HE Fans

[Riptide]

I read DOB's article on the HE fans and am considering removing them.

Has anyone actually done testing before and after under similar ambient air and driving conditions to determine the effect? I mean in a real supercharged car and not sticking the HE on top of a truck.

Just bought a set of replacement spal fans now and am wondering if I threw $200 in the toilet.

 

[01yellerCobra]

I installed a set on a buddies car. He said while driving they made no difference. If he was stopped they kept things cool. I'm of the mindset that if you need to cool down in the pits between runs then install them. Otherwise go without.

 

[Riptide]

If the fans can come out and go back on without having to pull the front bumper. For instance with the splash guard pulled underneath. I might be willing to do the testing myself and post results. Otherwise I'm just too lazy.

To me if it makes no difference out of the hole but helps while idling then that is still a net benefit.

 

[Pentalab]

Use the oem eng fan..that comes with the car. But on it's higher speed. Parked in the driveway, with high speed eng fan on, I can easily feel the air being sucked in through the upper 7 bar grille. Anytime you have air coming out by the dashboard vents, the high speed eng fan is on. AC does not have to be on either, AC off, and air coming out the top...or top+ bottom...( set temp control to coldest, but AC OFF). Reason the eng fan comes on asap, on high speed mode is, the AC kicks in.... but in de-humidifier mode. Leave cabin fan at lowest speed. This is on my 2010 auto, with small M90 blower.

That above combo is plenty good enough for a street car, even on a warm day.....at a red light. Once moving, like 20-30 mph, I still have the eng fan running full bore. IAT is a non issue.

 

[DiMora]

DOB’s article has so much wrong with it.

I actually bought a second AeroForce interceptor and a pair of water temp sensors, T-fittings and bungs to install at my heat exchanger inlet and outlet to test actual Delta-T with and without fans running - but I haven’t installed it yet; I have a lot going on right now so it may be a while.

I can tell you that just watching IAT’s while Cycling fans off and on appear to have a 1-3 degree impact at the most.

You have to keep in mind that with most supercharger set ups the 180 to 200° engine valley temperature is heating up the intake manifold - which in turn is heating up the inlet air. Even on a cool day with 40-50° ambient air temperatures you will still see IAT’s in the high 90’s/ low 100s after everything stabilizes in cruise.

With wide open throttle application, ambient air temperature really makes a huge impact. On a cold day, air passed through the air filter and throttlebody is cooler than the liquid temperature in the intercooler and the intercooler system is likely harming IAT’s. On a hot day, the intercooler liquid is cooler than the intake air - and the intercooler system starts to really matter - and provide big benefits.

I do think fans provide a benefit at both low and high speeds, but I do agree with the DOB that once the car is moving, the benefit becomes very minor. I do not yet support DOB’s conclusion that fans actually harm you at speed; So much of the heat exchanger on most of our cars is blocked from frontal airflow due to the bumper. The areas that are exposed to direct airflow are below the core of the fan - and thus I do not believe air flow is significantly (adversely) impacted by fans on most of our cars - and in fact fans may help at speed by sucking air through flow- blocked portions of the heat exchanger (behind bumper).

Modern fan design by a company such as Spal also takes into consideration airflow velocity through the fan that is greater than the airflow velocity provided by what fan speed alone would provide - and compensates by allowing the fan blades to free-wheel.

 

[Pentalab]

D

You have to keep in mind that with most supercharger set ups the 180 to 200° engine valley temperature is heating up the intake manifold - which in turn is heating up the inlet air. Even on a cool day with 40-50° ambient air temperatures you will still see IAT’s in the high 90’s/ low 100s after everything stabilizes in cruise.

With wide open throttle application, ambient air temperature really makes a huge impact. On a cold day, air passed through the air filter and throttlebody is cooler than the liquid temperature in the intercooler and the intercooler system is likely harming IAT’s. On a hot day, the intercooler liquid is cooler than the intake air - and the intercooler system starts to really matter - and provide big benefits.

I do think fans provide a benefit at both low and high speeds, but I do agree with the DOB that once the car is moving, the benefit becomes very minor. I do not yet support DOB’s conclusion that fans actually harm you at speed; So much of the heat exchanger on most of our cars is blocked from frontal airflow due to the bumper. The areas that are exposed to direct airflow are below the core of the fan - and thus I do not believe air flow is significantly (adversely) impacted by fans on most of our cars - and in fact fans may help at speed by sucking air through flow- blocked portions of the heat exchanger (behind bumper).

Modern fan design by a company such as Spal also takes into consideration airflow velocity through the fan that is greater than the airflow velocity provided by what fan speed alone would provide - and compensates by allowing the fan blades to free-wheel.

