My only comment is you have exhaust exiting underneath the vehicle.

There is a good reason most folks don't do that.

You get stupid before you get sleepy, so when you start getting sleepy you are too stupid to pull over and roll a window down or something.

Think hard on this set up.
not trying to preach but...

 

My exhaust has a downturn right off the muffler, dumps in the same place. No problemo senior. I don't have a tailpipe and I'm alive to tell about it.

 

FailWheelDrive, you get an A+ for your step by step modification. Hell ya got rid of the Mufffler, excellent work IMO.....

 

I may be just young and dumb, but what downsides are there for it being under the car Metaxa?

@Fail, From a stock setup, would it still be $20? or was this $20 off what you had already paid for your custom setup? Basically I'm running at 100% stock exhaust wise, and if I had wanted to do this what all is needed?

 

I may be just young and dumb, but what downsides are there for it being under the car Metaxa?

Think he was pointing out the under the car exhaust fumes can enter the cabin.
Personally don't think that's too much of an issue,
Cars are pretty well sealed from outside,
We used to run Y tubes from ex manifold, 1 opening was for open exhaust right under the vehicle, and other opening led to cat, some just used that for inspection.

 

Don't read me wrong, Its ingenious, a back yard fix that gets a sound and look together for a great price....all that I applaud. Now, if it came out the side or behind the rear wheels or out back where a million dollar company's big shot engineers placed it...

All the rest of you running like this...get a good CO detector in your unit, it is unsafe, period. It is how folks commit suicide, by pumping exhaust into a closed car.

You aren't exactly piping it in but on a long drive it will be coming in in sufficient quantities to befuddle you. Get it good and warmed up, hit a freeway, hit the gas and get up to speed and then lift off the throttle...I'll Internet guarantee you will smell exhaust.
It is what is tricking in when you can't smell the exhaust that worries me.

There is this thing called the Internet, use it to find out about how carbon monoxide acts on the human brain.

As I said...you won't notice because you get stupid first, then you get sleepy...by the time that happens you are too stupid to figure it out and all to often it goes to late.

I'm trained up on this crap, your Patriot is a confined space and you are potentially allowing a poisonous gas to infiltrate...not only allowing but have wilfully modified the exhaust system to do so.

This isn't "well I don't care if my mod makes the wheel fall off" and it does and you crunch a curb. This is your mod has a significant potential to kill you and any passengers you are carrying.

I am beyond serious here.

I've raced motorcycles and Jeeps, got as far as semi pro in that. I've customized cars all my life, I have been around the hot rod scene for almost 5 decades, I've worked at the drag strip in Saskatoon back in the very late 60's and early 70's. I've been around mechanics who really know their stuff, fixed what I broke...nobody does this...nobody who wants to live long and prosper.

Dumping your exhaust under you vehicle is illegal and more than that it is unforgivable in its wilful exposure to a significantly dangerous situation. Period. Ask your insurance agent about it, dare you...or a local traffic cop...

I also hold trainer certifications in closed space entry, asbestos environments, fume, FOG and all that sort of stuff. I'm even certified on a forklift!

And the one thing that 63 years of living with almost 50 years of driving (I got my first driver's at 14) tells me is this is dangerous.

You and Earthworm can feel as you want, Land of the Free and all...but remember, you are also free to die.

go ahead, I've stated my piece and don't know how much more emphatic I can be about this...

Its a profoundly dumb thing to to. I hope that is clear enough for you.
I strongly urge anyone else who may consider this to really think it through.

Those that have done it...happy trails to you.

 

Thanks for the feedback guys.

Metaxa has a valid point. This might not be the best exhaust setup if you have a lowered Patriot or if you sit and idle in confined spaces for long periods of time.

I'm pretty sure my Pat has plenty of breathing room under it BUT I am the kind of guy that lives (and maybe dies? ) by data. As a professional test dummy, I pledge to the forum that I will purchase and install a carbon monoxide detecter (with digital readout) in my Patriot. I just did some quick reading and 70 parts per meter and above is considered dangerous and may start to cause headaches and whatnot. I will post my results as soon as they are available.

