Let's do a muffler tuck.
10-26-2010, 07:47 PM
#1
Honda-Tech Member
Thread Starter
Let's do a muffler tuck.
Yep, I officially coined the phrase, "muffler tuck". 
We did this on PinkBatman's CRX.
When you need a bigger exhaust and muffler, and DON'T want it all hanging down under the car to attract unwanted attention... you need to tuck that pig.
We ended up with 1.5" between the top of the muffler and the floor as dead space for heat. We are using a 4x9 oval can muffler and it's still way up inside behind the bumper and this is all 3" exhaust. You cannot see anything out of the ordinary. This all motor beast looks stock.
Here's how we went about it.
My son enjoys a low, and relatively quiet car, that's still fast. If you do a burnout and people can hear you a mile away... your car is to loud, you're not getting away with anything and you're inviting the law to have a good look at you. And you might end up with some cranky old man in a red Monte Carlo bringing his baseball bat to your home to discuss the "noise" with you. True story... we called the cops on his a$$.
On his CRX (and all of them really, including the EF's), when it's low, there just isn't enough room under there to get a muffler and not have it hanging down below the rear bumper cover. So the goal was to cut out the tire well, keep the structure of the car intact and allow a LOT more room for a proper muffler. A good high end muffler, that can't be seen dangling out from under the car for the law to have a good look at. Tuck it up, nice and tidy, 3" exhaust all the way out the back, exiting in the stock location for the Rex. Hidden, stealth, behind the bumper cover.
Keep the car quiet and un-assuming, but still be able to rip it up when required without drawing excessive attention! With the room we are creating for a muffler we are also creating a LOT more room for new sway bar mounts and ideas. and possibly other suspension stuff down the road.
I'm not a body guy and this was our first attempt at this style of fabrication and It was a good time. By the time you get some seam sealer on this and a coat of paint, some undercoating and some carpet. It'll look factory. We're happy with how it turned out.
Start by pulling the bumper cover.
Get a bunch of materials together to protect your dash and glass from sparks. You're going to be welding in there. Cover them inside and out. No quicker way to ruin your glass than weld boogers and microscopic molten metal flying around in there. We used cardboard, tape, sheets, whatever we could find. We caught a corner of that sheet on fire.... We're planning on NOT telling my wife about that sheet.
Here's the bit we cut out. Weighs 9.62 pounds for those that have wondered about that kind of thing.
All the metal work we did was done with 18 gauge (.048" thick). I like how firm it is, for this kind of application. It's easy to weld to, compared to thinner stuff like 24 gauge which is about 1/2 as thick as 18 and can be tough to MIG to as it's (.023"). If you're new to sheetmetal fab. try 18 gauge.
traced the shape of the tire well onto some cardboard for a pattern to connect the lower cross member to the new floor. and cut, welded and shaped metal together until I had the shape.
This little piece to a LOT of time to bend, weld, grind and get right. Take your time on this piece, it'll be worth it.
Then we put rosette holes in the part so it can be spot welded together and fabricated the filler panel.
Here it is mocked up. The copper colored little tubes are called Cleco's. They're used to hold panels together for alignment. If you don't have any in your garage, GET SOME. They are very useful for lot's of stuff. Pick up a bag of them in 1/8" and the pliers. Seriously good things to have around.
We did this on PinkBatman's CRX.
When you need a bigger exhaust and muffler, and DON'T want it all hanging down under the car to attract unwanted attention... you need to tuck that pig.
We ended up with 1.5" between the top of the muffler and the floor as dead space for heat. We are using a 4x9 oval can muffler and it's still way up inside behind the bumper and this is all 3" exhaust. You cannot see anything out of the ordinary. This all motor beast looks stock.
Here's how we went about it.
My son enjoys a low, and relatively quiet car, that's still fast. If you do a burnout and people can hear you a mile away... your car is to loud, you're not getting away with anything and you're inviting the law to have a good look at you. And you might end up with some cranky old man in a red Monte Carlo bringing his baseball bat to your home to discuss the "noise" with you. True story... we called the cops on his a$$.
On his CRX (and all of them really, including the EF's), when it's low, there just isn't enough room under there to get a muffler and not have it hanging down below the rear bumper cover. So the goal was to cut out the tire well, keep the structure of the car intact and allow a LOT more room for a proper muffler. A good high end muffler, that can't be seen dangling out from under the car for the law to have a good look at. Tuck it up, nice and tidy, 3" exhaust all the way out the back, exiting in the stock location for the Rex. Hidden, stealth, behind the bumper cover.
