Exhaust back box options

[kdh]

I have a Dansk on mine - very droney around 2500 - 3000rpm.

 

I put an Ice Design DB killer on it but it's still there.

Danb, I'd be very interested in helping in some way. We could make millions.

Ive spent at least 5 years trying to eliminate drone in Porsche exhausts. I haven't quite cracked it yet but I won't sleep until I do.Most drone seems to be in the frequency of 107 on a sound meter and anywhere between 2-3000rpm.

[danb]

107hz ?

If you can make a recording/video of it then if it is in that region most mics should have a problem picking it up

anyone know what the volume of the rear storage cubby is - could be as simple as replacing the sliding doors with a tuned insert…..

[½cwt]

1 hour ago, kdh said:

I have a Dansk on mine - very droney around 2500 - 3000rpm.

 

I put an Ice Design DB killer on it but it's still there.

Danb, I'd be very interested in helping in some way. We could make millions.

Ive spent at least 5 years trying to eliminate drone in Porsche exhausts. I haven't quite cracked it yet but I won't sleep until I do.Most drone seems to be in the frequency of 107 on a sound meter and anywhere between 2-3000rpm.

Which Dansk did you get?  The standard sound the sports or super sports version?

Just checking on the Tech 9 website I thought they'd gone up a chunk in price but they are listed with VAT now.  Don't actually works out a lot cheaper than a Porsche system though, standard sound with 2 U bends and 2 clamps (what the factory part provides) for a 99 - 02 3.2 S is £1720.  Factory part is under £200 more IIRC.  Either way. not looking forward to when mine eventually needs doing.

[iborguk]

https://www.supertweaks.com/porsche/porsche-exhausts/porsche-exhaust-silencers/porsche-boxster1-exhaust-silencers/porsche-boxster-986-2732-dansk-sport-exhaust-oe-style-with-tuv

 

[zagamuffin]

If the Danske is favoured bar the price , these guys in Dublin have a new one for e800, might get vat off if you push lol

 

https://www.donedeal.ie/cars-for-sale/porsche-boxster-sports-exhaust/34459458
 

 

 

[02boxster968]

On 12/25/2023 at 12:00 AM, phazed said:

I’ve just ordered the Toyosports back box. Car will be used for track days mainly so hope it won’t be too loud used with standard cats.

Don't do it! Had a Toyosport exhaust on my 986 S.

Complete junk and terrible drone at just under 3000rpm destroyed the sound of the car and showed signs of rust after only 1 week fitted! Removed and got a refund.

A lot of engineering went into the original exhaust design to minimise and eliminate drone and the cheap boxes miss this.

I tried a Dansk sport exhaust very good would have no hesitation recommending and currently running a FVD brombacher exhaust and very happy with it two years in

[ATM]

Anyone tried one of these?

 

https://www.ebay.co.uk/itm/125640463609

 

[iborguk]

First post - assuming it's the same type...

http://986forum.com/forums/boxster-general-discussions/62285-circuit-werks-exhaust-resonance.html

 

[kdh]

8 hours ago, ½cwt said:

Which Dansk did you get?  The standard sound the sports or super sports version?

 

My mistake. Mines a DesignTek, which I thought was made by Dansk.

https://www.design911shop.com/p/exhaust-muffler---silencer-sports-system-porsche-boxster-986/

I’ll try and do an audio recording later today from inside the cabin.

 

 

[ATM]

3 hours ago, iborguk said:

First post - assuming it's the same type...

http://986forum.com/forums/boxster-general-discussions/62285-circuit-werks-exhaust-resonance.html

 

Ok thanks 

Another droner

[½cwt]

48 minutes ago, kdh said:

My mistake. Mines a DesignTek, which I thought was made by Dansk.

https://www.design911shop.com/p/exhaust-muffler---silencer-sports-system-porsche-boxster-986/

I’ll try and do an audio recording later today from inside the cabin.

 

 

OK, thanks.

I do get the impression that only way to have no drone without fitting extra bits is to buy something into 4 figures.

[ATM]

30 minutes ago, ½cwt said:

OK, thanks.

I do get the impression that only way to have no drone without fitting extra bits is to buy something into 4 figures.

What's the magic of the standard back box. 

I get the impression the versions with 2 little separate silencers just can't compete with the larger single full width silencer. Probably because the exhaust is so short on the 986.

But it is as short or shorter on the 996 - or is it. They have a cross cross arrangement at the back of the car so the left bank exits at the right and vice versa. I don't know if this length helps eliminate some resonance. The silencers on the 996 are tucked up in the bumper behind the wheel arch so right out to the side of the engine. I don't know whats going on inside but I presume not a straight through arrangement from the factory. After market options maybe are straight through but would obviously need a bend inside. I did see this one on ebay which uses 2 silencers packaged close together each side with the bend externally. It isn't cheap.

Some cars like the 997 gt3 had a single silencer similar to the 986.

The 987 and 981 manage without drone and they have separate silencers. I'm guessing they have separate chambers inside like the standard 986 box.

Or is it the thickness of the metal. Does a cheap exhaust made with thinner metal drone more?

