Hot Rods Differential cover testing

Have you ever thought about what goes on inside a differential? Gale Banks is doing a series on how a differential cover shape effects the oil flow at speed. Do oversize differential covers that are said to aid in cooling, actually create more heat by altering the flow? It should be an interesting series. Maybe a windage tray is needed with the oversize covers.

 

Fascinating.


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I have been following this mini series, it is really interesting.

 

Re-Invent the wheel???

 

Interesting.Lots of testing info on Banks site.

 

If there's a more qualified person...I can't imagine whom it would be. Kinda neat.

 

Auto nut, check
Induction guru, check
Turbo genesis, check
What do I do now? explore dif covers.

I got to spend a day at Joe Gibbs Racing several years ago. They had a dyno for rear axle testing. Perfecting polishing, clearances, and oils to improve horsepower output.

 

That’s actually quite interesting, I need to get a clear differential cover so we can show students what’s happening....much easier to understand when you can see it.


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Wow!

Yeah, just “ splash lubrication”

A lot more thought involved then just slinging lube !!

 

Or maybe a ring gear scraper.

 

Have a look: https://www.hedman.com/Clear-Differential-Covers

 

What he NEEDS to do is form a big squared off, clear plastic cover using the dimensions of one of the popular aluminum covers, so he/we can see "exactly" what's happening when you screw with the oil flow.
At least modify one of the current covers with a clear plastic, flat backside. Weld on some tabs to fasten it on. A gasket would be easy to make.

Also note that even the factories are using a square aluminum cover on later model trucks.

Mike

 

They could make a mold of the inside of the cover to produce a clear cover. You can really only see what happens above the fluid level. It isn't like a wind tunnel where smoke can be used to see the air flow since the fluid is recirculated. Maybe air bubbles could be used.

It's also interesting that different vehicle manufacturers use different fluid levels on the same differential. Vehicle manufacturers are spending millions to increase fuel mileage to meet regulations so efficiency and parasitic draw are likely very important to them. Aftermarket manufacturers don't have to prove anything. They just have to get buyers thinking that their products will increase efficiency or add power in some way.

 

True analysis of power related subjects usually ends up with a lot of theory.
Spell: Politics.

 

Absolutely fascinating! Gee, I wonder if those factory engineers know what they are doing? The OEM’s have a whole lot more at stake than the aftermarket companies do. I firmly believe that if there was a better way to do things than what the OEM’s do, than they would do it.


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When I built the 9" rear for my Shoebox I thought that since I was putting in 5.14 gears and would be driving it to and from the track and every where else I thought a lube cooler would help..I knew that Nascar cars ran rear end coolers with a pump driven off the pinion yoke but didn't want the complexity..I built a little scoop that tucks up in the front lip of the housing to catch what ever oil was thrown there, the rest of the oil would go as intended to the front bearing retainer oiling cavity..Oil goes from the scoop out of the housing to a small cooler at the rear of the housing placed to be below the oil level..Then back to the housing at the bottom just ahead of the center line of the ring gear hoping for a little "pull" from the ring gear and gravity..Thinking low cooler height will add to total oil capacity and be closer to air flow wrapping around the housing...I ran the car around for a year and the most temp I saw was 170° in the middle of August, with out the air deflector below the cooler in place..I wrapped the cooler with cardboard to try to simulate a "with out" cooler and saw temp get to 190°...When I finally got around to mounting the air deflector the oil temp dropped to 160°..

 

The automotive equivalent of 'don't fuck with nature.'

 

i like the description, but i need Lasik after looking at that picture

 

Yeah, sorry bout that pic..Its fine here on my screen but no matter what I try it doesn't fly well..

 

I run 5.13's in my daily driver. People freak out when they hear that, but then again, my top gear is 0.50:1.

No cooler. On a banzai run from San Francisco to LA (I5, 400-miles, no stops, ~85-mph), the non-contact pyrometer showed 155º, at the plain steel, OEM style rear cover. That was the highest ever recorded temperature.

 

Note the comment about "top gear is 0.50:1"......Overdrive in the trans, probably top two gears are OD.....

Ray

 

Ha, to continue the hijack...

In the early 70's, I had a 56 Chevy, small block, 4.88's in a Pontiac rear end. While not as bad as 5.13's, I was driving 55mph before it was mandatory..! Also no insulation or carpet., with a pair of mid-60's Mustang bucket seats.
My girlfriend lived 35 miles away..!

Mike

 

Yup. 6th is 0.50:1. 5th is 0.74:1. 4th is 1:1.

 

Another video is out today with a clear back put on one of the aftermarket covers.

 

Iv'e tested a couple of rear end covers....usually by throwing broken spider gears or ring and pinion parts at em from the inside. Haven't pierced one yet, but not from lack of trying. Usually end up looking like my nickname.....Lumpy

 

Outstanding series. He instructs a a nice level that most people should be able to understand.

 

In further testing of a differential cover, he wanted to run on the dyno for 2 hours at 70 mph.

 

Gale was my race partner for 20 years, you will not find anyone that will do more thorough testing than Banks. Gale is a very curious person and when he goes on a mission to find out about something, believe me he will and when he is finished there won't be any unanswered questions. He is a Hot Rodder to the core and always strives for perfection!

 

Very thought provoking and enjoyable to look at,
It something you dont think about,