Diff Cooler

[AGM]

I have fitted a harrop 9" Billet Aluminium Diff to my 1994 Q45, with a Tru-Trac 31 spline helical gear LSD. The set up works really well with OEM Ford Nascar 4:11:1 gears.

The diff is really quiet most of the time, which surprised me, given the diff is solid mounted. After hard driving, the diff whines at certain rev ranges. I assume this is due to the Redline oil thinning out as it heats up.

I have purchased the 300ZX diff cooler kit.

Before I fit it, I would appreciate any feedback from members on the effectivness of Diff coolers in cooling the diff oil.

The only reason I am considering fitting it is to reduce the noise when I have been driving the car for extended periods.

Please note the picture below is the same diff housing as mine, but in a different vehicle. For a larger image, click on the picture.

http://www.harrop.com.au/produ....html

Regards

AGM

[elwesso]

Im just curious, but how can you tell what differential whine sounds like..... Im not sure if what im hearing is from the tires or diff.....

[AZhitman]

AGM -

WOW! I'd hazard a guess that you're the ONLY one here fitting such a unit to a Q. Perhaps Dennis, fxjackso or Aries might have some feedback.

[Q45tech]

You place your vibration meter [secured from ebay] on the unit to be studied and feed the signal into a precision sound card and run spectrum analyser software on your lap top. Record and view the spectrum of the noise created.

Many techs [a few in US] have a device with 4 microphones, which are placed strategically under the car and you select different ones and listen while you drive.

Or you [a helper] runs the car to speed [60-80 mph] on a lift and you get under the car and listen.

Better some chassis dyno have a pit where you can get under the car while testing........that way you hear the tires and the diff under loaded conditions.

[maxnix]

Isn't the trick of employing a differential cooler is driving a pump to move the fluid? Probably would be wise to monitor the fluid temperature also.