Thermostat for Heat Exchanger - realistic?

[Doc Vegas]

Guys: a long time ago there was a thread on the HE fans. I have a Steeda and it has always bothered me. I am in a Vert, so maybe it is more noticeable, but it really annoys me. I do not want to wire in a switch as I am sure I will forget to flip it on those rare occasions I want to tear into it. Would a thermostat work? Would it respond fast enough? Or, is the entire point to keep the temp as low as possible no matter what? Regardless, I would prefer it kicks on when needed and stays off when cool enough - but - i am too lazy to turn it on/off manually (I would rather hear it all the time than flip a switch on and off).

Thanks

 

[fullboogie]

Without commenting on whether it's a good idea, there are fan controllers out on the market that are temperature controlled. I don't see why you couldn't use one to control your HE fans.

 

[Black Cobra '99]

I don't know about Steeda but VMP have their fans kick in when the IC pump kicks in. The pump can be programmed to go on/off in the tune.
So if its the same its really easy.

 

[ShelbyGT5HUN]

My VMP tune, has the IC pump on ALL THE TIME, which sucks because, the fan relays are triggered by the IC pump. I have a dual fan unit, and the fans are on all the time! So, as most of my driving is normal commuting, I pull the fan fuses, and run without them.

 

[Doc Vegas]

Interesting responses so far! So, I also have a VMP tune and my IC and fans stay on constantly as well. Can anyone else chime in if it is "really that easy"? I am sure BJ could modify my tune if that's all it takes. Do the fans really pull that many amps???

 

[VNMOUS1]

This has been cussed and discussed a thousand times. Our kit (as are others) is designed to have the fans running ANY time the pump is running. Pulling fuses, making switches or changing it within the tune are all bad ideas. Why? Because you can drive down the road at 70mph all you want and your temps would be fine without the fan on if you weren't in boost at all. But....stop in the local Mickey D's for 30 minutes and fire the car back up with no fans. Now look at your downstreams!!! They're through the roof because the conductive heat of the engine. You have to have the car running at 35mph to get enough air passing through the core to equal what could have been in your favor by simply starting the car had you not messed with bypassing the system.

Boost equals heat. These high performance cooling systems are made to cool and protect cars that make more boost, run more timing and are used as the car is intended. In traffic, on the track, to the drive through.

Normal operation (cruising) will show an average of 30 degrees over ambient (unless it's mofo cold out side), fans or not. But again, turn the car off and stop the fluid flow and watch what happens.

Downstream temps cause timing to be pulled, so you don't get the power you purchased. High temps are also a contributing factor to detonation.

The fact is simply this; they're designed to be on all the time. The math has been done time and again and it always comes out to this is how you should operate the system. If you bypass the system, it will void your warranty on the unit.

If you find someone that will actually find a way to let you turn off an intercooler pump, you'd better do a lot more homework before you even consider that!

FORD has your pump working every second. Do you really think they didn't do THEIR homework?

I can show you what a $10,000 race motor block and heads look like after 900 feet down the track at wot when the switch wasn't thrown back on. It has a number of lovely holes in it. This switch was designed to turn it ON while it sat in the pits. But human error won.

I have had a fanned heat exchanger in my car for years and I'm clearly deaf because unless I'm next to a wall or in the garage, I've never heard it running at any sort of operating speed with me actually behind the wheel. I did have a guy tell me that it bothered him because he couldn't have a conversation with anyone as they stood at the front of the car with the engine running. I wasn't quite sure how to respond.

So, do what you wish at this point. It's your car, your prerogative.

bj

 

[Catmonkey]

I'm not sure what a thermostat could do that you can't do with with the PCM. I have my on and off temps set around 70 degrees and it doesn't take long for the fans to come on and stay on even with lower ambient temperatures. There could be a way to reduce the fan speeds if noise is the major issue. But you'd be on your own exploring that possibility.

 

[VNMOUS1]

I'm not sure what a thermostat could do that you can't do with with the PCM. I have my on and off temps set around 70 degrees and it doesn't take long for the fans to come on and stay on even with lower ambient temperatures. There could be a way to reduce the fan speeds if noise is the major issue. But you'd be on your own exploring that possibility.

You can use a different pitch on the fan blades, but now we're getting WAY pricey if they'd do it at all. SPAL knows what they're doing, thus the pitch as provided.

