Anyone did straight pipe yet?

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08-14-2006, 09:23 PM

#11

Nutty Professor

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My Ride: 630i, H&R Springs, PSS9 coming, H&R ARBs, Sprint Booster, Eisenmann Quad, HAMANN Pedals, M6 Rims/Advan Sports...

Yes and No, as the Reasonator creates more back pressure for the Exhaust gas to flow, instead of free flowing all the way to the Back box, whereby, there's too little back pressure to generate any low end power...
Maybe u can try... where your current Reasonator is, put another one nearer towards the downpipe... remove your Cat, put it straight thru from the Headers... Use Hi-Op headers if avail....

Low end will increase tremendously...

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08-15-2006, 02:49 AM

#12

sua

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hmm.. what if i did like what Hamann5 did (no muffler but keep the resonator), will i loose alot of low end?

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08-15-2006, 05:02 AM

#13

gasterus

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My Ride: 645Ci black/red, Eibach springs, K&N air filter, Wetterauer ECU upgrade, Eisenmann 83mmx4 exhaust, 20" Sportec wheels-Michelin PS2 tires, Hamann front add-on lip

Quote:

Originally Posted by Nutty Professor' post='322312' date='Aug 13 2006, 09:31 PM

i took out my reasonator on my 630i before, and the low end totally drops... the car could hardly move forward until it reaches the high RPM zone...
any bros here face the same issue when the reasonators are out?

I think the inline6 engine suffers the loss of low-end torque more obviously compared to the V8 engine. ?'ve bypassed both the resonators on my 645CI and there a slight decrease in low-end tq. Upgrade my stock exhaust of my 530i to the supersprint and immediately feel the loss of low end tq, I could imagine getting much worse if you bypass both resonators.

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08-15-2006, 06:41 AM

#14

Hamann5

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My Ride: 2004 525i Jet Black on Grey Interior--- Tint: Sides 20% Rear Windshield 5% Front Windshield 35% Wheels: Zenetti Five's 20" by 8.5(front) 20" by 10(rear)-- Tires: Pirelli Asimmetrico 245/35/20(front) 285/30/20(rear)-- Body: Hamann Full Front Spoiler, Rieger Side Skirts, Rieger Rear Apron, AC Schnitzer Trunk Wing Interior: AC Schnitzer Pedal Set and E-Break Springs: H&R Sport Springs-- Audio: 2 12" Kicker L7's with a Rockford Fosgate 1501bd Amp With Custom Trunk Enclosure SOON TO COME: -M5 Mirrors -M5 Trunk Finsher -Brembo GT Big Brake Kit -Hamann 6 Series Front Spliter Molded -Hamann Roof Wing -Full Custom Sound System with TV's

honestly with the straight pipe I don't notice a dam difference with preformance but that wasn't the point of me getting it I jsut wanted the quad look and ended up having a decent sound.. but as for preformance I don't think it made it better or worsend it

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08-15-2006, 08:02 AM

#15

jet190rs

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My Ride: '05 545i - scheduled for ED pickup in Munich on 7/22!

Quote:

Originally Posted by Nutty Professor' post='322689' date='Aug 15 2006, 01:23 AM

hmm, in your example i'd assume that the low end boost is simply the result of just removing the cat, not adding a resonator. the cats are usually the most performance-robing component on a stock car.

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08-15-2006, 02:13 PM

#16

JDN

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When I removed the large resonator, there was no noticeable change in sound or power. However, there was a notceable resonance at highway speeds. When I installed a sport muffler, I put the large resonator back inline assuming that the resonance would be magnified at road speeds. As it is, the sport muffler is not a sound factor at road speeds cruising in sixth gear.

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08-15-2006, 07:41 PM

#17

Nutty Professor

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My Ride: 630i, H&R Springs, PSS9 coming, H&R ARBs, Sprint Booster, Eisenmann Quad, HAMANN Pedals, M6 Rims/Advan Sports...

As what Gasterus had mentioned. The inline 6 (Valvetronic) N52 does lose alot of low end when the exhaust is a straight thru design. It is not advisable to take out the Reasonator at all. It wil only give u a lot of sound, but totally no performance gains. I have tried it..

And trust me, to put back the Reasonator again, is one hell of a job, compared to removing it.

As I did said, if you don't mind ur car being quieter, but want great low end pulling power, add another Reasonator right after when the Downpipe falls... Try it... u'll be amazed...
And yes, the Cat is one bloody power robbing "tin"....

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