3.3TT Stock Exhaust Pic

[Kamauxx]

That is interesting. The workers at the muffler shop were talking about that same article, but I was already in possession of my Borla. I don't know the physics of it all, but wanted more sound, I got MORE.

It'll be a while before we know which systems are best, we will make wrong choices, or more likely often choices would be different later. Is part of it. Not the last wrong decisions I'll make

Well to be clear there are other restrictions in the stock exhaust. That crimp, the resonators, cats, and I'm sure the mufflers are all areas the aftermarket exhaust guys are improving on.

That post was speaking specifically about the crimp because at one point in time I was considering having a shop weld in a round piece in the place of it .

 

[JohnG7]

Whats the length of the body of the resonator? Looks like the tapered ends are maybe 1.5 inches on each sides?

The body diameter is 3.5"O.D. , the full body is 12" to start of taper. The hot end diameter mics at 2.6" O.D. where the cold end mics at 2.36"O.D..

OEM Hot end pipe looks 2.25", 2" cold end. Between 1.5-2" of taper, it varies with different inlet/outlet diameters.

 

[Kamauxx]

The body diameter is 3.5"O.D. , the full body is 12" to start of taper. The hot end diameter mics at 2.6" O.D. where the cold end mics at 2.36"O.D..

OEM Hot end pipe looks 2.25", 2" cold end. Between 1.5-2" of taper, it varies with different inlet/outlet diameters.

Perfect, thanks a bunch!

 

[JohnG7]

Perfect, thanks a bunch!

Anytime

I really wanted to get rid of the crimp. In my old way of thinking, restriction is bad. I'm lost I guess

 

[JohnG7]

Well to be clear there are other restrictions in the stock exhaust. That crimp, the resonators, cats, and I'm sure the mufflers are all areas the aftermarket exhaust guys are improving on.

That post was speaking specifically about the crimp because at one point in time I was considering having a shop weld in a round piece in the place of it .

I studied the pics, every pic I could find of this OEM exhaust and the aftermarkets as pics were released, almost settled for having the work you mentioned done- that crimp just doesn't look right to me. Ended up getting the Borla, it's ok, it's louder.

BUT IF I was going to do it again, I'd buy a set of Varex xforce (1in/2 out) 2.5" mufflers and have a shop custom build a 2.5" axle-back setup.
I'll leave this alone now. The Varex can be adjusted. If you want noise, you got it. If not, no noise.

Edit-> Duh, I went back looking at the pics in post #8 of this thread. The last pic in that post shows a varex setup laying in the middle.

 

[Sarge2070]

Honestly, At this point I go back and forth on the Borla Exhaust. One the one hand, it sounds really excellent on hard acceleration and when slowing down it has a really cool rumble. On the other hand, when cruising at highway speed there is some minor resonance roughly between 2000 RPM and 2200 RPM. It is not awful, and can be somewhat mitigated by gradual changes in throttle pressure but from what I am hearing from various sources this is really common in after market exhausts on all cars. I guess if you want a quiet ride you really should stick with the stock exhaust. If you want a more aggressive sound you are probably gonna have to make some minor compromises. I covered my trunk under the floor with sound deadening mat. That has helped a little... very little actually. Next I am gonna try some exhaust baffle inserts that fit into the exhaust tips. Shouldn't have to mess around like this but it is a cheap fix if it helps. Supposed to soften resonance. We will see. If that doesn't work I am gonna sit it out with the Borla as it is until something seriously better comes along. Magnaflow looks like a decent logical build, ( Straight through flow design, resonators in the two mid pipes and anti drone resonator connected directly to the mufflers. From clips sounds a lot quieter but still nicer than stock IMO.

 

[Sarge2070]

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[Kamauxx]

One thing we can learn by looking at the pics of the stock downpipe is there's probably no reason to swap them out for say a $600+ Jun Bl.

There doesn't appear to be any restrictions that can be approved upon by an aftermarket 2.5" downpipe.

I think the only way that a 2.5" aftermarket downpipe can improve on the stock one is by deleting the cat. But a cat delete can probably be done for under $100 instead of paying over $600.

I would be interested in hearing what the stock exhaust sounds like with an aftermarket resonator deleted midpipe.

 

[Kamauxx]

thanks bro. did a quick search as i supervise the preppers

Holy crap! I just came back and re-read some of this and I finally understand what your avatar is all about.

 

[Weareblondi]

Hahahaha. One of the members asked me why I would show weapons as an avatar, so I added live to cook, cook to live. But it doesn't show up well enough. Sigh. Working on a new one.

 

[Kazz]

Hahahaha. One of the members asked me why I would show weapons as an avatar, so I added live to cook, cook to live. But it doesn't show up well enough. Sigh. Working on a new one.

Nah, let them stress out. Not your fault if they can't think for themselves beyond some kind of visual trigger.

 

[jdogonroad]

I think its cool as it is.

Hahahaha. One of the members asked me why I would show weapons as an avatar, so I added live to cook, cook to live. But it doesn't show up well enough. Sigh. Working on a new one.

 

[Rey]

The big issue with any aftermarket exhaust is "drone", which seems to occur 1000-2000 rpm at light throttle (cruise). My experience with Magnaflow on Hyundai V8 was an annoying drone. I resolved this by adding Dynomax VT mufflers, which unfortunately are discontinued. These VT mufflers had a spring-loaded internal flap - exhaust went through several chambers on light throttle (virtually eliminating drone); and on full throttle flap opened to a straight-though design. This same basic muffler design is used on Jaguar XK mufflers.

 

[eflyguy]

Some aftermarket motorcycle exhausts have weird chambers of different lengths "sticking out" from the mid-pipe, that are specifically designed to reduce resonance at certain frequencies - drone, as we say. I would think that kind of approach would work just fine on a car exhaust system as well..

 

[Kamauxx]

Some aftermarket motorcycle exhausts have weird chambers of different lengths "sticking out" from the mid-pipe, that are specifically designed to reduce resonance at certain frequencies - drone, as we say. I would think that kind of approach would work just fine on a car exhaust system as well..

Those are probably branch resonators. I learned a lot about them today. They're supposed to be very good at reducing or eliminating unwanted frequencies (drone).

 

[jdogonroad]

An apt description of bagpipes.

 

[Sarge2070]

The ARK Grip exhaust has the Helmholtz resonators like that.

 

[Kamauxx]

The ARK Grip exhaust has the Helmholtz resonators like that.

Thermal R&D and some of the Jun BL systems do too.

 

[Dark_Knight GT]

The ARK Grip exhaust has the Helmholtz resonators like that.

It does, but these do not eliminate drone when cruising at highway speed. Comparatively, there’s no drone at the same RPMs at “city” speeds.

 

[Kamauxx]

It does, but these do not eliminate drone when cruising at highway speed. Comparatively, there’s no drone at the same RPMs at “city” speeds.

Are you speaking specifically about Ark's catback or about branch resonators in general?

I know StingerGTandme said his Ark drones a bit at hwy speeds. Hopefully that isn't the case with ALL exhausts using branch resonators since I just bought a Thermal R&D catback specifically because they focused so heavily on eliminating drone (and because it isn't conversation/music killing loud).

@Thermal is there a certain range in the speed/RPMs where drone should be expected with your catback or have the resonators been used to effectively eliminate the drone completely?