To clarify I just completely removed my Dynomax catback and started from stock. So starting with a stock exhaust this would cost you ~$20.

The chrome exhaust turn down, 2" ID to 1.5" ID adapter, and hanger (optional) can be found at AutoZone, but this same type of stuff can be found at any parts store.

In fact if you wanted to you could probably just cut the factory exhaust while it was still on the car (with a sawzall or cut off wheel or something) and only remove the back half. Super easy.

I just got back in from running some errands (luckily enough I didn't die from Carbon Monoxide poisoning Metaxa ) and have more feedback on the sputtery sound I mentioned in the first post. It happens when taking off from a stop in first gear if you let the engine bog while letting the clutch out. It sounds a little like there is an exhaust leak for a split second.

This isn't a huge deal, I'm just trying to set expectations for those brave souls who will try this mod.

While I was out and about I took the opportunity to get heavy handed with the throttle. At lower RPMs (<3kish) under heavy load (>75/80%) this exhuast setup has a slightly odd sound a little like an exhaust leak.

After several WOT runs at different speeds it's fair to say that under WOT through the low/mid RPMs it's not the best sounding setup. Once you start getting up into the higher RPMs it starts to sound like a plane taking off, which is actually kinda cool.

Again, I'm pointing these imperfections out for those of us who see a $20 exhaust mod that they think will make their 4 banger Patriots sound like a Viper, Ferrari, or my GTO. Not gonna happen. It's a 4 banger.

It's a safe bet that the majority of us drive our Patriots around modestly >99% of the time, so it's worth mentioning that under most normal driving conditions this setup does sound pretty darn good.

Also, I didn't mention this before but I have a 5 speed and am not sure how this would sound on a CVT.

I encourage people to try this and see if you like it. Maybe even try and experiment with a couple of different sized adapters to get the sound/feel that you like the best.

Just keep keep your expectations low (I mean c'mon it's a $20 exhuast mod) and you'll be all set.

 

That's a nice cheap way to make more torque by increasing backpressure [except for it being under the middle of the car].
But a good set of headers and a balanced exhaust system can increase power/torque across the board - but not for $20!

EDIT: You might want to keep an eye on your sparkplugs to see if they are getting too white [a light tan/cinnamon is OK].

 

You might want to keep an eye on your spark plugs to see if they are getting too white [a light tan/cinnamon is OK].

I've been monitoring how much the ECU has had to compensate fueling with my OBDII Bluetooth adapter/Torque Ap setup and it's well within the range of adjustment.

Good to go! :beerchug:

 

I'm more concerned with combustion temp due to increased backpressure.

 

It's safe to say that the combustion temperatures are fine. It's not like we're running a dry shot here...

Think about how much restriction is introduced by a factory muffler. When you remove the muffler there is a big enough back pressure drop to cause significant low end torque loss.

The reason for necking down the size of the pipe is to compensate for some of the back pressure lost by eliminating the restriction of the factory muffler.

 

Two things...

1) I agree with Metaxa; nice try but ultimately a FAIL because the exhaust does not exit from beneath the vehicle. As I've posted before, I race sports cars on the weekends (not autocross but genuine wheel-to-wheel racing) and that would never pass tech on a race car for the same reasons he states, and we've got air moving under the car at 100+ mph. You need to fix that.

2) It's not $20, but this muffler (and you had a motorcycle, so I'm sure it's not unknown to you) will solve your tuning/back pressure problems quite handily:

I used one on an old autocross/daily driver car I had and it did a nice job of making a bit of noise while still being quiet, with the bonus of extreme tuneability for back pressure. A little bit of pipe, a hanger and this and you'll have a nice system.

 

Let me start out by saying I greatly appreciate everyone's feedback. :notworthy:

In lieu of some potentially valid concerns raised in this thread but also because of my own curiosity and interest in getting to the bottom of this, I decided to step up the timeframe of testing out the possibility of this exhaust setup causing unsafe Carbon Monoxide levels for the driver/passengers.

