3 inch Injen Catback Exhaust - Weight Diameter

[Myx]

This is to answer the question that no-one asked and is only for documentation purposes. The item is a 3" Injen exhaust I purchased used for my 2018 Honda Civic EX Hatchback (CVT). I always weigh all my modifications. It's just a sick habit I have. I post it up in case my notes get lost, computer hard drive crashes, etc. I'll have another place to reference it. It's also for anyone that may be curious as to the same things I am.

3" Injen Catback Diameters
Outer diameter - 3" ***For the most part, see below***
Internal diameter - 2.864" (72.75mm).

Pipe that connects to downpipe - 2.388" (60.66mm) Wtf!?!?
**This is a very small section of pipe. See pics I uploaded**


3" Injen Catback Weights
Frontpipe connecting Pipe - 12.4lbs (5.62kg)
Midpipe - 8lbs (3.63kg)
Muffler Pipe - 12.6lbs (5.72kg)
Total weight = 33lbs (15kg)

Stock exhaust is 32lbs.


I bought this used but purchased it because I personally believed it is the best exhaust on the market for flow. Realize that your stock exhaust is adequate for flow, even after some bolt on modifications and no hp/torque benefits (Per PRL Motorsports dyno testing exhaust). My future may include a larger turbo but that's for another thread. I love the straight through design of the Injen setup. It's simple and un-complicated.

Two gripes (If you want to call it this):
1) The so called 'muffler'. That thing ain't muffling anything. It looks like a resonator attached to the pipe. No different! I was debating having it cut off and putting an actual muffler on it. The sound from the Injen video is very 'ricer' to me. I don't like loud and droning. So I was going to take it upon myself to correct it by cutting this piece off. I would only do this on a used piece...not a brand new Injen exhaust...which I would not have purchased new anyways.

2) It's not a true 3" exhaust. All the sections and bends seem perfect to me. The exception is the piece that connects to your frontpipe. It only has a 2.388" outside diameter. This defeats the whole purpose of the rest of the pipe forward of it. May as well have a 2.388" (or 2.5") exhaust the rest of the way through. It would've reduce any unwanted extra sound (or noise) and have the same flow potential. If someone pointed this out already, my apologies. I just didn't see it anywhere. This sucks for those thinking it is 3" all the way through.

BTW: The pipe you see me connecting the Injen's small pipe section to is a PRL Motorsports frontpipe. Look at the transition. Injen's small pipe piece is pointless and defeating the purpose of airflow through a pipe of consistent diameter. I don't care either way. It's a learning experience. I can have this section modified if I like but letting folks know what they are getting into if they purchase this exhaust. I may not have connected it to the correct side of the PRL Motorsports frontpipe or right angle. I'm just showing this as in illustration on the pipe size transitions.

 

[dc2turbo]

What is your goal with this CVT? I hope you know that the CVT is really weak.

 

[Myx]

What is your goal with this CVT? I hope you know that it's a good thing I didn't do very weak and someone is already having trouble with it ,

I just am putting this out here for information purposes. My personal goal is said to be 'un-obtainable'. Which drives me more. I'll keep that for another thread though. See you at the track.

Feel free to PM me if you want. I don't want to detract from the Injen exhaust info.

 

[dc2turbo]

I just am putting this out here for information purposes. My personal goal is said to be 'un-obtainable'. Which drives me more. I'll keep that for another thread though. See you at the track.

Feel free to PM me if you want. I don't want to detract from the Injen exhaust info.

opps guess it pocket texted and posted lol

I meant to say CVT is really weak and a few have broken them already when adding a decent bit of power.

this goal might be un-obtainable and if you do obtain it how reliable will it be

 

[Myx]

opps guess it pocket texted and posted lol
I meant to say CVT is really weak and a few have broken them already when adding a decent bit of power.
this goal might be un-obtainable and if you do obtain it how reliable will it be

I never answered this but I noticed you didn't PM me the question. Not sure what this has to do with the Injen exhaust info.

 

[Myx]

The box this came in was in shambles. I think I am going to package this up and sell it for much, much less than if you purchased it new. I can't get past that small section that reduces down to 2.388". I plan on having some exhaust pieces installed tomorrow (PRL Motorsports Front/Downpipe). When I get a suitable box and packaging material, I'll give peeps a heads up on price. Otherwise, the exhaust would have been perfect for me in a flow sense.

 

[indexcow]

The box this came in was in shambles. I think I am going to package this up and sell it for much, much less than if you purchased it new. I can't get past that small section that reduces down to 2.388". I plan on having some exhaust pieces installed tomorrow (PRL Motorsports Front/Downpipe). When I get a suitable box and packaging material, I'll give peeps a heads up on price. Otherwise, the exhaust would have been perfect for me in a flow sense.

@Myx If you are cutting off the "mufflers" for better ones why not hack up that slim piece and make it as wide as you want? It's used anyways might as well hack it to hell

 

[Myx]

@Myx If you are cutting off the "mufflers" for better ones why not hack up that slim piece and make it as wide as you want? It's used anyways might as well hack it to hell

Good suggestion and something I thought about. Look closer that the flange attached to the reduced pipe. The flange itself looks slightly smaller than the PRL Motorsports downpipe flange. It seem like if we were to open up the Injen flange to 3", it would be so wide it would come in contact with the bolt holes. Weird but looking at it in the pics, it seems this way. This made me decide not to pursue cutting the small piece out and having a 3" piece welded on.

