Exhaust, higher flow but quiet?

[Franco Cozzo]

I'm looking at getting the exhaust done on my TDCI Focus from the turbo all the way back, including a high flow cat when the tax man delivers his goodies next month

I'm only looking at going to mandrel bent 2.5" system, as there is no point in going bigger because you start going backwards.

Is it possible to have a high flow system but still keep it quiet? I don't want to attract attention and I assume a diesel 4 cylinder would sound rather odd with a loud exhaust.

Also whats the cost difference between mild steel and stainless, what are the benefits to stainless besides it probably won't rust? Is that worth the increase in cost?

Thanks much.

[cs123]

I take it before you start this exercise you know how much power you will be picking up and it will be worth it. And does fitting the exhaust affect the engine management system?

SS costs a lot more $$ than mild steel.

[mik]

i`ll leave the first question to the experts, but for the stainless question, the way i look at it you have to decide how long you are going to keep the car, i put a stainless system on my AU in 2005 as i usually keep my good cars for long periods, it cost $800 ish but it will out last the car, if your gonna trade/sell it in couple of years, i think it`s a good thing, a prospective buyer will like the thought of never having to replace major parts of the exhaust.
i have no proof of this but an engineer once told me two bits of exhaust one mild steel the other stainless identical size, they will have a different sound to them , his description of stainless "it barks", listening to the note on mine i`m inclined to think he`s right.

[fat4D]

Originally Posted by mik

i`ll leave the first question to the experts, but for the stainless question, the way i look at it you have to decide how long you are going to keep the car, i put a stainless system on my AU in 2005 as i usually keep my good cars for long periods, it cost $800 ish but it will out last the car, if your gonna trade/sell it in couple of years, i think it`s a good thing, a prospective buyer will like the thought of never having to replace major parts of the exhaust.
i have no proof of this but an engineer once told me two bits of exhaust one mild steel the other stainless identical size, they will have a different sound to them , his description of stainless "it barks", listening to the note on mine i`m inclined to think he`s right.

I would be believe the difference in sound, when I put the exhaust on my turbo I got stainless except for the middle muffler which cuts out the tinny sound. I've heard a fair amount of xr6t's with the same system but all stainless and think mine has a very distinctly different sound to the rest. I could be wrong thou?

[GTBenny]

For turbo petrol cars I can confirm that installing a stainless dump pipe will give a different sound. When I installed the stainless dump pipe on my FG Turbo the sound changed to a slightly tinnier note at idle. Still sounded good in my opinion. The reason for this is the thickness of stainless used was much thinner than the factory cast dump. At WOT the tinny note could not be heard.

Now a performance exhaust can be made for a turbo car without being overly loud. To achieve this you have to use the largest straight through mufflers you can fit in the space you have under the car. A good example of this can be found by looking at the factory FG turbo exhaust, all straight through mufflers with a respectable moderate note.

Benny.

[Franco Cozzo]

Originally Posted by cs123

I take it before you start this exercise you know how much power you will be picking up and it will be worth it. And does fitting the exhaust affect the engine management system?

SS costs a lot more $$ than mild steel.

Turbo spools up a touch quicker just with factory tune, but its only really going to have an effect after the car has been remapped.

I've got a bigger front mount intercooler sitting here for it too, its got a cold air intake on it, just covering all bases before it goes in for its tune.

The car is going to stay in the family after I'm done with it, so it might make sense for SS, depending on costs, I'm guessing for a turbo back exhaust I'd be looking at around $1500+ for mild steel anyway right?

[Franco Cozzo]

With the mufflers, would something like this work?

http://www.ebay.com.au/itm/HOOKER-AE...item27bb05e58a

Looks a bit small though.