blkbrd69

See tread #25 for new log and video. added Aviaid insert


Starting to play with data logging and of course oil pressure and temp are always a concern.

Changed the photos as they were not very clear.

Both average pressure logs are with a C6Z06 LS7 running the stock oil pump, LPE tank, and Redline 10w40.

The first log is some straight line high RPM testing for tune. Noticed a 10 psi pressure drop past 6000 to 7000rpm. Oil temp. @ 200 degrees & drops from 76 to 64 psi.
Figuring some cavitation and foaming, but pressure is still seems acceptable.

Second log is running Daytona on a 85 degree day last week, sorry guys up north! You will see pressure drops at 250 degrees to 48 psi at 6200 rpm.
Drops were not due to corners as I graphed the low pressure points & it didn't matter, straight or corner pressures were the same per RPM point. Granted I am using the stock sensor and not a high speed one.

Oil tests looked good from the first log, but haven't gotten them back for the second yet.
Cold pressures appear to show I am getting good flow and gaskets are good.
Is this a case of 10w40 being marginal for the track above 220 degrees, pump not up to the task, or are those pressures actually good despite the old 10psi per K rule?

I understand all pumps will reach an RPM where they cavitate. Normal oil pumps seem to do this in the 6K range depending on inlet pressure, temperature and viscosity. Is the LS7 dry sump pressure pump the same?

froggy47

lurk

blkbrd69

The video that goes with the Daytona data log.


Realize most of the engine builders are at PRI but would love to here from Katech_Jason w Katech, Lingenfelter, Golen, GM Performance Parts, Chevrolet Performance, MAST Motorsports, Texas Speed, Phoenix Performance, Scoggin Dickey, LG Motorsports, Schwank, Joe Gibbs, ext.

Does the LS7 drysump pump go negative on the flow curve like the LS6 pumps over 6K??

Bill Dearborn

Wouldn't cavitation and foaming be unacceptable? That could cause momentary losses of pressure that might not show up on a sensor.

Lower oil pressure may be just fine. If you have more pressure than is needed you are just wasting HP to get that pressure. It would seem that anything between 40 and 50 psi should be enough to protect the bearings.

Bill

waddisme

blkbrd69

Yes cavitation is unacceptable, but not sure if it avoidable to some extent?

Graphed out low pressure points cornering vs straights, and they are almost identical. Seems my pump just doesnt like rpm past 6k?

From what I understand all LS1, 2, & 6 oil pumps begin to cavitate at around 6k, just the nature of the beast. This is not to say they drop pressure like mine is showing, just the pressure curve slows its rise.

Cant find any really good data logs on the LS3 or LS7 pumps that graph out pressure vs rpm & temp.

Doing lots of searches and I am seeing many guys only getting 50psi at 6k when oil is hot, but 250 is not that hot? It seems with this engine that 40wt is just not going to provide the pressure when its truly hot like 280+ at Sebring in the middle of the summer.

I know I should be more concerned with oil flow volume than pressure, but really dont know if I like what I see in these graphs using 40wt oil?

Big question is, is this normal and OK for the drysump LS7 and LS3 pressure pumps?

Do I need thicker oil? A new high volume pump?
Have only graphed out 10w40 Redline, have not tried another oil yet.
Or is this normal and OK?

2002rich

What you are experiencing is normal for an OEM dry sump. If you want to improve the oiling system you will have to upgrade to a third party solution.

That is not to say what you have is bad just limited.


Rich
427 OEM dry sump

CorvetteZ51Racer

Understanding that there are limitations in the data logging due to the relatively slow rate of the OEM sensor and ECU logging, your pressure data looks happy to me. The old hot rodder trick of 10 psi/1000 RPM holds true until about 40 psi or so, and then it kind of tapers off. You don't really want or need 70 psi at redline. At that point, you're spending a bunch of power generating pressure that the bearings don't need to stay lubricated. That's not to say that having that pressure will hurt the motor, but it's not needed.

I run the exact setup that you do in my Z06 (OEM drysump and LPE tank), but with an aftermarket oil cooler. I've got probably around 5k track miles on my motor since I got the car, and my oil still comes out nice and clean and builds solid pressure across the RPM range whether track or street driving. And FWIW, I run Mobil 1 10w40 in mine.