Keep the car quiet and un-assuming, but still be able to rip it up when required without drawing excessive attention! With the room we are creating for a muffler we are also creating a LOT more room for new sway bar mounts and ideas. and possibly other suspension stuff down the road.
I'm not a body guy and this was our first attempt at this style of fabrication and It was a good time. By the time you get some seam sealer on this and a coat of paint, some undercoating and some carpet. It'll look factory. We're happy with how it turned out.
Start by pulling the bumper cover.
Get a bunch of materials together to protect your dash and glass from sparks. You're going to be welding in there. Cover them inside and out. No quicker way to ruin your glass than weld boogers and microscopic molten metal flying around in there. We used cardboard, tape, sheets, whatever we could find. We caught a corner of that sheet on fire.... We're planning on NOT telling my wife about that sheet.
Here's the bit we cut out. Weighs 9.62 pounds for those that have wondered about that kind of thing.
All the metal work we did was done with 18 gauge (.048" thick). I like how firm it is, for this kind of application. It's easy to weld to, compared to thinner stuff like 24 gauge which is about 1/2 as thick as 18 and can be tough to MIG to as it's (.023"). If you're new to sheetmetal fab. try 18 gauge.traced the shape of the tire well onto some cardboard for a pattern to connect the lower cross member to the new floor. and cut, welded and shaped metal together until I had the shape.
This little piece to a LOT of time to bend, weld, grind and get right. Take your time on this piece, it'll be worth it.
Then we put rosette holes in the part so it can be spot welded together and fabricated the filler panel.
Here it is mocked up. The copper colored little tubes are called Cleco's. They're used to hold panels together for alignment. If you don't have any in your garage, GET SOME. They are very useful for lot's of stuff. Pick up a bag of them in 1/8" and the pliers. Seriously good things to have around.
Last edited by vectorsolid; 10-26-2010 at 11:26 PM.
10-26-2010, 07:48 PM
#2
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
We cut a piece of 18 gauge for the new floor and tossed over the whole to mock everything up. Starting to look like something. Any gap where you see light in the photos, we finessed the metal to fill the gap before welding.
Everything is lined up, square and flat. So we started hitting the spot welds on the cross member filler piece.
Everything is lining up pretty well. We used a bead roller to roll a few structural lines on both panels. The filler piece and the new trunk floor.
Everything is lined up, square and flat. So we started hitting the spot welds on the cross member filler piece.
Everything is lining up pretty well. We used a bead roller to roll a few structural lines on both panels. The filler piece and the new trunk floor.
10-26-2010, 07:48 PM
#3
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
At this point, Start hitting those spot welds. I like to do about every third one and work my way around a panel so it doesn't heat warp. Have somebody push the sheet metal tight against itself so the spot weld can hold everything tight. You don't want to see gaps. Pop out the grinder and take off the high spots. I don't grind them flush, leave some weld. The seam sealer, paint, carpet, undercoat pretty much take care of hiding any imperfections.
We heated and hammered the little angle piece on the rear of the car below the tail light area (4th pic in this group) to fill the deep contours in the stock body. IF you don't hammer those in a bit, you're going to have to get seam sealer about 1/2" thick and stuff it down there. We felt hammering the metal into the contours added strength as well and helped eliminate potential leaks. It looks rough in the pics but looks smooth and relatively factory in person. We got a little to aggressive with the hammering and didn't use enough heat and actually put a very small bow in new floor just where it meets the rear of the car in the center. You can't see it when there's carpet on it, but I can feel it. next time, more heat and hit softer.
Time for sealing, paint, undercoat.
The reflections make it look wavy, but it's flat.
We heated and hammered the little angle piece on the rear of the car below the tail light area (4th pic in this group) to fill the deep contours in the stock body. IF you don't hammer those in a bit, you're going to have to get seam sealer about 1/2" thick and stuff it down there. We felt hammering the metal into the contours added strength as well and helped eliminate potential leaks. It looks rough in the pics but looks smooth and relatively factory in person. We got a little to aggressive with the hammering and didn't use enough heat and actually put a very small bow in new floor just where it meets the rear of the car in the center. You can't see it when there's carpet on it, but I can feel it. next time, more heat and hit softer.
Time for sealing, paint, undercoat.
The reflections make it look wavy, but it's flat.
10-26-2010, 07:49 PM
#4
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
Got it seam sealed up. This turned out to be more art than science. And as the case with most things, you get the hang of it on about the last 4 inches of it... We did it over bare metal, some say to prime it first. Either way....
