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Discussion Starter · #1 · (Edited)
Greetings all,

As promised in my other thread I am delivering a guide on an exhaust cutout mod. As some may be aware, I just recently got my RT back from a nasty failure of the rear suspension, which wiped out everything in the rear underbody, including my performance exhaust. Chrysler mostly covered the repair costs, but they wouldn't cover the performance exhaust. So here I am back with this stock exhaust that sounds like a box fan when you rev it up. That has to go.:thdown:

So after exploring options I set my crosshairs on exhaust cutouts, specifically the low profile oval cutouts from QTP. I just got everything finished today and oh.. my... god. When full open, the car sounds like the loudest, most angry lion roar you could possibly imagine. Beauty of it is that with the stock exhaust you can go full out stealth mode, you can crack them open just a hair and you get a nice 'reasonable' exhaust volume that sounds good, and you can open them all the way up and cause chaos, all with a switch in the knee panel.

So first things first. The raw materials you will need:
-The cutout assemblies (Example: http://www.summitracing.com/parts/QTP-QTEC66 )
-The turndowns (Example: http://www.summitracing.com/parts/QTP-11338 )
-Switch (optional recommended improvement) (Example:
)
-Tooling
--Wire strippers and cutters
--Splices and shrink wrap
--Drill with small and large bits
--Aluminum 'Speed' tape
--Ty wraps
--Screw drivers
--Welder (or a welding shop)

First thing I did was some prep work on the switch assembly. I drew up the schematic on what the stock switch assembly looks like:


This is what the original switch looks like:


The problem with this switch that I didn't like was 1.) The looks. I wanted a rocker switch. 2.) It was quite stiff, so much that I thought the plastic molding might end up cracking over time with activation of the switch.

Here's a side by side of the original switch, and the one that I chose to replace it with:


If you choose to replace the switch, the next steps are the how to. The wire terminals will transfer from one switch to the other without any terminal end replacements. Just move them from one switch to the other keeping the same order. The new switch will use 2, 3, and 4. 1 and 5 are the lamps. Here is the schematic on the new switch:


For this switch I wanted the red lamp to be the momentary switch to open the cutouts and I wanted the amber to close them. If you have the same switch from QTP you'll see one side of the switch are single wire jumpers to the other side of the switch. Put those jumpers on the side of the switch that you want to open the valve. So if referencing the 2nd schematic, the red lamp is 5A & 5B, you'll want the single wire jumper on 4A & 4B. Hopefully I didn't make that too confusing. If all else fails and wires get mixed up or don't come like my switch did, wire it like my schematic and it will work.

You'll want to wire up your lamps next. I wanted my lamps to be lit anytime the valves could be moved. To do this I spliced in two runs of wire on the power wire (red) and two on the ground (black).


Run the power to 1A and 5A and the ground wires to 1B and 5B. You could find a wire terminal to fit the switch or just solder them on. I like to solder, so that's what I did:


If you happen to have a power supply, it's good to be able to ops check everything at this point:


When you are done wiring it up, wrap it up in some electrical tape to keep everything secure and covered:


Next up is the work on the car.
 

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Discussion Starter · #2 · (Edited)
I put my switch in the knee panel. So that's what I'm going after in the next few steps. First thing you'll need to remove a few snap panels.

Pull towards you on the vertical strip shown here, there's two clips, one on top and one on the bottom. It is hiding one screw for the knee panel:


The bottom door trim will pull straight up too. It is hiding a screw for the corner trim:


There's one more screw on the underside of the knee panel in plain sight if you look up at it. The bottom part of the knee panel should be pretty loose now. Give it a tug down and back to pop out the clips holding the top in. Disconnect the connector for the trunk button and you can get this panel out of the way for now.

Next we need a power source. I chose to go after the power wires for the center console power source, since it is only receiving power when the key is turned and it has sufficient amperage to operate the motors without concern. You'll need to pop off the center console molding. Start here:


This panel can be a bit of a challenge. It's only held in by your typical pain in the butt quick clips, but mine were particularly stubborn. I just worked under that corner with two flat blade screwdrivers. Eventually that first clip will pop and you'll be in the clear:


The wires you want are the smaller bundle:


As you can see, not much slack to work with. I disconnected my battery just in case. Cut this wire bundle in a spot that will allow you a little room to work on both ends. Trim the covering back with a razor and strip the wire insulation back for a butt splice:


Splice red and red back together on one side of the splice and black and black on another splice. The other side of the splice will be a wire going to your switch:


Next you'll need to route some wire from the power wires you just tapped into to the switch location, which I have below and to the left of the steering column. I can't really get a picture of it, but you'll find a passage you can snake the wire through from the center console to the left side of the knee panel without too much trouble:



Next you need to cut the hole for your switch. I just used a drill and small drill bit cause that's what I had handy. A dremel would be great too. Nothing too difficult about it though. Just take your time, make sure it's straight and just edge it out until the switch will just fit through it:



Splice in both ends of your wire you ran from the center console to the switch. Make sure power (red) from the power source is going to the power wire on the switch with the fuse:


Now to run the intermediate harness. I chose to exit under the drivers seat because there's a convenient unused drain plug there. To get there is easy too. Just run the intermediate harnesses over to the right side of the knee panel and route them under the panel running back along the lower center console area. You can just tuck both wires up in there and it's snug enough that they won't fall out:


Run them all the way back to the middle of the drivers seat then have them exit and go down under the driver's forward/aft slider track:



Reassemble all the panels you've taken apart.
 

