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Old 12 January 2012, 18:44   #31
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Yes I know what freshwater cooled is. I was responding to Erin's idea of using raw water cooling. I wouldn't on an engine of this origin and value.

Not sure about that exhaust filter idea.
Given:
the volume of dry exhaust in an engine of this HP range,
the need to have near zero backpressure, and
the particulate size range (~2 um)that you need remove to accomplish your objective...

That filter is going to have a cross sectional area measure in many many square meters. And its going to clog up fast.
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Old 12 January 2012, 18:49   #32
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Originally Posted by captnjack View Post
Yes I know what freshwater cooled is. I was responding to Erin's idea of using raw water cooling. I wouldn't on an engine of this origin and value.

Not sure about that exhaust filter idea.
Given:
the volume of dry exhaust in an engine of this HP range,
the need to have near zero backpressure, and
the particulate size range (~2 um)that you need remove to accomplish your objective...

That filter is going to have a cross sectional area measure in many many square meters. And its going to clog up fast.
The DPF was probably fitted as standard by BMW which is why he's looking at reusing it.
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Old 13 January 2012, 00:27   #33
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To complicate the exhaust further, I am going to run a particulate filter to clean up the emissions...
My theory being that the exhaust is so short with little backpressure, that the gas will pass through quickly and the wrap will contain what does hang around, hopefully limiting much radiation.
A DPF is a difficult programming task...hope you've got the experience or have access to it. What are going to do with the trapped particulates?

Exhaust heat - sounds like you're planning re-writing thermodynamic law. In simple terms, 200kw is 200kw, regardless of gas velocity and back pressure. Consider this...if you've got boiling water flowing down a metal pipe are you saying the shorter the pipe the less hot the pipe gets?
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Old 13 January 2012, 04:00   #34
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Originally Posted by Leapy View Post
A DPF is a difficult programming task...hope you've got the experience or have access to it. What are going to do with the trapped particulates?

Exhaust heat - sounds like you're planning re-writing thermodynamic law. In simple terms, 200kw is 200kw, regardless of gas velocity and back pressure. Consider this...if you've got boiling water flowing down a metal pipe are you saying the shorter the pipe the less hot the pipe gets?
I am not expecting the exhaust temperature to be lower, if anything it will probably be higher. I was working on the basis the shorter the exhaust length, would equate to less metal to radiate the heat into the engine box and the thermal wrap would also help reduce the heat radiation, hopefully leading to lower temperatures in the box.

I am still looking at the diesel particulate filter idea, my initial thoughts are to mount the filter on the transom above the Castoldi, as it is dead space. This would also get another very hot item outside of the engine box.

There is a system made by Dinex that has a removable core that you take out and clean and refit once in a while. The crap coming out of it is toxic and has to be disposed of properly. This system is designed to cope with traffic use in cars. the more stop start use will clog the filter quite quickly, requiring it to be cleaned annually. If it is used in mostly middle to high speed situations, it may only need cleaning every couple of years. 4' from the turbo is a good distance for the filter as it will burn a lot of the crap off, but will get very hot doing it. The other option is as mentioned above, to use the original car unit and mapping. The other big problem is that the ceramic based core does not like thermal shocks, such as getting dunked in a wave whilst red hot, so this will need some thought as well.

I realise that this project is all sounding a bit Heath Robinson, but I enjoy exploring options and alternatives to the norm. Most companies stick to tried and tested as it is the most economical route to go with least risk. As this is a private project for my own use, I am happy to explore an apparently dumb route on the offchance that something worthwhile can come out of it. The speed that technology jumps these days often means that what wasn't possible 5 years ago is common place now.

Thanks for your input.
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Old 13 January 2012, 04:05   #35
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Nice answer

You'll have great fun doing it. There's hurdles to over-come but I like your can-do attitude. Good luck :thumbs
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Old 13 January 2012, 04:11   #36
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Originally Posted by captnjack View Post
I was responding to Erin's idea of using raw water cooling. I wouldn't on an engine of this origin and value.
Poor explanation on my part. I was referring to raw water cooling of the heat exchanger, not the engine block. I'd agree that it would be mad to send brine through the engine.
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Old 13 January 2012, 10:26   #37
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I'm with Leapy, like your attitude, no doubt you will sort something.
Still not convinced on the DPF though...
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Old 13 January 2012, 13:55   #38
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Good attitude.
I actually like the filter idea the more I hear about it. The heat and an air radiator is still concerning me though.
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Old 13 January 2012, 13:57   #39
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Poor explanation on my part. I was referring to raw water cooling of the heat exchanger, not the engine block. I'd agree that it would be mad to send brine through the engine.
At least on this side of the pond
"raw water cooled" = sending salt water through the engine block
"freshwater cooled" = using a heat exchanger.

I don't know what to call an air radiator on a boat.
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Old 13 January 2012, 14:41   #40
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I don't know what to call an air radiator on a boat.
Unique?

Going to make a good build-a-boat thread though
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