We used this 3m sealer. Body shop buddy said they use it. That was good enough for me. The one tube "barely" got all the seams. We had another buddy stop by and said they make a neat seam sealer that comes in a can, and you brush it on. personally, I'm thinking that would be a good one to try.
We no more than get it on there and are admiring our handiwork when we notice there's a good bit we now need to grind off for the roll bar pads... aint that how it goes.
Estimated location for the roll bar pad.
We did it over bare metal, some say to prime it first. Either way....We used this 3m sealer. Body shop buddy said they use it. That was good enough for me. The one tube "barely" got all the seams. We had another buddy stop by and said they make a neat seam sealer that comes in a can, and you brush it on. personally, I'm thinking that would be a good one to try.
We no more than get it on there and are admiring our handiwork when we notice there's a good bit we now need to grind off for the roll bar pads... aint that how it goes.
Estimated location for the roll bar pad.
10-26-2010, 08:07 PM
#5
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
So, the body has been modified, let's get a muffler in there.
Parts used.
Existing 3" exhaust.
(1) Magnaflow 4x9x18. 3" in and out, offset/offset muffler
(2) 3" obx v-band clamps
(1) 180 degree mandrel bent J-bend, 3"
(3) vibrant stainless exhaust hangers
(2) rubber exhaust biscuits
The reasoning for using the v-bands (which is a LOT of work by the way, as they need perfect alignment), was so that we could change mufflers for testing, and run different tips. Nice way to trick out the car. After it was done it was SOOOOooo worth it. To be able to simply take a wrench under there, loosen a bolt and change or rotate a part. totally worth it.
Here's where you start. Position the muffler where you want it. We left a piece of a wooden 2x4 on the top of the muffler to allow for some spacing between the muffler and the floor.
start lining pipe up.
Pinkbatman welded this pipe up, and I thought did a smoking job for a first time project. This is the input pipe for the muffler.
welded up and clamped. just need to make hangers next. We installed the muffler in this orientation so that the tip would be as long as possible for future upgrades and ideas.
Parts used.
Existing 3" exhaust.
(1) Magnaflow 4x9x18. 3" in and out, offset/offset muffler
(2) 3" obx v-band clamps
(1) 180 degree mandrel bent J-bend, 3"
(3) vibrant stainless exhaust hangers
(2) rubber exhaust biscuits
The reasoning for using the v-bands (which is a LOT of work by the way, as they need perfect alignment), was so that we could change mufflers for testing, and run different tips. Nice way to trick out the car. After it was done it was SOOOOooo worth it. To be able to simply take a wrench under there, loosen a bolt and change or rotate a part.
totally worth it.Here's where you start. Position the muffler where you want it. We left a piece of a wooden 2x4 on the top of the muffler to allow for some spacing between the muffler and the floor.
start lining pipe up.
Pinkbatman welded this pipe up, and I thought did a smoking job for a first time project. This is the input pipe for the muffler.
welded up and clamped. just need to make hangers next. We installed the muffler in this orientation so that the tip would be as long as possible for future upgrades and ideas.
Last edited by vectorsolid; 10-26-2010 at 11:27 PM.
10-26-2010, 08:13 PM
#6
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
getting the hanger mounts installed.
Complete system, ready to install for the LAST TIME! WoooHOOOooo.
Got a coat of paint in there.
10-26-2010, 08:21 PM
#7
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
Both sides located now. They are mounted to the chassis so that the muffler can be swapped out quick. We thought about how fun it would be to maybe even make a muffler delete tube to install on special occaisions. Although we tried it with no muffler in the shop (just as you see it in the next pic)... that's a fail (from a fly under the radar perspective). CRAZY loud. That's the nature of 3" though.
Clears the sway bar and mounts. I was a tad worried about that. *whew*
Clears the sway bar and mounts. I was a tad worried about that. *whew*
Last edited by vectorsolid; 10-26-2010 at 11:23 PM.
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10-26-2010, 08:23 PM
#8
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
Exhaust pipe tip is PERFECTLY in the center of the bumper cutout. We put a bit of an angle cut on the tip.
Looks utterly factory. Nobody (least of all the law) need know about the "all motor" horsepower lurking under the hood. Nice and stealth.
on these next 3 pics, if you didn't know what you were looking for, it looks stock. No modifications here.
