Stainless 2.5" exhaust, on two or 3 boxes

[GTD.]

I want to fit a Stainless Steel 2.5" exhaust to my GTD (91 SB IDI engine)

I was looking in the Bastuck Cataloge and they do systems for my car and engine but there three options for the silencers (mufflers to you in th US)

The do a front center and rear silencers but they also produce a streight though bypass pipe, instead of the front or center silencers.

Whats the best option to go for and why?

1. Front Silencer, Center Silencer & Rear Silencer
2. Front Bypass, Center Silencer & Rear Silencer
3. Front Silencer, Center Bypass & Rear Silencer
4. Front Bypass, Center Bypass & Rear Silencer

Thanks

[Dr. Diesel]

on my jetta, a silencer-less 2.5" was too loud. now i have a dynomax superturbo muffler on the rear, and it's very comfortable.

[RabbitGTDguy]

My old setup for the built IDI TD 1.6, and the setup I'm using for the m-TDI Rabbit.... 2.5 from the turbo back, TT mandrel bent, no silencer, flowmaster muffler = Mmmm...very nice sound. Used to be able to hear the turbo spin at idle like a truck. Not loud either...just "tuned"


Joe

[VWRacer]

The "muffler-ectomy", or rear silencer removal, is one of the most popular TDI mods here in the US. It hacks about 20 lbs off the car and adds no appreciable noise. Here the TDIs come with a center 'resonator', or straight-through silencer, plus the stock gasser rear silencer. Only the rear silencer is removed in the muffler-ectomy.

That isn't one of the choices you present above, but number four comes closest, and I notice that everyone who's voted chose number 4. One silencer is plenty for a turbocharged diesel. Do it - you'll like it!  

[GTD.]

At present from factory it was fitted with the small front box and the rear box, i guess looing the front box wont make much difference to the sound.

I'm in England and over here I dont think i could get away with loosing the backbox due to the annual MOT (ministry of transport test) in germany you have to have TUV approved pars so they have to fit all three mufflers :cry:

This is an IDI engine btw, the 1.6 SB intercooled GTD

[3beejay3]

When my exhaust rotted out a few years ago I had the exhaust installer cut the pipe off at the back of the catalytic converter. We then installed a a piece of stainless straight pipe(I'd have to check if it was 2.25 or 2.5") all the way out the back- no muffler or resonator.
The car isn't appreciably louder than it was - heck it makes more engine noise under the hood than what comes out the back anyways, always did.

The car is now at least 20-25 lbs lighter.

BJ

[VWRacer]

GTD, some States here require a visual check to see if a car has all the required parts, so I know what you mean about the MOT check. The key to a quiet exhaust system that doesn't negatively impact performance is a straight-through silencer (you can literally look through it from one end to the other) and as large a pipe diameter as you can legally and practically fit to the car - i.e., NO flow restrictions, such as pinched pipes and/or non-straight-through silencers. The perforated inner pipe of a straight-through silencer offers virtually no flow restriction whilst the padding inside the outer shell absorbs what sound does make it that far.

Good luck!  

[mk1vdub]

dunno if this is too late and you've done it already...
I'm running the same engine in my mk1 as you know simon, and I've just recently removed my back box (a straight through piper thing) and replace it with a straight pipe leading to a turned down end just before the bumper (this was partly in an effort to hide some of the smoke I'm making! :lol: ) leaving only my origional middle box in - it is not noticable louder at all and when I get round to makeing up a better downpipe I will make up the whole rest of the system straight through with no boxes as I'm pretty sure it will be perfectly accceptable for noise, theres no way it'll be as loud as a petrol motor with an after market system as someone said above all my noise comes from the engine itself anyway.

[GTD.]

Cheers Paul, I aint done it yet as I'm skint, the cars sorn at the moment as well :cry:

I wonder if powerflow would make a pipe from the center silencer back over?  after all its there boxes that rust not the pipe work.

Gonna put her back on the road in spring, wonder if it will pass MOT if unsilenced?

[mk1vdub]

ah shame mate, I know whatcha mean about being skint .

I'm sure powerflow could make you up a pipe from the centre box finishing in whatever you like'd at the rear (turn down or specific tail pipe or whatever) and I'm sure I heard somewhere that you can actually ask them to use some higher grade of stainless too :?: but it does seem to only be the boxes that are a problem anyway

as for the MOT I still had my back box on when I went throught mine but I'm pretty confident that it wouldn't matter if you have any silencers or not as long as the noise is acceptable? its not like the silencers help with emmissions or anything like a cat, I don't even think theres a specific decibel limit or anything?

I'll let you know what the noise is like once I've got round to doing my whole exhaust straight through