coolant reroute without heater
 

sorry if this has been asked and answered before but i cant find a straight answer without heaters. i am doing a coolant reroute on a racecar i am building but as it is a racecar it will have no heater installed. its a 1.6 turbo and has or will have a large ally rad fitted.

so the plan is to swap the front and rear covers switching the thermostat from the front to the rear and block off the heater pipes. to compensate for the lack of flow during warm up i will drill some holes in the thermostat. i will also have to cut off and switch the sensor bungs front to back as the threads are different. make up a hose from around the back to the rad and that's that. will this work ok?

no need to drill any holes. I blocked my heater off a long time ago and my car warms up just fine.

wont there then be no flow at all during warm up?

I searched "heater core delete" and found these

https://www.miataturbo.net/showthrea...er+core+delete

https://www.miataturbo.net/showthrea...er+core+delete

https://www.miataturbo.net/showthrea...er+core+delete

So it seems your conundrum has been solved at least 3 times.

To delete the heater core, remove the hoses that go into the heater core and connect them together. The coolant flow path absolutely must remain -or- you absolutely must run without a thermostat..

Any other questions?

if i connect the core hoses together it will mix the hot water into the cool before the water pump. surley it would work better with some holes in the stat to stop the pressure and allow some flow. that way all hot coolant goes through the radiator and can not bypass it. what do you think?

LOL sounds like you just really really want to drill holes into your t-stat despite what people say.
Drill away

no i just want to pump water back into the block uncooled. if this way is incorrect then i wont do it. i just cant see why its wrong. care to explain?

A 3/16 hole in the thermostat flange, removing the heater hoses and hard line under the exhaust manifold and putting a 1/8 water neck at the pump intake to the radiator bottom all together works nicely.

same here no problems

Since this is a dedicated racecar, and you presumably have plenty of free space under the hood, why not just do this the correct way by blocking the front outlet entirely, bolting the main water neck to the back of the head, and feeding it into a bypass-style thermostat? The "cold" outlet goes to the mixing manifold (or to a tee in the lower radiator hose), and the "hot" outlet goes to the upper radiator inlet.

That gives you full recirculation when cold (no coolant to radiator), and zero recirculation when warm (all coolant to radiator).

Stant model 13578:

http://ecx.images-amazon.com/images/...KL._SS400_.jpg

thanks for the positive replies. that's a great idea! why didnt i just think of that. time is a bit tight so that may have to be an upgrade later in the season. for now i think i will be blanking off the the heater hoses and drilling the stat just to get it going and get some testing in.

anyone know a good way to block off where the metal pipe goes into the mixer manifold?

I welded the port up.

Replace it with your front water neck. See post #8

all sorted then. thanks very much for the help. its easy when you know how.

I blew a headgasket in traffic from overheating after deleting the heatercore and taking the line strait back to the lower radiator hose. At low RPMs there is very little coolant flow. With no restriction in the route to the lower water hose (IE heatercore) there is very little flow through the radiator even when the thermostat is open.

As long as the car was at cruise it sat right at the 180 termostat temp. Once it was sitting at idle temps went up and the fans did nothing to cool it down. I was stupid and didn't pull over soon enough.

not good! that's why i will be totally blocking it off and drilling the stat. then there is always flow through the rad.

If.
You.
Completely.
Block.
It.
Off.
You.
Must.
Effectively.
Delete.
The.
Thermostat.

There.
Is.
No.
Reason.
To.
Drill.
Your.
Thermostat.
Just.
Throw.
It.
Away.

Your water pump will flow water through your cooling system regardless of the existance of a heater core route. If you delete the heater core route, your water pump is going to flow water through your closed thermostat. If your closed thermostat is impeding the flow of water, your water pump will still flow water, but instead of going through your closed thermostat, that water will force open pipe connections and gaskets and your coolant will end up (best case scenario) on the ground, or (worst case scenario) in your combustion chamber.

The only way to allow these engines to properly heat up is to bypass the radiator. The water pump isn't designed to just sit in "spin cycle" while it waits for your block to come up to operating temperature.

wont the car never warm up without it?

too.
cold.
is.
as.
bad.
as.
too.
hot.

;-)

thats the reason for the holes. to stop that pressure build up and allow the stat to work as it should. or am i wrong?

If you want the car to warm up, you'll bypass the heater core instead of block it.

Your water pump is designed to flow X gallons of water per minute. If the only path for the water to flow is through a thermostat with holes in it (*blocked* heater core route) then it is going to flow X gallons of water per minute through those little bitty holes, and your car will warm up just as slowly as if there were no thermostat to speak of.

In all likelihood, your car will never warm up enough to open the thermostat in a 'holes drilled' scenario.

In the summer, I fought overheating issues with my car. I ended up drilling two 3/16" holes in my thermostat and hoping that it would help. It didn't end up helping the situation at all.

Move forward several months, and winter rolled around. With two 3/16 holes in my t-stat AND the stock heater core route still completely intact, my car only heated up to operating temperature if it was parked. On the freeway, I was able to get the needle to climb up to about 1/4 of the full way (halfway to "normal" temp) ONLY if I was following a large vehicle closely AND had the heater switched off. At any other speed, I could barely get the needle off of the "dead cold" mark. These water pumps were designed to flow enough volume to completely cool the car while also flowing water through the heater core. Instead of the current option of drilling holes in the thermostat, I would recommend leaving the thermostat intact and installing the heater core bypass with a restrictor (such as inserting a short length of smaller hose into the heater core hose). If you feel the need to do this, you will also want to make sure you do a full coolant reroute because you will otherwise be significantly degrade the ability of the cooling system to cool the rear cylinders.

If you want to increase cooling, get a better radiator.

good point but without the heater core there is no restriction so there will be too much flow through the bypass during normal running. also the car will only idle during warm up so the pump will not be going very fast. i plan do drill a good few holes in the stat which will be equal to at leas half the diameter of the heater hose. cant see it being a problem. if there was no thermostat it would take ages to warm up then rapidly cool down as soon as i get on the track.