I couldn't find any photos of this. Running dual exhaust with bullets in the back. Thinking of cutting out the trunk so I can fit some larger case mufflers. Anyone done that?

 

Never seen it done. Seems simple enough.

 

After looking at that Holley/Speed Eng. set-up, I've thought the same thing. Let us know what you do!

 

Not familiar with what Speed Engineering has to offer.
Holley use to sell their Black Heart Series exhaust for our cars.
I bought one just before they got discontinued it. I didn't purchase in time to catch one of the LS swap long tube headers, but luckily the Hawks stainless steel heads match up exactly, at least in by basement, haha.
Will be a while before I have a motor to toss in this thing.

 

The mufflers are really small, so I imagine it is just as loud. These types of setups are great on stock cars, but on 500-1000hp cars they are just obnoxious.

Unfortunately, as you know there needs to be a balance between flow and sound to support the power. What I've found through reading is basically the largest case straight through muffler you can find will flow the most and have the most sound reduction.

Right now I'm thinking an 18x10 muffler where the cats normally would be (I have a turbo car, so 3.5" downpipe), split into the dual 3" and then two 14x10 mufflers in the back.

My current setup is a 4x12 race bullet and the two 3x10 bullets in the back, and it is kinda annoying.

-- Joe

 

I would think you'd be able to cut the trunk right out and weld a piece of back in flat across from frame rail to frame rail and have all that extra room

 

Yeah, you can do whatever you want with that deep trunk section pretty easily.
I modified mine to extensively (thread in my signature) to make room for a 15 gallon fuel cell to be mounted under the car.
Still fabricating.

 

I have the speed engineering kit as a base but have replaced the bullet mufflers with small spintechs, and have spliced in a borla resonator in the pipe section where the stock muffler would be. The resonator is only on one side of the duals as I am trying to figure out where to put one on the other. The chambered tubes are also an idea since their overall diameter is closer to your pipe size. Even after all of this, the car is still too loud. The drone is brutal. I am going to give it another shot but may eventually switch to a mufflex 4".

 

Don’t do that, get the rite muffler.

 

I use to have a 4" Mufflex on my 383 SBC back in the day. It was mated to a set of hooker long tubes 2210s.
Car was not quiet to say the least. But I guess everything is relative.

 

I've always wondered why GM made that trunk-well that deep. It's pretty useless. Back in the day we used to put massive sub enclosures in and amps. Other than that it's useless space. Cutting it to the level of the shelf near the spare tire would be the move. Then you could fit a better muffler and keep it away from the fuel tank. The whole fuel tank over the muffler is pretty poor. The whole bullet muffler on the sides of the trunk-well is a great idea but must be loud as hell.

I've thought about this for my car. It's wasted space, cut it out! You could easily get a custom spintech muffler to fit in there.

 

If only it were that easy. With a true dual set-up there is barely enough room for the pipes themselves. You can get a normal style muffler on one side of the dual in the stock location but the other side is severely space limited.

 

Rock Solid Motorsports has a panel for 4th gens with an install video on YT. That would leave a lot of room for a rear mount War Whistle!!

 

You can make the “trunk” any size you want, or not at all without compromising the structure of the car. It is mainly there to protect the fuel tank in a rear end collision.
I shortened mine 1.5 inches to make the rear of the car flush for the diffuser. With that being said, have you considered removing the rear seat buckets on a rear seat delete car and free up space for full size mufflers under the car? Just a thought.

 

I like that rear seat bucket delete idea. It would be fairly simple to do too

 

Well....that space is pretty valuable when you and your two best buds are driving from MA to Telluride for a ski trip. In that case, that space is priceless!

 

Dude, that's a crazy road trip in one of these cars! But yeah you're right, that would be valuable space. I've had a few 3rd gen's and never considered anything like that. Must have been a cool trip!

 

We made memories....that's for sure!

Came over Monarch pass in total blizzard/white out conditions. Looking back, I can't believe we did it.

 

The needs of a production daily driver are not the same as a 36 year old race car lol.

