Exhaust Gas Temperature

[piper106]

When running at a steady 70 to 80 MPH (115 to 130 KPH) on level ground, no head wind or tail wind, what is the exhaust gas temperature? Pre or post turbo.

I was reading on one of the other web sites of guys playing around with aluminum for the exhaust system tubing downstream of the turbo. I know diesels have much lower EGT than gassers, but an aluminum exhaust sounds a little lunatic to me for a car that sees the highway unless EGT is lot lower than I think.

Piper106

 

[GoFaster]

I don't have a gauge, but there's someone local with a chipped/injectored TDI who has a gauge right after the turbo.

400 F at idle.

700 - 800 F at highway cruise.

1100 F pedal to the metal at 160+ km/h.

 

[paramedick]

I'm seeing between 650-750 degrees F on the interstate with the cruise set at 80 mph. A3 Jetta.

Temp dependent on whether going up a grade and using more throttle.

 

[Powder Hound]

[ QUOTE ]
I know diesels have much lower EGT than gassers, but an aluminum exhaust sounds a little lunatic to me for a car that sees the highway unless EGT is lot lower than I think.

Piper106

[/ QUOTE ]

And right you are! The lowest of the low temps reported even at idle are enough to make an aluminum alloy have the strength of tupperware. The cheapest mild steel tubing would be much much better, cheaper, easier to weld.

Aluminum would have advantages in fabrication because of its softness, corrosion advantages because of resistance to rust. But the weakness at temperature makes it completely unsuitable for an exhaust system.

If that someone is really using aluminum tubing, it is most likely aluminized steel. Aluminized to help with resistance to rust. A good powder coating for very high temperatures or even chrome plating after fabrication would work as well, since aluminized coatings will be gone on any area that had to be welded.

 

[dremd]

As a former steel fabricator turned aluminum fabricator.

I'd guess that it would work fine for a Cat back. I'm not sure how it would sound though.

That said Titanium would be a better choice for a lightweight exhaust in terms of strength at temperature and lightweight and always great sound.