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Discussion Starter #1 (Edited)
I have a fairly loud metallic rattle/buzz coming from the rear of my '05 Elise. It happens from about 3500 - 4500 rpm, cold or warm and is worse when I'm on throttle. It sounds like it's coming from behind or under the engine, but hard to tell. A friend was following me the other day and he said he could hear it very loud and clear.

The local dealership diagnosed it as either loose baffles or a broken exhaust hanger. Neither was the case, since I just installed a brand spanking new cat-back from BOE. The rattle (or whatever you want to call it) is still there!

Any ideas what it could be???

Thanks in advance.
 

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I have a fairly loud metallic rattle/buzz coming from the rear of my '05 Elise. It happens from about 3500 - 4500 rpm, cold or warm and is worse when I'm on throttle. It sounds like it's coming from behind or under the engine, but hard to tell. A friend was following me the other day and he said he could hear it very loud and clear.

The local dealership diagnosed it as either loose baffles or a broken exhaust hanger. Neither was the case, since I just installed a brand spanking new cat-back from BOE. The rattle (or whatever you want to call it) is still there!

Any ideas what it could be???

Thanks in advance.
I had a similar noise on my 2005. It turned out to be my stage two exhaust tip. The system was loos and moved, so the tip was against the edge of the hole cut out on the under tray at the back of the car. I had the exhaust repositioned and tightened up. Problem solved.
Ron
 

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Discussion Starter #3
I had a similar noise on my 2005. It turned out to be my stage two exhaust tip. The system was loos and moved, so the tip was against the edge of the hole cut out on the under tray at the back of the car. I had the exhaust repositioned and tightened up. Problem solved.
Ron
I checked all that. Clearance, etc. is good.
 

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Right around the resonant frequency of the diffuser (depending on whether you are naked back or still closed up). Also the lidbone has been known to make a rattle sound as well. A go-pro camera stuck on the back of your car looking down will settle the issue.
 

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My stage 2 exhaust made the same sounds at certain frequencies. The welds joining the brackets were cracked. (examine them carefully) It was a $10 repair at a local muffler shop. Now it is much stronger than stock, and it has lasted for two years.
 

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All rattles and buzzes are standard equipment on Elises.

I had a terrible buzz at exactly 3200 RPM. I mean loud. I offered a "bounty" on the buzz of $100 to the Toyota mechanic who does my simple maintenance. No luck.

it eventually subsided.

Now, the squeak behind the passenger seat, the squeak from the rear bushings, the rattle under the headlight switch panel, the rattle under the dashboard, the rattle from inside the drivers side door, they are all still there.

I love my Elise, but I hate the way it sounds. And I'm an audio engineer so squeaks and rattles are especially annoying. But, as they say, it is what it is, and the Elise is not finished well.
 

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Discussion Starter #7
My stage 2 exhaust made the same sounds at certain frequencies. The welds joining the brackets were cracked. (examine them carefully) It was a $10 repair at a local muffler shop. Now it is much stronger than stock, and it has lasted for two years.
Are the welds part of the exhaust system itself or are they the brackets that the exhaust hangers attach to or...?? I just replaced my exhaust with a cat-back system, so the mounting rod, muffler, clamps, tailpipe, etc. have all been replaced. So, if the welds/brackets are part of the exhaust itself, I assume they've been replaced.
 

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I have the 3200 rattle/buzz, the squeaky shocks or bushings and I just took care of the squeaky seat and dangerous speaker covers. The 3200rpm rattle was claimed by Sean of the former Rothrock Lotus to be in the transmission and that many of them do it. I don't believe it because I can replicate in neutral- he might not of heard the same noise I was asking about. I even switched out the belt tensioner since their was a tech bulletin on the 3400~ rpm rattle for the Toyota's with the 2zz but that didn't help. I checked for cracks around the muffler brackets- I might swap it for my extra muffler. Now that it's summer and the windows will be open that rattle will drive me crazy.
 

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Here's a link to my old post. http://www.lotustalk.com/forums/f154/stage-2-exhaust-repair-ideas-photos-90019/

It turns out I spent $20 (not $10), but it was still a bargain. My cracks, as you can see, were on the exhaust itself. The solution was to clamp the brackets back into place and then run a bead weld around the "U" notch in the bracket , connecting it to the rounded surface of the pipe. Much stronger than stock, and no more buzz.
 

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Or.... use the search feature to see the other 42 causes for the rattle. This subject has been beat to death.
That would be great advice if

1. The search function on this site wasn't horrible.
2. You knew exactly what to search for.

I recently had a similar problem and had trouble finding the issue, so I started a thread as well. I hadn't even heard of the Stage II issue that GR82DRV outlines here and that ended up being my problem.

Do you search on buzz or rattle? What if someone said they were having a mid-low RPM buzz and I said I was having a 3000 RPM rattle? After trying many of the fixes that I had found searching, I eventually got frustrated and started a thread. It wasn't until HKFEVER mentioned the Stage II issue in my thread that I learned it could be a problem.

Sometimes when you have searched and searched and tried many fixes it just makes sense to start a thread.

Clark
 

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Discussion Starter #12 (Edited)
That would be great advice if

1. The search function on this site wasn't horrible.
2. You knew exactly what to search for.
Thank you! That's exactly what I was going to say... When you search for "rattle" you get 24 pages full of threads referring to anything from window rattles to someone that ordered a new Solstice. How is that even relevant?
 

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muffler brackets, diffuser and undertray bolts, sheer panel, heat shield, bad cat... it is never ending chasing down all of the rattles in these cars...
 

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when i had my elise i had to have the brackets re welded twice and the muffler was replaced at least once. (stage 2 exhaust)
if your problem isnt the brackets, the shield, etc, then my guess based on my experience with my car was the packing inside the muffler. nothing you can do except replace the muffler.
annoyed the heck out of me. my car was pretty much rattle and squeak free except for that.
check it out and let us know what you find.
 

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Believe it or not, try removing the rear license plate and see if it continues. I went to a full frame around my plate with top and bottom screws (euro type @ auto parts store) and solved a bad rattle. Since you recently had exhaust work done, chances are your diffuser or heat shields are loose or not installed properly as well.
 

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Discussion Starter #19
Believe it or not, try removing the rear license plate and see if it continues. I went to a full frame around my plate with top and bottom screws (euro type @ auto parts store) and solved a bad rattle. Since you recently had exhaust work done, chances are your diffuser or heat shields are loose or not installed properly as well.
The rattle existed before the exhaust work was done. The rattle was originally diagnosed (by my local Lotus dealership) as loose baffles or broken brackets. Since it's an entirely new exhaust (cat-back), that rules those two things out.

I made sure all the shielding was tight when I was in there. I also double-checked the diffuser panel to make sure everything was tight and aligned properly. All looks good.

I'll have to check the license plate, bracket at the header and O2 sensor to see if any of those are loose.
 

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