Removed my resonator on Saturday

**Mattkins99** · 10-31-2005, 01:08 PM

figured I'd post this here as well as my BMW boards. :-)

I'm leaning towards putting a performance resonator back in, or maybe even a glass pack (sp?) but I've been told by a friend with a similar setup on his '99 540-6 to hold off a week or two as it will mellow out.

Let me know what you think
http://home.comcast.net/~atkins.m/im...r/WAVE0047.WAV

**BoyNextDoor** · 10-31-2005, 01:11 PM

does it give you any performace advantages?

**Mattkins99** · 10-31-2005, 01:43 PM

Originally Posted by BoyNextDoor

does it give you any performace advantages?

No. Just sound. I'm sure someone somewhere would argue less turbulace in the exhaust system will give you more HP... but I don't believe it. I mean you'd have to be driving a car with a weed eater engine to notice that type of power gain.

That said... it sure sounds more powerfull

**Wiredwrx** · 10-31-2005, 02:12 PM

Originally Posted by Mattkins99

No. Just sound. I'm sure someone somewhere would argue less turbulace in the exhaust system will give you more HP... but I don't believe it. I mean you'd have to be driving a car with a weed eater engine to notice that type of power gain.

That said... it sure sounds more powerfull

Well, the removal of any type of impedence in the exhaust system will provide performance advantages, HOWEVER, as you noted, they may be too small to be noticed by the "butt dyno". It is generally believed that at least 10 hp must be added before the "butt dyno" registers a difference, though I think that more is actually needed.

In your situation, you may have added a few HP you just can't feel it.

Michael

**Mattkins99** · 10-31-2005, 02:29 PM

ya, I don't think I'd notice the difference between 345 and 347 ft/lb torque.

That said, I do need to do another dyno... probably wait till spring though.

**gnomad** · 11-01-2005, 04:55 PM

Originally Posted by Wiredwrx

Well, the removal of any type of impedence in the exhaust system will provide performance advantages, HOWEVER, as you noted, they may be too small to be noticed by the "butt dyno". It is generally believed that at least 10 hp must be added before the "butt dyno" registers a difference, though I think that more is actually needed.

The "butt dyno" is never a good thing as it is *far* too easily decieved. Making your car sound louder is going to make it feel faster, even if the reality is that you've reduced power by mucking about with a very carefully tuned factory exhaust system.

I don't know too much about automobile exhaust tuning, but I do know a thing or two about runing one- and two- cylinder motorcycle engines. One of the things about a properly tuned exhaust is that you want the pipes set up in such a way that exhaust from previous cycles works to help "suck" exhaust from the cylinder. A lot of people think they get more power from simply chopping off the mufflers, but in reality, the power increase is purely a psychological effect from the sound.

If you are just out for the sound, hey, go for it. But I'll never understand why people go mucking about with exhaust mods for performance without having access to a dyno...

-p.

**Wiredwrx** · 11-01-2005, 05:22 PM

Originally Posted by gnomad

The "butt dyno" is never a good thing as it is *far* too easily decieved. Making your car sound louder is going to make it feel faster, even if the reality is that you've reduced power by mucking about with a very carefully tuned factory exhaust system.

I don't know too much about automobile exhaust tuning, but I do know a thing or two about runing one- and two- cylinder motorcycle engines. One of the things about a properly tuned exhaust is that you want the pipes set up in such a way that exhaust from previous cycles works to help "suck" exhaust from the cylinder. A lot of people think they get more power from simply chopping off the mufflers, but in reality, the power increase is purely a psychological effect from the sound.

If you are just out for the sound, hey, go for it. But I'll never understand why people go mucking about with exhaust mods for performance without having access to a dyno...

-p.

The motorcycle engine you worked with, were they 2 stroke or 4 stroke engines.

The tuning done by manufacturers is for sound and performance, adn of course, they have to consider the cost of the exhaust. Removing any obstacles (such catalytic converters) and bends increases flow velocity, decreasing backpressure, and causing performance advantages.

A good article can be read here http://www.nsxprime.com/FAQ/Miscella...austtheory.htm

Michael

**HHdesign** · 11-01-2005, 07:04 PM

I dont think you'd see any gain from this. You might have altered the pressure in the exhaust system which could lead to carbon build up. That being said, to feel a real differnce you need to replace all the exhaust, headers to the muffler, to see a significant differnce.

I wanted to feel and see a big differnce in my jeep's preformance, so I did a FIPK, New Throttle Body, TBS, Headers, Muffler, Chipped it, synthetic oil and lubes, and got some new spark plugs. Spent a good deal of money, but I see and feel a great differnce, and I get 4 more MPG, no joke.

Edit: Your car is badass and sounds great.

**Mattkins99** · 11-01-2005, 08:17 PM

Originally Posted by HHdesign

I dont think you'd see any gain from this. You might have altered the pressure in the exhaust system which could lead to carbon build up. That being said, to feel a real differnce you need to replace all the exhaust, headers to the muffler, to see a significant differnce.

I wanted to feel and see a big differnce in my jeep's preformance, so I did a FIPK, New Throttle Body, TBS, Headers, Muffler, Chipped it, synthetic oil and lubes, and got some new spark plugs. Spent a good deal of money, but I see and feel a great differnce, and I get 4 more MPG, no joke.

Edit: Your car is badass and sounds great.

Thanks.

I'd love to do a full exhaust (Headers back) but there is only one maker of headers for my car and if I remember right (I'm to lazy to look it up) they're about $3000. Um.... NO THANKS.

BMWs are great fun, but MY GOD are they expensive to repair and mod. And that's just the I6 versions. The V8s are even MORE expensive, and that's if there's even a tuner out there making stuff for them.