slo

iTrader: (1)

I was thinking of wiring a PWM out based on speed controll to switch at say 45 MPH to turn the electric fans off where they will be making no difference.

The idea of course would be to save fuel and take stress of the electrical system when at speed.

Anyone have any idea what the appropriate speed would be?

Is this possible?

A good idea?

Thanks

setzep

If your fans are on for a extended period of time at 45mph+ that means you have cooling system problems.

Claudio RX-7

iTrader: (1)

Yes, definately, to do what you want you need to have a kick *** cooling system with a radiator that is efficient enough to work properly at speeds, and since the rotary is such a hot running engine, its gotta be race car quality good.

At any rate, you dont need speed to be a parameter, just temperature, if your radiator and cooling system work the way they should, at speed your temperature would drop to the point of shutting off the fans. Period.

sleeples

I drive in the desert often and it seems that if you don't turn the fans on early then the temps rise beyond what you want to see, especially with A/C on. I normally turn the fans on where the haltech indicates 195, aftermarket gauge indicates 190 or so and turn them back off around 185. With those settings the fans will ocassionaly come on when driving at speed. Also with the fans wired to come on whenever the A/C is turned on, that is obviously not nescisary at speed.

As for my cooling system I have a Koyo radiator, with the Black magic fan and the stock in front of the radiator fan. I have an FMIC, all of the stock ducting is in place. I cut out large parts of the bumber to provide more cooling air.

Claudio RX-7

iTrader: (1)

If your cooling system heats up at speed, even with the AC on, im inclined to ask, do you have a thermostat installed? The proper way for a 13B cooling system to work is by removing ALL the air inside the system, having a new thermostat installed, having the coolant reservoir in place, and having the fan kick in at temperature. If any of these components are missing from the equation, it wont work right, and you will get poor performance from it.

But, back to the question at hand, at speed temps should lower (if you have a thermostat), if not, you're just moving water constantly, and the entire system will heat up, no matter what, and it will overheat.

slo

iTrader: (1)

sorry about signing on with another SN, I created that one a while back and I guess the credentials saved on my wifes computer.

I actually have 2 thermostats. It is a 13b-re. I have tried to run with one of the thermostats blocked off by the vacuum diaphram, but it runs hotter.

I have tried to find out but I am not sure how the system is supposed work. I think that it is primarily intended to speed up the warm up time.

Claudio RX-7

iTrader: (1)

The thermostat stays closed when cold and opens up at a certain temperature, if you take it out you get a constant circulation of the water through the entire system, eventually it heats up and cant be cooled fast enough in the radiator, then there's the reservoir tank, its there to help relieve excess pressure (air) in the system, so that there arent any air pockets in the system, these air pockets also translate into heat spots and increase heating conditions.

This is something that i try to recommend to ALL rotary owners, tend to your cooling system FIRST! before any other mods are done, and most importantly when you add a bigger turbo system you are in fact increasing heat in your engine.

I leave you with this frase, "a cool running engine, is a happy running engine". i forget who said that.

RETed

TOO LOW, especially if you're running a stock thermostat.

I dunno why people are so paranoid about their engines running hotter.
Bump up the turn on to 210F.
Turn off at 190F.
Keep the range at least 20F.

Like Claudio RX-7 has already stated, you're cycling the thermostat to open and close.


-Ted

TrboRty

iTrader: (1)

Why do you want to keep them 20F apart? I am just curious,because I have my haltech set to come on at 205 and go off at 200, and I am running a stock t-stat.

RETed

If you narrow down the range, the fan tends to cycle a lot.
To understand why this is bad, you need to understand how the electric fan works...
Most electrical motors (which the electric fan is) tends to use the most current on start-up.
This puts tremendous loads on the electrical system and the electrical components (switches, relays, etc.) that's connected to the electrical fan.
You want to try and minimize the number of times the electric fan turns on.


-Ted