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Decreasing IAT on my Supercharged SOHC V6

I installed a Banshee M90 supercharger kit on my 2000 Explorer Sport with the 4.0L SOHC V6 engine.

The intake air temperature (IAT) climbed to 174 degrees during my last set of of pulls on the dyno.

As the IAT increases the PCM reduces spark advance to avoid detonation. Max power is reduced when the spark advance is less than optimum. The IAT is OK during normal driving and is excessive only during boost. There is an intercooler in the intake manifold between the output of the M90 blower and the head intake ports.

I installed a stock external ATF cooler on the driver side to act as a heat exchanger for the intercooler. Some airflow is blocked by hoses associated with my remote full flow and bypass oil filters, the passenger side external ATF cooler, and the thermostatically controlled engine oil cooler. Also, the lower part of the grille support blocks the lower two rows of the stacked plate cooler.

At first I thought the high IAT was due to the vehicle being stationary during dyno testing but during a short street pull a high IAT (164 deg F.) was also datalogged on a warm day driving at 50 mph.

There is about 1.5 inches between the back of the cooler and the front of the A/C condenser.

There is also room in front of the cooler if some of the hoses are relocated. I'm thinking about moving the cooler up and forward enough to place a puller fan between the cooler and the A/C condenser to increase airflow thru the cooler. My goal is to reduce the maximum IAT to about 150 degrees.

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That has the correct logic. The output relay closes on control input positive transition, the timer activates on the negative transition, and the relay remains closed until the settable timer expires. However, the operating temperature range would prevent it from being mounted under the hood. I don't particularly care for the 11 pin circular connector that also serves as a mount. Also, relay contacts are rated at 10 amps. I'll be looking for a separate timer/relay controller and relay instead of an integrated unit.

By the way, you're not interrupting. Your comments are encouraged.

Actually you could cab mount the control \ relay cube and have 2 pairs run to the engine compartment.

One for Switch lead and one as a control for a "High Amp" relay coil.

Lots of options out there in the field. I'll search in my spare time. I've seen what your looking for in the past but I just can't remember where.

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courtesy lamp delay module

There used to be available courtesy lamp delay modules for 1970s and earlier vehicles that didn't have that function. Newer vehicles (our Explorers) have a GEM or equivalent that provides the capability. I may build one to mount in the passenger compartment. I probably have all the components I need in my electronics parts bins (555 timer, resistor, capacitor, voltage regulator, prototype circuit board, etc.). It would be a fun project but I should be able to buy one for about $10. I just haven't found one for 12 vdc, correct logic, no relay and the desired time delay.
I could use the 10 amp max Car Delay Off Timer shown below for $15 from eBay for the intercooler pump and to control another relay for the heat exchanger fan.

Nice find!
I purchased one also. The price is really good, and shipping to Canada was only $3.00. Its a win!
This will make a truly automatic system.

Selecting coolant & antifreeze

Typical automotive antifreeze is ethylene glycol and it significantly lowers the engine coolant freezing point and raises the boiling point. However, it also significantly decreases cooling efficiency as does the alternative propylene glycol.

Coolant Type * Freezing Point * Boiling Point * Specific Heat * Latent Heat Of Evaporation * Thermal Conductivity

*** Water ********** 32 ******** 212 ******** 1.00 ********* 970 Btu/lb ***************** .60
Ethylene glycol *** -84 (70%) ***** 387 ********* .65 ********* 344 Btu/lb ***************** .26
Propylene glycol **** -74 ********* 371 ********* .69 ********* 393 Btu/lb ***************** .15

From the above it is obvious that water is superior to both glycols for conducting heat and for absorbing heat prior to vaporization.

Red Line's SuperCool Water Wetter is advertised to improve heat transfer compared to glycol based antifreeze but has no freeze protection. Liquid Performance's Ice Water advertises it is glycol free (but not what it does contain) and has no freeze protection. Using Royal Purple's Purple Ice is claimed to result in lower engine temperatures than using "straight water" but has no freeze protection. Maybe it contains additives that reduce the surface tension of water to increase heat transfer.

For my street engine I'll eventually try the least amount of antifreeze needed for freeze protection and possibly a corrosion inhibitor and a surface tension reducer to see if that has any effect on the heat exchanger performance.

