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Exhaust Tone

1559 Views 5 Replies 2 Participants Last post by  CinderBlock
Hey guys, forester 2000 5 speed

Just some questions for exhaust gurus,

When I bought it I removed the stock silencer in the rear put a straight pipe to an exhaust tip and added a glass pack, sounded alright (Still have stock resonator also)

Then over the summer did a lot of long distance commutes with it and my "flex pipe" popped a hole through it so I replaced it with a straight pipe (Was way up north and all I found was some pipe and my cheap welder)

Alright so my question is this : When I give STRAIN on the engine (hard low RPM pull in 2nd or 3rd gear from 2000-3500 you hear sort of a rattle in the exhaust or underneath, would this be caused by the fact that my exhaust is pretty much all "Rigid" ? (It doesn't knock up against anything under the car to my knowledge)

My other question is at 120km/h there's a really bad frequency resonance in the car like droning, it only happens from 2900-3500 above that the exhaust is at a tone you can't hear inside, and below that also..

Any of you have experience with this to find a way to get the vibration at a certain RPM to be much lower inside the body, and would reinstalling a flexpipe help reduce vibration inside the car?

Thanks! May seem obvious to some of you but have a flexpipe installed or other exhaust work done here in the winter is pretty expensive, wanna make sure I'm going for the right shot!
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As far as drone goes:
- Does your exhaust tip extend beyond the rear bumper?
- You could add a REAL resonator. (I believe has a stainless steel one.)
- Add more glass packs. (The 1st glass pack reduces most noise and decibels vs none. Adding a 2nd, 3rd, etc, will be noticeable but not significant.)
- Add a muffler.

I had a 2001 and did options 1, 3, & 4. I listed. Point 1 was a massive improvement. And point 3 helped too. This was done with a Magnaflow muffler. I still had a lot of drone. I think point 2 or going with an oem muffler are your best bets.
Hey man thanks for your reply, appreciated!

I forgot to mention I did add a muffler, though a cheap Thrush Turbo. It quieted the sound down a bit but I have the impression I have more drone with the muffler and NO flex pipe up front (All my flanges were welded shut on the exhaust manifold and cats by previous owner... probably had leaks) so the exhaust is quite stiff.

Basically I wanted to hear a bit more engine sound outside, make the FOrester sound less like a grandfather's weekend ride, I mean up to 2500, and 3500 up the sound is not annoying inside, its really in that RPM range...

Yes the exhaust tip I did make sure it cleared the bumper,

I mean if I'm on the freeway and downshift into 4th at 4500 RPM i don't hear the engine at all..its really a case of is there a way to cut vibration at certain frequencies, I don't consider the car loud at all!
Check exhaust hangers. Some are rock hard and others are very soft. Soft ones will kill vibration into the car, but not necessarily the exhaust drone. Every bit helps. ... I had a similar setup to yours, and the drone was always there. Member 2.5xsleeper (Bobby) has recommended a resonator to solve the drone on setups like ours, and I believe at this point it is your best bet. I don't know if it will kill the rumble or just the drone tho. But I have been there and done that, so I know what you're up against. I sold my Foz before I got to try the resonator idea.
So softer exhaust hangars and what about reinstalling a flexpipe ( used to have one between cat output and resonator.

I mean I could add a resonator but I want to keep my "not stock sound" i fear 3 resonators would just make it as quiet as a stock forester making all this mess a waste of time in the end.
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