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Discussion Starter · #3 · (Edited)
Now for the outside work. Right under the driver's seat there is a black 'drain' plug or something of the sorts that is basically an unused port. You can see it here, but I had it covered up with some speed tape at the time. You get the idea though:


Under the drivers seat there is a section of carpet that is cut that has your wires for your power seat stuff. If you look in that hole you'll see a round bump in the under flooring that is right above that drain plug. Basically all you are going to do is take a big drill bit and just drill through part of that drain plug and through the under flooring to allow a hold big enough for your intermediate harness to go though:


I didn't drill the hole big enough for the connectors to go through, because that would be a pretty darn big hole to go through. Instead I drilled a hole just big enough for the two wire harnesses to go though and cut the intermediate harness, leaving as much slack as possible for the wire going outside to the elements. The wires are red and black inside the harness also, so just splice them back together the way they were. Keep the splices on the inside of the car.

This under flooring isn't metal. It's a soft formed putty of some sort. Don't be like me and press hard with your drill bit expecting metal resistance. Almost drilled up into my seat!:worried: Just put light pressure and it'll go right through. Feed your wires through:


You'll want to probably work from the right cutout first. The cutout location is where the exhaust comes down from the cat converters and right after where it turns inboard is a nice location. In this picture you will see the right exhaust cutout and the intermediate harness. Route the harness under the aluminum shielding and over to the.. inner support block, or whatever you want to call that thing. If somebody wants to chime in on what the technical term for that is, feel free. I'm just a silly aircraft mechanic, not as sure about car terminologies.



Continue routing the harness left and under another aluminum shielding. Here is where you'll meet up with the left cutout harness. Also note here is a good picture of one of the unused drain plugs. This one is forward of the one you want to enter though:


The left cutout and where you can mount it securely to:


Run both wires under some aluminum speed tape back to the exit hole:



Coil up all your excess wire harness and stow them under the driver's seat neatly. I secured them to the seat adjustment motor too so they move with the seat and don't get pinched:


You should be ready to go. Here's the switch installed and with power:


Here's the two valves. I labeled them pretty thoroughly because I didn't have the tooling necessary to do the welding. I had some friendly folks at the local monro do that, so I made it as 'dummy proof' as I could:


I did file the right down turn just a little on the one corner because it was a little close to the valve. It cleared but I just wanted to make sure with a little wear it still would:



Since you probably don't have the cutouts welded on at this point, just put a bag over the connectors under the car and ty wrap it so moisture can't get in. Secure them and get an appointment at your local welding capable shop. I didn't have too many options to pick from. I went to a monro. They did a fine job. For them to weld it correctly they will have to take the exhaust pipe out of the car though. In my year there is not a gasket between the headers and cat pipes. If you have a different year you may want to check for this and have a gasket to replace the old. They dinged me about $170 for the job. I thought it was kind of on the high side, but again, not many options for me. You could probably do better.
 

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Discussion Starter · #4 · (Edited)

First rev is cutouts full closed and stock exhaust
Second rev is cutouts just barely cracked open
Third rev is cutouts full open

The camera phone audio doesn't do it any justice. To give you an idea on the loudness though... notice how you can 'see' how loud it is. The visuals on the whole camera actually shake LOL:browsmiley:

So I think that about finishes it up. I couldn't be happier. Let me know if there are any questions and I'll be glad to assist.
 

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Looking good, very anxious to see the end result and of course a video :)
 

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Nice write up!

Nice write up. I just picked up a set this afternoon, cant wait to get them installed!:banana: I'll probably go with the same switch, much better.
 

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Cool write up. Good job.
Im not sure about cut out location, but thats where I see most weld them in.
IMO id like cut outs just after the X pipe. Id get the benifits of the x pipe and i think if a car was on a dyno it would yield the most HP and TQ there.
FlatTop
 

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Probably lose a little on the low end and a small gain on the top, mostly for sound. The biggest gain I saw was 11 hp on the top and if I remember right that was on a car that was fairly modded with stock exhaust. Flat top, I'm going back and forth on the location, I got the y pipe version so it would be easier to splice into a straight section, I wouldn't think it would effect sound since it's still before the mufflers and since we have strict smog laws here in Ca, the further from the cats the more comfortable I would feel.
 