So today I took an early lunch and drove a couple of miles to Wally world with all of my windows up and the A/C on full blast (on recirculate). I brought my spare key with me so that I could leave my Patriot running (with the A/C on full blast on recirculate) while I went in and picked out a Carbon Monoxide detector.

It seemed like a good idea to spend a few extra bucks on a battery powered model with the digital read out on the front (Kidde Model#KN-COPP-B). The reviews on Amazon are really solid on this model.

I went back to my still running Patriot, got in, tore the CO detector out of the packaging, read the directions, and fired it up. After it went through its startup cycle it read “0”. This was promising and made me feel like impending doom might be farther away than I initially expected.

All of this optimism was making me hungry so I drove a few miles to a Subway (with the A/C on full blast on recirculate) with the detector reading “0” the whole way.

When I got to Subway I decided to switch things up a little and changed the HVAC system from recirculate to taking in air from outside. I left the Patriot running with the windows rolled up in the parking lot while I went into Subway, waited in line, ordered a sub, and ate it. 15-20 minutes later when I got back into my Patriot and checked the CO detector it was still reading “0”.

The good news is that the initial tests look good, and that we can put this issue to bed. I will be sure to leave the detector in my car long term and will report back if I see anything different.

BTW: I'm NOT a fan of Supertrapp.

A friend of mine had one on the end of a pretty tricked out G60 Corrado but he dumped it.

My first motorcycle (1992 GSXR750) had a Supertrapp with the external baffles on it when I bought it. I kept the headers but swapped out he can for an internally baffled Supertrapp can.

It's cool that you can tune them with the baffles... I just think that they sound and look horrendous.

 

Everyone has different ideas on modifications.

 

Moving forward the nickname for this exhaust mod is "The Big Dump".

That is all.

 

I love muffler swaps. My hold back, is fear that the 2.0 will sound like a weed-wacker. Yours sounds good, but sounds change once warm and on the floor. On my 2.5l Frontier I used a cheapo "Afterburner" from Checker, and dumped it out the side just in front of the rear tire. Sounded great no rattles, no weed eater noise, and no pupup-pups on decel.
The biggest concern with this setup is what an ADEQ inspector will say when the time comes. Since the exhaust exits under the passenger area it wont pass. Ya got a few years till it becomes a concern tho. Now that you know you like it why dont you run a pipe all the way out?

 

Now that you know you like it why dont you run a pipe all the way out?

I forgot to answer this yesterday but I considered doing a side pipe. To run the pipe where I wanted, it would have to go under the unibody frame rails which decreases ground clearance... which goes against one of my initial design specs.

My question back to you is:

If the sound and performance are good, and we proved that carbon monoxide isn't an issue, Why bother running a pipe all the way out?

It's a little early to say, as I haven't run a full tank of gas through it yet... but it looks like my MPG have gone up some. I'll report back when I have more info.

If anyone else out there is interested in doing The Big Dump, it's worth mentioning that it allowed me to make some other mods that have really made my Patriot look much better. Check it out in this thread.

 

Inspection is not really a concern with this setup...

the factory exhaust can be reinstalled with a simple sleeve in about 15 min.

 

If the sound and performance are good, and we proved that carbon monoxide isn't an issue, Why bother running a pipe all the way out?

For me its just SOP... No "dumping" under the passenger compartment.
I did something similar once. I had a GMC Yukon GT diesel that I put a 3.75" pipe on and was unable to fab up a bend over the rear axle so it ended a bit infront of it. I heard the same comments as what you are getting from board members, but smells fumes werent the issue. The problem was the horrible drone sound that got annoying on the hwy. It was fine around town but on road trips with cruise on steady speed it was freaking obnoxious.
I ended up running a side pipe, which actually isnt up to code either, but solved the drone issue.
I do realize the added difficulty the bends pose trying to run it out the back but I bet if you stopped by an exhaust shop and had your old stock pipe expanded/bent a little to make it work youde be happier. Since theres only 500 exhaust shops down there in Phx, finding a guy to whip it out quick under the table for cheap shouldnt be a problem.

