Thread: Discovery 1 300Tdi mufflers - Wheres the sound!

[QUOTE=rick130;1270371]
Can't recall $, four years ago mate, the brain can't remember what i did yesterday




i like that

so even though it has a resinator etc etc it would make it sound different just by having a 3" compared to standard size exhaust i would asume? and are you going to do what rijidij done and get a old truck engine or are you going to find a 4bd1T somewere? it would be good because then you will have disc brakes all around compared to stupid drums like on my county and a better dash than the piece of S#@T dash in most countys!!!

Yes, I think being 3" really amplifies the noise.

Initially, being just a straight through pipe it was painfully noisy.

Years ago when a mate and i were dyno testing race car exhaust systems we had made a box full of merge collectors, diverging cones (megaphones) and dump pipes in 2", 2.25", 2.5" and 3"
(all on a 1600cc engine )

The 3" system, even though it came from the same headers and merge collector was so loud it hurt
The amplification in noise really surprised us.

Sorry this may be a stupid question but what's the purpose of the dump pipe or what's the upgrade?

Originally Posted by **Discovery300Tdi**

Sorry this may be a stupid question but what's the purpose of the dump pipe or what's the upgrade?

Umm, in which context ?

In a turbo system the dump section is generally the bit straight off the turbo exhaust housing and first little bit of pipe, either or or both, it's sort of an interchangeable term.

I'm probably not even using it correctly sometimes.

Originally Posted by rick130

Umm, in which context ?

In a turbo system the dump section is generally the bit straight off the turbo exhaust housing and first little bit of pipe, either or or both, it's sort of an interchangeable term.

I'm probably not even using it correctly sometimes.

ah ok so how come alot of people refer to it as a "dump pipe" if it's part of the exhaust system? Is it a major part of a upgrade to the exhuast system? Obviously if you go bigger there you must do the same to the rest otherwise you'll get a restriction of air flow..

I cut the rear muffler off my disco yesterday (i have already removed the big centre one) makes it sound alright suprisingly, the turbo whissle at idle and on take off is cool

Originally Posted by **Discovery300Tdi**

ah ok so how come alot of people refer to it as a "dump pipe" if it's part of the exhaust system? Is it a major part of a upgrade to the exhuast system? Obviously if you go bigger there you must do the same to the rest otherwise you'll get a restriction of air flow..

Traditionally the dump pipe most people refer to is the cast bolt on bit straight off the turbo, usually a 90* bend.
On, say, Nissan TD42T's the stock one is a restriction if you go up to a 3" exhaust as it's only around 2.25" or so, so fabricated or cast ones are available that are a true 3" bend to remove that restriction.

This isn't possible to do on a stock 300Tdi obviously as the dump section is cast as part of the turbine housing and exhaust manifold, but that short bit doesn't really stuff things around too badly, and the turbo isn't the most efficient anyway. It didn't take much work for me to open the stock housing up to match the 2.5" exhaust that I used that was then flared up to 3".
If you go to an MTQ TD04, or a VNT, or Bruce Davis' 300Tdi turbo upgrade you could make a true 3" dump pipe for them.

FWIW when i first dropped the exhaust off the dump a few months prior to making the new system, there was a mig bead between 4 and 6mm deep around the inside of the flange projecting into the system.
It looked like a hell of a restriction, so out came the die grinder and I ground it out flush.

The bum dyno couldn't feel any difference at all.

well had some time and after a few beers and encouragement from a mate, the centre and rear mufflers got lopped off yesterday.

sounds like a bit of a truck now, moderately louder in the cabin at 80km/hr. yet to get it up to 100km/hr (will do tomorrow morning) its not unbearable, just a lot louder than before.

sounds like a bit of a hoon mobile if you boot it in the carpark etc.
and definately sounds like a truck when under load.

turbo boost does seem to be acheived easier (with less load/throttle) though could just be the placebo effect
yet to take EGT readings.

David.