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Lets make some noise (exhaust system discussion thread)

colin129

PCGB Member
Member
Post all your exhaust system stuff here!

Here's my issue:

One of the aspects of my car which has disappointed me is that it is sometimes a little too refined, a bit quiet, even when being extended.

Imagine my surprise then, on the way down to Le Mans last month, hitting the long tunnel on the Autoroute, drop own to 3rd & give it some beans. I was expecting the usual, not quite loud enough mild disappointment, but not this time, really quite fruity. Must be something wrong. On closer aural inspection, the back box seemed a little noisy & perhaps it might be blowing.

I have my annual service/MOT booked for next month so I called them up & asked them to add an exhaust check to the list. I had a little discussion about the back box & they said that it is most probably the original back box & they are starting to see them going now (20+ years isn't a bad innings after all!).

The options are:

Replace with the standard system, approx cost £1,500+

There used to be a Dansk stainless steel back box which will 'improve' the noise for approx £500.

Go for a G-pipe [8D], lots of noise & only £150 odd.

I already have a de-cat pipe & I would like a bit more excitement in the noise department but I have heard that the combination can be too much, too loud for some tracks, not that I really go on track but I wouldn't want to rule it out in the future. What's it going to be like in general use, cruising on the motorway etc.

My mate has a Heyward & Scott system on his 3.2 & it sounds like a racing car, really loud, but it doesn't half drone on the motorway. Am I in for that sort of noise with the de-cat/G pipes combo.

Budget is important, so I'm not that keen on shelling out £1,500 on the standard system, but I am more inclined to use the car for touring, so I don't want to intrusive a note.

Maybe I'm imagining the whole thing, I did have my ears syringed a few weeks ago [8|]
 
The final silencer is still proving to be a very robust piece of kit. Although, there are a few cases where it's split when combined with a cup pipe. I would get it thoroughly checked over first in case it's something more serious like a broken head stud causing the extra noise.
 
I have the Dansk system on my 964, with g pipe and cat bypass. It sounds fantastic - like a can am racer, but is very loud. It's marginal on 105db track day noise test. It's fine on long trips, as noise goes backwards away from you, mine is single exit as is RS style. Horses for courses, depends what you like, but it does get you noticed, and in town it's perhaps not for everyone.
 

ORIGINAL: Steve Brookes

The final silencer is still proving to be a very robust piece of kit. Although, there are a few cases where it's split when combined with a cup pipe. I would get it thoroughly checked over first in case it's something more serious like a broken head stud causing the extra noise.

What other symptoms would go along with that?
 

ORIGINAL: colin129


ORIGINAL: Steve Brookes

The final silencer is still proving to be a very robust piece of kit. Although, there are a few cases where it's split when combined with a cup pipe. I would get it thoroughly checked over first in case it's something more serious like a broken head stud causing the extra noise.

What other symptoms would go along with that?

Most likely a bit more vibration from the engine and an oil weep on the affected cylinder. I'm not trying to frighten you I'm just saying that we're all sensitive to the slightest changes in our cars. So if it's now noisier than before, have a thorough check over to find where the noise is coming from. Hopefully it's a problem with the exhaust itself or one of the couplings. But it's best to find the 'new noise' before putting on a louder exhaust component that could mask a more serious problem that is developing elsewhere.
 
Absolutely Steve.

If they find it's something else then I'll leave the exhaust system alone.

The question really is, if I need to the replace the back box, what is the best option for me.
 

ORIGINAL: colin129


The question really is, if I need to the replace the back box, what is the best option for me.

Cost wise, you can't argue with a G pipe. With your de-cat, it'll be 105+ db which is too loud for trackdays. However if you change the standard tip (that you still need to fit to the G pipe) to a round one, you can fit a decibel devil if you ever want to do trackdays. The devil will reduce the noise by 2 or 3 db and just bolts on when you need it.
 
Hi Colin

I have a Cup Pipe if you are interested. I bought it sometime back from Type911 or Porscheshop cant remember which without looking for the receipt but it cost over £200 with delivery and I have been storing it ever since. I only used it for about 50 to 100 miles before deciding that I prefer the standard sound. It did sound very nice though and there is a big weight saving. I have not advertised it yet but if you are interested I will sell for £100 + P&P inc brackets. Apart from being a little discoloured (stainless steel) its as new.

