So a late night drive last night got a bit hairy due to the windscreen misting. I know- ditch the screen but I kind of like it....
Can a heater matrix be left permanently connected? Is an inline hot water switch only used to change between cold and hot air IE if I only ever want hot is it okay to leave it permanently connected? And presumably it's not such a stellar idea to have the heater sucking air out of the engine bay- as much as it's pre-warmed presumably it's also full of RON95 smells and potentially an engine bay fire could pose an even bigger issue if you're venting the engine bay air into the cockpit???

I've got a tiny little oil cooler and a 50W centrifugal blower fan off a server and they're going to meet in a Scrapheap-esque tiny heater. Just working out how to do it in practice..............

Dont sees why you couldn't leave it permanently in line. As long as if you do have a tap it doesn't interfere with the main flow.
Normal older cars have the matrix in the car and hose to it through the bulkhead, so same for that , and for these cars just use cockpit air rather than engine bay air

for IVA heaters are not allowed to take air from the engine compartment.

Cool. Leave it plumbed in and take air from under the scuttle it is then Let's hope I can fabricate it under 1.5kg- any heavier and I could have just bought a micro heater from Demon Tweeks- although they do use a an axial fan and they tend to suck in the presence of any restriction so I still reckon a centrifugal is the way forward.... Infact I'm thinking of flogging the Eaton Mini blower and going down the Rotrex route for a full on centrifugal love fest. In fact at my mates stag do a couple of weekends ago I remarked in a "club" to a lady of questionable affections "if I was spending that much on getting anything blown tonight it would be a Rotrex C15 supercharger for my motor". Ladies of my fantasies my arse- didn't even know the difference between a supercharger and a turbo. Pffff.... LOL!

I have a water-cooled pc radiator and an old server fan.

153 CFM 120mm fan


gtm heater

Nice idea! One of those pc rads would fit the blower fan better anyway. .. cheers!

On my diesel tin top leaving the heater valve open doubles the warmup time. Variable valves are readily available?

My sierra matrix is plumb in all the time in the bypass flow. I Just turn the fan off/lower setting. It currently only feeds the windscreen. This causes a bit of heat leak at other times, but not an issue being open to with some times a flint style hood and side screens can get a bit warm

I think the computer style heater matrix may be a bit small to get a good de-mist, but cheap simple and light so probably worth a try.

Dan

If you're worried about weight, look in to the PC market water cooling kit. They've got lightweight radiators to get rid of the CPU heat and fit PC fans by design (or did when i last considered this a few years ago).

If you don't fancy water, you might want to investigate the electric pre-heaters as fitted to Smart Car and a few others




Something I've been meaning to look at, but not sure if my alternator could cope with it.
I really only need something to take the chill off, as I have a heated screen fitted.

My alternator would freak out- it's only 28A. In fact I'm currently doing an LED conversion (everything other than the main headlights) to try and save my battery. I've switched to a lithium which is great and light but doesn't offer much reserve. I'm also fitting a battery charge light so I can see when I'm using more than I'm making!

Those watercooling rads are lovely- and I've checked- they'll handle pressure and heat nicely- not sure why though- presumably water cooled rigs are unpressurised?? Perhaps not- not my bag anyway.

Coyoteboy- presumably in your diesel it takes so long to heat up that they put the heater matrix before the thermostat (otherwise the heater would be all but useless). I think for ease of installation I'll just leave it plumbed in but have the take-off after the thermostat. To be honest somewhere I've got a cut-off valve but

a) I'd have to find it
b) It would mean hose adaptors because I'm unlikely to find the hose take-off nipple and radiator nipple are the same size let alone the same as the cut-off switch
c) I'd have to find some way of actuating it from inside the car. Unless I had an electric solenoid activated by the demist switch but then I may as well leave it connected 100% of the time...

These just seem to be the same setup.

if you fit a water valve controlled heater in the by-pass coolant circuit then the coolant must have an alternative path to flow through when the heater is turned off.

One way to do this is SAAB 90 & 900 valve also adopted by MG-Rover towards the end of production using this you could control the heater temperature with a simple ball valve.


GENUINE SAAB 900 2.0 90-93 B202 B212, COOLANT BY PASS VALVE, NEW, 4073706

[Edited on 6/10/15 by britishtrident]

This below requires a secondary bypass during warmup so can't have the valve. But bin the valve and use an air-flap and you'll be fine.


[Edited on 6/10/15 by coyoteboy]

I've got suitable 8mm hose going to and from my header tank so was planning on making use of those hoses. One goes from the bottom hose, think the other one is from the rad vent.
I suppose I could go from the bottom hose into the heater then into the header tank then into the rad top? Presumably if I had the header tank and heater in parallel the water would just not go down the heater route....