bostonspgs

iTrader: (1)

So i look at aarons write up all the time and wonder why the external thermostat?
Fc's have an electric cooling fan already , why not tap into that so you dont have to buy a probe thermo switch etc. Here is a paint version of the setup im talking about.
by all means let me know if this is wrong

Hazard15301

iTrader: (5)

There must be a reason. Why would AaronCake base the entire write-up on using an external temperature probe if using the stock one would be that much easier?

Heres my prediction: He's going to answer this thread like this:

"Because the _ _ _ _ _ _ _ _ _ _ _ . "

10 words or less, and make us all go "Aaah..."

Because all of Aaron's walkthroughs are epic.

bostonspgs

iTrader: (1)

the idea is simpler no doubt , the thought is to have the two fans in sync one shuts off at speed or low temp they both do not one over the other .

rx-7 obsessed

just wait for Aaron annny minute now.....

Alex_n/a

iTrader: (1)

someone questioning Aaron? why not question gravity too... lol

texFCturboII

iTrader: (17)

My 2 cents:

Because the newest FC is 18 years old. I wouldn't trust 18-24 year old sensors or wiring for jack considering how much is resting on a properly functioning cooling system.

RotaryRocket88

iTrader: (7)

Because only TIIs and automatic NAs had a factory backup e-fan. The TII uses a 210*F thermoswitch, which is too high for a primary fan, while the automatic NA had one set for 190*F (IIRC it's 190*F). The TII one could be replaced with a more appropriate switch, and the auto one could be used as is. But that doesn't help anyone with a manual NA. There's just no pre-setup system for it, so you'll have to use a custom switch setup.

turboIIrotary

iTrader: (9)

what he said^^^my n/a doesn't have the fans

arghx

iTrader: (3)

Your diagram will not work on s4 fan thermoswitches, but it will work on s5 and other switches. see this thread about wiring up a factory or aftermarket thermoswitch: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-control-electric-fan-factory-thermoswitch-886862/ . If you have a manual transmission N/A car you will have to get a thermostat housing that has been tapped for the M16 x 1.5 thread of the factory switches.

All s5 as well as the s4 T2 fan switches come on at 97C/207F and after activated the fans will stay on until temps drop below 95C/194F. This trigger is higher than some people prefer, but it is actually the same temperature at which the Rx-8 fans come online from the factory:



The Rx-8 also has an "aftercool" function for the fans like the FD. Remember too that the thermostat doesn't fully open until 95C/203F. So IMO the factory 97C/207F thermoswitch will work fine for most applications as long as it is in good working order. But that doesn't mean you can't use the fan switch from an automatic s4 car or from some other application. The automatic non turbo s4 fan switch comes on at 88C/190F and I presume cuts back off below that.

This type of control logic is used on a lot of OEM applications through the ECU. Sometimes the fans will come on in series. One fan will turn on when coolant temps climb above a certain threshold, then the other fan will come on with the A/C or with some kind of vehicle speed logic. A resistor (earlier Mitsubishi applications like 3000GT) or switching the circuit from series to parallel (Subaru) are two ways used to control fan speed. Some fans are duty controlled, like the fans on the Evo. Some fans have two or three speed inputs requiring two or three separate trigger signals. The FD factory fans are three-speed and will take three separate inputs to ratchet them up to full speed.

Aaron Cake

iTrader: (1)

What they (RotaryRocket88 and argx) said.

Not all RX-7s had the temp switch and there is no guarantee that one that does has a switch that activates at the appropriate temperature.

bostonspgs

iTrader: (1)

that said if it does have it and it turns on around 190-195 this theory would work right?

clokker

iTrader: (2)

Yes.

Hazard15301

iTrader: (5)

Like someone already said, if you do plan on doing this, I would replace the sensor with a new(er?) stock one. It makes no sense to trust something as crucial as cooling to an old sensor.

bostonspgs

iTrader: (1)

if you ask no questions in life you learning nothing , monkey see monkey do is not me , without questioning and just following what someone else said is what leads to regimes

clokker

iTrader: (2)

It's easy enough to check the sensor's function before automatically assuming it's bad.

bostonspgs

iTrader: (1)

plus even brand new sensors can be bad off the bat and not last as long as the probably antique i have

SirCygnus

iTrader: (1)

just because aaron cake has done it or talks about a certain subject does not mean all the other ideas or brainstorms are any less logical.

texFCturboII

iTrader: (17)

Just intrinsically flawed.

SirCygnus

iTrader: (1)

not quite. other ideas work. its just that things are getting more and more common because of the COOL factor.

think about it.

texFCturboII

iTrader: (17)

Haha, I know. That was just my pitiful attempt at humor. Damn sarcasm not being able to come out through text....

Aaron Cake

iTrader: (1)

195 is a bit high, in my opinion. I like to turn the fan on between 88 and 90 degrees (thermostat temp is 84 or 86 degrees). This keeps the temperature fairly constant and stops the temp gauge from wagging up and down when driving around in the city. Unfortunately there aren't too many temp switches in those ranges (they are either far lower or far higher) so one must go to an adjustable thermostat.

just startn

iTrader: (33)

Were did you find a adj. stat at aron!!

jackhild59

iTrader: (7)

http://www.summitracing.com/parts/DER-16749/

duo2999

iTrader: (1)

he came, he saw, he conquered.

just startn

iTrader: (33)

Thanks Perfeect i love living by the summit warehouse!!