W124 24Valve Diesel Induction System

[TVRTASMIN]

Does anybody understand what all the butterfly valves etc do in the 24 Valve E300D engine.

I've removed the aluminium induction system for cleaning, as the EGR system has coated the internal ducts with a fine exhaust powder.
I have blanked off the EGR valve at the exhaust manifold and plugged the vacuum hose top the first butterfly valve just after the air filter.

What i need to know is what the other two butterfly's in the induction plumbing and if any form of tuning is possible.

Thanks in advance.

Ian

 

[bolide]

The butterflies change the length of the inlet tract. I believe the idea is that it makes it longer at low revs (for more torque) and shorter at high revs (for more power). It's all pneumatically driven, as is the EGR and the link to the auto box to soften gear changes

I think you could try and tune it but, unless you have the time & resources to better the efforts of the Mercedes development engineers, I think you might be better off leaving it alone

The best tuning procedure for a Multivalve is a clean air filter and correctly-adjusted throttle & kickdown cables

Nick Froome
www.w124.co.uk

 

[TVRTASMIN]

Thanks Nick, i thought the butterflys might be some kind of power delivery cushion.
The Cosworth 24Valve V6 on the Ultima Scorpio has something similar.
http://www.fordscorpio.co.uk/vis.htm

By the way, have you removed an inlet manifold on the E300D and found the inlet ports to be restricted in any way by exhaust soot?
I've yet to remove mine (gasket arrived Friday).
If the rest of the system is anything to go by, i would expect lots of soot to remove when i dismantle mine.

Cheers
Ian

 

[bolide]

By the way, have you removed an inlet manifold on the E300D and found the inlet ports to be restricted in any way by exhaust soot?

Yes - on every multivalve I've had the inlet manifold off!

The EGR system has a lot to answer for. The state of the crosspipe, inlet manifold & ports is always appalling due to carbon crud build-up

Nick Froome
www.w124.co.uk