Someone needs to buy a welding rig and experiment. 

[iborguk]

12 minutes ago, ATM said:

Someone needs to buy a welding rig and experiment. 

Or chat to someone like Gert (of Carnewal fame) he'll probably know the deal, he's been helpful when I've emailed him.

[kdh]

Here's my Boxster S exhaust, which came on the car and is a DesignTek model sold by Design911 for about £850. (Link in post above).

The Tip size can make a huge difference to the sound of the exhaust and how much drone it produces.

On the left side you'll see the smaller diameter pipe that joins the tip. If this was extended and used as the exhaust pipe with no tip, then you'd have less drone. It's the big 3" + tips that can cause drone.

On the right, you'll see a DB killer by Dark Ice designs. By turning the allen key in the centre and opening the hole you can adjust the tone to an extent and the amount of drone you get. I have mine adjusted to try and replicate the smaller opening on the left and it works fairly well. I had them on both exhausts at one point but it did kill quite a lot of the tone, so I've kept it to one for now. The wire to the left of it is a precautionary measure.

The best sounding exhaust I've had was on my original Boxster S which was a standard backbox with bypass pipes fitted. The loudness kicks in as the revs rise and remains totally stock the rest of the time. The mod was about £200 if I remember. It was a great sound and I'll try it again one day if I can find a decent original backbox that's not rusty and split.

 

 

 

 

 

[½cwt]

1 hour ago, ATM said:

What's the magic of the standard back box. 

I get the impression the versions with 2 little separate silencers just can't compete with the larger single full width silencer. Probably because the exhaust is so short on the 986.

But it is as short or shorter on the 996 - or is it. They have a cross cross arrangement at the back of the car so the left bank exits at the right and vice versa. I don't know if this length helps eliminate some resonance. The silencers on the 996 are tucked up in the bumper behind the wheel arch so right out to the side of the engine. I don't know whats going on inside but I presume not a straight through arrangement from the factory. After market options maybe are straight through but would obviously need a bend inside. I did see this one on ebay which uses 2 silencers packaged close together each side with the bend externally. It isn't cheap.

Some cars like the 997 gt3 had a single silencer similar to the 986.

The 987 and 981 manage without drone and they have separate silencers. I'm guessing they have separate chambers inside like the standard 986 box.

Or is it the thickness of the metal. Does a cheap exhaust made with thinner metal drone more?

Someone needs to buy a welding rig and experiment. 

That's my point, unless you have the resources to undertake and R&D project, off the shelf solutions that have similar sound characteristics to the factory exhaust cost into 4 figures as a system.  I take the point about 996 systems, however the do sound different to the 986 (more woofle is my description) most likely due to different spaces and routings, the 987 is more like the 996 and 997 as the main mufflers are split not a single box.  Acoustics is a strange science/art; case materials, deadening materials, (and their thicknesses) volumes, shapes all play their part.  To get the Porsche or Dansk type of sound you need a lot of R&D and cheaper manufacturers clearly don't do that as you are not paying a price that would fund that.

The system in you picture looks lovely, but as you say you pay for it.  Al comes down to you pays your money and makes your choice.  Get Porsche or Dansk and you now what you are going to get, chose another and.... well reports vary rather a lot.

[kdh]

16 hours ago, danb said:

Has anyone got a recording of the drone? I’m wondering if you could vastly reduce it with a suitably tuned Helmholtz resonator but would need to know the primary frequency of the drone  to calculate what might work.

 

I'm just back from a sound Test.

Droning is at its worst between 2600 - 3000 rpm.

In that rev range the DB Meter read between 78 - 80dB

[½cwt]

20 minutes ago, kdh said:

 

I'm just back from a sound Test.

Droning is at its worst between 2600 - 3000 rpm.

In that rev range the DB Meter read between 78 - 80dB

Exactly where the revs sit at legal motorway speeds....

[phazed]

That is annoying.

Is that the cheap stainless steel box with standard cats?

[kdh]

It's the DesignTek at about £850 with standard cats, so not the cheapest.

I have heard cheaper versions like the Toyos and they sound appalling from inside the cabin.

 

[edc]

5 hours ago, kdh said:

My mistake. Mines a DesignTek, which I thought was made by Dansk.

https://www.design911shop.com/p/exhaust-muffler---silencer-sports-system-porsche-boxster-986/

I’ll try and do an audio recording later today from inside the cabin.

 

 

Designtek is Design911 own branded/imported parts. 

[phazed]

3 hours ago, kdh said:

It's the DesignTek at about £850 with standard cats, so not the cheapest.

I have heard cheaper versions like the Toyos and they sound appalling from inside the cabin.

 

Amusing as this is what I have ordered, but will only be used on the track pretty much. And advantages it seems that it is much lighter, and of course Cheap! We shall see.

[kdh]

It’s by no means a bad exhaust and perfect for track use I would say. Fine on the road too, unless you’re super fussy like me.

[ATM]

5 hours ago, kdh said:

inside the cabin.

 

No

 

It's a cockpit

[kdh]

Sorry Squadron Leader.

[ATM]

1 minute ago, kdh said:

Sorry Squadron Leader.

Bombs away