Thus making the argument against K&N filters and the like (?)...

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-Ken Harris
1984 Mercedes 300SD
2001 VW Passat 1.8T
2004 Harley Davidson FLHRSI
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Der Dieselfanatiker

Packing more air in the cylinders is like upping the compression ratio. Even with out more fuel being added it will increase the power output and fuel efficiency of an engine.

Mercedes probably didn't wrap the cylinders because it was more expensive. You didn't see cars doing insulated exhaust systems until the late 90's. The 300SD wasn't aimed at high end sports car market so it didn't make the cut in the cost/beniffit analysis.

Conn

You must also consider that upping the compression ratio increases the pumping losses of the engine. Nothing in life is free. By squeezing the mix harder you are inducing negative torque that isn't likely made up for by the expansion of air alone. Raising the boost without adding fuel does the same thing. Whenever you raise the boost on a turbo you are also increasing the backpressure the same amount. So without more FUEL you actually loose power to raise boost on a diesel engine.


FUEL!












FUEL!

Wrapping the exhaust and turbo like the Wadeperformance kit won't hurt anything. It will keep more heat in the exhaust stream and this will help keep exhaust gas velocity up. Wrapping the exhaust turbine section of the turbo won't increase temps on the intake side. Wrapping will likely decrease turbo lag. I have done this on a truck. It works. Kalifornia turbo cars have an ARV, or air recirculation valve (at least the 84's do) This valve allows some of the boost to escape back to the intake side of the turbo under part throttle cruise situations. I am guessing it worked simultaneously with the EGR system. It is easy to remove the spring diaphram section of the ARV and drop in a 5/16" nut under the spring to preload the ARV closed. Disconnect or plug the ARV vacuum line to totally disable it. Now the turbo works just like a non-EGR, non ARV turbodiesel. Boost is much more immediate and satisfying. With the ARV functional "matting" the accelerator on the highway was very dissatisfying. It takes a while for the ARV/EGR system to shut down and boost to build. With it all disabled the boost is instant. Try it, you'll like it. RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

Here's an interesting link...http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4593012389

I would not wrap a street car/truck headers due to shortened life.
The benifits of wrap are so small as to be equivelent of removing the STAR from the hood to go faster !

It cooks the carbon out and causes the mild steel to loose it's strength.

It would be better to do what most japanese manufacturers do with the down pipe/s.....use a loose fit stainless or aluminium cladding. This is primarily to reduce radiated heat.

Wrap a set of RV headers and your maybe get one season out of them.


.

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"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

the truck the turbo is a lot further from the intake (v8 right?), so the benefit would be greater. on the benz the plumbing is all right there and being cast iron it would be more likely to warp from excess heat.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

After reviewing my Thermodynamics book, I can say that wraping the exhaust manifold and cat will help. As far as the turbo goes, efficiency will improve because the reduction in heat loss before the turbine will have the same effect as burning more fuel. Diesels will always improve efficiency and power with more boost using the same amount of fuel. Yes adding more fuel will boost the power more, but as I stated before fuel cost money.

The system can be viewed as a compound Brayton cycle with a very poor (lossy) regeneration cycle feeding back between the compressor stages flowing from between the two turbine sections. The header wrap will reduce the energy in this lossy feedback system and result in a net gain.

The only issue is if the manifold can be wrapped without it warping or cracking. I may just pull the exhaust manifold off and spray it with ultra high temp white paint and wrap the hell out of the cat ( I don't care what happens to the cat).

By the way, I finally got the new air filter in the car and it help with acceleration a bit.

Conn