Exhaust Manifold heat exchanger??

[clackdwack Member Find all posts View Profile Close clackdwack]

hi all
I was wondering how a steel 1/2 pipe with fittings on the end and mounted to the exhaust manifold would go as an exchanger, because the heat transfer and radiation from the manifold would be quiet high. But how high would the manifold temps get, and would they be to high for the wvo??

Has anybody though of this?? and tried it out??
the start up time on diesel would probably be halved then waiting for the water exchanger to heat up..

cheers mike

[Guest Close David]

Re: Exhaust Manifold heat exchanger??

This topic comes up every so often so you may find it helpful to look at one of the last threads on the subject.

In answer to your question, Manifold temps can get over 500oC which would be just a tad on the warm side by about 400oC for heating oil.

Yesterday I did a purge on my fuel lines after leaving some blend in my tank which was too oily for starting without throwing some meth down the inlet.
I found from dead cold, in my 300D it took a little less than 200Ml of fuel to allow the coolant to well and truly come up to operating temp at a fast idle. At todays prices, that's about .26C worth of Diesel or .07 C worth of bio if your brewing your own.
Even if one errs on the cautious side and doubles these figures as may be the case if the car was driven instead of idleing, I can't see it would be at all worth while to try and save any fuel by adding more modifications to a vehicle to save a few cents but gain a lot of extra added risks to the engine.

Of course with longer warm up times, more parts of the engine can come closer to ideal temp as well, not just the coolant.

Given the amount of fuel used in warm up and the savings to be made by using oil once the engine is hot, I am even more of the opinion that taking longer to heat the engine on Bio or Diesel before changeover is a far wiser thing than being in a rush to get onto oil as soon as possible to save a few cents.

[clackdwack Member Find all posts View Profile Close clackdwack]

Re: Exhaust Manifold heat exchanger??

hi david,
thanks for the advice i will just stick with the water exchanger,
cheers mike