friction reduction in ring and pinion

[wst333]

We race a truck on oval tracks, it has a 305 2bbl with an automatic. I am looking to reduce friction in the rear end in order to free up alittle horsepower. Does any body have any suggestions as to how I could accomplish this? Thanks in advance.

Steve Turner

 

[GregLocock]

Switch to straight cut gears, rather than hypoids.

Cheers

Greg Locock

 

[Xtrema]

Many folks try synthetic racing rear axle lubricant like Royal Purple or Redline.

 

[drwebb]

It makes sense that churning loss would be strictly a function of viscosity. But papers have been published showing that PAO gear oils may have measurably lower internal friction than mineral oils of the same viscosity, and that multigrades made with PMA VII have lower losses than those with PIB.

These effects are on the order of 1% or less, but still measureable and not chump change when certifying for CAFE standards- maybe not for close race days too.

 

[Tmoose]

Are you really power limited?
If the driver isn't on the gas early and hard due to chassis or skill, I'm not sure freeing up power will really help much, except maybe as a "magic feather" (Walt Disney reference).

If you are REALLY on the gas just 25% of the time you might be able to cut back on the viscosity and maybe even quantity once the gear set is broken in. Keeping a CLOSE eye on the gear faces (maybe even between heats?) might be one way to sneak up on the limits.

EP and antiwear additives might keep the gears alive when operating at the edge, but I wonder if that would eliminate the power advantage, as they are not particularly "slippery."

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"churning loss would be strictly a function of viscosity".

In my opinion, based on one or two unpleasant big-name planetary gear experiences, the oft quoted high 90's gear efficiency ignores the heat generation from churning completely. And especially at high rev low loads the heat generated (churning loss?) is 10X worse than both OEMs predicted

My current opinion is the Oil volume and lube method are mighty important too, as they effect how much not-quite-in-contact mesh is simply squishing oil, with no real purpose. Like a well submerged bath, versus a minimal spray or oil spot system with a "dry sump."
If you are running a spool, pumping oil via jets directly into the pinion and carrier bearings and gear mesh looks fairly straightforward, but if you have a differential the diff side gears and limited slip clutch pack may simply demand the oil storm provided by an oil bath.

 

[bigtomwcp]

contact REM chemical in CT. they have a finishing process to drastically reduce friction. not oo expensive either. used by nascar and winston and stuff like that. you should see 1-2% increase in power and much lwer temps.

 

[crashbox455]

also, Mark Williams has a "Supra-Fin" micro polishing service, although i have no impartial data about it.

i would like to know more about straight cut differential gears, as G-Lo mentioned. i've heard of hypoid and spiral cut, but not straight cut.

 

[evelrod]

crashbox455, The straight cut (bevel gears) ring (crown wheel) and pinion is pretty old technology. Most, if not all, cars prior to the mid 1930's used them. I used a set out of a 1937 Buick once upon a time. Not so much for friction reduction as that was just what was available at the time. None the less, that would be one area to look into for design considerations. Hypoids came about to reduce noise would be my best guess. Maybe to lower the "floor tunnel" for the drive shaft could be another. I currently race a car with front drive so I don't encounter your problem but, in my other cars I tried several synthetics and even ATF once (not a good idea) and ultimately ended up using an SAE 80 viscosity synthetic. All the effort to pick up the "last hp" was pretty much wasted. I never saw much effect aside the previously mentioned "magic feather" effect. Take a peak at some of the racing transaxle mfgrs. or quick change setups for stock cars for some "straight cut" technology that is more current.

Rod

 

[EfiOz]

I've used these "micro-finishers" or "isotropic-finishes" and they do work. Especially wothwhile as it's fairly inexpensive (and looks cool!).

It does reduce the diff temp in a V8Supercar by 8-9C so it must do something.

 

[ShaunT]

V.P. Racing Fuels offers a very low visc. oil. I know it is very expensive as far as gear oil goes. You have to buy a pretty large quantity to get it. Maybe you hsould look into it.

Shaun TiedeULTRADYNE/LUNATI Austin,TX(stiede@ev1.net)

 

[red300zx99x]

We've been testing a military plating on ring and pinion with a couple of WC teams and 1 Busch team. Were able to see a ~10hp gain over a restrictor plate engine with the rear end that they normally run, ~7hp gain on coastdown. Pricing for a ring and pinion has yet to be set but expect about $375 if previously rem'ed, yes I will make up a verb and $450 if not. Whew, transmission testing is next, along with different solutions for the materials that the ring and pinion is made of, then plated. You can contact G&T coatings at 540-752-1942 and ask for Cordell if you would like to know more.

 

[PartsMike]

You will have less friction if you use differential with a lower angle on the hypoid surface (less swept area on the tooth engagment). Ford 9" differential design is used in a lot of race vehicles for light weight and strength but due to the gear angle they use as much as 15 horsepower more then most automotive differentials.

 

[idano]

Other than using synthetic gear lube (I recommend Redline 80-90 and not the hi-impact part) you will be spending some time and $$$.

"automatic transmission"......that will be a huge absorber of hp....you might take a look at a higher efficiency torque converter, if you use one.

I usually tell people in your situation that it is easier to bring the driver up to speed first, then the car setup then look for the 10ths with a microscope....also try to find out what the front runners are up to in your group.

Good luck and have fun.

 

[carnage1]

quote from PartsMike
You will have less friction if you use differential with a lower angle on the hypoid surface (less swept area on the tooth engagment). Ford 9" differential design is used in a lot of race vehicles for light weight and strength but due to the gear angle they use as much as 15 horsepower more then most automotive differentials.

wow that is a lot.
where could i find info on how much power is consumed by various rears?
or could i calculate it from another piece of data that is easy to find?

 

[MaxRaceSoftware]

Chrysler did a few back-to-back DragStrip tests a long time ago in ProStock "Mowtown Missile" (Carlton ??)
Ford 9" -vs- Dana rear end
Chrysler recommended using the Ford 9 inch as it was definetly faster down the DragStrip

their 8 3/4" was supposedly better than the Ford 9" but couldn't holdup even under just the amount of Torque & HP they were only making back then ..it was a combination of that Torque going thru a Hi-RPM launch with manual 4-speed
that prevented use of 8 3/4..so the Dana 60 was tried & used instead..and then replaced by Ford 9 inch in Chrysler ProStock Cars after those tests.

Straight cut gears have better efficiency than hypoid gears
..you won't see any Hi-Tech Slot-Cars with hypoid gear designs

Most Books i've read state that Differentials have anywhere from .965 % -to- .990 % efficiency
the baseline efficiency in my Computer Program is setup at .97 % PerCent for Differentials

you can play around with this totally "Free to Public and Racing Community" Computer Program on my website

http://www.maxracesoftware.com/race_car_physics.htm

the Differential Efficiency is multiplied times the Transmission Efficiency , and inputted as one value


Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
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