For the summer, it would be nice to just run demineralized water with a corrosion inhibitor of some sort. The down side of this is that in fall you have maintenance that must be done before catastrophe strikes.
Don't most of the water wetter products offer the corrosion inhibitor?

finished cutting

I finished cutting out the metal to allow mounting the heat exchanger/fan assembly. The upper cutout makes room for the 1/2 inch brass elbow.

I plan to drill a few holes in the center section to secure the assembly with cable ties.

Pex fittings

Today I started replacing the 3/4 inch and half inch dia. Pex fittings with the larger internal diameter standard brass fittings in an attempt to reduce coolant flow restriction. I hope to be ready for a leak test on Wednesday and to start wiring the cooler blower. I have yet to determine a 15 amp power source for the intercooler pump/cooler fan combination.

coolant leak test

I finished plumbing the heat exchanger.

Apparently even though the new cooler is larger than the stock ATF cooler it holds less coolant. The new fittings have larger internal diameters than the Pex fittings and short lengths of hoses are larger diameter. I did not catch all of the coolant when I drained the system but I could not get all of what I caught back in. I ran the system for several minutes to make sure all of the air pockets were filled. Fortunately, there were no leaks.

I pulled out the driver seat to improve access for wiring the fan/intercooler pump controller. I plan to use the cigar lighter circuit (I don't smoke) for power. It is a 25 amp fused, hot at all times circuit with nothing else connected that is fairly accessible. I hope to mount the controller behind the HVAC control panel. I'll probably just use a toggle switch to activate the controller until I determine what to do for a Hobbs switch equivalent.

I disconnected the AN fittings/hoses from the engine oil cooler and thermostat and began experimenting with rerouting combinations to lower it. I never did like the loop I installed in my first installation.

Isnt that fan just going to draw air where its open and not covered by the cooler? ?I know when I had the HHR fan mounted to my radiator it had an open space like that and it wouod not keep my truck cool at all..I gave the fan to my buddy with a sohc radiator which it fits on and he has never had a problem. theory was it draws the most air from the place that offers the least resistance. ..obviously some was sucked through the radiator but lower the cfms enough to where it didnt keep it cool..

personally would have went with a 8" fan or really just a bigger better cooler

fan aerodynamics

I had the same question before installation. Since the pitch of the blade is constant the greatest airflow will be near the tips where the blade speed is fastest. The more distance there is between the fan blade edge and the cooler the less effective the fan will be. In my installation there is only about 1/4" so air should be pulled thru fairly well. Obviously, the upper section of the fan will have no effect on the heat exchanger but will assist with cooling the A/C condenser and the radiator. It will be interesting to examine future datalogs with the fan being switched on and off. There's also the potential to add a plate that covers the upper part of the fan.

Car delay off timer

The car delay off timer arrived today from Thailand.

It came with a schematic diagram as advertised and it was even in English. I confirmed from the specifications on the relay that it is rated at 10 amps. Tomorrow I'm going to see if I have Fuse 9 (40 amps) installed in the battery junction box for air suspension. If so then I'll open up the Aux Relay Box 1 and see if the air suspension control relay is installed even though I don't have air suspension. The control module for the option is normally installed somewhere near the radio. I'm hoping the wiring, relay and fuse is present and I can use them for the fan and intercooler pump.

oil cooler thermostat refitted

The engine oil cooler thermostat has been remounted and its associated oil hoses rerouted. I had to cut one of the barbs off the horizontal end of each elbow to make room for the T fitting.

I was able to eliminate the loop from the thermostat to the cooler by making a bracket and mounting the thermostat lower and more forward.

By using another elbow below the T fitting I eliminated another loop.

I plan to install a 90 degree elbow in the ATF hose from the remote filter to the radiator and maybe another one between the radiator and the ATF cooler. I don't want any hoses or flexible conduit in front of the heat exchanger blocking air flow.

