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Discussion Starter #1
Hi, guys. Sorry to cross-post, but I was wondering if there's anyone else in the area who has a BOE supercharger. Since I had mine added, it makes a nasty high-pitched sound around 25% throttle, 2500 RPM, and I'm trying to figure out if that's normal or not. Sounds like squealing brakes. Can't seem to capture the sound when I try to record it, so I'd like to hear someone else's car in person to see if theirs does the same thing.

Thank you,
Josh
 

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Discussion Starter #3
We've been kind of going back and forth with BOE. I originally got the answer that the supercharger just makes noises that I'm unaccustomed to. I love the sound of the supercharger spinning up. Sometimes I will start shift to a higher gear early just because the rising whoosh gives me the giggles. This is something completely different.
Despite multiple attempts by both Collin from Soul Speed and I, we have been unable to record the sound. It's plenty loud in person, but for some reason, our recording devices don't pick it up well, so we haven't gotten a good repro of the sound sent to BOE. Collin thinks it might just be a whistle produced by the butterfly valve. To me, it's a loud and ugly enough sound that I would have done everything I could to engineer it out. Plus, no one has said TADTS to the way I've described it, so I suspect it's not supposed to be that way.
 

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Discussion Starter #5
I'd say it's probably a whistle. It occurs at common cruising throttle and is especially loud when decelerating with no throttle and clutch engaged. It sounds almost identical to someone with bad brakes.
 

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Hmmm, well, the intake sound that it normal is directly connected to throttle angle. Like, you can make it whistle by applying the right amount of throttle. If it's making a squeal under closed throttle, deceleration, then it's not normal and should be looked into. If it's squealing, it's probably something rubbing some where and is probably evidenced by some sort of material shavings. Look for shavings around the pulleys and snout mounting area.
 

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Hi.

Does the car have to be moving to make the sound? If you take a digital recorder and place/mount it in different locations in the bay and record the noise, the area where it is loudest can be found. I taped a recorder under my jeep to find a sound only while in motion and was able to find the loudest spot and focus there.

I still have the mike and recorder if you want to use it. Hell I would love to hear it for myself and help if I can.

Good luck finding the sound. Random car noises irritate me, and yet I bought an Elise. Hahaha.

Alex
 

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Discussion Starter #8
Thanks, guys. Yes, the noise happens with closed throttle while decelerating with the clutch engaged (engine braking). It's loudest then, so although I believe I could probably repro the 25% throttle whistle, I'd have to be moving to get the louder squeal. Soul Speed has had my car for a couple weeks looking into this, otherwise I'd be glad to have you listen to it, Alex. Thank you for offering. I'll ping them today to see if there's any news or word from BOE. I'm kind of surprised that BOE hasn't been very responsive on this until I sent them an e-mail with an F-bomb in it, and it seems like SoulSpeed has had a similar level of responsiveness.

Thank you,
Josh
 

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It's a super simple mechanical set up and install. If Soulspeed can't find the problem then damn... that's surprising. I'm shocked that they can't find the issue.

Possible culprits:

1) bad install of components near supercharger snout
2) defective supercharger

What else was installed at the time? Did they upgrade your clutch or anything?
 

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Discussion Starter #10
I don't think the issue is that they can't find the problem, but rather the uncertainty that it's a problem in the first place. This was a supercharger install only. They looked for vacuum leaks and double-checked the installation, but couldn't find anything other than a broken bracket that was causing the cicada-like noise I noticed when idling. They fixed that. He's going to try again to get a recording that sounds like it does in person, since the one he sent to BOE didn't really capture the sound, so naturally BOE said they didn't hear anything abnormal.
I get the impression that perhaps Collin didn't understand me when I explained how to repro the sound during deceleration, and now I have a new theory- maybe I'm just driving like a hooligan. Half the time I don't disengage the clutch when approaching a stop. I just let the engine compression slow the car rather than use the brake because I'm easily entertained and the sound kind of tickles me.
I've been told that's bad. I've been told it's fine. I don't know which is right, so I do what strikes my fancy. But maybe no one else does that and so they don't hear it make that sound. To me it sounds like air pressure being bled off, and maybe it's supposed to happen like that.

Josh
 

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Discussion Starter #11
Picked the car up yesterday, and the cicada and squealing sounds are gone. I guess that broken bracket that Collin welded fixed them both. I'm surprised that it was just vibration making that loud squeal. At any rate, the car sounds and feels beautiful.
 

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Discussion Starter #13
No, the supercharger kit was brand new. I'm pulling pretty hard from my memory banks now, but I think he said it was a bracket on or near the muffler. When he told me, I was at the office on a balcony and two vultures had just landed on the rail in front of me, so I was a little distracted while listening.
 

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Which exhaust are you running? My stage 2 broke all 8(!) welds holding the tips to the can and made a noise at higher RPMs that had me thinking the trans was coming apart.
 

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Discussion Starter #16
I'm still on the stock exhaust, but that's probably something I need to change in the future, but the first thing I'm going to need to look into what I need to do to improve grip a bit. With all this new torque, I get little tiny bits of tire spin sometimes. :)
 
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