Whether it's a hot..or cold day outside, cruising at 50 mph in OD @ 1500 rpm, the intake air is moving pretty slow through the hot manifold, and gets...RE-heated, hence my typ 118-125 Iat's. Same deal if in 4th gear @ 30 mph. Mash the gas, drop down into say 2nd or 3rd gear, and now the rpm is sky high, and air screams through the CAI.... and doesn't have time to get RE-heated by the hot manifold. My IAT's drop asap..down to 100 F..and stay there. I never have the blower on for more than 5-10 secs on the street / hwy.

The roush HE on my 2010 M90..which is the same HE as used on the 2010+ roush TVS-2300 pd setups, is 18" tall x 21" wide. It's tall enough that it gets hit by air from both upper ( 7 bar upper) + oem lower grille. But you are correct, the damned bumper blocks the middle of the HE. Didn't know the spal fans free wheel when outside air velocity is greater than spal fan velocity.

I calculated the actual fan velocity on several fans, complicated math exercise, but for a single 18" diam HE fan, that's rated at 1800 cfm, the actual air velocity through the fan is an abysmal 16.8 mph on the test bench.
Air impact pressure goes up to the square of the velocity. With the car at 67.2 mph, you now have quadruple the cfm, and also 16 X the impact pressure. Problem is.... you have that damned bumper in the way. So your theory that the fan(s) still might be of benefit at speed, might just be valid. The worse that can happen is they will free wheel, so no big deal. At lower speeds, like 20-35 mph, the fans could be of benefit.

Back a few yrs ago, I found a slimline 18" diam x 1800 cfm, that would fit behind my roush 18" tall x 21" wide HE...and also came up with this semi elaborate shrouding scheme. Then I discovered how to easily fool the oem eng fan into being in high speed mode. Gave up on the 18" diam HE fan install, and opted to just use the eng fan instead..which is ample for my street application.

Summer of 2017, it was blazing hot. Bumper to bumper traffic... on my trip to local hosp to visit my Brother. This was like 7 pm. Car heat soaks of course. Come out at 8 pm, fire up eng, and IAT is a whopping 145 F..which rapidly dropped to 138 F after just 10 secs. A few blocks away it was down to 132 F. Got the eng fan cranked up to high speed, and got it down some more, like 128, then down to 125. Didn't get any lower than that the rest of the trip home.

Would be nice to just lift the hood, to dump a bunch of heat. With the insulated hood, and bottom eng cover, it's all trapped..bad news.

 

[1950StangJump$]

I have VMP's dual fan setup. Would I do it again after reading DOB's article? I don't know.

Here is the thing. . . I don't believe comparing AITs under various operating conditions tells you much. Instead, I think it is about how quickly AITs come down when you get on the throttle from an idle.

My logic is this: When idling, the fans are inevitably keeping the HE fluid cooler. However, because you are not pulling much air in over the IC, you don't see much benefit of it. But, as soon as you goose the throttle, the cool air rushes in. It is as that point that the AITs come down. Logically, HOW FAST THEY COME DOWN WILL BE INFLUENCED BY THE FLUID TEMPERATURE IN THE IC AT THAT MOMENT.

So, by the fans keeping the fluid cooler while you idle, you see the benefit in the speed by which AITs come down after leaving idle. Whether the difference is material is certainly debatable.

And, like Dimora, I don't necessarily believe that, at speed, the fans do more harm than good. But, I could definitely see where their benefit is diminished.

 

[Riptide]

We need actual apples to apples testing in controlled conditions. Ideally take readings first at various conditions, mark ambient temperature, and then repeat the exact same testing with no changes other than removing the fans.

Currently after the car has been warmed up fully (20+ minutes driving) I see around 40-45 degree over ambient temps at 40mph. Sitting at a light for 3+ minutes and it's 55-60 over ambient until it's back to cruise. I have been told something is wrong, and that those temps are higher than normal. I don't know what's wrong though as the pump clearly is flowing and there is no air lock. Pinched the lines many times over, doesn't help. Could it be the sensor? Maybe but that seems doubtful.

Regardless I'm going to drain the mixture this summer and start over. I'm debating whether to replace the bosch pump at the same time along with pulling the fans or not.

 

[1950StangJump$]

We need actual apples to apples testing in controlled conditions. Ideally take readings first at various conditions, mark ambient temperature, and then repeat the exact same testing with no changes other than removing the fans.

Currently after the car has been warmed up fully (20+ minutes driving) I see around 40-45 degree over ambient temps at 40mph. Sitting at a light for 3+ minutes and it's 55-60 over ambient until it's back to cruise. I have been told something is wrong, and that those temps are higher than normal. I don't know what's wrong though as the pump clearly is flowing and there is no air lock. Pinched the lines many times over, doesn't help. Could it be the sensor? Maybe but that seems doubtful.