Looks utterly factory. Nobody (least of all the law) need know about the "all motor" horsepower lurking under the hood. Nice and stealth.
on these next 3 pics, if you didn't know what you were looking for, it looks stock. No modifications here.
Last edited by vectorsolid; 10-26-2010 at 11:17 PM.
10-26-2010, 08:34 PM
#10
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Thread Starter
Re: Let's do a muffler tuck.
And there you have it. *WHEW*. Looks easy when it's all right there in a few posts. Fun project with a purpose. Fly low, keep unwanted attention away. 
Now get out to the shop and make something!!!
Now get out to the shop and make something!!!
10-26-2010, 10:42 PM
#12
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Re: Let's do a muffler tuck.
thats is pretty damn sweet, looks a tad naked in the rear but thats only cause im used to seeing a muffler hanging low. Great write up, i can see alot of people doing this to their ef's and da's now.
10-27-2010, 03:45 PM
#21
Honda-Tech Member
Re: Let's do a muffler tuck.
I'm with Mark on this one. You could of installed the same exhaust without cutting out all that and doing all that fab work(great work btw!) and it would of looked like a factory exhaust lol.
Unless the point of this was to tuck it for show purposes ONLY, b/c it that would look factory to a cop if it was in the stock ef/crx exhaust set up location. Im kinda lost but great job nonetheless and it looks great!
Unless the point of this was to tuck it for show purposes ONLY, b/c it that would look factory to a cop if it was in the stock ef/crx exhaust set up location. Im kinda lost but great job nonetheless and it looks great!
10-27-2010, 04:07 PM
#23
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
Thanks for all the kind words everybody.
I'm not sure it would have looked factory hanging way down below the bumper. Probably would have in mild steel with rust on it. Get some shine on it and then it looks modified. I guess it's a preference and perception. What we gained is the ability to "lay low and keep the flow". Around here (and likely most places) the kids with the big chrome cans hanging under the car attract all the attention from the law. And rightfully so in most cases. They're the ones making all the noise and interested in performance mods. Odds favor that cross section of drivers to be "potentially" of interest to law enforcement. Like it or not.
I believe we can go up to an 8-9" diameter muffler, and it's still not visible from behind the car. AND we gained total tunability of the exhaust from the axle to the bumper.
Right now, I'd like to test a 5x9-22" long unit to see if it takes just a smidge of "rasp" out of it around 5 grand. Likely going to take something with fiberglass or something like that in it to take out the metallic rasp of that design muffler. At idle through 4 grand at reasonable throttle, it's more than acceptable. Like I mentioned before, nothing is really "quiet" when it comes to muffling 3" tubing.
Fun project.
I'm with Mark on this one. You could of installed the same exhaust without cutting out all that and doing all that fab work(great work btw!) and it would of looked like a factory exhaust lol.
Unless the point of this was to tuck it for show purposes ONLY, b/c it that would look factory to a cop if it was in the stock ef/crx exhaust set up location. Im kinda lost but great job nonetheless and it looks great!
Unless the point of this was to tuck it for show purposes ONLY, b/c it that would look factory to a cop if it was in the stock ef/crx exhaust set up location. Im kinda lost but great job nonetheless and it looks great!
I believe we can go up to an 8-9" diameter muffler, and it's still not visible from behind the car. AND we gained total tunability of the exhaust from the axle to the bumper.
Right now, I'd like to test a 5x9-22" long unit to see if it takes just a smidge of "rasp" out of it around 5 grand. Likely going to take something with fiberglass or something like that in it to take out the metallic rasp of that design muffler. At idle through 4 grand at reasonable throttle, it's more than acceptable. Like I mentioned before, nothing is really "quiet" when it comes to muffling 3" tubing.
Fun project.
Last edited by vectorsolid; 10-27-2010 at 09:08 PM.
10-27-2010, 05:03 PM
#25
Honda-Tech Member
Thread Starter
Re: Let's do a muffler tuck.
I feel, for me, this is the best way to illustrate the point of doing a "muffler tuck". One of cars in the following picture has 230whp and is regulary taken to the track, both road and drag. The other car has 92whp and is used to get it's owner to and from work. Which is which? If you were law enforcement picking out trouble makers, or even a thief, which car would you spend more time looking at? Likely, the one that looks modified, which ironically, it isn't.
also, it's just cleaner looking from the back, which is the other good reason. Even the tow hook got a shave.
Fly low. Don't attract un-needed, or unwanted attention. If I were parked behind these two cars at a light, I'd put money on the car on left doing something stupid.