Wow, is there ever a lot of stuff going on up there.

power source selected

I doubt that air suspension was an option on the Sport. Anyway, I was not surprised that the associated fuses (8 & 9) weren't present or wired in the battery junction box. Using the cigar lighter circuit as a power source for the intercooler pump and heat exchanger fan would require running a large gauge wire from the passenger compartment to the engine bay which I wanted to avoid. I considered wiring another fuse into the bus in the power junction box but that would require disassembly and reassembly of the box. Then I realized that existing fuse 6 (20 amps) is only associated with the transfer case which my RWD doesn't have. So I was able to thread a 16 gauge wire thru the flexible corrugated loom (that contains all my other wiring additions) from the passenger compartment to the inner fender well near the ABS where I plan to mount the relay. I purchased five 30 amp 5 pin relays (normally open or normally closed) with mating connectors and pigtails on eBay for $12.39 (includes shipping). The relays have a removable mounting tab which I plan to use to attach to the inner fender well. The 16 gauge wire will connect to the relay solenoid blade contact on one end and the delayed off relay controller near the radio on the other end. I'm running 12 gauge wire in the flexible corrugated loom from the planned relay position to the heat exchanger fan connector and the smaller gauge wire for the intercooler pump. The relays probably won't arrive until next week but I don't need them to leak check the ATF and engine oil connections that have changed.

Hobbs switch & relay

The 1 psi Hobbs switch and the five 30 amp relays and mating connectors with pigtails arrived today.

I used the aft mounting bolt for the power junction box (PJB) bracket to mount the relay for the intercooler pump and heat exchanger fan.

Yesterday I finished routing the wire from the relay controller area behind the radio to PJB area. I also spliced a wire to the wire connected to the output of the transfer case fuse in the PJB and ran the wire from the relay area to the heat exchanger fan. I still plan to pull the other seat and fold the carpet back to run wires to an "energizer" switch mounted on the center console next to the defeat switches for the Accusump and the A/C compressor.

There's room for the Hobbs switch where the boost gauge port is but the hose to the bypass valve is almost directly above the port.

That's my gloved finger pulling up the hose during the original installation. I'll remove the EGR valve to get access to the area and then try to install a street T and a 90 deg elbow but I'm not optimistic they will fit.

air filter enclosure mods

I finished wiring the heat exchanger relay.

I decided to leave the intercooler pump connected to the fuel pump relay circuit so I can see how much effect the fan has. Later I'll move the intercooler pump to the fan circuit to extend the life of the pump.

I've been wasting a lot of time trying to determine how to modify the stock air filter enclosure to accept the 4" dia. MAF sensor adapter tube. The way my main intake is built I need to slide the adapter tube about an inch into the enclosure in order to separate the MAF sensor outlet hose from the pre-throttle body coupler.

I'll probably end up cutting a 4" deep by 4.5" high notch out of the corner of the enclosure and then covering the notch with aluminum angle stock with a 4" dia. hole in the vertical part. I'll also need a sliding seal to prevent unfiltered air from being drawn into the enclosure. It's bound to be a real kluge. From a maintenance standpoint I pity who ever owns this Sport after me.

Hobbs switch installed

The Hobbs switch I purchased has normally open contacts. I checked it with my hand pump and the switch closes right at 1 psi and opens just barely below 1 psi. There wasn't room to install it where the boost gauge port is because of the bypass valve hose directly above it so I replaced the 90 degree double male elbow with a 45 degree male/female elbow and a NPT male to hose barb fitting.

I made a simple bracket and mounted it to the windshield wiper motor assembly mounting bolts.

I attached a street Tee to the bracket using cable ties.

Using my trickle battery charger, an instrument panel lamp, and some test clips arranged on the breakfast table I verified that the delayed off timer could be activated with a ground signal. With the existing components the delay after the ground signal is removed varies from 14 seconds to 9 minutes using the potentiometer on the circuit board. Using a ground activation allowed me to run only one wire from the delay timer to the Hobbs switch. I routed the wire thru the flexible conduit that contains the wiring for the fuel rail pressure sensor. The other terminal of the Hobbs switch is connected to the ground strap via the bracket.

The Hobbs switch does not interfere with disconnecting/connecting the wiper motor connector.

I removed the passenger seat and folded back the carpet to run a ground wire from the delay timer to a switch to be added to the floor console. That way I can manually activate the heat exchanger fan and intercooler pump.

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Very nice. I'm going to be copying your setup.