All of that being said, given the climate you're in (and I'm in a similar one here in Texas), you're best off spending your time worrying about supplemental cooling to keep the oil temps down to 250F max, instead of worrying about how to keep pressure at 280F at Sebring.

I've had good luck with the LG Motorsports radiator and oil cooler that is currently in my car. I'd look at a solution like that if I were you, and then keep running the 10w40.

Maynor29

It may not be your oil pump. There maybe a restriction elsewhere and your oil plumbing system such as a line that is too small or a restrictive oil cooler.

I'm running an LS3 motor/OEM pump with an ARE dry sump set up. I have the opposite problem. My oil pressure is too high the greater the rpm. 80-100 psi at 6500 rpm and it would continue climbing if I let it.

Cavitation is hard to pin down but looking for other possible mechanical sources, might be easier.

John

RX-Ben

The OEM oil pressure sensor is a very able unit and has very good response time. The oil pressure gauge has glacial response.

I have no idea on the reason for the OP's pressure drop, not sure if anyone else with that setup has logs to compare. I would think cavitation or a restriction would level off pressure, not decrease it. The decrease is worrisome in that the oil may be a bit aerated - 48psi of oil is one thing, 48 psi of oil and air is another, in terms of keeping the bearings happy.

blkbrd69

Thinking I may need to add an Aviaid insert, or do a full Aviaid upgrade to complement the LPE tank?

Supercharged111

I don't know if the LS7 runs a gerotor pump with its dry sump (I'm thinking not?), but if so this thread may be of interest.

http://forums.corvetteforum.com/engi...pump-data.html

Hi Volts Z06

While I do believe the stock dry sump setup is inherently limited, the advice that you address oil/ water temps is solid. Heat kills.....it also robs power. After building my 416 cu in. stroker I constantly fought water temps of 250-270 on tracks like Pocono (although my oil temps were at about 235 max due to my huge oil cooler setup. I would also notice that my oil pressures were dropping to unacceptable levels. I was already running a Ron Davis radiator so I turned to Evans for a custom LS water pump. These guys are AMAZING. They spent a long time on the phone with me and built me a unit that dropped my water and oil temps BELOW 200 (and on cooler 60 degree days as low as 160!). Needless to say that oil pressures stabilized when I got the temp ranges into a more acceptable range. Your selection of oil is dependent on your operating temps. FWIW- I run Redline 30w race oil (I'm strictly a race car) but this would be the equivalent of a 10w-30 street oil.

RX-Ben

did you add the water pump before or after you vented your hood?

Hi Volts Z06

After...hood was vented before the new motor. The water pump in the car prior to the Evans was just a stock rebuilt piece and from what I am told was the post 2004 version which were junk. The guys at Evans made sure they matched the pulley to my RPM range which ensures the proper flow at all times. We also run a t-stat bypass.

Supercharged111

What makes the pump itself special? Larger inlet to reduce cavitation? More/less flow?

Hi Volts Z06

They have their own custom designed impeller to increase flow but also match the pulley to your balancer to prevent cavitation. I was cautiously pessimistic until I ran it at the Glen and was blown away by the difference. If you don't need to run a t-stat they weld in a block off which further increases flow. I should have added one of these years ago and I don't know why more people don't run them. I tried everything to reduce temps but this made the biggest difference. I don't run their special coolant though.....plain water works great.

Supercharged111

you think a dual duty car could benefit from this? I see more sacrifice being made on a do it all car.

Hi Volts Z06

I think it's worth calling them and discussing your setup. The first time I spoke to them they spent an hour on the phone with me asking a ton of questions and telling to check a laundry list of items. The call ended with the tech telling me "I know our product will work for you BUT we want to make sure we don't mask another problem." it wasn't until I checked everything they suggested did I call back and discuss again before ordering.

My comments here aren't to be a salesman for Evans but to just point out there is a huge relationship between operating temps, oil selection and oil pressure.

Supercharged111

I might be an easier customer because my car just runs normal hot like all the others. I'd never considered the water pump as a means to reduce the on-track coolant temperatures, so this is very intriguing for me.