 

[RedVenom48]

Had this convo with bj as well. For a little noise, the protection the dual fans provide ( along with performance capability) trump any ability to turn off the fans.

BJ, what's the exected life of the fans? I've got your unit, and its a well crafted piece. Should I have a fan fail in the future, do you have any part numbers from SPAL I could reference for replacement?

 

[Doc Vegas]

Any got the specs on the amp draw? Is that an issue for the stock charging system? Thanks

 

[ShelbyGT5HUN]

Hey BJ,

What temp does the stock IC pump get triggered to turn on, on the factory tune?

 

[ShelbyGT5HUN]

Any got the specs on the amp draw? Is that an issue for the stock charging system? Thanks

IIRC, Van told me over 30A for a second when they kick on, and 8A when running. These values are for both fans combined. These cars are known for their weak alternators, and small batteries. That's why I like to limit the fans.

 

[802gt500]

fan temp switch

I have vmp 800hp kit. Afco HE. I could not stand listening to the fans so installed an 88 degree snap switch thermostat found on ebay. Attach the signal wire to the thermostat. Intalled the thermostat to the inlet of the HE. (coming out of the supercharge HE) It works perfect. When I abuse the car or its warm out the fans are on. When cruising and taking it easy idling around they are off. I like to hear the supercharger whistle over the loud fans. It was annoying when idling and people would ask whats that noise and have to explain the entire system.

My 2 cents

 

[VNMOUS1]

Hey BJ,

What temp does the stock IC pump get triggered to turn on, on the factory tune?

There are two 'starters' , if you will; ACT2 and time after start. In SCT Advantage, they're in the SC section.

bj

 

[VNMOUS1]

Had this convo with bj as well. For a little noise, the protection the dual fans provide ( along with performance capability) trump any ability to turn off the fans.

BJ, what's the exected life of the fans? I've got your unit, and its a well crafted piece. Should I have a fan fail in the future, do you have any part numbers from SPAL I could reference for replacement?

Expected life (based on our use of them as well as AFCO and C&R) is 7+ years. Warranty on a SPAL fan is 3 years.

Buy replacements here http://vmptuning.com/misc-items/af-a700050045x/

For those of you interested in the facts on them (versus "..but I read on the internet"), here's the SPAL tech data on the 11" fans we use.

bj

 

[ShelbyGT5HUN]

So is it 16 amps with both fans running?

 

[fishpick]

Much to the chagrin (I'm sure) of BJ @ VMP - I'm designing a computer controlled fan module for this heat exchanger. I have a working prototype at this point using an old radiator, old fans, and a cheap circulating pump... I'll be getting a real blower / cooler (Stage 2 VMP) later this year and will move this developed example into a production model. The car is a convertible 2012 and the fan noise is a serious consideration. Seems to me there's enough people that want this that it might make sense to "figure it out"

Here's the logic I have applied and the controls in place - I'm very interested in folks feedback.

I'm using an autoparts store Ford coolant temp sensor - it's in a T in the effluent line from the heat exchanger so it's measuring the coolant heading into the intercooler. The tip of the temp sensor is cone shaped so it just "touches" the coolant flow without disrupting it.

I have the sensor wired into an Arduino board and a dual high amp fan controller board. This works great because the board can run on 12V.

The sensor equation utilizes the Steinhart-Hart Thermistor Equation - and maps temps exactly as resistance changes - and it responds as fast as the stock one in the engine block - so very sensitive / responsive (watch your engine temp on a tuner - it's very responsive).

I also have an external ambient temp sensor - just like the standard "outside temp sensor".

The programing logic is as follows - since the fans are variable - and I'm basing this on some of the forum posts about this unit (so the numbers maybe should be adjusted for expected performance of the HE and/or optimal performance of an intercooler).

If the coolant temp is within 20F of the ambient AND ambient is less than 70F - there's no call for fans. I kinda just picked this number hoping for some feedback here from the HP chasers that can tell me if that's still too warm or if it could go warmer. I know cooler = more HP, but I don't know what that translates into numbers as.

When there is a call for fans - ever - they start at 100% and then adjust after 1.5 seconds to wherever they need to be - this gives them enough juice to spin up without underpowering the start up.

The fan logic is "generally" a sliding scale of speed vs temp delta from ambient.

