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Underdrive Water pump Pulley Installation: 4.0 SOHC

aldive

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1999 XLT
Eureka, my new 20% underdrive water pump pulley finally arrived ( after a backorder wait ).

My water pump is currently being underdriven due to the UDP/harmonic balancer (http://www.explorerforum.com/forums/showthread.php?t=151951&highlight=underdrive ); however, I had a hankering to further underdrive it in hope of further increasing gas mileage.

I obtained this pulley from Underdog Performance ( http://underdog-performance.com/index.html ). The pulley cost $90.00 to my door, and was red anodized aluminum. Its aluminum construction allows for less rotational mass.

Underdog is a great company with which to do business; extraordinary customer service and excellent communications. I highly recommend them.

To underdrive an accessory, its drive pulley needs to be larger in diameter than the stock pulley, as a result the underdrive water pump pulley is larger in diameter ( 6” ) than the stock Ford pulley ( 5 1/8" ).

The first step in the installation was to disconnect the negative battery terminal. After that, my Mac intake (http://www.explorerforum.com/forums/showthread.php?t=130982&highlight=mac+intake ) was removed. This was followed by the removal of the serpentine belt after rotating the drive belt tensioner counterclockwise with a 3/8” breaker bar. Next, the electric fan (http://www.explorerforum.com/forums/showthread.php?t=140251&highlight=electric+fan ) was removed and set aside. After that, access to the stock water pump pulley was gained. Next, the water pump pulley was detached by removing the 4 x 10 mm bolts and detaching the pulley. Air tools rendered this task painless.

The new underdrive water pump pulley was installed by reversing the removal process and torquing the bolts to 18 ft/lbs. A new serpentine belt ( Goodyear Gatorback 4060865 ) was required, After installing the belt, the electric fan and Mac intake were reinstalled. Finally, the battery was reconnected.

The motor was started and checked for any maladies; none were observed.

The motor was allowed to reach operating temperature and then the water temperature was monitored with my OBD II scanner ( http://www.autoxray.com/default.htm ). The water temperature at idle was 194-195 F ( idle temperature prior to this installation was 190-192 F with 75 F ambient temperature ). At 70 MPH, the water temperature was 190 F ( the water temperature at speed prior to the installation was 190-192 F; 75 F ambient temperature ).

Further, a test drive around town, in traffic at 75 F ambient temperature, showed no problems. The water temperature was 190 F except at idle where it was 194 F.

The installation took about 20 minutes. Removing/replacing the electric fan was the most time consuming component of the job.

Now that the underdrive pulleys (the water pump, and the UDP crank/harmonic balancer [ http://www.explorerforum.com/forums/showthread.php?t=151951&highlight=underdrive ]) have been installed and road tested, a 2000 mile trip ( to Atlanta and SC ) will be undertaken in the very near future to evaluate the pulleys synergistic performance and effect on gas mileage. Data will be reported.

I am still awaiting the backordered overdrive alternator pulley to arrive ( from http://underdog-performance.com/index.html ).

All things considered, I am very satisfied with these underdrive pulleys. Is a trip to the dyno in the plans? Only time will tell.
 

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One Question how did you know what belt to use? other than that cant wait to see the results and by the way great job on the write.
 






zhanx said:
One Question how did you know what belt to use? other than that cant wait to see the results and by the way great job on the write.

Good question and it once concerned me too. The supplier of the underdrive water pump pulley made the recommendation to me and he was right on.
 






Took a 130 mile trip today with no problems.

The ambient temperature was 78 F and the coolant temperature never exceeded 192 F.

Mileage data coming soon.
 






Al
I don't understand what this mod has done for you, or will do.
All you doing by using UD pullys on the WP and Alt is bringing the rotational speed back up to factory spec.
In the absence of cooling or charging problems, why do it, just curious.
 






spindlecone said:
Al
I don't understand what this mod has done for you, or will do.

All you doing by using UD pullys on the WP and Alt is bringing the rotational speed back up to factory spec.

In the absence of cooling or charging problems, why do it, just curious.

Read what I wrote in the first post ....

My water pump is currently being underdriven due to the UDP/harmonic balancer (http://www.explorerforum.com/forums...ight=underdrive ); however, I had a hankering to further underdrive it in hope of further increasing gas mileage.

That simply is not true. I don't think you understand underdriving/overdriving.

Again, read the first post for my reason for further underdriving the water pump.

This has nothing to do with an alternator.
 






I have read it Al, with the ASP UD you are underdriving all driven items by 25%,Correct?
By going with a larger WP pully you have brought the impeller speed back to OEM, same holds true for the Alt.
The parasitic drag you reduced on the WP with the OEM pully, back to being OEM again is negated, is it not? just asking.
 






spindlecone said:
I have read it Al, with the ASP UD you are underdriving all driven items by 25%,Correct?
By going with a larger WP pully you have brought the impeller speed back to OEM, same holds true for the Alt.
The parasitic drag you reduced on the WP with the OEM pully, back to being OEM again is negated, is it not? just asking.

Obviously, you do not understand underdriving/overdriving.

Again, to quote from a previous post on the sunject ....

To underdrive an accessory, its drive pulley needs be larger in diameter than the stock pulley, as a result the underdrive water pump pulley is larger in diameter ( 6” ) than the stock Ford pulley ( 5 1/8" ).

Whereas to underdrive the crank, the pulley needs to be smaller than the stock one.
 






Thx for the detailed education, like I said, was just asking a question that was not answered
 






Everything I presenterd above was in the original post.
 






Just got an understandable explanation from Wayne at underdog.
Being that I spend alot of time during the summer in socal and mexico, I think it best to stick with my OEM WP pully.
Thx for your time.
 






Al, have you considered going to an electric water pump? I have a Meziere on my Mach 1 and it works great. Constant flow no matter what the engine rpm's are and no parasitic drag.
 






Not one available for the V6
 












JDraper said:
Al, have you considered going to an electric water pump? I have a Meziere on my Mach 1 and it works great. Constant flow no matter what the engine rpm's are and no parasitic drag.

Jeff, yes, I would love to; just havn't found the part.
 












Hey aldive, we're not going to stop until we find you an electric water pump, you know that don't you? ;)

If we have to turn this entire cyberworld upside down we will not rest until you have this part!!! Come on guys!!! Let's all get busy and win one for the diver!!! :usa: :ca: :uk: :australia
 






Buzzsaw said:
Hey aldive, we're not going to stop until we find you an electric water pump, you know that don't you? ;)

If we have to turn this entire cyberworld upside down we will not rest until you have this part!!! Come on guys!!! Let's all get busy and win one for the diver!!! :usa: :ca: :uk: :australia

You are de man .....
 






What do you think of the electric pump that is on a Chevy V8? I know that it is held on by 4 bolts, and the blocks are different. What about adapting the pump with plumbing fittings, like threaded flanges, and high temperature orange gaskets?
 



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Al will be one of the last to do the Mod, but the first to do a writeup, keep us posted Al, your doing good work, somebody needs to do this stuff, I applaud your efforts
 






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