**Changed to Myxal Reduced Diameter Exhaust on 10-10-14**

Went to Meineke earlier to take a look at my stock muffler and decided to change it out immediately. I like the stock exhaust in general but the muffler needed to go. The piping going into the stock muffler is approximately 1.75". The Flo Pro Max muffler I had installed is 2" in and 2" out. I decided to keep the stock exhaust piping diameter reasonable to keep sound levels in check and to not impact exhaust flow velocity too much. After having the Flow Pro Max muffler installed and driving around for a bit, it sounds no different than stock which pretty much shocked me. I mean, NO different.

I'm expecting a small hp/torque gain from this modification. Why? The stock muffler's flow is not straight through. The best way for me to describe it is from my horrible picture that I drew up. Look at this -->

The arrows are an indication of the air flow going through the stock muffler. As I was trying to look through the muffler, the piping did not go straight through. The air flow has to stop, make two 180 turns before coming back out again. It's silly! I've had good results from changing out to a straight through muffler on my cars so I do not see this Fit as being any different.

Here are some pics.
The box the Flo Pro muffler came in.




Stock muffler up top and 2" Flo Pro bottom right



Stock muffler on the Left, 2" Flow Pro on the Right



1.75" Stock Muffler on the left, Flo Pro Max on the Right



Stock muffler inlet. Look closely! Notice the metal at the end of the tunnel?

That is where your exhaust gases will come crashing down at. It needs to make a 180 turn (some going through the small holes) and go into the piping beside it (inside the muffler) before coming back out. This is not smooth flow.

Now look at the Flo Pro Max piping inside.


Notice the light at the end of the tunnel? Your exhaust flow will like this. No restrictive bends or turns to slow down your exhaust velocity. There has to be some gains here, no matter how small.



This is all for now. Just wanted to share. I'm off to work.

 

Looks good. Any sounds clips per chance? I'm sure it must give it a little different tone.

 

I did have before and after clips but it wasn't worth posting because they both sounded the same. So I deleted them. Really, it wasn't even worth posting up. I'm actually wondering if a straight pipe would be suitable for some folks.

 

Have you tried running it without the muffler?

 

No I haven't! I'm getting old and don't want it to be any louder than it was (which was sounding like stock). Needless to say, this setup is now history.

I have since moved on to a new setup with sound clips. It is louder than stock now. Here --> Myxalplyx Reducing Exhaust Diameter

 

**Update 4/6/15**

Will be adding this muffler back on. It will be put back on in addition to a 2" J's Racing B-pipe (If it fits) and 2" J's Racing Cat delete. It should be an excellent 2" combination with (I'm hoping) not to loud sound. I'm also hoping that it doesn't somehow choke off the top end since the CVT is all topend during wide open throttle. Testing should be interesting! Hoping the 'B' pipe comes in this week, installation and a possible 1/4 mile run if the rain holds out (rain is forecast to Tuesday, Wednesday, Thursday, Friday and Saturday....all possible track testing days). ~~Reflashed the ECU with Ktuner back to stock cam settings from a Cam 40 profile earlier this week. This is looking to be very promising. Was testing cam settings for about 2 months. Stock actually looks best but need to test it out. Haven't been able to hit low 15's since toying with the cam settings.~~

Shooting for two high 14 second 1/4 mile runs naturally aspirated and hoping to hit a trap speed of 91-92mph. May as well reach for the stars!

(BTW: I do these posts to help track my own progress to know what changes I have made when comparing 1/4 mile tickets and datalogs from street & track. I still reference changes done from last year by referring to posts like these and comparing personal notes.)

 

What 1/4 mile numbers were you hitting stock?

 

17.1-17.2@82mph

 

**Update 4/24/15**

I'm about to head out to the track. About 2hrs earlier, I had the inlet and outlet to this 2" muffler modified. It was just fine with the stock 1.65" piping on the inlet side and the smallish piping on the exhaust side. Even still, thoughts of restriction kept cropping up in my mind. So I had the small outlet pipe cut off and a 2" put on. On the inlet side, I had the stock 1.65" piping removed for a crush bent 2" pipe.

As it sits, the exhaust is as follows:
J's Racing Circuit Coverter (Cat Delete) 2"
J's Racing B-Pipe - 2"
2" Flo Pro Max muffler (Inlet and outlet pipes are now 2" instead of 1.65" inlet/outlet)


It may or may not have made a difference. Who knows! That's why we test!

BTW: Despite the cats being gone and only a resonator in place, the exhaust still sounds relatively quiet. My wife could not tell any change in the exhaust. Sounds pretty much the same (AKA...unexciting, nothing to see/hear here, blah..blah). Yes...you'll never notice me driving by you. Interesting! I'm still waiting for my 2" J's Racing SUS muffler to arrive from Japan. It may be another month and a half or so. So.....we'll make the best of what we have. I don't expect it to perform any better that this setup to be honest. And if it doesn't but is significantly louder, I can simply install this back on and sell it. We'll see!

I'm off to the track.

 

4/24/15 Cecil County Dragway
Outside Temp 54F

I did 5 runs. Here were the results -->

15.391@90.53mph
15.503@90.76mph
15.415@90.09mph
15.567@89.70mph **Was trying a different way of launching**
15.501@90.22mph

I'm satisfied! The car was running back to back 90mph trap speeds. It's making good power. It's quick for what it is for getting in the 15.4-15.5 over and over again. I really can't complain!

I'll install the 2" J's racing muffler when it arrives. I'm really not expecting any performance gains since the Flo Pro Max muffler has straight through piping pretty much. The only extra improvement I can see is the piping between the muffler and the 'B' pipe. It has a small crush bend so the diameter of this section being widened to 2" may make a difference. As it sits, our little cars can move. And I was getting 40.4mpg on the way home to boot.

Here's some footage from tonight.

After reviewing the runs I did tonight, something has changed significantly. My timing advance was retarded on all my runs by two degrees. It has always been pegged at 15.5 degrees. All my runs the timing went down to 13.5. I made changes last night to my intake but I tested it on an empty road several times and my timing stayed pegged at 15.5. The only thing I did different is the modification to the exhaust that I listed above. I may have to run some tests for knock. Also, my air/fuel ratio went up to 13.5 or so. It usually stays at 12.5:1 or less. Both of these took place with only changes to this exhaust. Even my 2.5" crush bent piping exhaust didn't do this. Looks like I have more homework to do. Something is not quite right.....or too right and I need tuning.

 

**Update 4/25/15**

I think I may have found out what the problem was. The coupler that is connected to the outlet of the maf sensor was loose. This appeared to have been letting air into the throttle body, after the maf sensor. This would explain why I was running as fast as I was with leaner air/fuel ratios but my maf sensor grams per sec (g/s) was reading 10-15g/s less than it should have. I was expecting the maf sensor g/s to read somewhere between 105g/s - 109g/s. I'll be doing some more tests tonight to be sure it is tight and that the maf sensor is reading all the air going through it. I should've caught this at the track but I never review the runs until I get home. Losing at least 2 degrees of timing is pretty significant to me. Will see if I get it back tonight.

 

That makes sense, glad you found the culprit. thanks for the updates.