BTDT (sort of). That's exactly what I suggested to FatCat and I sold him a spare oil t-stat I had; he plumbed it in so that it blocks flow when hot. The way the oil tstat works it effectively maintains flow on its output at 82*C. When it's hotter it closes, so no coolant flows through the heater and bypasses the rad. In the winter, the act of turning on the heater cools the coolant flowing through the oil t-stat, so it opens enough to keep its coolant at 82*C.

He tested it and it works as advertised - quick warmups, good heater function in winter, and lower coolant temps on a very hot day.

At the track if you still overheat you can still turn on the heater to cool the engine.

I'm lazy and I don't like super hot track days, so I just use vice grips to close off the heater flow at the track LOL.

Yes, some water passing through the heater goes back to the radiator. I don't know how much in the grand scheme of things. I guess I could put a restriction in the heater core line. I was big on making sure I got lots of cold water when that t-stat opened for max cooling on the track. I'd much rather deal with the slow warm-up or blocking the rad than overheating at the track.

Hmmm. Jason, I think we may have a winner. I'd been supposing that it was necessary to provide a return path for the heater at all times, however returning it to the mixing manifold, having blocked it completely when over-warm, sounds like a simple yet effective alternative.

Anyone have links to a good appropriate oil-stat for this purpose?

http://www.batinc.net/thermos.htm

Perma-Cool 1070 - Perma-Cool Remote Mount Oil Thermostats -

Remote Oil Thermostats

Remote Oil Thermostats

http://rover.ebay.com/rover/1/711-53...7C240%253A1318

http://cgi.ebay.com/ebaymotors/Porsche-911-Carrera-RS-911S-Oil-Thermostat-NOS_W0QQitemZ220303563951QQcmdZViewItemQQptZMotors _Car_Truck_Parts_Accessories?hash=item220303563951 &_trksid=p4506.c0.m245&_trkparms=72%3A543|65%3A12| 39%3A1|240%3A1318

So would drilling some holes into the outer edge of the t-stat provide enough flow b4 it opens?

Im just tryin to figure if there is a way to completely remove the heater lines and just plug the inlet in the mixing manifold.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

With which system, and in what configuration?

When you eliminate the mixing manifold and plug the heater outlet at the back, you create a compromise situation insofar as warmup is concerned. Drilling some holes through the thermostat plate is probably sufficient to create circulation through the engine during warmup, but all that circulating water is going to wind up in the radiator. Thus, you have the same problem as the Bell system where the heater outlet is teed into the upper radiator hose. It's like having the thermostat partially open all the time.

I'm really liking Jason's suggestion of using the oil thermostat to selectively block the heater core return. In such a scenario, coolant circulation happens entirely within the engine while cold, so warmup is not compromised. Once operating temp is reached, the action of the oil thermostat effectively does block off the inlet to themixing manifold, achieving 100% coolant flow through the radiator whenever the thermostat is open.

My only concern in such a situation would be to ensure that the oil thermostat and the main thermostat are never fully closed at the same time. This would block all coolant flow through the system entirely, and while I can't point to any specific failure that situation might cause, I assume it would be non-optimal.

So basically I might have longer warm up time? WIth the South FL heat and a water cooled turbo I wonder if it would really be a problem.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

Hard to say. Tronik, who is in the DC area, reports 18-20 minutes to warmup, driving at 55mph. This is obviously unacceptable. Steph reports 4 to 6 miles in Texas, without noting the speed or time elapsed. To me, that's not really acceptable either, as my whole commute is only about 5 miles.

It is easy enough for you to approximate this on your car, however. Remove your thermostat and replace it with a round metal plate with a 1/2" hole drilled through it. (You need to have some restriction there, or no water will flow through the engine.) It's not an absolute, 100% accurate simulation, but it'll get you in the ballpark.

