anyone do E-fans on a obs??

[sparg93]

u will need the high spd if u use the AC.

Apologize for my directness, but you do not need high speed if you use AC. Low/High speed are supposed to be temperature dependant...even if he has the AC on and he's sitting in traffic, with a Mark VIII the high will never trigger unless he has a gunked up cooling system.

If you decide to trigger your fans when you turn on the AC, start with LOW. If it turns out you need High, it's a very easy switch.

BUT...you don't need the fans to kick on with AC. Is nice to happen when you first start your truck up, absolutely (AC won't be cold unless there is fresh air blowing in), but there's also the catch that you don't need fans blowing when you're on the highway.

For me personally, I did not tap into my AC line...but most people do.

to make it simple & cheap get the volvo
2 spd relay and efan at the jnk yrd we will talk u through it to wire it.....the mount i made 4 the relays theres 1 in back and another 1 on the side of the volvo relay.

The Volvo setup is the cheapest and easiest way to do it - if you know how to wire. If you're offering help, I have a feeling you will have to jump on the phone b/c if he's never wired relays, a diagram is going to be really confusing.

Sorry for jumping in so much...i used to have no idea about electrics until someone walked me through the setup in my garage with my hood open...if he's a newb with this, he'll need something very close to that.

 

[Monstar_est87]

Yea sparge thanx for clearing that up... I am a newbie at the electrics gig... I was at the junkyard and lookd for a 96 volvo relay but no luck....

If any1 can grab 1 and help me out with the wiring I can pay 4 it and 4 ur time...

 

[SunlitComet]

I disagree. When you turn on the a/c the condenser just become an instant source of heat and will add to the heat in radiator so the faster you can move it out the better. It won't over cool you engine in cold weather. And it is complicated for most to build a switch system that can independently measure airflow and determine from temp sensors what speed a fan should run. Not to mention you a/c would not be to efficient as it can be and with that heat comes more pressure to deal with in the system just making it work harder. I have never been in a vehicle that did not have a fan running when a/c was on. It would seem to me that having a fan on with a/c is a no brainer.

 

[sparg93]

Yea sparge thanx for clearing that up... I am a newbie at the electrics gig... I was at the junkyard and lookd for a volvo but no luck...

check out ebay, there are usually a few on there for sale.

I disagree. When you turn on the a/c the condenser just become an instant source of heat and will add to the heat in radiator so the faster you can move it out the better. It won't over cool you engine in cold weather. And it is complicated for most to build a switch system that can independently measure airflow and determine from temp sensors what speed a fan should run. Not to mention you a/c would not be to efficient as it can be and with that heat comes more pressure to deal with in the system just making it work harder. I have never been in a vehicle that did not have a fan running when a/c was on. It would seem to me that having a fan on with a/c is a no brainer.

My thoughts:
The original reason I did not wire it in is b/c I see no need to draw that much power while the vehicle is moving. (my rig sees 95% highway)

From a real-life testing standpt, the only time the AC doesn't work well is on startup...until i start moving, cold air doesn't exist. What i think is interesting, is that after i get moving, the AC stays cold forever...even in stop&go traffic.

My thoughts - once my rig is moving the engine is warm...the coolest it's going to to get is around the 160 mark (i have a 185 thermo). If I ever get stuck in traffic and the fans are not on, it only takes a few minutes for the temp to rise and fans to kick on. When they kick on, I now have my fresh air blowing over the condenser.


Net net - my AC is always cold once I get going and I've wired in a system that is temp dependant. As you noted, it's very tough to wire in speed & temp dependant system....however, our computers have an "Aux Fan" pin in them, but I couldn't figure out how to tap off that pin (but I did have it activated by BB). If I was able to figure that out, I would have saved huge $$$ on this setup.

Am I causing any harm to my AC system by not having air flowing over it continuously? (this would be the times my engine is 160 - 185 degress)
What do you think??

 

[SunlitComet]

If a/c is on then a fan should be on. If compressor is not on then no airflow thru condenser is needed although it will still have some because the radiator behind it needs it eventually. If you have the fan wired to a/c then of course you would have air at all times regardless of vehicle speed. The thermostat will keep the engine from getting over cooled. Also unless your engine is boosted some how I would leave a stock 195 thermostat in there. You are just going to increase emissions and gas consumption. Also 98 and older don't have the ability to be programmed with a pcm fan control. As far as I know anyway.

 

[sparg93]

If a/c is on then a fan should be on..

But if my AC stays cool (since it's only sporadically there is no airflow), then why do i NEED the fans to be on?

You are just going to increase emissions and gas consumption. Also 98 and older don't have the ability to be programmed with a pcm fan control. As far as I know anyway.

Why would a lower average operating temp increase gas consumption? (i honestly don't know, interested to learn more)

Interesting on the PCM fan control - mine is a '99 so I can't comment on <'98

 

[gpracer1]

But if my AC stays cool (since it's only sporadically there is no airflow), then why do i NEED the fans to be on?



Why would a lower average operating temp increase gas consumption? (i honestly don't know, interested to learn more)

Interesting on the PCM fan control - mine is a '99 so I can't comment on <'98

You need the fan to be running because the high side (head pressure) will be too high. Normally you would see (in your cooler area) 160-220 psi on the high side. Without the fan running you will see 300-400 in a matter of 30-60 seconds. That will mean less AC performance , increased pressures, more wear and tear on the compressor / engine/ belts / AC hoses etc.
Your truck's AC wouldnt last 10 minutes here in 115F without a fan running.
The reason it works for you is because your ambient temp is not that hot.


The cooler an engine temp is, the richer the air fuel ration has to be to make it run correctly....thats why the old carbs had a choke. It is arguable at what point it makes enough of a difference. Myself, I am going to install a 180 so I can get more timing when pulling a trailer in the extreme heat....more torque.

 

[sparg93]

You need the fan to be running because the high side (head pressure) will be too high. Normally you would see (in your cooler area) 160-220 psi on the high side. Without the fan running you will see 300-400 in a matter of 30-60 seconds. That will mean less AC performance , increased pressures, more wear and tear on the compressor / engine/ belts / AC hoses etc..

Very interesting, really appreciate the details

The cooler an engine temp is, the richer the air fuel ration has to be to make it run correctly....thats why the old carbs had a choke. It is arguable at what point it makes enough of a difference. Myself, I am going to install a 180 so I can get more timing when pulling a trailer in the extreme heat....more torque

Hmm, I currently have my low fan triggering close to 190 so I bought a thermostat @ 185 so it was open before the fan kicked on so I'd get a more accurate response.

For the sake of testing, maybe I'll run my higher fan temp sensor (198) in conjunction with my old 195 thermo and see if I notice a mpg difference.....

Forget to mention - thanks Sunlit for the info before...I'm still a newb with some of this stuff and still learning which is why I'll ask a bunch of questions.

 

[AtomicHoe094]

holy shit this thread is crazy.. too much shit going on

 

[sparg93]

holy shit this thread is crazy.. too much shit going on

I was thinking that too...poor guy originally just wanted to know how to install an Efan!!

Atomic - to make this complete, do you have any extra efan or relay kits for sale??