Heater Box Modifications
Discussion
Well, the heater in my car is so ineffectual, it is really unpleasant to drive, so I removed it, and disassembled it. Its the PVC? folded and welded box. It seems the airflow is all wrong inside the box, the air flow has to be bent through two 90 degree corners by the time it leaves the box for the demist or footwell holes. So I have decided to make a small air diverter, to get the airflow increased. So far, with the Matrix removed and armed with a home-made manometer I am getting twice the fluid displacement (with me cardboard deflector model), and aka 40% more air velocity out the vents. Not sure what the improvement will be when the Matrix is reinstalled. Just wondered if anyone has actually measured the improvement from any mods in this box ?
-Jim
-Jim
Hi Matt,
If you give me the dimensions of your mod, I can test it in cardboard, see what increase there is. It may be much the same as I am getting, in which case I may as well use your mod.
One thing I did notice is that the air flow is very uneven as is, with almost all the flow comming out by one edge, for both the demist and the footwells. I haven't put much effort into the face vents, just blocked them off with tape. However with my cardboard diverter the face vent output seems to reduce to almost nothing until you block off both the demist and footwell holes.
-Jim
If you give me the dimensions of your mod, I can test it in cardboard, see what increase there is. It may be much the same as I am getting, in which case I may as well use your mod.
One thing I did notice is that the air flow is very uneven as is, with almost all the flow comming out by one edge, for both the demist and the footwells. I haven't put much effort into the face vents, just blocked them off with tape. However with my cardboard diverter the face vent output seems to reduce to almost nothing until you block off both the demist and footwell holes.
-Jim
My bulkhead has a black plastic panel in the middle ( 1987 350i FHC ) pop riveted into place, roughly the size of an A4 sheet of paper ( from memory ! ).
Does anybody know if it is possible to get to the heater & matrix etc that way rather than removing the entire dashboard
Cheers
Al
Does anybody know if it is possible to get to the heater & matrix etc that way rather than removing the entire dashboard
Cheers
Al
Well, I can take some pictures of the insides, and the mess I made of totally destroying the box- it is now held together by lots of aluminium angle and pop rivets. Where do I host such pictures ?
To get the matrix out you have remove the fan centrifuge assembly to gain access to a screw holding the matrix steel carrier to the RHS of the box. You also need to emove the big LHS panel, as well as the footwell ducting and the top grey bit with the vent doors in. Taking out the dashboard took 30 minutes - removing the matrix three hours!
I have had my matrix modified too so both heater pipes are on the passenger side - in theory I only need to release airlocks from the return hose (19mm one). but that is assuming I can get decent airflow.
The matrix asembly is much bigger than I remember, so I am going to have to modify my diverter. Looking at it, the airflow seems it would be much better if a long thin fan was installed behind the matrix- then the air would be going in the right direction to start with. I guess this would not work with the A/C equipped cars though, as the evaporator sits behind the face vents (according to the parts book of mistruths anyway)
-jim
To get the matrix out you have remove the fan centrifuge assembly to gain access to a screw holding the matrix steel carrier to the RHS of the box. You also need to emove the big LHS panel, as well as the footwell ducting and the top grey bit with the vent doors in. Taking out the dashboard took 30 minutes - removing the matrix three hours!
I have had my matrix modified too so both heater pipes are on the passenger side - in theory I only need to release airlocks from the return hose (19mm one). but that is assuming I can get decent airflow.
The matrix asembly is much bigger than I remember, so I am going to have to modify my diverter. Looking at it, the airflow seems it would be much better if a long thin fan was installed behind the matrix- then the air would be going in the right direction to start with. I guess this would not work with the A/C equipped cars though, as the evaporator sits behind the face vents (according to the parts book of mistruths anyway)
-jim
rev-erend said:
Mime .. HAHA .. sadly Ted has not seen fit to put a spell checker on PH - maybe one day
Ted don't need to because of this www.iespell.com which I think was a PH tip. Grady
Night mare - I've got A/C
I have my car pics on :
[url]www.showoffyourcar.com/youraccount.asp[/url]
I'm sure MikeB would be very interested in your writing up your exploites on this .. for wedgepages
[url]www.tvrwedgepages.co.uk/[/url]
and a scan of the heater diagrams who really help everyone
>> Edited by rev-erend on Tuesday 26th April 10:09
I have my car pics on :
[url]www.showoffyourcar.com/youraccount.asp[/url]
I'm sure MikeB would be very interested in your writing up your exploites on this .. for wedgepages
[url]www.tvrwedgepages.co.uk/[/url]
and a scan of the heater diagrams who really help everyone
>> Edited by rev-erend on Tuesday 26th April 10:09
A Bit difficlut to get dimensions as its now taped / riveted inside my heater box but it was basically a curved strip from the fan exit into the heater 'entrance chamber' which diverted most of the flow towards the heater matrix entry slot and so into the demist and footwell ducts. I left a small gap at the end ( about 10mm) to keep some air going to the dash vents as opposed to the full blast you get as std. Another tip is to replace the screen outlet vents with those from a MKII Ford Feista as these have vanes which protrude into the airflow and help turn the air into the vent.
Also check everywhere for leaks and the bent plastic tends to lose air all along the route.
Matt
Also check everywhere for leaks and the bent plastic tends to lose air all along the route.
Matt
Hmmm. Well, I wouldn't bother following my mods.
I installed the matrix, and the matrix holder plate, and have flow tested the box with the face vents tightly sealed off. I made three types of deflector, moved the matrix about, made a different matrix holder, and guess what - NO DIFFERENCE in air flow out the Demist vent. Bummer. Haven;t tested heat transfer, but assume it will be unchanged.
The flow just gets stagnated at the matrix, and it is really down to the pressure inside the box. Not all laminar flow like in other heater boxes I have disassembled. So the key is block the leaks to raise the internal pressure in the box - a bit of a rubbish solution, but the geometry of the heater box has stumped me. - I got a nice home-made pitot tube manometer now though....
I installed the matrix, and the matrix holder plate, and have flow tested the box with the face vents tightly sealed off. I made three types of deflector, moved the matrix about, made a different matrix holder, and guess what - NO DIFFERENCE in air flow out the Demist vent. Bummer. Haven;t tested heat transfer, but assume it will be unchanged.
The flow just gets stagnated at the matrix, and it is really down to the pressure inside the box. Not all laminar flow like in other heater boxes I have disassembled. So the key is block the leaks to raise the internal pressure in the box - a bit of a rubbish solution, but the geometry of the heater box has stumped me. - I got a nice home-made pitot tube manometer now though....
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