I'm trying to figure out how to fit a decent size case where the cat normally is and I'm thinking the two 14x10 ultra flows in the back. Gonna be a lot of cutting and welding though.

 

same here, my anxiety would get the best of me, eyes glued to the gauges the entire time lol. That valuable space in the trunk would be filled with every tool imaginable due to my fear of breaking down.

 

I think if you angled the corners of the trunk well a decent amount, you could probably fit a decent sized oval muffler on each side mimicking the trunks new angle. would save you as much trunk space as possible while still getting a larger muffler in there.

 

It's funny, I had an 82 ta high school in the late 90s. It was terrible in the cold rain/snow. I lived in new England and would drive a beater truck in the winter. I had a friend put snows on the rear and weight in that back area of his 84. He would drive up to the ski mountains in that car. It was such a disaster, I always had a tow strap for him.

The weld in panel from rock solid looks like a good idea, it would work great for this application. There would be plenty of room for mufflers under it. You could still have room in the hatch area for sand bags/ballasts for winter driving!

 

I’ve owed cars where PO’s had good ideas 🤬

 

Were they 1,000hp cars?

 

I don't think reshaping the cargo well would cause any structural harm to the car.

 

Oh, I "get it"....and if I were you, with that car/purpose, I'd chop as needed, to meet your goals. I agree w/quicktrip....and the others who've already done it, that it would be structurally and functionally fine, and also get you the space you want underneath. Give'r hell!



That's funny! I grew up in New England too and drove my '83 TA all over carnation, year round. Ski areas/skiing, to college -and around/ski outtings at college in Maine, I drove it everywhere/all the time. The trip to Telluride, and at least two other road trips to CO, one to ski the front range and another time to hike/ski Torrey's peak*. That car went everywhere and did everything...towing boats, ski trips, ......for me? it was a car for all occasions! Never had a snow tire on the thing!

 

I wonder if I could get this muffler setup to fit. .

 

With all due respect to the fellow posters.....

I think people are missing the point that this car ain't gonna be any kinds of grocery getter, , or need to carry a trunk full of tools, , or even a few pounds of (now legal where I live) pot.

It's a full on race car that needs a trunk about as much as a Turtle needs a nice set of Brembo disc brakes

Lookin forward to pics of the abbreviated trunk with a couple of sweet mufflers where the trunk formerly resided........

 

I was actually thinking a muffler design just like that would be ideal. Either just like that or a split design. If you put a flat panel in where the valley was I wonder if there would be any resonance issues.


even turtles need brembros!

 

It looks cool. Would that support your 1k hp? The piping looks small in the pic....

 

Spintech makes stuff that will work. I've used their mufflers on a bunch of cars.

one of these


Or 2 of these.

 

If you haven't run the car yet, you might be surprised how much a turbo tames the sound. You might just get it on the road first and see what it is like. Can always change things up later.

Another option is to use a normal muffler (that actually works...) and then bypass the muffler using a fast acting Kuster stepper motor exhaust valve. Drive the valve with the Dominator ECM just like the OEM's do. I think maybe the Dodge Chargers/Challengers with active exhaust option have 3" Kuster valves. Can maybe junkyard a set. The Mustang with active exhaust also uses those valves but not sure what is the size.

That's a project idea I've had in my back pocket for a while, just never got to it. Start at post #48 if you want to look more into for yourself, https://ls1tech.com/forums/forced-in...st-cutout.html

 

Been running the car since March. It's fun and fast but the exhaust noise is a bit too much for me. I guess I'm getting old.

Now that it's winter / snowing, I'm trying to redo the exhaust and also I think I'm going to switch back to an air to air intercooler.
The pump and intercooler fans are obnoxious and I can't get the pump to stop leaking.

I have some plans about switching to a 4th gen overflow and moving my air filter down to grab fresh air from the fender, and maybe a heat dam that seals to the hood.