Gary
 

ORIGINAL: Gazza3501

Hi Colin

I have a Cup Pipe if you are interested. I bought it sometime back from Type911 or Porscheshop cant remember which without looking for the receipt but it cost over £200 with delivery and I have been storing it ever since. I only used it for about 50 to 100 miles before deciding that I prefer the standard sound. It did sound very nice though and there is a big weight saving. I have not advertised it yet but if you are interested I will sell for £100 + P&P inc brackets. Apart from being a little discoloured (stainless steel) its as new.

Gary

Excuse my ignorance, but are a Cup pipe & a G pipe different things?

This YouTube video compares a Cup pipe vs Cup pipe & cat bypass pie, although it's hardly conclusive:

http://youtu.be/7Pzx6IQ3Oaw

I also found this historical piece which is a bit more conclusive, note the complete change of wardrobe with the change of exhaust [;)]

http://youtu.be/iYcPJihLhAI
 
Yes the cup pipe replaces the primary silencer and G-pipe replaces the final/secondary silencer. Replace one only or it's too noisy. Obviously you can get a cat bypass also.
 
My thoughts, nay findings;

My grey 964 had a cat bypass and G pipe and with standard tail pipe - I liked the sound. One day I swapped the tail pipe for a 102mm round (the common ones you see on fleabay or Porscheshop etc). A different and louder tone/note - I liked the sound. Curburough I was something like 104db - close enough...

My red 964 has that same cat bypass (swapped it over) but now with a cup pipe and this time no G pipe (just the standard secondary muffler) with that same 102mm tail pipe. Much more 'gruntier' and what sounds like a lower frequency (the 'grunt'). Here's the major difference... the inside of the cabin is quieter on those m'way and a'route journeys. This is not down to any of the exhaust arrangement - it's all down to the fact I had the engine bay sound deadening replaced in full (it's cheap stuff). However, that 102mm tail pipe was a tad too annoying for my neighbours in a built up area (would occasionally set off parked car alarms!). Swapped the tail pipe to a 98mm (I think 98 anyway) - mucho better and sounds just right.

So my experience is that there are many variations or options when you think full end-to-end - from the header square flange (that bolts to the cat) to the very end of the tail pipe. Experiment - you can always recycle what you don't want or like back on fleabay.

Right now, I've just moved to the country (stones throw from RPM) from a built-up and traffic rammed SW12. Ha, now with open road space, flooring the throttle (on change-down) in 3rd or 4th under load gives the most beautiful roar ever - and the biggest grin!

BTW - I still have my badly bruised grey 911 on a SORN and just can't let go of it....
 
Cheers Colin... foglight? hmmm... they came off the other week for some replacement RS ducts. TBH, they wern't actually in good nick as it turned out (cracked on closer inspection).
 

ORIGINAL: colin129


I also found this historical piece which is a bit more conclusive, note the complete change of wardrobe with the change of exhaust [;)]

http://youtu.be/iYcPJihLhAI

Oi....cheeky swine! [:D]
 
The news is worse than I thought. [&o]

There is a blow where the near side heat exchanger meets the de-cat pipe, which means that I will need a replacement heat exchanger. JZ Machtech, where it is currently in for an annual service said they'd be inclined to leave it for the time being as it's only a bit of extra noise & it passed the MOT. They could fit a new gasket & some sealer as a temporary fix, but he said it wouldn't look very nice.

A new heat exchanger is, wait for it, £2,417 + VAT [8|] so I have a year to save up for it or try to get a 2nd hand one for a sensible price.

Any suggestions?

Fair play to JZM, I have nearly a page and a half of advisory items, but the actual additional extra work that is required is not even £200 worth, which includes new bonnet struts which he said wasn't really worth doing as they don't last that long but I decided to have done anyway.

Next year, however, will be an expensive one as there are 1 or 2 items which will almost certainly need to be sorted next time round.

Edit: Who or what are Bischoff?
 
Colin,

What you have has affected a few of us. It has been solved by cutting off the flange and welding a newly fabricated one on. Expect to pay about £300.
 
Thanks Steve, I will run that passed them & see whether they can do it for me.

tbh, he didn't seem that fussed about it as it passed the MOT alright, although it will obviously only get worse.
 
In case they say it can't be done, below are some pics of mine before and after. Someone got a similar job done in you part of the country but I can't remember who or where at the moment.

SDC10524.jpg


SDC10563.jpg


SDC10615.jpg


SDC10613.jpg
 
Thanks Steve, I'll run that by them.

If anyone darn sarth can remember where they got this done, please let us know.
 

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