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+--- Thread: Straight pipe exhaust (/showthread.php?tid=625)
Straight pipe exhaust - ForcedInduction - 08-23-2009
Total cost was $24.85 from Ace Hardware for 1x24" and 1x18" 2.5" straight pipes, 1x30" 2.5" straight pipe with turn-down tip and two rubber hangers.
Before and after. No crappy guillotine clamps, just welds.
Mounted in place. I only used two hangers since the exhaust is so much lighter.
ROL Exhaust #511176 hangers. Cost was $1.76 each.
I'm actually surprised to find that both the resonator and muffler are straight-through designs with no baffles or packing. Both had a fair bit of carbon/soot trapped inside. (right is the inlet on both.)
Volume is not nearly as loud as having an open down pipe dumping under the passenger floor. The VNT significantly quiets the exhaust and opening the vanes makes it far louder.
Now its time for some fun, I'll be heading up to the summit of Pikes Peak tomorrow!
RE: Straight pipe exhaust - DeliveryValve - 08-24-2009
Nice tip and pics. I didn't realize the bends the exhaust has around resonator. The straight pipe cleans it up pretty good. Maybe I'll just go straight on resonator portion and leave the muffler.
RE: Straight pipe exhaust - winmutt - 08-24-2009
Interesting I didnt realize the muffler was straight through. From the diagrams it looks like its baffled chambers.
RE: Straight pipe exhaust - ForcedInduction - 08-24-2009
(08-23-2009, 11:18 PM)ForcedInduction Now its time for some fun, I'll be heading up to the summit of Pikes Peak tomorrow!
The trip was fun and the Mining Museum was cool, but this was the the view from the summit.
RE: Straight pipe exhaust - winmutt - 08-25-2009
How were your EGTs on the climb?
RE: Straight pipe exhaust - ForcedInduction - 08-25-2009
In 3rd gear, 1700rpm, 5psi boost, 1100*f.
In 2nd, 2500rpm, 5psi boost 900*f.
I didn't have time to test boost response or acceleration near the top. Thanks to the fog, I reached the summit before I knew it and then the Weather Nazi ranger shooed me back down the hill almost right away.
RE: Straight pipe exhaust - CID Vicious - 11-24-2009
Got a vid of this car running this exhaust? Wondering how feasible it would be for me...
RE: Straight pipe exhaust - ForcedInduction - 11-24-2009
These are what I have for now.
http://www.youtube.com/watch?v=8czY5s03Qo4
http://www.youtube.com/watch?v=g7HRDq3RdJU
I'm going to switch out from the 300D to the 240D for the winter tomorrow. Its got the T3 turbo but a stock exhaust so I'll try to remember to make a comparison video of the two.
RE: Straight pipe exhaust - CID Vicious - 11-24-2009
Not bad. I think I might try the resonator first, though. Take it from there.
RE: Straight pipe exhaust - GREASY_BEAST - 11-25-2009
No way I'd pass VT inspection doing that.. The muffler is damn near the only thing the look for! Good to know the stock exhaust is straight through tho.
RE: Straight pipe exhaust - CID Vicious - 11-25-2009
I keep hearing that the resonator is the bigger restriction out of the two, what's the theory behind that?
RE: Straight pipe exhaust - ForcedInduction - 11-25-2009
(11-25-2009, 12:09 AM)GREASY_BEAST No way I'd pass VT inspection doing that.. The muffler is damn near the only thing the look for! Good to know the stock exhaust is straight through tho.
Both of them would be very easy to open from the top and replace the holey tubes with straight pipe. You could also cut off the turndown tip of the muffler and insert a thin pipe to block the holes.
(11-25-2009, 12:12 AM)CID Vicious I keep hearing that the resonator is the bigger restriction out of the two, what's the theory behind that?Its closer to the engine where the exhaust is hotter and expands more.
RE: Straight pipe exhaust - JB3 - 11-25-2009
I did this too, and they forced me to put in a resonator as well, but it still dramatically changed the note of the car. For a generally simple mod, its SOOOOOO worth it, even if not for performance! I did it so I could hear the engine while blasting music.
Gives these cars a nice rumble at idle and kinda a small cummins engine note!