Back to the exhaust, I don't know why this thing is so loud. It's a mild cam 5.3. I'm not even talking in boost, just normal driving sounds like NASCAR. I suspect the speed engineering bullets do nothing.
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I like spintech, they sound cool. Unfortunately they don't flow very well.
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I've got really two options here, use a quiet poor flowing set of mufflers and an electronic cutout for the track, or moderate flowing mufflers (like ultra flow) and deal with the noise .

The ctsv mufflers I posted above are good for about 600hp before you see a rise in back pressure.

I watched some interesting videos from Richard holdener, and on the Dyno going to a restricted muffler lost about 4 psi and 100+ hp. Crazy!

 

Speed Engineering is well known in the 4th gen world for being obnoxious. Many people end up removing it after some time.

 

The Magnaflow resonators that I used in the beginning actually made the car louder. Go figure? I think it was an acoustic thing, like a trombone. It was far more annoying than open headers.

 

If you switch over to an A2A intercooler I would also consider adding a progressive water/meth system with dual nozzles to keep the IAT's in check in the warmer summer months

 

Yeah I guess what can you expect from a 10" bullet.

​​​​​​I ordered a vibrant super quiet resonator which I'll add and try the ultra flows in the back (after I cut the trunk pan out). If it's still too loud I'll try some turbo mufflers.

Adding an electric cutout for track use regardless.

 

Yeah that's what I was thinking. Maybe setup like a 10psi street tune and a 16 psi track tune with meth.

My only concern with meth injections is I had a solenoid fail 20 years ago and blown up an engine. At the time, the ECU/it wasn't fast enough to pull timing when the meth stopped spraying on a run.
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I'm currently running an AEM v3 kit with dual 1000cc nozzles 91 octane 20 psi @ 11 degrees timing. I also have a bunch of fueling safety stuff on my Dominator ECU so if anything is triggered everything bleeds to wastegate.

I accidentally tested my safeties before I put the car away for the year. I was doing something unrelated and noticed my fuel pressure was dropping as load increased but my second pump was kicking in at the same time. I go check the datalogs and sure enough pressure dropped to 32 psi triggering a safety. I have things happen fast like 0.1 seconds kinda fast. Never buying shitty Ractronix pumps ever again. Walbro 350 pumps ftw now

 

I kinda hate the idea of meth injection just like I hate DEF on newer trucks, but at the same time the fact that you can run 20 psi on 91 octane is kinda amazing to me.

On my MS2 the injection is just on/off at a given RPM/MAP/air temp but MS3 offers control over pump and solenoid:



However, the only safeguard is timing retard based on air temp. My boost control does not offer a boost cut for air temp.

I'm still running batch fire MS2. I considered going to MS3 and running full sequential, but I'm not sure if it's worth the effort.

 

I would like to have my ECU control the water/meth system eventually. I've been playing with that part of the software to wrap my head around it. I like the AEM controller where I have the start point at 6 psi and all in by 15 psi and it's a nice and linear

 

Back in the time when I daily drove one and it was our family car, that deep storage well was extremely useful. All the groceries went in there, tools and parts went in there on junkyard runs, plus it let us fit all our luggage in there whenever we went on vacation. It was probably the single most practical part of the car when used as a DD.

Besides all that, it had to be that deep so you had somewhere to put the full size wheel and tire when you got a flat.

None of that matters at all in this case though, lol.

 

This what my fabricator/shop owner/ good friend suggested twenty years ago when I brought my Camaro in for a y-pipe. He'd been cutting up 3rd gens since they were new (developing prototypes for the Canadian market) and said that this was a move they had made a couple of times.
It didn't appeal to me then as I actually used the the back seats when hauling my grandkids around!

 

Looks like it can be done mildly enough to keep the back seats.

https://www.thirdgen.org/forums/exha...stom-dual.html

 

I think those are really small flowmaster 10 series mufflers. There is no way I could fit a 14" case muffler by cutting the seat base out, and given how much bigger my 9" housing is I don't think I could run the pipe up and over like that either.



This is on the four post lift at ride height.

Plus I'm a single 3.5" downpipe turbo, so crossing over to the driver side would likely cause issues with the torque arm.