Regardless I'm going to drain the mixture this summer and start over. I'm debating whether to replace the bosch pump at the same time along with pulling the fans or not.

I don't think those temps are alarming, per sae. It's not as easy as "X over ambient" because you also have to figure in the 180-200 degree engine. So, 60 over ambient when it's 30 degrees will be much less alarming than when it's 100 degrees outside.

And, again, you could have the best cooling system in the world but, at idle, there is simply very little air going over the IC. So, the heat soak will far overcome the IC in those conditions.

But, THE EFFECTIVENESS OF THE COOLING SYSTEM WILL BE OBVIOUS IN HOW FAST THE TEMPS DROP WHEN YOU GIVE IT THROTTLE ON TAKE OFF. It is my opinion that the rate of drop is more important than the static temp under an unchanging condition.

 

[Pentalab]

Not only is the aluminum eng block hot, so is the aluminum heads, aluminum manifold, and aluminum blower casing, and ditto with the coolant flowing through the eng block. It's all stupid hot. The only thing warm to the touch under the hood, 2 mins after the eng has been shut off...is my ceramic coated LT's.

Some hood vents might be more effective. All that air going through the upper / lower grille ends up in the eng bay.....and with the bottom cover, you only have either side of the lower portion of the aluminum block, to dump hot air out the bottom of the car. It doesn't help any, with oem cats at base of eng bay, and non ceramic coated oem exhaust primaries...sitting at a red light. If hood vents used, an alternate path to dump hot air would help.

With ceramic coated LT's... and hi-flow catted H..with catted H portion sitting beneath front seats, my eng bay temps dropped 40 F, using a fluke 62 IR device. Before the exhaust change, my steeda black STB over the eng was burning hot to the touch. Now the stb is luke warm.

 

[Riptide]

I do understand the points presented regarding the more important data like IAT values under load vs. sitting at lights. That metric is a little harder to pin down vs. static values (cruise, idle) so the latter gets drawn into comparisons more frequently. Whether my system is genuinely under performing at this point is up in the air. I'm not inclined to agonize over it much since it'll be drained and filled this summer.

I am considering upgrading to the 2013+ GT500 pump while I have the bumper off. Is this a worthy upgrade? And can someone explain this to me please?
http://departmentofboost.com/PDF/13_GT500_Pump-Remsen De-Gas_Mod _nstructions.pdf
It looks like DOB has you connecting the inlet and outlet hoses together with some t-junctions at the degas bottle. I don't understand how that is a good thing wouldn't you want the input/output completely separated?

 

[1950StangJump$]

Along with the VMP dual fan HE, I recently did the GT500 pump upgrade. Got it from DOB, as a matter of a fact.

The reason they show it hooked up that way is because the GT500 pump flows so strong, it can create too much agitation in the degas bottle -- putting too much air in the system and eventually locking it up. So, by having a bypass, most of the fluid goes around the bottle and avoids the problem.

In my setup, I ended up with a different result. I put the T's down lower. So, in my case, NO FLOW goes up through the degas. Instead, the bottle becomes a true 'coolant overflow' only -- just like the reservoir for your engine coolant. You literally see no movement in the bottle, as all the flow goes through the bypass. At first, I thought the pump was airlocked, but it's working great.

But, again, at idle, how well my IC system is working becomes virtually inconsequential. But, when you start to give it gas, or when driving around, the improvement is noticeable.

 

[Riptide]

That makes sense. Is there any reason you went with your T's in a different spot vs. what DOB recommends?

Where is your pump mounted? I've been told there is no wiring work needed to replace the bosch but I will have to mod the bracket if I keep the pump where it's at currently. Thanks

 

[1950StangJump$]

That makes sense. Is there any reason you went with your T's in a different spot vs. what DOB recommends?

Where is your pump mounted? I've been told there is no wiring work needed to replace the bosch but I will have to mod the bracket if I keep the pump where it's at currently. Thanks

I have a Kenne Bell. On the KB, the water line from the IC/manifold comes around on top the driver's side valve cover. It normally loops up to the degas bottle on the driver's side. That's the opposite of my SCs.

So, to use a Moroso GT500 stainless tank and keep roughly that same KB water line routing, it was easiest to have it 'T' down low near the antilock breaking system. It creates a direct path for the fluid to bypass the bottle entirely. The routes to and from the degas end up going upward to get to the incoming and outgoing barbs of the tank. Based on gravity (and probably the infamous KB water flow restrictions), the fluid takes the path of least resistance and comes around from the manifold and flows downward to get to the pump under the left headlight. I can see no flow in the bottle -- it just expands and contracts based on temp, just like the engine coolant setup. Hope that makes sense. See the picture.

