Scorpion/HFC's/Y-pipe drone - Arghh!

[scottyp]

For some reason, since fitting the Y-pipe (may be a coincidence...) the exhaust seems to have bedded in with a really annoying bassy drone at 2-2500 rpm when hot - makes long journeys uncomfortable and I end up either flooring it to bypass the drone spot or trying to coast under it

 

Does anyone else notice this on their same exhaust combo? (scorpion Y-back, Berks HFC's and Cobra Y-pipe) really annoying as it sounds fantastic elsewhere in the rev range

 

Any suggestions to remedy? - been underneath and no leaks that I can see..

[Paddy78]

Tends to happen when you start adding bits to the exhaust system I'm afraid. I don't do many motorway miles in mine (Kinitex HFC + Nismo Cat Back) but there is definitely a sweet spot for a slight drone around 70mph / 2.5k RPM. Mine isn't bad at all, but can see how this would be really annoying if it was a lot louder.

 

Not sure there's really much you can do other than turn the stereo up or drive over / under the 2-2.5k range? You could be forever trying different combo's of Y-Pipe etc. to make it better, but the only people that would really benefit are Tarmac and CS!

 

Sorry I can't be of any real help, but this is always a potential issue once HFC's are added to the system.

[Ceejay29]

I have been considering gutting the boot, ie removing carpets, sound proofing, plastics etc, in order to shed a bit of weight and expose a bit of colour. However I am not sure if I could handle the drone, especially as I still need to purchase an aftermarket y-pipe. Does this exhaust section make that much of a difference, or is he noise mainly down to the de-cat/HFC's?

[scottyp]

I didn't notice it so much before the Y-pipe - however the original was leaking so it sounded a lot louder in volume, so hard to tell

[Tarmac@TarmacSportz]

 

Surprised your getting drone, I've heard that set up but with Stillen Ypipe rather than the Cobra, it sounded sweet on ChrisS' car. Don't think it was droney.

 

You will always get a bit of noise, par for the course... Drone is K1/N1/Buddyclub

 

Try a Stillen Ypipe 'just kidding'

[Paddy78]

Mine got a hell of a lot louder over about 2k RPM after the HFC's were added. I would have thought the HFC's were the culprit over the Y-Pipe. Obviously, the increased noise comes from higher flow / more gasses going throught the system. One Y-Pipe to another doesn't make a huge difference (Although I could be wrong).

[scottyp]

Noticed the scorpion system doesn't include a box in the mid pipe like some other systems, wonder if its worth getting a small resonator box welded in?

[spursmaddave]

Surprised your getting drone, I've heard that set up but with Stillen Ypipe rather than the Cobra, it sounded sweet on ChrisS' car. Don't think it was droney.

 

You will always get a bit of noise, par for the course... Drone is K1/N1/Buddyclub

 

Try a Stillen Ypipe 'just kidding'

 

Very true, if you want to hear proper drone get a Buddy Club...... proper ear bleeding mind warping drone

[370Ad]

Dont get this with my system, same as yours apart from silenced decats not HFC's.

 

Sorry I can't help anymore!

[Tarmac@TarmacSportz]

Noticed the scorpion system doesn't include a box in the mid pipe like some other systems, wonder if its worth getting a small resonator box welded in?

 

Possibly, the scorpion bar the Miltek is pretty much one of the quietest systems going though, which is why I'm surprised you are getting drone, roar yes but drone is surprising.

[scottyp]

Wouldn't be caused by a leak haven't discovered by any chance?

[MITZ@CougarStore]

Worth checking all the joints and gaskets...

[scottyp]

reckon there may be a dodgy joint that's expanding an leaking when hot - going to get it checked at the weekend, fingers crossed!

[Toon Chris]

I've had three different Y-pipes with my lovely exhaust ( btw), East Coast Racing, Janspeed and Cobra, and every one has had a drone at that rev range. Can be annoying when you want to accelerate and can't be bothered to change gear as the sound levels get very boomy, but you get used to it.

[scottyp]

Fixed it!

 

Wrapped the y-pipe in thermal exahust wrap and gum sealed all the joints again - volume seems the same, but resonance is minimal now, happy again

[MITZ@CougarStore]

Fixed it!

 

Wrapped the y-pipe in thermal exahust wrap and gum sealed all the joints again - volume seems the same, but resonance is minimal now, happy again

 

Good result...

[RobPhoboS]

Good work - which sealant did you use ?

[spursmaddave]

[scottyp]

I used the gum stuff from Halfrauds (unfortunately!) just went over the joints to give a smooth coverage and left it to dry for a few hours.

The wrap stuff was a bugger - probably much easier to do with the exhaust off the car!

 

didn't realise it contained fibreglass either so was covered in itchy shards after being under the car - still, no pain no gain!

[helimeddaz]

I have been considering gutting the boot, ie removing carpets, sound proofing, plastics etc, in order to shed a bit of weight and expose a bit of colour. However I am not sure if I could handle the drone, especially as I still need to purchase an aftermarket y-pipe. Does this exhaust section make that much of a difference, or is he noise mainly down to the de-cat/HFC's?

 

This is a sound idea. (Good one).

 

Stripping the boot and sound proofing will make a difference beyond the small change made by the boot divider. Pound for pound and surprisingly fom a thereputic level as a DIY project it' will help a lot. Exhaust or not.