Heater Core Bling
 

NB heater cores are aluminum you need the whole mode housing to fit it though. As a side benefit the NB heater core is 1 lb lighter than the NA copper brass unit. But I can weld AN bungs on it.

The Valve I have is an oil thermostat. It shuts down the flow to a trickle at 190f the way I have it plumbed so it sends all the flow to the more efficient radiator. I am convinced It improves peak heat rejection capability for the cooling system.

Bob

Good stuff man!

badass

What size are they? -10 or -12?

-10 or 5/8' pushlock. I cut one of the barb rings off each of the push lock fittings to make them shorter and fit better. the hose is rated at 300 pisi with 3 sealing barb rings per fitting I figure it should be fine with ~20psi to only have two rings on the barbs.

Bob

I've been talking about doing this for a while..."talking" of course rather than "doing."

Why did you decide to go with bulkhead fittings instead of just a grommet in the firewall and extend the hose all the way? Seems like it would fit a little better without the extra fittings.

Most likely something to do with engine removal and install ease. That's my guess. Provided a handy mount for the thermostat too.

Ah good point... didn't really consider that aspect.

For ease of working on the car. Engine removal etcetera. It seems when you drive a 350 hp car on the track quite a bit you tend to work on it a lot.

Bob

Very nice! Any idea how well the heat continues with the flow at just a trickle? if its enough heat I may be looking into doing this as well.

Very nice sir...something to keep in the mental files for the future...
(G)

I absolutly love you right now!!!! I wanted to hook heat back up in my car but being where the lines come out I had no room with this solution the problem is solved I can now go back to owning a legitament street car with heat. YYYEEEAAAA!!!! I never though to do something like this but I will be shortly for sure.

Your heater core coolant lines look better than my turbo oil lines.

When it is cold out the heater works like normal as the car comes up to temp. About the time the cabin gets warm as well as the engine the heater doesn’t put out full heat quite as hot but it doesn’t have to maintain comfortable cabin temperature at that point.

Running the car full blast on the track on a 100 degree day the heater won't blow very hot air at all.

Bob

:) I posted about this back in like 2003 :) Shaikh implemented it with my oil t-stat and posted the results.

The oil t-stat should be in the heater outlet. This way, if you turn the heater on to cool the engine, the cooled coolant coming out of the heater will open the t-stat. Win.

Coolant flows through the heater constantly It rejects heat constantly and when you turn the blower on it rejects a little more but I am fairly certain it doesn’t reject as much as if all the coolant flow was going to the big radiator in the front and not bypassing it.

I wanted the thermostat on the hot side of the heater core so it would shut off the flow better. The thermostat also doesn’t shut off the flow entirely. It’s got about the equivalent of a 1/4" hole bypass when it is shut.

And I will admit I got the Idea from your post way back.

Bob

If it's on the outlet of the heater, with the heater off the coolant will be the same temperature as what's exiting the head, so the shutoff will be the same. But then when you turn the heater on, it then allows more flow as the heater cools its outlet's coolant. This allows the heater to work as an aux radiator, and also for heating the cabin.

I think the problem is I would need a cooler thermostat to get the flow to shut down. even with the blower off the temperature drop across the heater core is quite a bit.

I did have it the other way before but thought the heater should shut down more.

Bob

Are oil t-stats available in like, 160*F?

Yea the thermostat is a 180 +- 10 so say it has to see 190 before its fully closed. I don’t know how much temperature drops across the heater core with the heat off but it wouldn’t surprise me if it is 30 or 40 degrees compared to where a standard radiator thermostat and temperature sender is located. So it may not close fully until the engine is hotter than Id like it if it is after the core.

I run a 180 degree main thermostat in the back of the head for the main radiator. With the heater core thermostat placed before the heater core it should start shutting flow down about the same time as the flow starts going to the radiator. when I took the valve apart and fiddled with it I could still blow through it with the path shut so there is always some flow going to the heater core just a significantly reduced amount.

So yea I think a 160-170 thermostat placed after the heater core would be better. The only thing I have found so far is this.
http://www.summitracing.com/parts/EAR-501ERL/
I think some OEM’s BMW? are setup this way I wonder what there heater thermostats look like.

Bob

Bob, your bay looks amazing.

I am pretty sure that copper is better for thermal transfer.

Indeed, copper has a significantly greater thermal conductivity per surface area.

But you've completely missed the point.

Here is one kinda bad picture of it.

http://img15.imageshack.us/img15/1203/dsc01568im.jpg

Trying to find another.

Edit: After a bit of reading it looks like they implemented that back in the 80s as a recall to try and eliminate some coolant system over pressurization that was causing heater cores to explode and scalding drivers' legs.

