Are synthetic oils and lubricants any quicker

[Ross Family Racing]

Just got done installing a new braced up rear end housing in my Cuda and now I,m wondering if synthetic gear lube is worth the money and is there any Et in it. If so what brand , weight ect did you use??
Jeff Ross

[1320racer]

more ET to be had in running less lube/oil than there is in type.

[340Cuda]

My experience with synthetic oil in the rear end is that the first run of the day will not be slower than the second run all other things equal.

Bill

[Ed Wright]

Bill, that is about all I noticed.

As far as running less lube, I would not recommend that. I use Royal Purple 80wt in mine.
It holds almost two bottles. I was running one thinking about drag, or "windage". At Indy in 2011 James Lee rode up there with me. We were parked across from long time hero of mine Jimmy Bridges. He told James about testing he did on the bench with a rear end he rigged up with a clear back cover so he could watch the line at speed. I don't remember the speed he told James, but most of the lube goes out into the axle tubes. Low lube levels cause the gear set to run out of lube sooner, or at a lower speed.
After hearing that I dumped the other bottle of lube in my rear end. Ran my first MPH over 132. Wasn't sure if I could believe it until my MPH stayed about half a MPH for the rest of the year. My gear life is better to boot. With the lube going to the axle tubes, drag on the gears running in the lube becomes moot. If that info came from somebody other than Jimmy, I might have not been so quick to believe it. Jimmy tests about everything.
Hope this helps somebody else.

[1320racer]

The fact is many class racers and some bracket racers run less than "2 bottles." I haven't run more than 1 quart of Mobil 1 Synthetic gear lube in over 2 decades and the R&P on my Firebird failed after 700+ runs 60 footing low 20's to high teens and my 3880 lb. chevelle typically got 200 passes on a R&P 60 footing 30s and a best of 1.28.

[Ed Wright]

Many people doing something does not make it correct.

I don't break rear ends, they just stay quieter longer. Less wear.

When it comes to listening to you or Jimmy Bridges, well....

[bdixon]

Ditto

[Tom Meyer]

From my sons dirt track car with a 9 inch ford, they make a seal that slides in the axle tube to keep lube in the center section don't know if they make them for any thing else.I have been told that most major nascar teams have a diff dyno to run there gears on. Was told that it takes 47 hp to get a 9 inch up to speed and then 3 hp to keep it at speed. With that being said any thing that we can do to make less drag in the diff, the car should go faster. Most of us run small motors 350s or less and what some 500 plus does not apply to us. Tom

[buzzinhalfdozen]

At least on a 9 inch it's very easy to keep the oil in the gear area. Fitting and welding small "dams" in either side of the housing works good. For the most part 2 quarts in a 9inch is what I run, have tried the 1 quart deal but honestly saw no measurable difference. I'll put this one in the running 2-3 quarts of engine oil column, use at your own risk. Your results may vary I would think that if there were a gain to be had at least in drag racing....heating the oil would be of greatest benefit.

[Ed Wright]

I was surprised Jimmy had built , or saw, a rig like that run. I never thought about dams, or baffles in the housing. I'm old.

I've heard of guys running ATF for gear lube. Never tried that. I know a Pro Stocker that uses a heater in his 9.5" housing. The cord is tied to the left wheelie bar, so is easily plugged in. Thought about putting a heater in my 12 bolt rear cover. I have drain & filler plugs in it now. I carry some Dexron for that, I may try that if I have a heads-up that worries me enough.

If I just bracket raced I wouldn't have to worry about crap like that, would I? LOL