ok, so i live in fl and heat sux 4 my engine, so how about rigging the cooling fans so they run to a switch? they r electric arent they? so no power would b robbed from the engine, and if we want that extra cooling for a race we could flip the switch and cool down the car a little yes? maybe? how the hell i would rig this i'm not sure yet, but just throwing a random idea out there....

 

it is very possible, my friend had a 87 jetta, and he had one of his friend hook up a switch to turn the fan off and on worked very well. what he did was connect the fan wire directly to the batery and put a switch in on his dash console.

 

I imagine if one looks in an FSM, you can find the correct wire closer to the interior, and use it, or else jsut cut the wire on teh back of the fan, and splice in a switch all the way back at your dash.

 

I think the idea might have some merit. If you open your hood after the car's been driven for a while on a hot day, whuh, it sure is hot in there! If we can evacuate the heat from the engine bay somehow...

Where would the fan be, though? The front opening of the engine bay (grille) is already filled with the radiator and 2 fans in it. If I look down at my engine bay, I can see there's some opening at the bottom, in front of the engine. Maybe put a small fan or two there? But that might 'sabotage' the airflow going into the engine and might actually cause overheating. Ideally it would be more toward the back of the engine bay, pointing down. But I'm not sure there's any room there to put any fan.

But if the idea is just to fan some cold(er) outside air into the air intake opening so it won't suck any hot air from inside the engine compartment, then a small fan in front of the opening may be all we need.

Again, just another random ideas!

 

maybe I'm reading your post with my dsylexia, but I think what Maximajism94se was talking about was figuring a way to control the 2 fans behind the radiator. Not to add fans to the bay.

Or I maybe reading Maximajism94se's post with dsylexia...

then again, I might be posting all this stuff with dsylexia...

 

Rigging the two fans to work together would be a fine idea. Only likely problem would be addtional wear. I would also want to keep the condenser fan funtioning normally with the AC on.

 

yup.. definitely a good idea.

there's a couple ways you can do it.

1. unplug the temp sensor on the engine, and the ECU turns on both fans to make sure the car doesn't overheat since the sensor is "dead" and it doesn't know what the engine iss doing.


2. wire into the 2nd fan's relay to make it come on with a switch. the 2nd fan already switches on when you turn the AC on, so there should be a wire in the dash running to the relay already. all you need to do is splice a switched +12V into it with a diode in the AC's line, so that the +12V from the switch doesn't turn on anything in your AC system.

thta's about it. it's not THAT easy, but it is. the hard part is finding the wire you need to switch to it. Again, be sure to use a switched +12V line so that the fan shuts off when you turn off the car (just in case you forget to turn the switch off, it won't run the battery down)

 

Actually its not that obvious, the relays are negativley switched by the ecu. So a two way switch placed in line with the computers switch will allow the fans to be switch with the most ease. If you energize the relay with a + signal and at the same time the ecu wants to also switch the fans on, it would then fry the ecu b/c it would send full current (a dead short) through the transistor in the ecu.

This is really easy to do, but It must be done right other wise plan on buying a new ecu. You would need to look at the wiring diagram to correctly understand how the ecu switches the relay (in the FSM), then its just a matter of inserting a switch in line with the wire that the ecu energizes and make it so that you can switch the fans on by giving it a negative signal (the relay that is).

 

Out of curiousity where in Florida are you, I'm in S. Fla. My take on this, considering our temp needle always hang right below the center mark regardless of season, ac off or on it stays the same. Our temp gauge doesn't have numeric numbers so who knows what exactly the eng temp is. I once had a hand held scannner hook up while driving my car and the eng temp always stayed about 190-193 deg. so I don't know if the heat soak is caused by a "hotter" running engine (meaning running hotter than normal) or just a normal side effect associated with the VE eng. Wouldn't a lower thermostat setting be a better solution instead of having the fan run whenever you want. Keep in mind our thermostat is rated for a 190 deg, so if you turn on your fan to cool the coolant the thermostat will start to close since it sensing the cooler coolant. Do you see where I'm heading with this? I onced had that "heat soak" problem until I check and adjusted my ignition timing as per the suggestion from another .org member. When I check the timing it was 5 deg below spec. I advanced it to 20 deg BTC and it solved "my" problem, but being the person I am I advanced it to 25 deg and it made a BIG difference. I drive with my ac on frequently in the middle of the day, and when I floor it I'm never dissapointed.

