you can

red454

Finally clamped while the silicone sets up. It is a lot of work and I may end up with garbage, but it is worth a try...

Clem

Wow, you must have even more free time than me! I've seen plenty of gutted cats, but gutted mufflers? Looks like you know your stuff (nice torch work!), but I would not want to see those siliconed covers blow off at six grand on the freeway.

I'm strangely fascinated. Please let us know how it turns out.

red454

I will probably put a couple of extra large hose clamps temporarily around the mufflers to make sure the covers stay on until I get the sound where I want it. I thought about gutting the whole thing, but decided to start with small changes first. I am no muffler expert, and I know that the baffles are sized and located for good reason. But I figure what the heck, I may end up with something that sounds, well different...

Hatchman

Very interesting, looking forward to some sound clips. It will be interesting to see how you can custom tune your own mufflers to your liking.

Boltzman

sound clips..pleasse

slammer223

You could take it to the next level by having a plate that slides back and forth to cover or uncover the hole you cut in the interior tube. Make it adjustable from the outside by using a threaded rod or rack and pinion or something like that. Then you could power the adjustment with a small motor, then you could have remotely controlled motors. It would be a challenge to get both mufflers adjusted to the same degree at the same time though. Sorry, I got a little long winded. Muffle me!

SRQ05GT

Dosn't the silcon get really hot?

red454

The silicone is good to 350 degrees, and it is only used as a temporary seal during testing. I doubt if the muffler temp will get over 150 degrees while I test the sound.

If I don't like the sound, I can easily open the covers and make some changes. When I get a sound that I like, I will remove the silicone and weld the covers on permanently.

red454

As for sound clips, my plan is to get the mufflers on in the next few days. Maybe even today. Since the car is in storage until April - the sound clips for now will only be idle and a few revs. (Any volunteers to host the sound clips?)

The hard part is that if the idle and rev sound good, it will be tough waiting until April to drive it.

red454

I know there are a few cars out there that have mufflers that do that - I know the high end Mitsubishi 3000GT had mufflers that did something to that effect. Not a bad idea. I would like to cut one of those open to see how they are set up.

red454

Well, I installed them this afternoon.

It is a subtle change at idle. It may even be a little more quiet at idle. But what I do like is when I rev it, there is a nice burble when you let off the throttle.

And it does sound different, maybe a little deeper tone when I hit the throttle.

The real test will be how it sounds under a load, going through the gears.

I have two sound clips if anyone can host them...

UPDATE:
(Hatchman contacted me and I sent him two files to host - it may be tomorrow until they are available)

THRUST_

I like the whole idea of custom tuning your mufflers, and the idea about adjustable ones is even cooler, good luck with your project.

hatchttu

Great work with the exhaust it is interesting to see the inside of themufflers. My dad had a 91 3000GT VR-4 with the adjustable exhaust and adjustable suspension. they NEVER came off sport mode. They were just gimicks that added weight. however the active aero was really cool and I loved seeing, hearing the spoilers move at 60 mph.

Hatchman

I got the first file twice, but the second one didn't make it. It should be able to viewsoon. It has to get approved to make sure it's not **** or something after I submit it.

Frankenmuffler sounds good. It does have a little more burble to it, but had you just started the car up from cold? I noticed mine always burbled a little bit cold, but it goes away once warmed up.

It sounds a little deeper, with a little more of a mellow lower tone hum to it. Not like a drone, just a deeper hum.

Hopefullyclip one will be up soon. Email me the second clip and I'll submit it tonight.

RaGsHoCkEy88

this is definitely a cool project