I've read the threads on Mugen Cooling Mods and most of it makes sense to me. I understand the thermostat and fan switch portion - the thermostat will open earlier at 155 degrees F and the fan switch will trigger at 176 degrees F. These two items work in combination to keep the motor cooler.

I'm not sure if I understand the need for the radiator cap though. If I understand the cap's purpose, it's to increase the boiling point of the coolant by increasing the pressure in the system. With the addition of the Mugen thermostat and fan switch, coolant temperature is reduced already. My line of thought is that boiling over the cooling system will never come into play unless there's a problem. If this is true, the radiator cap will have a minimal effect in normal situations. I would rather not increase the pressure in the cooling system if it's not really going to make a difference as far as cooling or efficiency.

Any help would be greatly appreciated.

 

I don't know how much advantage you’re going to get from the increased pressure. IOW, I'm pretty sure you will NOT see any performance increase in your normal, day-to-day driving.

The thermo switch + thermostat obviously reduce the cylinder head and other temps and a cooler air charge is going to give you more power. As you already pointed out, the water temp should be lower too, and in general that should equate to less pressure.

However, if you are running the car hard, and you are creating a lot of heat, you are going to see an increase in pressure in the cooling system. If you've ever looked at a pressure cooker, if you release the pressure, you get small bubbles at the heated surfaces (typically the bottom near the burners). The same analogy holds for the high-performance radiator cap. More pressure == higher boiling point. There are few benefits: As the pressure increases -- and presuming the factory system is designed to handle the increased pressure of the Mugen cap -- you can get a higher temperature at the radiator without loosing the cooling (boiling off). The amount of heat that can be removed is related to the difference between the radiator and the surrounding cooling material -- which in this case is flowing air (Δ T). The other issue relates to hard running and again -- higher temps at the higher indicated radiator cap pressure. You will generally have more margin -- with the higher pressure cap -- before you will create a less efficient heat transfer layer between the metal surfaces and the flowing water (especially between the engine block/cylinder head and the coolant. Those little bubbles in water/coolant do not conduct heat very well. Water wetter is basically altering the surface tension to help the heat flow by reducing this bubbling -- and the higher pressure radiator cap will do the same thing. All of this is predicated on the car putting out enough heat energy to actually raise the water temperature enough to exceed the factory radiator cap's pressure.

If you never run the car very hard, it will probably never matter. OTOH, I don't know if anyone has put some instrumentation on the car's radiator system to see just how much pressure depending on situation, ambient temperatures, and duration (WOT, uphill, stopped, 150 MPH, dessert, track, etc, etc).

 

In addition, here is an article and a few additional points:

http://www.streetrodstuff.com/Articl...g_Suggestions/

 

I knew I could count on you Eric

Yes, I'm working on the assumption that there will not be enough pressure or temperature to exceed the stock radiator cap. I'm also working with the assumption that the stock cooling system has enough excess capacity when working properly to cool a SC'ed motor. You've also clarified one of my concerns - Is the stock cooling system designed to handle the Mugen cap pressure?

I guess I have to determine this part as this becomes an opinion or preference: Is the additional margin of boiling point using the Mugen cap worth adding the additional pressure on the stock cooling system?

Thanks for the feedback and confirming my thoughts.

 

I didn't get the cap. To me the lower temps from the switch and t-stat reduce the need for it. It's a good idea if you're going to run the car a lot on a road course though.

 

everyone seems to get all 3, and this isn't something new, so i can't imagine it being a bad thing.

 

There's a benfit to the new cap? I thought it was just for looks? I have all 3 & haven't had any real problems. My temp was a little high last month, but I had some air in the system.

 

where can I get this part at? Any part #'s I need?

 

see this thread for part numbers from Kingmotorsports.com

https://acurazine.com/forums/showthr...ght=thermostat

 

hit up Arnold (blxmjx) he can help you out with the cooling mods. Good prices too.

 

Cheaper the better... thanks silver and dj

Is it difficult to install for a novice? I've only installed exhausts, CAI, wiring kit

 

nope its pretty easy actually. Do a search for the directions on how to do the install. I believe there are pics as well. Good luck!