Heres another video, although not as clear as forced inductions on direct note-
I was trying to record what the exhaust note was inside the cabin as I got on the highway, but instead the camera picked up 100% of the radio which was actually super low volume. If you have headphones, you can definitely hear it though.
http://www.youtube.com/watch?v=RzAzX9hp_gI
RE: Straight pipe exhaust - benztek - 11-25-2009
I have already straight piped the resonators. I am cutting the muffler out next weekend and putting in S-600 tips. What does everyone think will look better? Both on one side, Both in the middle, or one on each side?
RE: Straight pipe exhaust - Rudolf_Diesel - 11-25-2009
(11-25-2009, 12:06 PM)benztek I have already straight piped the resonators. I am cutting the muffler out next weekend and putting in S-600 tips. What does everyone think will look better? Both on one side, Both in the middle, or one on each side?
I think both on one side...One on each side and you have a Camaro, in the middle and you a have a BMW, JMHO.
RE: Straight pipe exhaust - ForcedInduction - 11-25-2009
I have always liked the "in the middle look", especially on BMW.
Don't forget about soot, without a turndown you'll probably end up with a sooty back end.
RE: Straight pipe exhaust - JB3 - 11-25-2009
(11-25-2009, 12:52 PM)ForcedInduction Don't forget about soot, without a turndown you'll probably end up with a sooty back end.
Yes, I agree. this was a major problem for me. It also blew motor oil all over the place as it worked its way back to the tip over time. I had black spots on my rear window even.
RE: Straight pipe exhaust - CID Vicious - 11-25-2009
I'm thinking of doing the resonator as permanently gone, and the muffler will be set up to be fairly modular. Even though my 616 with just a resonator wasn't all that bad, I did get followed by a cop one night because of it. So I might have the muffler in for general use, and swap it out for a straight pipe when I feel like getting frisky
RE: Straight pipe exhaust - benztek - 11-25-2009
I like the in the middle look also but It will be a lot bigger PITA to do it right.
RE: Straight pipe exhaust - W116Lorinser - 11-25-2009
does the straight effect the MPG?? does it offer any performance or slightly increased HP or TQ?
RE: Straight pipe exhaust - ForcedInduction - 11-26-2009
(11-25-2009, 08:36 PM)W116Lorinser does the straight effect the MPG?? does it offer any performance or slightly increased HP or TQ?
Anything that reduces backpressure on a diesel will improve efficiency and power. Not nearly as much on these "small" diesels as on the pickups and semis, but its there.
(11-24-2009, 10:16 PM)ForcedInduction I'll try to remember to make a comparison video of the two.Here it is: http://www.youtube.com/watch?v=OnWc425YxZs
The next few days are supposed to be really nice so I decided to get a tank of B20 to clean out the system before putting it away for the winter.
RE: Straight pipe exhaust - 300SD81 - 11-26-2009
I got a turndown on mine, and still get soot all over my back side. I'm wondering if I didn't make it extend out far enough. Has anyone found a way to avoid the soot getting on the body short of putting a stack on? Next exhaust I'm gonna try making it extend out a couple inches..
RE: Straight pipe exhaust - ForcedInduction - 11-26-2009
The tip I use on my 300D doesn't leave any soot. Even my bicycle stays clean behind the trunk.
RE: Straight pipe exhaust - W116Lorinser - 11-26-2009
So the muffler is a straight pipe by itself so no need to remove it.... But how about the resonator? Is resonator straight flow also? Doesit rumble more/ soundmore aggrrssive with it removed?
If both muffler and resonator are straight flow design anyway whats the point of straight piping it??
RE: Straight pipe exhaust - ForcedInduction - 11-26-2009
(11-26-2009, 01:24 PM)W116Lorinser If both muffler and resonator are straight flow design anyway whats the point of straight piping it??They allow the exhaust to expand (and cool) through the holes/slots which causes restriction. Anything that changes the exhaust's sound, flow direction, gas volume or temperature will cause backpressure.
Removing them eliminates 4 direction changes (pipe angles in/out of the resonator), stops expansion and maintains velocity. The exhaust exiting the system is hotter, denser and moving faster.