Drive Accord Honda Forums banner

DIY: Installing a Magnaflow Cat-back Exhaust (EX-L V6)

74257 Views 147 Replies 40 Participants Last post by  Marou017
How To: Install a Magnaflow cat-back exhaust on a 2008 or 2009 EX-L V6 Coupe.

This process is done to replace your OEM dual exhaust with an aftermarket high-performance exhaust. While these directions specifically discuss a Magnaflow brand cat-back exhaust, I would imagine they can be duplicated to install almost any after-market cat-back system.

Approx. Installation Time: Less than one hour (if using a hydraulic lift). This is a simple plug-and-play type installation.
This can be completed with a floor jack and jack stands but will significantly increase difficulty and duration of installation.

Things You'll Need:

  1. Hydraulic lift or drive-on lift stands
  2. 10mm Socket
  3. 14mm Socket
  4. 15mm Socket
  5. Socket Wrench
  6. Mechanix Gloves or similar
  7. Someone to help you
  8. All OEM rubber flanges (do not discard yours)
  • Like
Reactions: 1
1 - 20 of 148 Posts
Step 1: Removing the OEM Exhaust

Step 1: Removing the OEM Exhaust

I completed this section of the installation by working from the catalytic converter backwards towards the mufflers. You will need at least one person to help you throughout the course of the installation to hold the exhaust in place while you remove and re-install the exhaust pipes. I would highly recommend you and anyone helping you wear a pair of Mechanix gloves or similar because the pipes will be hot, especially around the cat, and you may cut yourself (like I initially did) handling metal with sharp, machine-cut, edges.

  • Using the 10mm Socket, disconnect the negative battery lead from your car battery. This will automatically reprogram your car's computer with the Magnaflow installed when you reconnect it at the end.

  • Using the 10mm Socket, start by removing the 4 nuts securing the catalytic converter heat shield.

Auto part Automotive exhaust Exhaust system Suspension part Pipe

  • Use the 14mm to remove the 3 nuts connecting the down-pipe to the cat.
Auto part Tire Automotive wheel system Automotive tire Brake

  • Remove the rubber flange securing the forward-most section of the exhaust pipe.

  • Work your way down the exhaust pipe, using the 14mm socket to unbolt the pipe from from the mufflers. (This step is optional. You don't have to remove the mufflers from the down-pipe to uninstall the whole exhaust, but you may find it easier to manipulate in terms of weight and space.)

Auto part Pipe Wheel Vehicle

  • Remove the mufflers from the rubber flanges attaching them to the underside of the car. There are two for each side.

Auto part

At this point, the entire OEM exhaust system from the catalytic converter back to the mufflers should be removed. Time to install the Magnaflow! :banana:
See less See more
Step 2: Installing the Magnaflow Exhaust

Step 2: Installing the Magnaflow Exhaust

Work again from the catalytic converter backwards toward where the mufflers will be. Do not fully tighten anything until the entire exhaust is in place so that you can correctly position/align the pipes. The metal clamps that came with the Magnaflow exhaust require the 15mm socket to tighten.

  • Connect the down-pipe portion of the Magnaflow to the catalytic converter.
Automotive exhaust Auto part Exhaust system Muffler Catalytic converter

  • Attach the Y-pipe of the exhaust to the down-pipe, making sure to put one of the three metal clamps that came with the Magnaflow around the down-pipe.

  • Someone will have to hold the Y-pipe of the exhaust while you attach each muffler to it, using the remaining two metal clamps provided by Magnaflow.
Automotive exterior Pipe Auto part Bumper Vehicle door

(Say hi to Tim, the one with the garage and hydraulic lift in it.)
  • Attach each muffler to the underbody of your car using the OEM rubber flanges from the OEM exhaust.
Bumper Automotive exterior Auto part Glass Metal

  • Securely tighten all nuts and bolts, including the metal clamps connecting the down-pipe and y-pipe.

  • Re-install the catalytic converter heat shield and double check all connections.
Automotive exhaust Auto part Exhaust system Vehicle Tire

In reality, this installation takes 4 broad steps. Raise the car, remove the OEM exhaust in one piece from the cat to the mufflers, install the Magnaflow down-pipe, y-pipe and mufflers, and lower the car back down. It took my brother, Tim and myself about 30 minutes to complete this installation.

There ya go!
See less See more
Thoughts, Review, Pix

Here are just a couple snap shots of the Magnaflow muffler tips. I didn't take before and after shots because you all have/had OEM muffler tips and probably know exactly what they look like. Here are the new ones:
Land vehicle Vehicle Car Automotive exhaust Bumper

Architecture Vehicle

Automotive exhaust Auto part Exhaust system Alloy wheel Wheel

I did a couple drive-bys and neutral-rev sound clips but the camera didn't pick the sound up very well for whatever reason. I am going to try again with a different camera in the next couple days and hopefully capture something with better quality.

This is my first vehicle with an after-market exhaust installed and my initial reaction is largely positive.

Looks: As you can see from the pix above, the Magnaflow looks really good (IMO). The tips are not very large, certainly no larger than the OEM tips, but they have a wider mouth (mainly due to the thinner lip). I really like that the tips don't stick out at all past the bumper. They're tucked nicely up underneath like the OEM tips were. And of course they're uber clean right now, which makes those babies shine!

