miata2fast I am unclear if you street this car or just drag race, do you have the block grouted? If I was going to do this with a drag only car (have done this on non Miata) I would have coolant from pump into one end of head, and out the other, with grout, and virtually no flow in the block (un necessary to cool the block in drag only, and can actually make better power not cooling it).

I have been looking at the electric pumps for my next build, for road race, and will grout the block partially, with reverse cool. This will be a high compression, NA, ITB motor, and hope to control some detonation, have used it with great results. I am a fan of Evans coolant, and have/will also use it.

 

Let us know how the evans coolant goes. I've been very interesting in switching to it once I take care of my leaks.

 

I have not personally used grout before, but know of a few that have. I was under the impression that grout was used to strengthen the bottom end and nothing more.

I have seen one racer that overfilled the block with grout, and he had problems with heat soak. Once the block got hot, it would not cool down enough to make it from round to round. Motors running alcohol are more forgiving to grout filled blocks.

I am not so sure it is a good idea to fill a BP motor to the top with grout. Maybe it would work, but it would be one hell of an expensive experiment. I personally am not willing to try it because I do enjoy driving the car from time to time, and plan on future road coarse trackday excursions.

 

I'll add this link to the relevant list:
https://www.miataturbo.net/engine-pe...troller-69420/

 

As someone who does not follow drag racing at all, I had never even heard of this concept. I've been googling it and have found numerous discussions as to technique, one product vs. another, and so forth. But I have yet to find a clear answer to one question:

Why on earth would you want to fill the cooling jackets of the block with solid material?

I understand that in a drag-race application, the engine is run only for short periods of time, and thus, cooling the engine is not a high priority. In the air-cooled VW world, the "serious" drag racers don't run fans, and the cylinders and heads which they use have minimal cooling fins as compared to street-type components.

But in all seriousness, what is the supposed advantage of pouring grout into the engine to fill the cooling jacket? Especially in the context of a road-race engine?

 

I would imagine it's to keep coolant from getting in there, while still flowing through the head?

 

It's really about adding strength to the cylinder bores. Cast is quite flexible, and they like to shift about.

You don't (normally) fill the water jacket to the top, and coolant still circulates. Think about where the heat is, mostly at the top (cylinder head) from the combustion process. Proper cooling in the head produces more power, and controls detonation.

The bottom of the motor is not where a lot of heat is produced. Some cars have trouble getting oil up to temperature, and once it is at temperature, it is actually quite capable of controlling temperature. (with proper oil cooler) Higher temp in the bottom end can also free up some power. (Mean effective pressure effects)

Relying on the oil cooler to manage the bottom end, and the water cooling has a better chance at managing head temp.

So if you control head temp, and control bottom end temp, the net result is more power.

 

It is used in faster class drag racing where motors are pushed to the point where block failures occur. Never in road race or any other circumstance where the motor is running for any length of time. Consider that a small block V8 making 800 hp in a road race car would be considered very stout, but it might take 1800 hp to barely qualify in some drag racing classes. That kind of power is real hard on blocks.

When you fill the block with grout it is harder for a cylinder wall to blow apart from extreme cylinder pressure from high boost or large doses of nitrous. It can help stabilize the crankshaft as well. I think some builders will grout a motor in an attempt to get a tad bigger bore size. The down side, regardless of the circumstance, is that a motor can't run very long, and once hot, is very difficult to cool down. Since most big boy drag racers are using aftermarket blocks, it is not used much anymore in the big classes, really for the folks that are budget minded or have no access to good blocks.

 

found this interesting on the filled block topic.

751WHP stock sleeve hoodrat setup block full of concrete!WTF - Honda-Tech