They also put restrictors into the HC inlet pipes to slow that down. I was talking to our local hotrod radiator shop and they suggested doing that to my stock HC since the OEM Mazda cap was only 13psi, where we have an 18-20psi (can't remember the exact) cap on it now. They said it actually takes very little coolant flow to keep the cabin warm.

Yea that is my theory that full flow needed to warm things up in the cabin starting from cold. Once the cabin is warm and the engine is warm it dosn't take much flow to keep it that way. Pretty small air space in the cabin of a miata. It also dosn't get very cold in this part of the country. The themostat I am using dosnt close entirely it just reduces flow quite a bit.

Bob

Interesting I took the thing apart wondering if I could just find something to replace the wax thingy with and it is stamped 77C / 171F. The wax plug part looks the same shape and dimensions as some other thermostats I got maybe I can just take one out of a 160F standard thermostat.

Maybe it was working correctly with it after the core if it was a 171F stat I just don’t know for sure what the temp drop is like across the heater core. That is actually how I had it prior I must say it seemed to work but I didn’t record actual data to prove it. I can certainly re plum it back that way again.

Bob

I kinda disagree, I lived with a 1/4 NPT tap / 1/2" hose in the back of my head as a heater source for a while, and it was a bit wimpy. And I live in CA.

Update I found a 160 Motorad thermostat at O-Riley’s had the same wax pellet dimensions as the True Cool oil cooler thermostat.

I put the thermostat assembly in a pot on the stove.

With the 171F pellet it came with it was fully closed at ~195 F
With the 160F pellet it was fully closed at ~175 F.

So if I put this in post core it means it won’t allow much flow through it if the heater core unless it can reject enough heat to get it below 175 F thus somewhat preventing it from possibly being a short circuit of the radiator while still allowing it to resonably function well as a heater when needed for heat.

Any Idea what the temp would typically be at the outlet of the main radiator if say it was 210-220F where it left the head? I havent found where anybody measured it yet. and Im too lazy to measure it myself.

Bob

LOL you're such a stud...

When the t-stat is wide open, it depends on RPM (and thus water flow rate) and airflow through the rad. Circa 10-15*C drop across the rad at like 50 mph on a steep mt. road doing ~4000 RPM, fans running, on a hot day. At higher RPMs the deltaT will be a bit lower. If the t-stat is partially closed, it'll climb to 30*C delta or more.

Ok that sounds about right then. With it at coming out of the heater core and headed back to the engine at a regulated maximum of 175F then that path won’t return coolant to the engine any hotter if any than what the radiator will do. Thus the total heat transfer from the radiator and the heater core together should be about maximized.

Important if you want to drive the piss out a car making 3X stock hp and have it maintain temp.

Bob

That looks great. How did you connect the AN fitting to the water pipe under the manifold?

I'm using a hose barb and hose clamp, but I've drilled and tapped my mixing manifold for a 1/2" NPT. Or 3/8" NPT, I forget. Anyways a NPT to -AN fitting could obviously be screwed in to connect a hose on.

I welded a steel AN fitting to it.

More bling. note: all the turbo lines are AN fittings. Custom fabricated inlet to the water pump to work with my turbo location. I finished it off to look like it was cast like that.

Bob

Update,

I changed the installation a bit. Moved the heater thermostat to the other side of the firewall and cleaned up the engine bay. Also have it installed after the heater core with the lower temp wax pellet I ripped out of a different thermostat.

Bob

This is great stuff! It’s getting my own creative juices flowing. I want to do a hot side coolant reroute and I need to do something clever like this with the heater core feed and return lines.

So I want your reasoning on bumping a thread on 9 years ago.

Fairly major thread necro there.

But I did find it useful. I asked about using a thermostatic valve on the heater line in the cooling system thread and it didn't sound like anyone had tried it. The implementation post heater matrix looks like just what I was thinking of.

Because fuck you. Is that good enough?

An attitude like that wont last on here for long...

https://cimg6.ibsrv.net/gimg/www.mia...eb38102090.jpg

Everybody chill out

kyle what is your deal. Something other than tobacco slide into that pipe of yours?

My deal is I don't like anybody giving me shit unnecessarily for bumping an old thread that's still pertinent and of interest to me. Don't like the topic? Don't open it or comment on it. It's as simple as that. matrussell122 gave me shit for necromancy or bumping an old thread as if I was some noob asking a noob question because he had to be a self-important, self-appointed moderator. Fuck him. I don't have to explain anything to him. I'm giving you the courtesy of a reply since you're old school like me and we've met in person many years ago and are cool in person. Cheers.