Sound: Just starting the car up, the exhaust is noticeably deeper and resonates in the cab more. Accelerating at a reasonable speed will result in some drone between 1000 and 2500 rpm, which I wasn't really expecting. It's not bad per say, but it might annoy some of the more fickle Accord enthusiasts. If the engine is under load and stays in that range, like going up a slight hill for example, you will get a constant tone. Opening the car up creates a nice rich and deep tone that sounds really good. One of the best parts, however, is when you're just cruising along between 45 and 65mph. The exhaust sounds no different from our OEM system - it's virtually silent. It's not until you accelerate to pass someone, change lanes, or rip it past some goof-ball [insert compact-class coupe; i.e. Eclipse, Altima, RX-8, A4, S40, tC, etc,) that the Magnaflow makes itself heard. It doesn't sound ricey or fart-pipe-ish. It's more of a deep buzz or hum than anything else.

Neutral Revs - In my driveway
Drive By - About 40 mph
Revving then Coasting between 20 and 40mph - Good representation of lower tone
0 to 40mph and 45 to 55mph Hills - Good range of tone
Engine Under Load between 40 and 60mph - Crusing with various pedal pressure
Full Acceleration from 10 to 75 mph - Vroom. Intake is actually louder than exhaust
Windows Up (In-Cabin) 30 to 45mph - Windows close at 7 seconds, tone from inside cabin

Performance: Nothing really definitive yet. The dyno will be the true demonstrative factor. Out the gate, I couldn't really feel a change in power. Granted, I didn't get the car above 60mph so it's impossible to tell what affect it will have when I'm really pushing the car. No change in pick-up speed, that's for sure. I do think that when I was accelerating very quickly from 30-60, the Magnaflow helped, but it could have just been placebo affect too. I can't wait to pair this exhaust with my CAI however. Then we can really talk performance!

That's all I got for now DA Denizens. Stay tuned for sound clips and drive-bys to be posted on Youtube and linked here.

Happy According,

See less See more
Thanks again for your wonderful DIY write-up! I can't wait until you write one for the TSX anti roll bar :notworthy
Great write up!
Thanks guys.

Update: On my way in to work today, I really pushed the car. Between 60mph and something much higher :naughty: the exhaust really rips and I can feel a difference in acceleration. There is less of a bottleneck feeling when you stomp the gas. The car just picks up and goes. I'm liking this mod more and more by the minute. :thmsup:
I might have missed this info but could you reiterate the exact part number and cost?

Nice write up, and great pics of the system.

Product ID #: 16817
Product Name: 2009 Honda Accord 3.5L Coupe Dual Rear Exit Cat Back Exhaust System Magnaflow (#16817)
Product Price: $670.81
Quantity: 1

SubTotal: $670.81
Shipping: $0.00 (Free Shipping)
State Tax: $0.00
Grand Total: $670.81
would u put up a video so i can hear it, thanks in advance
Thanks man! That was great! can't wait for the video's.

Kinda disappointed to hear about the drone sound though. I really wanted to avoid that at all costs.

I think i'm going to end up having to stop at the CAI and not go to an exhaust afterwards.

When you post vid's it would be great if you could also post some 'in cabin ones'

I know it'll be pretty difficult to determine differences between oem and aftermarket on an in car cam, but I'd still like to see what kinda sounds it makes.

One question though--- Have you ever been in a stock 350z or G35/G37 coupe?

The sound of thier OEM exhausts are what I really wanted, something nice under accelleration but almost nothing in the interior unelss you're really accelerating.

thanks in advance...
See less See more
Excellent DIY. I think it looks great. Exactly what I'm looking for. Thanks for doing these DIYs. They should help a lot of people out including myself. What are the chances of you doing a DIY for the TSX rear swaybar?
Can't wait for vids! Get one on the dyno if you can!
Excellent DIY. I think it looks great. Exactly what I'm looking for. Thanks for doing these DIYs. They should help a lot of people out including myself. What are the chances of you doing a DIY for the TSX rear swaybar?
Can't wait for vids! Get one on the dyno if you can!
You buy me the bar, I'll install it and do a write-up! :thmsup: Lol.

It's on my To-Do List of mods. I'm just not convinced it's really going to benefit me that much since I've already installed Eibachs and don't plan on track-racing the car. I'm eventually going to do it, it's just not a priority at the moment.
Nice pics and really looking forward to the video clips with sound. How does it sound at 75mph? you said between 45 and 65 it sounds stock. Are you driving a manual or Auto. Reason I ask is because at those speeds in an Auto it probably shifts to 5th so you've got really low load rpms. At 45 I might be in 4th in my manual and that could be a little loud. Also, when I use the handsfree in the car on the highway at 75mph high way speed i wonder if it will be too loud, in my civic it definately was. Your comments are appreciated.
man great write up!!!! i hope you will do the same for the TSX sway bar..cuz i want that too!!!!..this exhaust looks sicks....i hate the big ricey cans that have been put out for our car so far...these tips are perfect. I cant wait for the sound clips!!!
Are you driving a manual or Auto. Reason I ask is because at those speeds in an Auto it probably shifts to 5th so you've got really low load rpms.
His sig says auto

One question though--- Have you ever been in a stock 350z or G35/G37 coupe?
That's what kind of sound I would like too... nothing too loud, annoying, ricey at all. Even at 24-25 I feel like I don't need the extra attention of a loud exhaust ... yeah, must be getting old.

And I love the way the exhaust looks from the back... love round tips!
Looks good!
any sound clips yet!!!???
1 - 20 of 148 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.