When I pulled the front bumper off, I found that mounting the pump to the front frame right below the left headlight made the most sense. Again, this was a direct, gravity fed route from the water line just above it by the antilock brakes. I just drilled a couple holes and used the GT500 pump mounting bracket.

And yes, you will need to splice the GT500 pump connector in lieu of the Bosch connector. They are different. But, it is two wires and easy to do.

 

[Riptide]

Hah they told me it was plug and play no wiring work required. Yah I get that there isn't much to it but I don't have any tools for that right now. I wonder if they sell this to make it a plug/play scenario:
https://www.vmpperformance.com/2013-Intercooler-Pump-Installation-kit-for-07-12?quantity=1

They also sell another, cheaper pump that is supposed to flow 30% more than the bosch. No idea which one it is.

Love the tank in your setup, looks great. Way better than plastic junk.

 

[eighty6gt]

I have a 2013 GT500 high temp rad and electric pump, TVS1900 on M90 lower manifold.

My IAT's are 100+F cruising. 140F idling.

*shrugs*

 

[1950StangJump$]

Hah they told me it was plug and play no wiring work required. Yah I get that there isn't much to it but I don't have any tools for that right now. I wonder if they sell this to make it a plug/play scenario:
https://www.vmpperformance.com/2013-Intercooler-Pump-Installation-kit-for-07-12?quantity=1

They also sell another, cheaper pump that is supposed to flow 30% more than the bosch. No idea which one it is.

Love the tank in your setup, looks great. Way better than plastic junk.

DOB, to their credit, says it's not plug and play, but it is easy. That's true. The wire connector amounts to splicing two wires. And, the pump can go where you want it, so you can decide what works for you.

Thanks for the compliment on the tank(s). The red topped one is the Moroso GT500 tank. The smaller is the power steering reservoir, which I relocated to the valve cover. The bottom one is a Canton stainless tank meant to be a degas bottle for the Kenne Bell cooling system in the earlier years. I modified it to be the windshield wiper reservoir.

 

[Riptide]

Yah it was vmp who told me plug and play with only some work to get the pump mounted. I don't know what the deal is with that harness they sell I may have to call and ask about it. Don't have any tools to do the wiring work currently. Would probably follow DOB's instructions with the t-junctions near the degas tank.

I have a 2013 GT500 high temp rad and electric pump, TVS1900 on M90 lower manifold.

My IAT's are 100+F cruising. 140F idling.

*shrugs*

Mine hardly ever gets that warm idling but if it's a 70+ degree day it definitely is warmer than that cruising.

EDIT: DOB instructions makes it seem like you only need to do wiring work if you're using the pierburg.

 

[1950StangJump$]

Yah it was vmp who told me plug and play with only some work to get the pump mounted. I don't know what the deal is with that harness they sell I may have to call and ask about it. Don't have any tools to do the wiring work currently. Would probably follow DOB's instructions with the t-junctions near the degas tank.

Mine hardly ever gets that warm idling but if it's a 70+ degree day it definitely is warmer than that cruising.

EDIT: DOB instructions makes it seem like you only need to do wiring work if you're using the pierburg.

If you're getting the GT500 pump from VMP, I think there is a good chance it is plug and play. When I bought the VMP HE, I also bought their plug and play harness for the HE. But, that was to wire in the HE fans in conjunction with the pump. At the time, I had the Bosch pump. It was later that I added the GT500 pump from DOB and had to splice in the new connector.

Bottom line, VMP made a nice harness for the HE, and it was truly plug and play. So, if they are selling the GT500 pump as a kit and advertising plug and plan, I'm guessing they had already done a GT500 pump harness for you so you don't have to splice. Call them and ask.

Not to sound condescending but . . . if splicing two wires is a problem for you because of work space and tools, I have a hard time imagining that upgrading the pump is realistic. Wait until you have the space and tools to do it right.

 

[Riptide]

They don't advertise it as such per se, it was what they told me on a phone call. Maybe it is if you go through them. Your VMP HE didn't come with fans and a harness? I guess that makes sense that the full supercharger kit comes with that, since it includes the bosch, but maybe not if you get it separately.

Sadly most of my tools are still in storage 1000 miles away. Mounting the pump and getting all the hoses and clamps in place probably is no big deal. I have zero tools to do wiring work with though so may have to bribe someone if I do end up needing it.

Getting together a laundry list of items to take care of later this summer only thing I haven't really made my mind up yet is the issue of the HE fans. Very tempting to remove them I just don't like being the test subject. If someone else does a before/after with reasonably good testing methodology I'd follow up on it.