RHKTriton wrote:Well Tritoneers, I've been running with EGR blanked off for over 6k now and no probs. Thought I'd check the inlet to the manifold (where hose from Intercooler connects) and WTF there's a throttle valve!!
Just pulled mine off and the 2.5 has it too. The clamp wasn't exactly overtight and I got another full turn putting it back on to get the paint dob back on top again so the other clamps are getting checked too.
Biggest butterfly I've ever seen apart from on much bigger engines.
Spring loaded in the open position so we can assume disabling the electrics driving it will leave it open but I suspect it only closes on the over-run. That's based on the assumption it's linked to the EGR valve.
Although the exhaust before the turbo always has more pressure than the boost pressure that might be less pronounced on the over-run? Restricting the intake, before the point the EGR valve dumps it's toxic load into the manifold, would cause a vacuum and increase the toxic flow. Maybe it operates at light throttle, off boost, to increase the flow so it actually burns the stuff twice?
It might be beneficial by providing additional engine braking and could be the source of that subtle roaring I can hear on the over-run? There is certainly excellent engine braking right down to idle that I think?? is more pronounced with the EGR blocked although it's not something I was looking for.