Again - I set an upper limit here not based on knowing anything - but from reading things where people start to notice heat soak issues... So here's the "math-ish":

I said the hottest the coolant can get is 150 - so if we hit 150 or higher then its 100% fan duty cycle.
As the temps drop, so does the fan speed until that "within 20F of the ambient AND ambient is less than 70F" - OR - if it's warmer out we achieve 20F > ambient (since again that seems to be the efficiency VMP mentions in these forums)

Finally - if the fan slows to any level, say 40% (really any % based on the sliding scale) and it's held there for more than 3 minutes AND the temp delta between coolant and an above 70F ambient is GREATER than 20F - then the system assumes we are in a "loaded" state (aggressive driving, not fully cooling) - and the fans will ratchet up in speed until we get to that 20F over ambient state - and then slow back down.

I know the "keep them on high all the time" opinion - but I think I can have the best of both worlds (like a lot of factory cooling systems) via a controller that knows what's going on, responds quickly, and ensures that things are always as cool as they need to be / should be - without excess fan.

Thoughts? Am I nuts, crazy, stoopid? This make sense?

 

[rotor_powerd]

Sounds like a complex solution to a self-induced problem. When you up the performance of anything, it always comes at a cost. If you want the benefits of an active cooled heat exchanger, that cost is the noise of the fans. By manipulating the running profile of the fans, you are giving up the performance that you were looking for by installing the heat exchanger in the first place. By the time you have the fans come on, the intercooler is already heat soaked and your IAT's are way up. At that point, why not just remove the fans or reinstall the factory heat exchanger?

 

[fishpick]

By the time you have the fans come on, the intercooler is already heat soaked and your IAT's are way up.

How so? (and I'm not asking that like a jerk - maybe I'm fundamentally misunderstanding something in the system) The IC dumps to the degas, the pump pulls from there - pushes through the HE - and the HE fluid out is what the IC will use temp wise in the intake to cool the compressed air entering the engine. I'm NEVER stopping the IC coolant circulating pump - EVER.

So - when you start up and begin adding heat to the system the pumping IC coolant temp increases, the sensor at the output of the HE detects the rising temps and basically the fans increase "faster" to keep the coolant at a temp that's no more than 20F over ambient... (again - that's the operating efficiency I have managed to guess at from the VMP posts).

The point here (even BJ says this) - if you are driving around town gently on a not FL hot day - the fans don't do much, if anything, over what the triple pass HE does with driving airflow over it... so why have them running at the "cost" of noise? If cruising at 50 MPH on a 80 degree day without aggressively pushing the blower and generating a ton of heat - the HE dissipates that naturally without the fans and just airflow - why would I NOT want a system that doesn't run the fans?

By the logic of "just leave them on" - I'd argue that the tune on my car now should NOT wait for the 170F threshold to turn on the radiator fan - and it should just run all the time (I guess this is a little different as the thermostat only opens at 170 - but to that point a factory tune does not run the fan all the time is runs the fan to manage the heat).

Said differently :

Driving style A is WOT / racing : you would want the 100% fan output to MAX heat dissipation from the fans at the HE to drop temps to the 20F over ambient.
Driving style B is cruising around town in the evening with the top down day : you are not slamming the engine but it's "warm out" and you have good natural airflow over the HE generated driving. Maybe maintaining that 20F over ambient is only 50% effort for the fans. - so blowing on the HE "harder" with more fan is akin to having 9 ladies pregnant for 1 month - you aren't getting a baby faster - it's wasted effort.

 

[rotor_powerd]

By allowing the coolant to heat to a certain point before truly active cooling is applied, the cooling ability of the intercooler is diminished and the system will be playing catch up once the fans are triggered to 100%.

At 50 MPH with the top down, is the noise of the heat exchanger fans really a concern? The fans help to maintain temperatures at low speed to eliminate recovery time once you get into the throttle. I don't have a convertible car, but I have to imagine that low speed situations are the only time when you would be able to hear them - even then I'm hard pressed to ever hear the fans with the windows down, the only time they are obvious to me is if I'm standing outside and in front of the car. You're essentially designing a system that will run the fans full bore at stop lights, in drive throughs, etc. and then relies on air flow at highway speed to stay cool. That sounds counter productive to fix the noise complaint.