 

Yeah I hear you.

It's important for me to clarify that I'm not getting any drone with The Big Dump. I mean you can hear it around town & on the highway but it's not obnoxious and doesn't resonate inside the car.

Also, one of the potential negatives I brought up in the first post ended up being a nonissue. I was afraid it would blow up dust on trails but it ended up being fine.

I'm so happy withThe Big Dump that I put my Dynomax up for sale because I know I'll never go back to it.

 

I like this set up a lot. Something to jot down/keep in mind when I get my Pat.

 

I do like the sound of the "Big Dump" better vs. the DynoMax. That being said, I am going to rehash the safety aspect a little. As a former Pennsylvania state safety and emissions inspector, it would absolutely fail the safety portion that way. In PA, all exhaust must exit from under the body, and do so past the last opening window. The only exception is for pickup trucks where it is allowed to exit under the bed of the truck, provided the bed is a separate structure from the cab (sorry Honda Ridgeline, no separate bed). I do agree that our Patriots are pretty well sealed on the bottom for water fording, but sealing against water, which is a fairly large, and heavy molecule, vs a gas such as CO (which rises being lighter then air) is a very different affair. I would definitely avoid idling while standing still and if caught in a large traffic jam, open the front windows or shut the engine off between moves. Probably wouldn't hurt to read up on CO poisoning symptoms so that you're informed on what to look out for as well.

All that being said, kudos on a cool design!

 

And it wouldn't be trips around town or over to the next town I'd worry about so much.

It would be that long drive back across State to school or a three State vacation drive...about hour 6+ of a ten hour trip.

Fail, have you tried the totally warmed up, on a highway, from say 30 mph, full throttle acceleration to as fast as you are comfortable, full lift off the throttle and draw down yet?

My XL7 has a small leak in the exhaust, is in great shape for a 10 year old but every time that (above) happens we smell exhaust...window up or down, air on or not.

So a full throttle pass of another vehicle, pull back into my lane and off the gas to settle down to less speed gives us a smell in vehicle.

I'd check that part out because if its creeping in, it will build over a long trip.

 

There's been a carbon monoxide sensor in my Jeep since I bought it the other day and it hasn't made a peep. Creeping along on the trails, out on the highway, in traffic, from WOT runs to idling have all proved safe so far.

I agree that The Bug Dump won't pass inspection but since there are no carbon monoxide issues I'm fine with mounting up the facory exhaust (quick/easy job) come inspection time.

 

I should also add that I'm not trying to chastise you on the design or it's use. I'm a firm believer in allowing folks to do what they please so long as they are not hurting/bothering anyone else. I think there are more then enough nanny laws out there (and that some are blatantly defeating the law of natural selection). I'm merely concerned for your well being is all. Be safe!

 

Totally understood & appreciated todde702.

 

For me, I wouldn't do this, but I do appreciate the OP's continued testing with the carbon monoxide detector and addressing the concerns of we naysayers. A proper reaction to a genuine concern, and you deserve applause.

re: the Supertrapp. I'll agree it's a muffler you either like or hate. I had one on my '78 Fiesta because nobody made an exhaust worth a damn, I could get them at cost, and I was intrigued by the tunable aspect. I was happy with mine, thought it sounded ok on the 1.6 Ford engine and it was a simple solution to a problem back when getting a custom made exhaust wasn't an easy thing to do. There probably are better alternatives today but for this task it looks like it may work, so it's something for folks to at least consider.

I've tinkered with exhaust systems on various cars with both custom made and off the shelf items and it amazes me how much can be accomplished with very little expenditure. Most aftermarket systems are incredibly overpriced for what they are, and only half of them seem to offer actual power gains. Most just make noise and look good.

 

good job there failwheel. i have had several mustangs in the past and been around the street racing scene for years. I think just about half of the mustangs, camaros, and trucks i have ever seen with borla or flomasters have allways dumped under the car. i myself have had several mustangs and a truck with dumped exhaust. never any issues. it is obvious to me most of the naysayers have never had or been in a car with dumped exhaust and probably should not be commenting IMO.