Intermittent squeaky noise fixed! HKS Hi-Power sound clips updated!
 

Hi guys

I recently have my HKS Hi-Power (single outlet) exhaust installed and the exhaust is connected to my after market CAT & resonator.

The exhaust was great, but ever since I installed the exhaust, I start hearing an intermittent squeaking noise from underneath the car. I couldn't locate the exact location and thanks for the "intermittence", my mechanics couldn't find it neither since it wasn't making any noises during the preliminary test.

So far, I found the noise occurs intermittently after the engine is well warm-up. In other words, the noise only starts after around 5~10 mins of driving (depending on whether it's a cold start or not). It can happen when I drive on Freeway, rough surface road or even when the car stands still (basically anytime..).

This is driving me crazy guys. Please help here! Thanks a lot!


Cheers


Ian

I would try loosening up the rear flange nuts (2 of them), moving the union between the midpipe and cat-back around a bit to better settle the joint, then retighten them.

That sounds like a good idea, I might give that a shot. Thanks! Maybe i should change the gasket too? I heard people change gasket after they unscrew the flange sometimes..?


Any other recommendation guys?

Does that HKS use the OEM flange/donut type of gasket? If so, it probably needs no replacement.

Yep it uses the stock gasket...not sure what ian is using so ill let him answer this.
This was my exhaust and i have never had squeaky noises.
make sure its not rubbing on the diff (the hks is known to do this) or on the exhaust shroud (might have to cut some plastic away or it may melt).
sorry i couldnt be anymore help Ian, hope your still enjoying your purchase :)

me thinks is the bushings on the hanger of the exhaust.

Well, my original plan was to retain the entire HKS exhaust piping. However, as my exhaust system are fully custom made (from CAT to muffler), I have to do certain "adjustment".

A picture says 1000 words, so i will refer to my picture below to explain my "adjustment". Initially, i was going to just use the last part of the muffler (the part circled in YELLOW), so my mechanic loosen the bolts and was going to fit it that way. But at the end, it was decided to include every part i circled in red. It means the exhaust would be "cut".

P.S. Sorry Justin, i just do what i need to do...it's definitely NOT my first option.

Anyway, there are good chances that the squeaky noise are coming from the joint section. And possibly just like what Charles said, it might be because the bolts/pipe are in awkward position or the gasket might need to be replaced. Hopefully it's the first one, not the second.

Any idea how much to replace a gasket? As long as i don't need to source from Jap, and wait for weeks, i am happy..?

BTW, I post a clip to demonstrate the squeaky noise I referred to in the post. You should hear that clearly from around 0:25 secs. You probably need to turn your speakers' BASS down a bit before you hear it, coz man, the exhaust is bassy....

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Yap, aside from my previous post, yes, it IS rubbing my Diff right now. I have got to sort that out too....any suggestion? I might bend the metal hook to position the exhaust slightly further away from the diff...IF possible...

And here is the rubbing sound...

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Taka, that was my initial suspicion. However, when my mechanic (Nelson) went underneath the car and tried to shake the exhaust, nothing made any squeaky noise. Or maybe he was just in a hurry and didn't do/"shake" it thoroughly on that day?:P

As I mentioned before, the squeaky sound only starts after the engine is well warmed up. It means a good 5 to 10 mins drive before the it starts squeaking.

What interests me though is that it seems the exhaust also only start rubbing the diff after the engine is well warmed up. In other words, the squeaky noise starts around the same time as the rubbing starts. The difference is, the rubbing is more apparent when the car is idling and the squeaking is more apparent when the car is moving..

Argh~~it's driving me nuts soon...

And the worst bit is, i won't have time to fix it anytime soon. Damnit i should quit my job and get it fix.....well, at least I wish I could :P

BTW, thanks for the input everyone! Much appreciated. I am getting there...hopefully...

The OEM rear gasket is about $40 from your dealer.
The reason the "rubbing" starts after the engine is warmed-up is because exhaust systems can grow in length something around 1/2"-1" as the pipes get hot.

Thanks Charles, I will have to find a time to see my mechanics and figure out where EXACTLY that squeaky sound came from. It's annoying when it happens, but it's even more annoying when you can't find where it is...

Just a question though, is gasket all the same? I meant, do i have to opt for an specific one? (e.g. HKS exhaust has to get HKS gasket)? Or i can just get a replacement as long as they fit well?


Thanks heaps for the input again!

You will have to look at the rear union to see about that. If the HKS is a TRUE 3" cat-back (like the Turbo XS) you may have some issues with the rear OEM donut being a bit too small to fully seal the joint. That is part of the reason why TXS includes a new rear donut; their piping is rather large when compared to the OEM sizing.

hey there, I had a similar squeak on mine and it turned out to be the mid pipe rubbing up against a piece of metal. sorry I cant identify which "piece of metal it was" but it was somewhere around the mid pipe section. The mazda mechanic bent it "out" a bit so that it wouldnt rub against it - problem solved.

PS. your car sounds sick!

Hi guys

The problem is SOLVED today. FYI, the squeaky sounds was coming from the exhaust's "hanger" rubbering the metal part around the diff


Thanks all the help! FINALLY i can start really enjoying my exhaust~~!! HKS Hi-Power is one naughty baby..

I was close

Yes, Taka, you are the master of troubleshoot~;)

Guys, I have finally fixed out the squeaky and rubbing noise, here are some video clips of my original 3" exhaust and the HKS exhaust, hope you like it. Btw, I still have the Custom 3" exhaust available for sale, let me know if you are interested.


Metal Cat + Resonator + Custom 3" exhaust: Start Up

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Metal Cat + Resonator + Custom 3" exhaust: Revving

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Metal Cat + Resonator + HKS Hi-Power exhaust: Start Up + Revving

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Metal Cat + Resonator + HKS Hi-Power exhaust: Running + full throttle

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