When I had the bypass connected to the upper radiator hose I was seeing warm up times similar to what Steph reported though at speeds averaging 30-40 mph for 7-10 minutes followed by speeds averaging 50-80 mph (highway). Usually the car is warmed up by the time I get onto the highway. But, it was not very stable since the coolant temperature would vary a lot based on speed during my commute, say 20-30 Deg F.

I could probably dig up some of my Megatune commute logs (if anyone is interested) with the upper hose setup and the lower hose setup. It could be interesting. Some potential data skewing issues are that damn MS 215F peak temp ceiling, and large seasonal variations in ambient temperature between the two setups.

Warmup is much quicker and temps are much more stable now that the bypass is reconnected to the lower hose. If you try a setup using the water heater core circulation back into the upper radiator hose you should use some kind of in-line thermostat to regulate it. Or, use a tee thermostat configuration splitting it between the upper and lower hose based on the bypass flow temperature. Either way I agree there needs to be some continuous circulating flow to avoid stagnant coolant in the motor. Thus I like the tee approach better.

I thought seriously about trying this myself. But, the oversized radiator and lower radiator hose return setup I am using now works fine. So I abandoned the regulated upper radiator hose return approach for now.

Hell if it was a track car you could even just use a manual proportioning valve and adjust it for each session based on the ambient air temp at the time. But that would be a trial-and-error PIA IMO. A thermostat would be better.

Plug the upper rad hose splice into the lower hose instead. Save and re-use the coolant. Warm up time will be bone stock. Thermal rejection slightly less, but probably not missed much. With that you will live happily everafter.

As an alternative to the oil thermostat, you could build a simple circuit with a CLT signal, a couple of relays, a NAND gate and a pair of these: Pneumatics & Hydraulics > Valves > Hydraulic Directional Solenoid Operated > Valve,Directional : Grainger Industrial Supply

At the moment I'm hating my FM Race radiator, takes a long time to warm up and put some heat out in 25 degree weather. Thinking of sliding some cardboard down between the condenser and radiator to let it get hot.

Same here, longer warm-up. No worries if it doesn't overheat on the track this summer (. I need to linearize my temp gauge and install an oil temp gauge.

Chris

Joe,

Here's Shaikh's post from 2004
MX-5 Miata Forum - Heater t-stat plumbed in-line with heater outlet hose

Here is how a 4-port oil t-stat works
Pelican Technical Article: Remote Oil Cooler Installation

You use the 2 "engine" or the 2 "cooler" ports. It only shuts when it's fully warmed, which is quite a bit above the 82*C rating. The 82*C rating is when the pellet starts to move.

You are right, you don't want an engine t-stat that's hotter than this oil t-stat; else they may both be shut when coolant is hot enough for the oil t-stat but not hot enough for the engine t-stat. The other thing you need to do is plumb is such that excess pressure in the coolant will push on the pellet to open it. (upper right port comes from heater, lower right port goes to pump inlet).

Or, just add a restriction in series between the pre-thermostat outlet at the back of the head and the inlet to the heater core. Give the coolant some extra incentive to flow past the thermostat (which is restrictive) and into the radiator when it's open, yet still allow coolant to flow through the heater core at all times.

Cheap & failure-proof.

Just to interject,
Removing the BEGi radiator scooper is all I needed to do for 30F Atlanta. With the scooper, I could cruise on the interstate at 160F coolant temp and oil temp. Without it, I get to about 205F coolant and maybe 220F oil. HUGE difference. Car is running the BEGi reroute that comes with S4 kit.

I like the BEGi scoop alot, but I can not run it in the city. When I said that the scoop was removed, I should clarify that it was removed by a city street. ;)
A slightly smaller (less height, specifically not going down as far) version would be awesome.

now I'm definitely sold
https://www.miataturbo.net/forum/t29067/

i rarely post here and i can not attach pics from the ps3, and typing with the controller sucks. but i promisse tomorrow i'll post my set up, and my point of view. this topic is going to be flaming!!!:vash::vash::vash:

There is the understatement of the day(first post).:eek5: