matttheniceguy

I'm looking into doing a coolant reroute on my new car, and haven't found anyone who has done quite the one I am planning on doing.

A little background; this is for my new car which is a 94 with 99 head, FM2 2560r, Link, 550s, bla bla bla, with a built bottom end (Belfab rods, FM wisecos). I'm hoping to push it to right around 300rwhp if the turbo and injectors can get there.

My primary purpose for the reroute is more even cooling. I live in Canada, so ambiant temps won't be very high, and I am NOT a highly skilled track driving monster. The car will be used as a daily driver, autocross toy, and the occasional track day. I will have a Mishimoto rad, so that combined with the low ambiant and my lack of ability to really push the car makes me think I won't have overheating issues.

A lot of the reroutes make the car take longer to warm up or impair heater function. That is not really acceptable for me, as it is a daily driver and I need the heat to see through the windshield in the winter. With the forged pistons I also want it up to temp as soon as possible. Also, due to the large rad and cold ambiant, I can't have any appreciable flow to the rad that isn't through a thermostat.

Attached is what I am thinking is the best reroute option for me. Essentially, leave the entire cooling system intact, including the mixing manifold and front mount thermostat. All you do is add a coolant path from the back of the head to the upper rad hose, with an inline thermostat in it. Because the front thermostat and rad hose are still there, the rear one could be smaller than a rear mounted thermostat system. I'm thinking something like a 5/8" ID hose would be plenty. Putting a small inline thermostat in that hose that opens at a slightly lower temp than the front thermostat would also be a good idea. This way when the car was cold the system would be just as stock. Once it was up to temperature the return line from the back of the head would flow to the rad and there would be good flow across the head. If the flow from the back of the head can't handle all the cooling, the front thermostat will open up as well to increase flow to the rad, and you would still have good flow throughout the head.

The tricky part is finding the remote thermostat. I have found some $100 units for sale with zero information about size or temp or anything, and not much else (aside from rover or BMW remote thermos, with a bypass). There is also that picture posted by M-tune in the posting for their reroute kit, but I can't find that thing for sale either (and it's bigger than I want anyway).

Does anyone know where I can get a fairly small remote thermostat? If I can't find one I will probably make one from a small motorcycle thermostat and make my own housing.

Any thoughts on this reroute? My only hesitation is the worry that when the the front thermostat opens there will be as much pressure in the upper rad hose as there is in the back of the head and the line from the rear of the head will stop flowing. I don't know what sort of pressures there are across the system though so I have no idea if this is actually likely. If a heatercore plumbed straight back to the upper hose still flows this reroute should work.

paul

iTrader: (21)

I think you are gonna have the exact problem you fear once the front t-stat opens.

Here is my plan for my 94 daily driver for more even cooling. I don't have overheating issues but since the design of the cooling system leads to uneven cooling I want to address it. It'll be very cheap to do too so it's perfect for the members of this board.

• Take the heater core outlet at the back of the head off. Remove the CLT sensor from it and install that just to the right of the outlet. It's currently plugged from the factory. Same thread.
• Take the t-stat housing outlet cap off the t-stat housing neck. Remove t-stat. Install t-stat in back of head with 1.6 t-stat outlet cap. Use plug removed from rear.
  
• Install heater core outlet onto t-stat neck at front of motor. Find plug for clt sensor hole.
• Run 5/8" heater core hose from front outlet to heater core.
• Run 1 1/4" radiator hose from rear outlet to radiator.

This way coolant is traveling through the whole block/head before exiting to the radiator. The heater core is still routed and functional and feeding back to mixing manifold so engine will take no longer to warm up and will maintain operating temps.

Thoughts?

TurboTim

iTrader: (9)

$57. Uses inexpensive GM thermostats found anywhere. Fancy $2 napa gasket #1091 also required.

http://www.meziere.com/ps-571-540-wn0071.aspx

ArtieParty

iTrader: (1)

Got pics?

Joe Perez

iTrader: (8)

Starting to wonder here... Not finding QMax on the 949 main page anymore, and haven't heard from M-tuned either.

M-Tuned

iTrader: (6)

We are just waiting on our CNC guy. We expect another sample in the coming days. We want to release a product which fits

Joe Perez

iTrader: (8)

Oh, the agony!

J/K- I forgot you guys had been out of the shop for a while, just got back from your thread on the subject, and it looks pretty sweet. Having recently moved to FL has made me realize that I need to get one of these for myself. Mark me down for a '90-'93 kit as soon as they're shipping. Hopefully you've got something for the radiator inlet that will clear my largish intake up-pipe.

matttheniceguy

I was also considering this sort of option. There are a couple things about it I am unsure about though. First, prior to the thermostat opening there will be no flow path from the back of the head at all, so I would worry about getting very uneven warmup, and even localized boiling at the back of the head. I realize there will be some flow throgh the closed thermostat so that should help, but it might not be enough. This makes me want to keep the heatercore at the back of the head. With a 1.6 housing on a 99 head, I think you have to send the coolant out the hot side as well, which I am not a big fan of.

The coolan reroute M-tune is putting together also looks like an attractive option. It is the only comercial reroute I have seen that is actually something you could run on a daily driver as it won't hamper heater or warmup function.

Thanks for the link the the remote housing Tim, I wonder if there are any smaller ones around.....

olderguy

iTrader: (19)

Agree with Paul's statement on Mattheniceguy's reroute.

Would not do it Paul's way either.


Think it through: The object is to have a small loop of coolant moving at a high rate of speed completely through the engine and the heater core until the thermostat opens and then to have the additional loop in parallel going through the engine and radiator. This gives you a constant high flow and allows the thermostat to open and close to augment the flow and run it through the radiator as needed.

The easiest way that I can see to accomplish this is to run the large line off the back to the top of the radiator with the thermostat in that line.

The heater core can be tapped into the bottom heater hose and to the large line off the back before the thermostat. NOT on the radiator side of the t/stat!!

If you do not run the heater core, holes need to be drilled into the thermostat flange to get the initial flow at a reduced rate.

If you use the heater core, a very small hole in the t/stat flange will serve to let the t/stat see the temperature rise so that it will open.


The front of the engine needs to be blocked at the original t/stat position.

matttheniceguy

The reroute you are describing is exactly the reroute M-tune is working on. Basically the entire cooling system remains the same as stock, but the thermostat and return line to the top of the rad moves from the front of the head to the back of the head.

I guess I will just have to add my name to the list of people with money burning a hole in their pocket until M-tune finishes their parts.

M-Tuned

iTrader: (6)

I'm breaking ***** daily to get it finished... I hope it is not far away..

Here are the pics of our first prototype..

Since I keep getting a bunch of PM's asking for more info got permission from John to show you a quick Camera phone picture of the rear housing. So here is a sneak peak picture of the rear housing? This is still a prototype and we will have a few minor tweaks in another version getting made this week. If all goes well after we test the next version on a 90-93, 94-07, 99-00 and 01+.

Coolant Sensor goes above the Brass Nipple for the heater core. Spare port for Turbo feed is also in the same general area.





We have just spun off a ton of these and I believe OUR NEW version will work with the Miata T-Stat, or the GM IIRC.

Savington

iTrader: (31)

949 still has Qmax on their site, found it via google.

Arkmage

iTrader: (3)

sweet deal... the m-tuned unit even leaves plenty of clearance for my redneck EGR

Is there enough space for two CLT sensors in that sucker? I need one for MS and one for stock ECU... for some reason they don't play nice and need their own sensors.

paul

iTrader: (21)

That is a nice piece from m-tuned. I do like the fact that you can run the 1.25" line up the cold side but $219-249 is a lil steep for me. If there was a piece actually available at a reasonable price that would be nice. That spacer from highroller would be nice but that hasn't happened yet. Does anyone know if that spacer moss sells is milled for the t-stat?

Joe Perez

iTrader: (8)

Yeah, found that too. The fact that they de-listed it from the main page makes me wonder. I guess I could just pick up the phone and as Emilio, however I'm currently predisposed to laziness in this regard. Plus I really want to see the whole M-tuned system once it's done. The bits I've seen so far cause me to be aroused, and I'm leaning in their direction. So long as the hose / pipe running from the back to the radiator inlet does not look like total ***, they're very likely to get my money. The ability to run a larger-opening GM thermostat is very encouraging.

supersuk

iTrader: (5)

I know for a fact that the Moss piece is not milled for the thermostat. I have one at home if anyone wants to buy it.

Laur3ns

My shop has done this today:


This will keep the heater core circuit open at all times, The BEGI racer re-route spacer will go on top of that. The temp sensor will be replace in the head or inline in the heat core inlet hose.

Q: Is the flow through the heater core always the same, unrelated to setting the fan speed or temperature from within the car?

olderguy

iTrader: (19)

The flow through the heater core drops when the thermostat opens, but there is no control over the loop through the heater due to the fan or temperature setting.

Laur3ns

Excellent!

patsmx5

iTrader: (16)

So, you're saying something like this would work:

Put a 1.6 thermostat housing on the back of the head. Don't put a thermostat in it, just the housing. It acts only as an outlet to get water moving out the back of the head.

Plug the front of the head where the old T stat housing used to be with a freeze plug.

Add an inline T stat housing and thermostat between the new rear outlet and the upper radiator inlet.

Tap the new hose that goes from the rear outlet to the New thermostat/housing to feed hot water to the heater core.

The other heater core line goes to the mixing manifold as normal.

Is that right? So you would need an external t-stat housing w/thermostat, a 1.6 T stat housing to put on the back of the head, a means of tapping water between the new rear outlet and new thermostat housing/thermostat, and hoses.