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Discussion Starter · #10 ·
Cool write up. Good job.
Im not sure about cut out location, but thats where I see most weld them in.
IMO id like cut outs just after the X pipe. Id get the benifits of the x pipe and i think if a car was on a dyno it would yield the most HP and TQ there.
FlatTop
One problem you may run into would be ground clearance after the X pipe. There's not much to work with if your mufflers are in the stock location.

Awesome ! I love this. What kind of power gains over stock exhaust ?
From what I've read and experienced, the performance gains of cutouts on a stock exhaust are about equivalent to putting on a good aftermarket catback. If you have a good performance catback already, you'll probably see little to no gain overall. Some track results show that it's best to run them at 3/4 open.

What you are really getting is fun factor gains. I love having a volume control on my engine. I run them almost 100% of the time just barely cracked open. Just cracked open is about as loud as any performance exhaust is. It has that soothing low idle rumble as you are going through the gas station/parking lot/wherever that just makes heads turn. My face hurts when I'm driving now because I'm in a constant smile.

Probably lose a little on the low end and a small gain on the top, mostly for sound. The biggest gain I saw was 11 hp on the top and if I remember right that was on a car that was fairly modded with stock exhaust. Flat top, I'm going back and forth on the location, I got the y pipe version so it would be easier to splice into a straight section, I wouldn't think it would effect sound since it's still before the mufflers and since we have strict smog laws here in Ca, the further from the cats the more comfortable I would feel.
I'm not sure about the Y pipe. I haven't seen any on a Challenger. All would be good as long as it's not hanging much lower than the rest of the body. It would be tragic to go over a speed bump and come out the other side with a cracked or bent exhaust pipe.

One other thing I should caution anybody that wants to do this mod. In most states it technically won't pass state inspection if the inspector wants to be a jerk about it. It might take a little shopping around to find a low key kind of place or just make friends with an inspector. Shouldn't be too hard though. If you don't know anybody, just call up some inspection joints and ask if they would have a problem passing a vehicle with a capped off exhaust cutout. If they would have a problem, just keep shopping around.
 

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I have the room being I have 3in mids going to 2.75in X pipe to the srt bottle mufflers that go back to resinators.
Heres my deal. Right after the X pipe it goes to the bottle mufflers that are 18in long. I am going to do the cut outs Right There. Cut out the bottle mufflers and exactly after the X pipe I put in the Y pipe with the cut out.
It is resessed right there in front of the rear end, where the bottle mufflers are now. My RT is lowered 1.5 so clearence is an issue.
From there I found at summit a 9inch long bottle muffler that will go in after the cut out Y pipe the the new 9inch long bottle muffler. I keep the resinators to keep the ol girl quiet.
When I want no back preasure to let the blower work it will be nice and free flowing with use of the x pipe. IMO thats the best spot for performance.
I do like quiet cruzing. I did years of the rumble already. A flip of the switch gives me the performance i may want. Im going to dyno the car and see if I get anything from going open right after the X pipe. Hope I do as I already have the kit now with cut outs and Y pipes. I did do 3inch for cut out also. More than souind for me is performance. Dumping before all the mufflers and resinator should give me extra hp.
Well see, as its going to happen next week. Along with a few other new mods to get me to low to mid 10s goal.
FlatTop
 

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Flat top...

Awesome man! Please let me know how it goes and post a few pics if possible! I have plenty of room for the y pipes as well (SRT lowered on Sportline springs) and run a full 3" exhaust. I'm really leaning towards locating after the x pipe as well so please keep us posted. Mine wont be delivered until late next week but I will be installing the day I get them. Your feedback will be a crucial factor in my decision, lol. Thanks.
 

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Flat top, have you had a chance to get them installed?
 

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Flat Top, where'd you go man? I'm scheduled for install Thursday, looks like it's going to be a very tight squeeze, most likely I'll be installing in the straight section of the mid pipes. With the length of the Super 44's I don't know if there will be enough room between them and the x pipe. Any chance you got yours installed yet? If so any pics of the fit would be awesome.
OP, that drain plug under the seat is key! I can almost guarantee I would have missed it and spent a bunch of time running through the firewall. I'll probably use 1/4" metal straps and short self tapping screws to run the wires under the car, that tape would make me a little nervous. Thanks again, greatly appreciated.
 

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Discussion Starter · #18 ·
I am really thinking about this myself I have a charging port inside my console would this be adequate power to rum this? Love the sound.
You're talking the one inside the armrest/center storage console? That charging port has hot power, meaning it is wired right to the battery and always has power. If you were to use a switch with a light, that would kill your battery. Aside from that, if you are using a regular switch it should work just fine to tap into that for power.
 
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