Also, I'm trying really, Really, REALLY hard not to do any personal modifications to this vehicle. I have a habit of getting made custom pieces a specific way. I just want to purchase parts I think will work and bolt it on for once. If I keep running into crap like this resistance will be futile.

 

[indexcow]

Good suggestion and something I thought about. Look closer that the flange attached to the reduced pipe. The flange itself looks slightly smaller than the PRL Motorsports downpipe flange. It seem like if we were to open up the Injen flange to 3", it would be so wide it would come in contact with the bolt holes. Weird but looking at it in the pics, it seems this way. This made me decide not to pursue cutting the small piece out and having a 3" piece welded on.

Also, I'm trying really, Really, REALLY hard not to do any personal modifications to this vehicle. I have a habit of getting made custom pieces a specific way. I just want to purchase parts I think will work and bolt it on for once. If I keep running into crap like this resistance will be futile.

@Myx I see what you are talking about. Do you think that it came from the manufacturer like that or is that a modification done by the previous owner?

 

[Myx]

@Myx I see what you are talking about. Do you think that it came from the manufacturer like that or is that a modification done by the previous owner?

@indexcow I have no idea! This is why I posted this up. There are people that have purchased the Injen exhaust. Maybe they can have some input on this. This is what I got so I take it that this is how it was made. I don't fault Injen though. I should've been more observant and try to look at the exhaust from all possible different angles before purchasing if this was a concern of mine. It just makes me more cautious on future purchases. Double cautious from anything from Injen.

One other thing! It also makes me wonder how a downpipe the size of the PRL Motorsports one makes power if the stock exhaust flange is smaller than it. And if it does make power, why doesn't it continue the trend if you make the whole exhaust 3" (or just bigger than the stock exhaust). You know what I mean? I am an 'it is what it is' type of person. And the dyno results were what PRL Motorsports got. It doesn't make sense but I leave making sense of things to the 'pros'. I just test stuff for the results.

 

[Shankmeyster]

Well you have to take tests with a grain of salt as no exhausts were actually tested and different setups will produce different losses or gains. Who knows because no outside source has done runs on any of the current exhaust setups in different configurations.

 

[ferdinand]

https://www.procivic.com/p/ym/2016/civic/injen-stainless-steel-exhaust-system.html?ctid=3038

if you look at the second close up pic, you can see the reduction myx is talking about on a new catback - so it looks like injen made it this way.

 

[Myx]

I have some interesting pics to post up later on today and a video or two. I ended up making a hybrid Injen 3" catback. There are a couple of things changed on this exhaust. The two main things are that the 2.388" piece I had cut off and replaced with a 3" piece. I apologize as I meant to take a picture of after I had this piece modified however you can see it in one of the video links I'll have posted. Also I had the Injen 'muffler' (Resonator in my book) replaced with a 3" Xcelerator muffler. It's a straight through design. I have the exact model number in the pics with pics of it from both ends and on the car. A made a quick video where you can hear it being revved in the shop. The exhaust note is very deep and subtle. No ricer drone or noise. The guys at the shop seem to love it as well and stated it doesn't sound like a Honda at all.

Also, the Injen's midpipe didn't exactly fit perfectly. The midsection was a little too far to the right (Looking from the back to the front). One of the rear bends came in contact with a heat shield in the rear. I have pics of it all. It all has been adjusted in corrected. Your experience may be different and I am just sharing mine. And warning others! I'm ecstatic because I take what I think works well and try to make it exactly how I like it. Others may want to just be bolting this on and be done with it (As it should be). Just sayin' it is possible you may run into that scenario.

Also, the exhaust was slightly too short to come in contact with the front pipe. I had this section modified so it would reach. I have the PRL Motorsports front pipe installed along with the downpipe. That's for another thread. But there was a 1" gap between the front pipe and the stock exhaust.
So instead of modifying my stock exhaust pipe, I went home and grabbed the 3" Injen exhaust to be modified and made to fit. I didn't like the Injen exhaust at this flange anyways and had plans to modify it so it all worked out. This gap was there with the 3" Injen exhaust and PRL front pipe as well. Oh....the issues. Just reporting! Don't shoot the messager. Will post more info, pics and probably videos later today.

 

[Myx]

Video of my Civic being revved with the 3" Injen Exhaust and 3" Xcelerator muffler. I apologize for the crappy sound quality when I got closer to the muffler. Never heard my videos sound like that before but it's not the muffler. It's a deep sound. Never raspy, sharp or droning. I have uploaded some pics of the Xcelerator muffler itself.

Here is an link example of how cheap this muffler is. For $43.00 at Summit Racing you could have one. Save yourself a buck or two on your exhausts. Xcelerator Muffler at Summit Racing

I took pictures from both ends of the muffler. Note how you can see straight through it and the holes inside are smooth, not protruding into the air path as it flows through it. This is the type of muffler I look for to have installed on all my cars.

 

[Myx]

Here are a couple of pics with the 3" Xcelerator muffler installed on the 3" Injen exhaust. It's not to bad.

The picture below is NOT my car. The picture is here to provide a visual to anyone that wonders why I had a 3" exhaust installed in the first place. Look at where the 3" PRL Frontpipe attaches to the stock exhaust pipe. From the large pipe to the small brownish exhaust pipe. This is how a large majority of people's setup is because they were told it is ok. I'm not one to argue. Just providing a visual for those that are curious.