Here are some facts that I have collected:


Data collected from:

2003.5 G35 Sedan A/T
OEM Thermostat
PWR Radiator
Hayden Fan Clutch
Ambient Temp 89-95F (mid morning - afternoon)


Data Collected Using OBD port / (Infrared Thermal Thermostat).

While Driving on highway speeds Temperature at OBD= 177-183 150-160

City Driving Temp @ OBD = 185-191 165-174

Heavy Stop and Go = 189-197 179-183

 

HAYDEN FAN CLUTCHES


Standard Duty Thermal



Thermal Fan Clutch

•Varies the fan speed with temperature of the air behind the radiator.
•Engaged (high speed) operation provides maximum cooling.
•Disengaged (low speed) operation provides fuel savings and noise reduction.
•Greater life expectancy than a non-thermal clutch.
•Briefly engaged at cold start-up.
•Engages at about 170° radiator air temperature, (about 30° lower than coolant temperature).

•Turns fan 60-70% of shaft speed when engaged.
•Disengage to 20-30% of the shaft speed •Used with lighter pitch fans. (1-1/2” of pitch).
•Flat plate impeller design with 11.4 Sq. In. of working surface.
•Identified by a smooth steel faceplate & thermal spring assembly on the front side.

 

20-30% @ disengaged = power loss (regardless of what loss it is)

So lets say 25% is the target.

@ 5000RPM - 25% Fan engagement (when disengaged) = 1250RPM (fan speed)
@ 6500RPm - 25% Fan engagement (when disengaged) = 1625RPM (fan speed)

Try moving your fan @ 1625 RPM

(heck try moving it 1 full spin cold or hot) (CAR OFF)

 

Fan Bolt Circle: 5.650
Rotation: STD
Fan Mount Height (Inches): 2.1700
Pilot Depth (Inches): 0.50
Bolt Hole Size (Inches): 1.25
Overall Height (Inches): 2.740
Thread Size/Diameter (Inches): 5.650
Bolt/Nut Type: M6x1.0 (4)
Pilot Shaft Diameter/Thread Size (Inches): 1.25
Number of Bolt Holes: 4

 

Air Resistance:

http://en.wikipedia.org/wiki/Drag_(physics))

^^ Sort of irrelevant for the time being



The Fan blade/Hayden Fan Clutch (Hayden is Lighter, OEM a slight bit heavier) come in a bit over 8 lbs using an analog scale). Lets revert to "pulleys" for some data.


http://www.350zevolution.com/Article...y/Default.aspx < Link to quote v

So just in weight savings according to Unorthodox Racing's tests 2.7hp x 8 lbs shed off the crank relates to 21.6 bhp.

Say drive-train loss is 25%

21.6bhp - 25% drivetrain loss = 5.4whp (Just in Weight Alone)

 

When I first purchased my car I saw a drive train loss of 20%

car dyno'd @ 200.02 whp even. (Car comes stock 260bhp)

So saying 25% is the loss for above said post should be a great reflection of gains.

 

AIR DRAG:


I takes about 7 ft lbs of force at the tip of the blade to rotate the blade(air resistance will push this the opposite way), and nearly 15ft lbs of force to rotate the spindle (where the 4 bolts connect to the fan clutch)(engine to fan clutch).

1 full rotation is 360degree's. @ 15 ft lbs of force = this means that it takes 15ft lbs of force to get it moving and you have to keep it moving at this pace to make 1 full rotation.

So lets make an equation:

15ft lbs-f x 360degree's / 25% (of engagement) = 4ft lbs-f per rotation when the fan clutch is engaged at 25% to make 1 full rotation.

Please remember this is not considering AIR DRAG just what it takes to rotate the fan clutch ALONE.

 

http://www.pumpcalcs.com/calculators/view/79/

HP = Torque x RPM / 5252

So at (25% engagement) 4ft lbs of force(torque) x 6500 RPM = 26000/5252= 4.95HP

So you are losing 4.95HP at 6500 RPM with just rotational force needed to move the fan @ 25%.


Can we round this figure to 5HP ?


So round numbers:

5 HP


Remember this is without reverse AIR Drag.

 

To gain the opposite we have to do just that the opposite:

7ft lbs of force x 360 / 75% = 1.33ft lb-f of apposing power.

remember to go twice the speed it requires 4 times the power.

So:

(1.33 x 6500/5252)x8= 13.20 ft lb's of force against the engine rotation at the crank.

So lets round this off round

13.00.




5hp Needed to rotate + 13 required to make the 5= 18 BHP (4.5whp lost) + the 21.6bhp with the added weight at the crank.


Updated forgot to add weight to the crank.

 

Updated and Completed.


Vote for sticky

 

For those whom only care to know about how much HP gain that is @ 6500RPM


with 25% drive-train loss it equates to 9.90 whp

 

This information is more aimed towards 2003 Sedans whom want to seek PERFORMANCE GAINS. For their Cars.


I made these mathematical calculations based on 25% engagement (meaning the fan clutch was barely kicking in). Remember that at 170degree's the fan cluch begins to engage MORE AND MORE as the temperature rises.

With that said. Revert to Heavy stop and Go for temperatures in tracks with lots of turns. With lots of turns means you will not have lots of time for air to superseed the heat under the hood. Therefore that means you WILL overheat if you don't have the fan clutch engaging.

According to 25% engagement you are losing 9.90 WHP (10WHP) So if the fan engages higher, expect higher losses.



