Breathing Fire

http://www.bobistheoilguy.com/motor-oil-104/

Read all of it if ya want some more technical reading. 101-201. Good stuff. Forums there are full of great stuff. Nice links Paul.

Paul Bell

iTrader: (9)

That post mentioned that as synthetics are slicker, they don't stick to the gears or "climb" as well as regular oils. And they tend to leak past seals much easier.

As pressures, temperatures and exposure to combustion is considerably lower in a rear than engine oil, the advantage to using a synthetic in your rear is minimal.

Some posi units such as Auburn CANNOT have synthetic lube used in them.

BADD SS

iTrader: (4)

Ive been running Redline 10-30 for almost 8 years, it started at 370 rwhp, up to 502 rwhp. I would say out of the 46,000 miles I did (24,000 when I got it), and over 1000 passes at the strip (when I was young and stupid I would go to the track and run back to back all day almost, 27 passes once) and never had trouble, at all. Also had probably over 100 dyno pulls. The last setup routinely saw 7500 rpm, and never so much as a hint of trouble. Every day I drove it it would see 7000+ at least 5 times. It finally got killed by a clutch that blew apart and ripped the starter off the block, opening up the water passages and cracking under the headbolts. When I disassembled I had 1 bearing that wore a little bit more than the others, but not terrible, and not ready to go, at all. That pretty much makes me a customer of theirs for life.

Other than for break in, it's in my 366 ls2 now as well, seeing 7900 rpm on a daily basis....

vtec

iTrader: (1)

in situations such as a clutch type limited slip diff or auto transmission clutches, a synthetic can inhibit some of the friction needed to function correctly. that is hearsay though, i have not used synthetic trans fluid, but i have used it in a rear diff and had issues with chatter in turns. went back to conventional gear oil/additive and it did fine.

96capricemgr

iTrader: (1)

I agree about the wiper blades comment, that and head light bulbs BEFORE they burn out.
I bought a few things from Molakule back in the day, still have almost a pint of his air tool oil.
Far as synthetics in a diff. the only downside I know of is clutch posis don't agree with some oils. The pressure between the meshing gears is substantial.

1963SS

Thanks Paul for the good information. That's a good read. When I said that I played around with oil I was pretty serious. I live in Ashland, KY and have seen some of the effort that goes into Valvoline oil. It's made right here. I have talked to some crew chiefs and engine builders from Everham, Petty and Roush as they have come here to talk about oil and some specific requirements customized for their needs. Doug Yates and Mark McArdle have lost me in some oil discussions but backup was available. There was and is a lot that I don't know but I'm ahead of the average Joe.I don't profess to know all of it but there are people that I've worked with and spoken to that know most of it.

I guess that's the advantage of living in a small town with a big business including a good sized refinery.

When I mentioned earlier that oil didn't wear out I wasn't talking about contaminants. I was trying to keep this on a car forum level as opposed to a Petrochemical Engineering white paper. I really meant to say that the base stock doesn't wear out. If it were possible to remove all contaminants oil could last indefinitely. I still use synthetic because of the reasons listed in my earlier post.

The ability of oil to stick to a rotating gear is primarily related to viscosity and at room temp the Dino oil in a differential will have a thicker film strength than a synthetic. At 200 degrees F the synthetic will lubricate better as it will be "thicker" than the mineral based oil which thins out significantly with temperature increases. I still use 80W90 in my differential and have never had a problem.

I've also ran Valvoline 10W30 in my 1989 Silverado for the last 248,000 miles and the engine is perfectly clean and makes no more noise than a new engine. It's been changed every 4000-6000 miles pretty religiously. The Vette and the Impala run hotter and I feel that synthetics are best in those applications. Of course that's just IMHO.

Paul Bell

iTrader: (9)

Hey Breathing, interesting how your link says synthetic sticks better than dino oil.

The thing to remember is that synthetics have greater advantages at higher temperatures, which is not seen in a rear end.

Good reading tho!

vtec

iTrader: (1)

well, that depends.... cup cars have a pump/cooler setup for the rearend. 800+hp and 9,000 rpms with 4.88 gear will create a ton of heat in the rear. driving to walmart with a 2.73 rear will not.

Paul Bell

iTrader: (9)

True that BUT I doubt NASCAR teams seek advise around here!

BizZzatch350

iTrader: (33)

You got to think all those LT1s taxi and cop cars, they all got bulk what ever regular oil was the cheapest and ran till 200K+ miles taking some of the worst abuse you can subject any vehicle to.

Stroked96Bowtie

iTrader: (22)

Im pretty familiar with a few of the baddest big cube motor builders in the area...guess what they use in thier $30-$50k motors....Castrol GTX 20-50.

If that doesnt tell you something Im not sure what will

FAD2BLK93

So to sum up are we talking synthetic in the engine( brand x) synthetic trans (brand x) and regular 80/90 for the diff. Is there any reason not to run syn in the trans? At the track in the summer time is when i get concerned with the exsessive heat, syns breakdown alot higher than regular atf like regular is what 280? How high would be syn in trans be?

Paul Bell

iTrader: (9)

I would say, yes, you've got it correct. Synthetic in the engine & transmission & dino squeezings juice in the rear.

As lubricants can be a touchy subject and most people are passionate about what they believe is the best, simply using decent oils and filters with regular changes should be all that's needed to have a healthy car. I don't think there's any oils or filters on the market that will cause harm to your ride. Except most Fram filters, that is. Additives are also usually a no-no.

taner

iTrader: (6)

i guess i am spoiled, up until recently, (as of last week) i have worked for one of the big three at the corporate level in the Powertrain division on current and advanced programs.
some of the testing perfomed as a part of development specifically for some of the "performance platforms" is pretty severe. synthetics provide the required protection for different types of drivetrain components to pass the required life cycles as a part of prodcutcion validation testing.
i do plan on trying the Joe Gibbs oil next year! my engine builder has had numerous engines on the dyno, well it is what he is putting in his big block, which makes well over the 4 digit mark on motor.
again, just adding my .02

gregrob

iTrader: (8)

If you had chatter issues it was due to too MUCH friction, not too little..

05HD

Diffs get hot too, just depends what you do with them.

Oh and on topic, royal purple sucks.

Big Al

iTrader: (1)

When a trans or rear axle breaks at the drags it's a lot harder to clean up synthetic oils. They go out with a giant blow torch and it won't even burn off.

Al 95 Z28

54inches

iTrader: (4)

and.....

Rob94hawk

iTrader: (1)

I would like to see RP handle this:
http://www.youtube.com/watch?v=WK2EWkQfTec

vtec

iTrader: (1)

i would say you are correct, but i do not know. i do know that a synthetic gear oil and limited slip additive made noise in turns and the gm stuff did not. that was the extent of my testing.