[RPEker]

I know this has been covered in great depth on this forum but I though I would say how happy I am with the result! Not quiet, not loud, just right!

[Zoog]

Interesting tip choice

[Ruddigger]

Originally Posted by Zoog

Interesting tip choice

I agree, but I don't think it's bad. Props for doing something different with the tips. A muffler delete sounds great, in my opinion, until you do headers.

[Twoforty]

Drone??

[RPEker]

Originally Posted by Zoog

Interesting tip choice

I like it. It fills the space nicely but is a bit different than the standard 2-pipe setup.

Originally Posted by N52B25

Drone??

Little to none below 55 mph and none at all at highway speeds.

[hongsc]

Sound clip? Reminds me of a 320.

[Pixel8ed]

Keep debating on doing this. But don't want it to loud as it's the daily commuter. Anybody near DC that has this done that I can check out?

[Dan Bilzerian]

The tip looks a little ricey in my opinion.

[Camman]

I think it would have been ricey if he did the dual tips that go out and stick up like this



I think his looks a little classier. Though, I would have stuck with traditional tips.

[hassmaschine]

Originally Posted by Dan Bilzerian

The tip looks a little ricey in my opinion.

it's a muffler delete.. it's like pushing a bolder uphill.

[STR8-6IX]

just because something sounds good, does not mean its good for your car. you need a bit of backpressure for the engine to run well. the best option is to delete your secondary cats and add a high flow muffler.

[STR8-6IX]

Originally Posted by Pixel8ed

Keep debating on doing this. But don't want it to loud as it's the daily commuter. Anybody near DC that has this done that I can check out?

I recommend you delete your secondary cats.. the gains will be exactly the same but without the ricey un muffled sound..

[Blueeyesredpanda]

Thats a 320i tip LOLL

[3002 tii]

Originally Posted by Camman

I think it would have been ricey if he did the dual tips that go out and stick up like this



I think his looks a little classier. Though, I would have stuck with traditional tips.

Ironically those tips are dtm style

[desertman123]

Originally Posted by 6IX-F10-N52

just because something sounds good, does not mean its good for your car. you need a bit of backpressure for the engine to run well. the best option is to delete your secondary cats and add a high flow muffler.

"backpressure" is nonsense

[STR8-6IX]

Originally Posted by desertman123

"backpressure" is nonsense

I wouldnt say so entirely.. Its useful for cold starts and for producing low end torque, although you dont need it once you start to rev her out.. I think a muffler delete on an NA car isnt good though

[desertman123]

Originally Posted by 6IX-F10-N52

I wouldnt say so entirely.. Its useful for cold starts and for producing low end torque, although you dont need it once you start to rev her out.. I think a muffler delete on an NA car isnt good though

We agree that the purpose of an exhaust pipe is to carry the gases away from the engine, right? And also the faster an engine spins, the faster we need this gas to move out of the pipe to make way for new gas being emitted.

So why would back pressure be good then? Short answer - it wouldn't.

What we're trying to do is maximize exhaust gas velocity - so we do this by minimizing back pressure. The higher the velocity, the better scavenging we get for the next exhaust pulse (because fast gas = .

Where 'back pressure' comes from is when people increase their exhaust pipe diameter. Doing this decreases back pressure, but also decreases gas velocity. Think of it like your garden hose, when the water pressure is all the way on, the water at the tip will just flop out, but if you stick your thumb over half of the nozzle, now the water is spraying at a higher speed.

Decreasing exhaust velocity decreases performance, so that's why you'll hear people say they lost some 'bottom end power' when they upgrade their exhaust. The scavenging at low RPMs sucks because there isn't much volume of gas, nor is it flowing very fast. But once the RPMs increase, scavenging improves. Here's also why an exhaust pipe might be tuned for high RPM (like in a race car).

So in conclusion, it's not back pressure that you want, but rather to maintain sufficient exhaust gas velocity throughout the RPM range.

http://www.gomog.com/allmorgan/exhaustbackpressure.html

Check that out, it elaborates on what I explained but better.

On top of everything, you still have 4 cats and a resonator. That's still plenty of restriction.

Sidenote: I don't want this to sound condescending or anything, I just tried making my explanation easier to follow.

[STR8-6IX]

Originally Posted by desertman123

We agree that the purpose of an exhaust pipe is to carry the gases away from the engine, right? And also the faster an engine spins, the faster we need this gas to move out of the pipe to make way for new gas being emitted.

So why would back pressure be good then? Short answer - it wouldn't.

What we're trying to do is maximize exhaust gas velocity - so we do this by minimizing back pressure. The higher the velocity, the better scavenging we get for the next exhaust pulse (because fast gas = .

Where 'back pressure' comes from is when people increase their exhaust pipe diameter. Doing this decreases back pressure, but also decreases gas velocity. Think of it like your garden hose, when the water pressure is all the way on, the water at the tip will just flop out, but if you stick your thumb over half of the nozzle, now the water is spraying at a higher speed.

Decreasing exhaust velocity decreases performance, so that's why you'll hear people say they lost some 'bottom end power' when they upgrade their exhaust. The scavenging at low RPMs sucks because there isn't much volume of gas, nor is it flowing very fast. But once the RPMs increase, scavenging improves. Here's also why an exhaust pipe might be tuned for high RPM (like in a race car).

So in conclusion, it's not back pressure that you want, but rather to maintain sufficient exhaust gas velocity throughout the RPM range.

http://www.gomog.com/allmorgan/exhaustbackpressure.html

Check that out, it elaborates on what I explained but better.

On top of everything, you still have 4 cats and a resonator. That's still plenty of restriction.

Sidenote: I don't want this to sound condescending or anything, I just tried making my explanation easier to follow.

what you're saying makes sense, but I think the first step to reduced backpressure is removing the cats (secondary and also primary if you can) then, I would upgrade just the muffler. this is how i would go about it anyway

[desertman123]

Originally Posted by 6IX-F10-N52

what you're saying makes sense, but I think the first step to reduced backpressure is removing the cats (secondary and also primary if you can) then, I would upgrade just the muffler. this is how i would go about it anyway

I'd agree on that, AA catless headers I hear has a great improvement in sound but not so much volume.

[STR8-6IX]

Originally Posted by desertman123

I'd agree on that, AA catless headers I hear has a great improvement in sound but not so much volume.

true, ive recently deleted my secondary cats. the engine and exhaust sound is very nice even with stock muffler. I will be eventually upgrading my muffler. any suggestions? Eisenmann perhaps? I think no muffler is not the best route. I've gotten the same gains, especially in the high end getting rid of the sec. cats with no where near the same amount of sound volume. I think this, along with a good high flow muffler would give you better gains. not to mention a sound appropriate for a sonorous I6 packaged in a sleek body..

[alx.]

I don't like the tips, but i'm going to try this soon also