 

hmmmm....i like this lower thermostat thing...would that have any negative effects? thanx 4 the replys...i think i'll just unplug the the thrmostat if i'm gonna race at the track cause i have no fsm and that's just waaaaay 2 complicated 4 me (at the moment anyway...in time....

 

Looks like I have the dyslexia!

So has anyone tried disconnecting the coolant temp sensor and drive around with it? What possible side effect this might have? Will the ECU operation be affected, because it now has no idea about engine coolant temp? Will the temp gauge inside the car still works? Will check engine lights, etc. light up?

Anyone brave enough to experiment?

 

Actually I think our factory thermmostate is rated at 180F. I'm using a 170 currently with only a slight noticable gain. And just to point out that there is an issue in a technical service bulletin, that states for added performance to use the lower 170 rated thermostate that should be available from nissan, I bought mine from pepboys (I think its a stant). So this is an issue that nissan is aware of, most likely most nissan dealers or parts guys are not aware of b/c they never read the TSB's

I dont have the part number for the nissan 170F thermostate with me but I might have the old TSB printed out somewhere. The quality of the stant 170F thermostate is not a ruggedly built as the nissan, so I think the nissan built one would be the better way to go and they arent really that expensive anyway.

stay cool

 

GRRR yeah, Eric.. I forgot most of the stuff controlled by the ECU has negative triggers on it. (it's easier for microprocessors to send a ground signal than +12V).. shoulda thought of that, but it's as simple as knowing where to run the wiring on it.

That's also why I mentioned the diode in line with it. had the diode been installed correctly, it wouldn't have shorted the ECU- just wouldn't have done anything to the computer since the diode would be reverse-biased and open the circuit.



situation #2...
Unplugging the temp sensor may or may not be okay for long term.. I've only done it while testing stuff in my driveway with the engine idling.. pull the connection and the fans come on about 5 sec later. leave it off for more than about 30 seconds, and when you pulg it back in the engine will sputter and die. I'm going to assume that it's because the ECU is changing the A/F ratio to make the engine run cooler, and when you plug it back in, it changes things too far the other way and the engine leans out and dies.


Situation #3.
I forgot about this one earlier, but it's what most of the 4th geners do.
unplug the AC compressor relay to keep from engageing the clutch on the compressor, then turn the A/C switch to on inside the car. the ECU thinks the AC is on, so it fires up the second fan, but the compressor itself doesn't engage. same basic deal as above.


Also installing a cooler thermostat is a good idea if you want to do this stuff long term.. around here, the only times I race (on the track, of course the engine doesn't even reach true operating temps because I fire it up and shut it off before it ever gets that hot.

 

and running a cooler temp sensor has no long term effects does it? especially considering the tsb for it correctamundo? good job

 

dude its not a temperature sensor that you'd be replacing its the Thermostate, and you want the 170 degree farenheight one.

 

I'd say you are better off racing at full operating temp. Driving hard on a cold engine is a no no. Check the new M3..it has an led display that changes with temp. Until the engine is fully warmed, it idicates rpm limits you should not exceed. Once it has warmed to op temp, clearances reach there design conditions after thermal expansion, oil has fully circulated and has reached lower viscosity limits (less drag, especially on the crank counterweights), rings and valves seal better. Plus, if you have a cooler thermostat and heat soak has been taken care of, your car should run much better at operating temps. Just a thought. Anyone disagree?

 

male, this is an issue nissan had posted in there TSB, and its somthing that most ve and vq owners already new. Heat soak in our engines is excessive thats why they made the 170F thermostate available from nissan. Now if you live in a very cold climate then I would say to stay with the stock themo. but for the rest of us if you want you engine running with performance in mind, switching to the 170F is the way to go.

 

I agree w/ your statements. But there is a big difference between warming the engine up to operating temps(alot colder) and running the car at a slightly colder operating temp.

 

I agree with both of the previous responses, but Matt93se said he fires it up and shuts it down before he gets to operating temps. That is what I think is a mistake. Running a t-stat that opens 10 degrees lower is not the issue. In fact, my vg is a dog on hot days and am considering swapping out a lower temp t-stat. But once you have the t-stat, does it solve the heat soak issue? If so, then I would race at operating temp..fully warmed. Not saying race after you just drove 30min at 75mph to get to the track, I'm saying idle for a few until the temp is at normal operating.