NO exception,

Electric Fan will also have a LOSS of power when they are on, and just because you have an electronic fan does not mean it will not kick on in the middle of a session.

So lets figure out what Loss would we have as far as power is concerned with E-Fans.

I will use my fans as an example:

http://www.haydenauto.com/upload/Hay...ctric-fans.pdf

226112 (12 Inch FAN) amp draw @ 12 volts = 8.8
226116 (16 inch fan) amp draw @ 12 volts = 16.5

Total of 25.3 AMPS when on.

1 hp = 746 WATTS (http://en.wikipedia.org/wiki/Horsepower)

We now need to know how much is 25.3 amps converted to WATTS.

http://www.powerstream.com/Amps-Watts.htm

So 25.3x12 volts = 303.6 WATTS

When the fans are engaged (ON) you are Losing .40 of a horsepower (with my setup).

OK So your charging system is running at 14 volts?

So lets say, the fans are drawing how more than just 12 volts right? Well technically you'd be wrong because the manufacturer made these fans to run at 12 volts. But for ***** and giggles lets just throw it in there.

25.3amps x 14volts = 354.2 WATTS Which is still less than half of a horsepower.


E-Fan myth put to rest.

 

The only thing against efans is WEIGHT.

My setup INCLUDING custom stainless steel 16 gauge panel comes in around 25lbs.

But 25 lbs as dry weight and not on the crank. So the gains are decent.

This is quite possibly one of the top 10 best bangs for the dollar.

I paid 76.00 for the 22616 fan and 65.00 for the 22612 fan, 34.88 for the electronic thermostat. (you can mount this on the radiator directly so my optional plate is just that optional. $20.00)

So 76+65+35= $176.00

So lets compare a GREAT BANG FOR THE BUCK

(MD 5/16 Spacer ALONE) Costs $230.00 and gives about 10hp. Thats 23.00 per HP.

for 176.00 You can basically make the same gains for 17.60 per HP.

 

IMO, there's some flaws here.

1) You're assuming the OEM fan clutch behaves exactly like Hayden unit in terms of engagement. I can't prove or disapprove your use of this unit as an example because the G35 FSM doesn't discuss the exact specs of the unit.

2) As a long term 03 owner, you know when the fan is fully engaged. The sucker is loud and it roars. However it is VERY rare, at least in my car, the unit ever comes on. The only time is at a long stop in 90+ degree weather. At all other times, it's not fully engaged. I don't race at the strip in 90 degree weather, only sub 70 degree weather. I've never heard the fan come on at the strip, even after hot lapping. If the fan was truly sucking out 20whp, I'd see it in the ET and MPH for sure. That would easily show at least a 2mph drop. The car is terribly consistent, whether hot lapping or running every 30 minutes. I'm usually within .5mph between all runs on the same night. MPH is HP.

3) At speed, under hood temps are very close to ambient. Therefore much of the heat coming off the radiator is going to be mixed with much cooler ambient air. The fan won't be engaged because there's no way temps are close to causing engagement. On a 90 degree day at a 30mph+ roll, I'd venture to guess the hot air blowing against the fan clutch is only 120-130 degrees. At stop, yes, the fan may engage because there's no air movement.

4) IMO, the wind resistance argument is a bit of a stretch.

5) I've had a UR UDP on my old VQ30 Maxima. I did numerous before and after 1/4 mile passes over the course to 2 years. I also did dynos. The UR removed ~6.5 lbs from the crank. On the dyno, there was absolutely no gain. Over the course of 40 passes on the strip, absolutely no measurable difference in MPH or ET. I've gotten it into numerous times with the owner of UR about his 2.7hp per lb claim. It's simply BS. There is so much to consider in that calculation than what he states.


The easiest way to prove if the e-fan conversion is truly worthwhile is to do a before and after test. Unfortunately no one has done this effectively and most everything is simply a claim or the analytical data like you've posted. This winter I may end up dynoing my G at my buddy's shop and for the heck of it, I may end yanking the mechanical fan and see what it does to the numbers. I'd hope to see a huge improvement like you claim, but my guess is 3whp to 4whp, possibly less. I think too many latched on to the e-fan gains made by the Trailblazer SS. On those trucks, the e-fan conversion is good for around 20whp, BUT the 20whp claim stemmed from a full engaged fan. Under normal conditions, the e-fan swap that LS motor is good for around 8whp. If you've seen the TBSS mechanical fan, you'd know it was much larger and much heavier than the composite one found on our G's.

I don't believe for a second that the mechanical fan on the G is sucking out 20whp+ even when it's fully engaged. People constantly say the 03 5AT sedans were some of the slowest, mostly because of the e-fan, but oddly the 03 5AT sedans claim some of the fastest and quickest ET/MPHs on this site. My 03 went 14.32@98mph with a Z-tube and has backed up numerous 14.3s and even almost 100mph with just the MD spacer. My strip is not great nor known as a fast track either. If I were to run at one of the quicker Northeastern tracks in the fall, I'd have no doubt this car could go 14.1-@98-99mph basically stock. Other 03 5AT sedan owners have done 14.1-14.2s at these strips in basically stock form.

 

Dave, when you state the fan is not engaged is the fan actually not rotating?

Reason I ask is because regardless of it being oem or aftermarket it's rotating. Thus requiring energy. Ps, the oem fan clutch is substantially larger and heavier.