Hi there,
This is just my second thread, and I am a little anxious not to be considered cheeky (for not replying to an existing relevant thread ).
The subject is coolant routes in an 1.8L NB '99 engine (BP4W).
A lot of miata owners seem to hate all those little coolant hoses that travel from the back of the car to the thermostat housing, after visiting the oil filter plate and the throttle body housing, for being so difficult to access.
I, personally, have one more reason to hate them. They are almost impossible to inspect! And I payed for that with a blown engine a few years ago, when the hose that leaves the engine and travels to the oil filter plate, decided to fail and leave me running at top end speed for 30 minutes ignorant of what was going on down there...
Anyway now this is all past.
The first thing I did before installing the new engine was (guess what!): get rid of all that coolant route altogether.
I sealed the coolant output at the bottom/right/back of the engine and the corresponding coolant input on the thermostat housing, instead of just bypassing the oil filter and the TB, by connecting the two (now sealed) spots.

Here comes the question. Did I act wright or wrong?
I have no issues at idle speed, I have no other indication that something is wrong, but my main concern is:
Does the back half of the block (cylinders 3-4) get even worse cooled than before or no?
I am well aware of the miata's inherent cooling issue. My mod was not intending to heal this fault. It was a way to get rid of a 'weak' point of failure that cost me a lot in the past.
Here is a diagram of my setup to make things clear.






Coolant bypass setup

Do you think I should revert everything or just stop worrying?
Thanks and sorry for the long post...

 

Wrong wrong wroooooong!

Go undo it, you novice.

Edit: Never mind, you just deleted the throttle body lines. That's fine, the water pump inlet must suck from the block at all times else there is no flow when the thermostat is closed among other problems.

 

By "undo it" you mean connect the two sealed ports together and just bypass oil filter and TB?
Or run as stock?

 

I see nothing wrong with this. Deleting that path doesn't substantially decrease coolant flow during warmup, since the heater core is still feeding back into the system in the proper place (post-radiator).

 

After reading this, I am interested in your DIY CAI.

Also, I can't see your diagram

 

I guess the picture did its magic and it is clear that I haven't completely blocked coolant flow.

Anyway, a question still remains unanswered. If I connect the sealed ports, will I 'force' more coolant to travel towards cylinders 3-4, compared to my current setup?
If the answer is yes, I might do it, even if I hate that hidden route...

Thanks for your replies already

 

Could it be due to the size of the pic? (272.13 KB)
Anyway, regarding my CAI, I will try to post details shortly. In 2 lines it's like that.
1. remove the left headlight - 5 minutes
2. enlarge (and I mean ENLARGE) the hole that lies underneath - 30 minutes to 1 hour
3. form a flexible alu tube to guide air from the leftmost side of the smile to that hole - the most difficult part, many hours to form a nicely curved path that allows smooth airflow
4. remove the oem tube and air filter and replace with a 90-degree bent, a straight tube, then the AFM and finally a KN filter
5. Cover the filter with a custom made (preferably carbon made) cover that protects it from the heat of the engine bay.

I know pictures would help, so I will come back shortly with a detailed how-to.

 

Invalid attachment - https://www.miataturbo.net/attachmen...ine=1453410873

This stuff?

 

Yes, this staff but a big diameter. Actually it won't stay cylindrical. If you see the available space you will understand why. But is quite flexible to get reformed. As a permanent solution this path could be made from plexiglass or carbon

 

Still no picture, just assumed you were an average noob doing dumb things. You know what they say about assuming...

I would think that reconnecting that pathway for coolant might actually hurt coolant flow to the back cylinders on stock miata.

There is vacuum on the rear of the head from the water pump pulling on the heater core. If you hook that run back up it will just divert some of that flow instead, total flow will be the same. Flow through the heater core should be easier than the throttle body and oil warmer.

That's my half assed guess at it, anyway.

 

I edited my initial post.
I hope you are able to see my picture now.
Thanks