Thread: Exhaust Options - 300 Tdi

Hi All

Gale Banks says that for power a turbo motor should have a 20 degree ever increasing cone and thats from hundreds of hours of dyno testing.

Personally I believe that mufflers on diesels are exhaust brakes and havent seen an exhaust upgrade in size that wasn't beneficial to some varying degree.

The turbo is a very expensive muffler and usually all that most vehicles need unless you do deep water crossings and would like to slow water from entering the turbo via the exhaust

If fitting bigger turbo and exhaust then it might be a good idea to get the injection pump tuned to the new mechanicals as it may be possible to lean the motor out.

Regards Mark

I ended up fitting the 3", it seems to have opened it right up

I can now hit 100 in 4th if need be and it's not overly loud with the muffler on

Although when the turbo loads up is does get a noisy

Originally Posted by marko66

Hi All

Gale Banks says that for power a turbo motor should have a 20 degree ever increasing cone and thats from hundreds of hours of dyno testing.

Personally I believe that mufflers on diesels are exhaust brakes and havent seen an exhaust upgrade in size that wasn't beneficial to some varying degree.

The turbo is a very expensive muffler and usually all that most vehicles need unless you do deep water crossings and would like to slow water from entering the turbo via the exhaust

If fitting bigger turbo and exhaust then it might be a good idea to get the injection pump tuned to the new mechanicals as it may be possible to lean the motor out.

Regards Mark

All that EXCEPT, you don;t lean out a diesel.......unless your talking about depriving it of oxygen( lean of air) by adding to much fuel and melting the pistons

I'm guessing Mark has fallen into the common trap of assuming issues with petrol engines might apply to diesel engines.

Your diesel engine will love you more, the leaner you run it.

Originally Posted by Bush65

I'm guessing Mark has fallen into the common trap of assuming issues with petrol engines might apply to diesel engines.

Your diesel engine will love you more, the leaner you run it.

Yep, very common misconception, with those that haven't been around desiesal engines

Originally Posted by marko66

Hi All

Gale Banks says that for power a turbo motor should have a 20 degree ever increasing cone and thats from hundreds of hours of dyno testing.

...

A turbo needs a diffuser immediately after the turbine exducer (where the gas exits from the impeller). A 20 degree included angle cone makes for an excellent diffuser, particularly with axial flow turbines, fans and compressor.

The turbines used with small turbos are radial inflow - a type for which has received virtually no treatment in classical or any other texts on the subject of turbines etc.

The turbine on Jock's new turbo has an exducer diameter of approximately 44mm. The diffuser in his turbine housing is not conical, but rather more complex, which makes me believe that Garrett have carried out comprehensive computer modelling using computational fluid dynamics (CFD) software to arrive at the shapes used (mad if they didn't, if they want to stay competitive).

One million hours of dyno testing will not reveal the complex behaviour that good computational fluid dynamics modelling will show.

The exit of this diffuser where the dump pipe connects is 70mm inside diameter (for everyone claiming the exhaust shouldn't be greater than 2-1/2", should know that 2-1/2" is 63.5mm).

This exhaust was with the VNT fitted?.I think most people though it was with the OME model. Pat

Yes that is with the VNT fitted