Angled Can

[SSonic]

I know this many sound a tad "ricer" but I actually like the look of an angled muffler as you see on quite a bit of STIs, Evos, MS3s, etc.. Has anyone done this on their Sonic with a custom exhaust yet. Also, Im curious if this is possible with the small outlet cutout on the rear bumper. Feedback is appreciated....thanks!opcorn:

 

[Eric Smit]

It's not just the muffler that is bent, there is apparently performance merit to it.

http://www.d-series.org/forums/general-tech/105069-theory-behind-angled-exhausts.html


-Eric Smit

 

[gotboost]

the less the bends the better the flow. thats why all EVO model except EVO X have them designed that way.

 

[CoHPhasor]

It's not just the muffler that is bent, there is apparently performance merit to it.

The Theory Behind "Angled" Exhausts - D-series.org


-Eric Smit

Of course there is, the POSSIBILITY for it to be a good thing.
The question is, is that the case for the Sonic?
"As few bends as possible" is the goal, like I've said before, intake and exhaust, the less bends the better.
(AS I'm sure most know already)

 

[keto06]

It's not just the muffler that is bent, there is apparently performance merit to it.

The Theory Behind "Angled" Exhausts - D-series.org


-Eric Smit

Best link ever posted on this board.

 

[mitdr774]

Unless you find a way to route the exhaust straight under the axle I dont see any flow restriction in teh exhaust being eliminated vs upsizing and routing the same as factory. Most of teh cars that you see with an angled muffler have independent rear suspension and can route the exhaust fairly straight.

 

[laborsmith]

So I measured (not perfectly but close enough for me) and there is about nine inches to the bottom of the rear axle beam. Now my exhaust is about 2.25 inches as it passes over the beam and there is about 3+ inches from the top of the beam to the bottom of the exhaust. If one runs the exhaust on an angle under the beam, it looks like there will be about 3.5 inches from the ground to the bottom of the exhaust. My front air dam (less than 4 inches) already scrapes sometimes.

Now I am on lowering coils so that means the rear beam is closer to the ground than otherwise, BUT, I also have the equivalent less travel, so I suspect overall my conclusion would apply to HB Sonics in general.

If I only drove on smooth roads or if I only used the Sonic at the racetrack, it would seem to me the angled exhaust would be a viable alternative to a side exiting exhaust, either method of course doing away with both cats to get the freest flowing exhaust possible.

Laborsmith

 

[Preloader]

About 3.5" clearance from ground to BOP for 2.25 exhaust.
Thanks for the dimensions LS. Is that a hard measurement? Or a thumb/pinky/eyeball kinda estimate?

 

[laborsmith]

I used my tape measure, but I was reaching the length of my arm, as I was in the driveway. So it was more than an eyeball but not as good as if I was standing right there.

Laborsmith

 

[Machine]

I think you could run an exhaust under the axle with minimal problem. as this is obviously center with the wheel, the exhaust would rise up and over anything It might scrape on. This excludes any object that would be narrower than the cars track width.

IMO, the Ideal exhaust (for a factory turbo) would be 2.5 from the turbo back. straight under the rear beam and out the center of the bumper. you could even possibly route the front pipe under the steering gear and subframe, but this would create noticable clearance loss on the front.

but i think we're splitting hairs here compared to a properly designed and bent system.

 

[laborsmith]

I too think we are splitting hairs as there is a nice power bump just going from 1.875 to 2.25 and deleting the muffler.

I don't know about running through the center as that would bring the pipe under the fuel tank, which I understand is illegal in some places. Also, I do not recall if the heat shield goes that far. I know I would not want an exhaust pipe near an unshielded fuel tank.

Laborsmith

 

[Eric Smit]

Fun fact: the fuel tank has a heat shield under it.

Some exhaust wrap from autozone/O'Reilly's solves that concern.


-Eric Smit

 

[laborsmith]

Partially under it.

I can't see heat wrap being as effective.

And I am not about to find out.

Laborsmith

 

[Eric Smit]

Well, I'm about to wrap mine anyway, for peace of mind.


-Eric Smit

 

[CoHPhasor]

I too think we are splitting hairs as there is a nice power bump just going from 1.875 to 2.25 and deleting the muffler.

2.5" Sees a gain and you'll definitely see a gain from going bigger still.
Less restrictions (ie; cats, downpipe, muffler) will all improve power but you'll still see more by a proper 3" system, guaranteed.

 

[laborsmith]

No dispute that there are gains from a larger freer flowing exhaust system; the question in my mind is how much the drivetrain (transmission) can handle. Travssonic believes the clutch is the weak point and has pictures posted to support his point. I suspect that in addition to the clutch, the limitations of the M32 itself has to be of concern. We are already exceeding 220ftlbs at the wheel on a tranny rated at up to 234ftlbs at the crank.

Does anybody on the forum have access to info that can be shared about the F40? (weight, size etc. compared to the M32) I have found some info but not the kind that would indicate a direct drop in to be feasible, notice I said feasible, not possible.

Laborsmith

 

[CoHPhasor]

^ I agree, the transmission is a failure point.
But either way, if you have the free-slowing exhaust/intake setup your spool will be so smooth and early that it alone will be satisfying.

Your mpg will benefit, the turbo won't be working as hard, and temps will go down.

There's no downside.
Transmission won't handle max power? Then don't tune it to the moon, the early spool makes the car fun enough to drive that peak power isn't needed.

 

[sx sonic]

Has anyone tried a side exit exhaust in front of the LR wheel?

the bend after the resonator already angles the exhaust right in front of the wheel!!
It would eliminate 3 or 4 bends! Only problem I could see is road clearence, and requireing some additional heat shielding to protect the paint and parking brake cable.

-tyler