Apocolipse

I may have missed this but you are recording the oil pressure after the coolers yes?

Also, has anyone calculated the forces on the bearing at WOT @ MBT? I'd be curious if that 44psi (at the top of his temperature chart @270deg) would be enough to have no issues...

Might give me something to do today lol I'll find the ol' textbooks

blkbrd69

Have now done lots of street and track driving in hot and "cool" weather.

Improved Racing thermostat does a fantastic job of helping oil get up to operating temp.
Before on highway on a 60* day oil would sit at 145* at the tank oil temperature sender, now it is up around 180*. In a normal 15 minute street drive it is now averaging 25* warmer.

Noticed a significant pressure bump at every RPM on track using same weight 10w40 Redline oil as verified by oil analysis. Can only assume it is due to less restriction through #10 lines, Improved Racing thermostat and Setrab 172 cooler.

This Autocal EFI Live oil pressure datalog is from a 90 degree day at Sebring.

Yes pressure is recorded at stock pickup location after cooler and filter.

Yes now that logs are done I will be bumping oil weight up for hot days. My conclusion is 40 weight is just not enough for the track in Florida in the heat. Thinking 1/2 and 1/2, 40 and 50wt.?

Log photos not showing up worth a darn on a phone, so I included a smaller link that can be blown up.

You will notice pressure peaks at 5400 rpm then drops 3 to 5 psi as rpm goes up. This is something I have seen with every LS oil pump driven at crank rpm. Does not seem to matter what tank, pan, baffles, pump, oil, ext. Pressure just drops above 5400, rotor cavitation or flutter is my bet?

parsonsj

Yep. It seems to be true across the board, and I think the only real fix is to go with an external pressure pump. I saw pressures on mine drop (with 30w oil near 270*F) into the 40s near redline. That's with two scavenge stages, ARE baffles, Lingenfelter tank mod, etc.

This data logging thing can really take away your sense of security!

Apocolipse

Or maybe you guys are over thinking it. I'll ask again has anyone calculated the approx pressure needed for the bearing at those typical power levels? How about any oil analysis to see if any bearings are getting worn or if people are worrying about useless things.

blkbrd69

Oil analsis looks good for no bearing wear.

Really wish some engine builders would chime in to how low is to low on oil pressure, seems like the old 10psi per 1 thousand rpm is changing.

Data logging does give you too much information some times. My problem is I am 50% mechanic 50% engineer...

No freeken way could I calculate pressure actually needed. Not sure anyone could. Real world testing would provide the real answer.

Lots of guys have ran factory M1 5w30 at 300 degrees+ and survived.

Apocolipse

You are going to make me bust the textbooks out...arent you...

That rule has been around since engines have been running 20w50 as an all around engine oil lol. Says a lot I think...

Here is a quicky for how journals work:

http://www.substech.com/dokuwiki/dok...ournal_bearing

This one has some calculations for lubrication for different style of bearings (shows some maximum pressure from other engines):

http://www.substech.com/dokuwiki/dok...9ed8475a44ca2f

Classic engine oil page:

http://www.substech.com/dokuwiki/dok...9ed8475a44ca2f

And this one is for engine bearing clearances and viscosity (would be what you are worried about with your temps and pressures):

http://www.substech.com/dokuwiki/dok...9ed8475a44ca2f

parsonsj

Me either. I can probably follow along if somebody laid it all out in a comic book level explanation.

Yes, please.

Apocolipse

What clearances are you running? (approximately)

Ill see if I can use some computer programs to simulate it as well.

parsonsj

Clearances (from my engine builder, Crume Racing Engines): 2 to 2.5 thousands on the mains, 1.8 to 2 thousands on the rods.

blkbrd69

Had to post a photo I took this weekend.

The new Pirelli World Challenge twin turbo Cadillac racecars of Johnny O'Connell and Andy Pilgrim are just sweet setups.

This take on cooling may drive some in a different direction. Thinking it would open up some airflow, help warmup, and make packaging easier especially for the C7Z guys having problems.

Note the large water to oil heat exchanger in the center of the photo.

Do not know who makes this one but looks something like a 18 plate C&R?

miracle_whip4130

Nice. Another OEM for in-line oil to water heat exchangers is Laminova. One of my friends has one on his supercharged BRZ that he tracks and likes it. Not sure if Laminova makes units that are much bigger, though.

NemesisC5

http://www.laminova.se/products/oil-coolers/

Whis9

Nice read

mesospeedy

Would something like the Laminova cooler put too much strain on the stock coolant/radiator? It seems like a nice, simple solution to helping the oil stay cool on track and getting it up to temp faster on the street vs a bigger cooler and thermostat. But will it actually decrease oil temps in the summer on track, and will it have a negative affect on coolant temps? My thinking has been go to the setrab and a thermostat to reduce oil temps, and hope it also helped coolant temps some so the stock radiator would be sufficient, saving the cost of the bigger radiator. The Laminova type cooler would be (or seems like it would) a pretty simple install assuming the fittings could work with stock lines for the oil and I guess adding T fittings in the coolant hoses. Anybody have a more info on these?

miracle_whip4130

Not sure about the C6Z, but for the C5Z, the stock radiator is already undersized for track duty, so adding the Laminova to an otherwise stock system wouldn't work too well. If I remember correctly, the Laminova coolers aren't too cheap, either (~$400). My solution on my C5Z was to buy the Dewitt's radiator with oil cooler integrated in the end tank. This was only $620 and took care of the oil cooler and radiator issue for me, and lets the coolant warm the oil up quickly, as you said. I'm not sure if anyone makes a similar cooler for a C6Z, though, as they are already plumbed from the factory to run a standalone EOC.

Maybe someone else that has a C6Z will chime in......

trackboss

I installed a laminova on my C5 a few years back. I double passed the radiator which made packaging the laminova pretty easy. I also built a complete custom cradle for the cooling.
The things that stand out about the laminova is:
It's a modular and very easy to service/repair/modify
Lots of surface area
Very robust although a bit heavy
For me, the built in oil coolers for the corvettes are just not large enough. I have seen over 300* oil temp with them on a stock motor driven hard, but kept well under the factory redline. There is not enough room to install a adequate size oil heat exchanger in a drop in radiator for the corvette.

bjmsam

That is great to hear. I am looking forward to the new kit from Improved Racing that integrates with the stock oil cooler.

I use an OBDLink MX to feed Torque on an Android Head Unit and have noticed that readings from that oil temperature PID are inconsistent with what is displayed by the DIC as shown here. Any theories?

skxf430

Blkbrd,

How long are the oil lines that you ordered?

Thanks,

blkbrd69

I build my own lines, mocked them up and cut to length.
Didn't write down exact measurements.
Have an offer to Michael to come buy and measure them if he wants.

skxf430

I will probably do the same. I think about 8' will be enough to cover both lines.