topmover

I have a 02z that I broke the bottom end on last year. I had a forged 417 Ls3 built which made it necessary to add a Avid dry sump on the scavange side. First time out(this spring) shaking the car down at VIR second session once I started to push the car I got low oil pressure coming out of the lower esses. I backed off the throttle drove back to the pits and once the oil temp cooled oil pressure returned. Long story short we added a dedicated oil cooler(was using the Dewitts intergated one before). My local shop felt that the clearences in my motor .28 were to large so we decided to run 50 weight oil. Took the car to Summit Point my home track and first time there on a cool day with the heavy oil I had no pressure problems, second time there with some heat the some issue came up.

My local shop felt strongly that the clearence needed to be tighted up inorder to maintain pressure. So I had the motor pulled and redone(this is a high quality shop) took the car to VIR yesterday for open track testing with NASA mid Atlantic..........first session I ran about 6/10's with no issues. Second session second lap of pushing it coming out of lower esses got low oil pressure again. Went out for third session with Nanny's on inorder to read oil temps to see if there was a temp that was triggering it the hottest I could get it with the Nanny's on was 243 and no loss of pressure. Turned the nannys off and made one hard lap and once again coming out of the lower esses lost pressure. My shop assues me that they are going to test everything and get this figured out however as most of you know its hard to replicate the heat and motion these cars get anywhere but on the track.

Anyone have this problem before or any ideas.....as you can image this is getting pretty frustrating.

redtopz

Sorry to hear about your troubles. That does sound frustrating! You can check oil pressure with the nannies off if you hit the reset button after hitting the TC off button. It will clear the "TC OFF" display and let you see all the usual display info (oil pressure, temp, etc.).

So you have a scavenge pump but are using a stock oil pump for pressure correct? You might want to go to a stage 3 dry sump system which eliminates the factory oil pump completely. It sounds to me like your oil pump just can't keep pressure at high temps.

Woods

I have the ARE drysump and coming off of VIR or Summit my pressure drop to 19 psi. Once the oil cools it goes back up to 45 psi. The stock internal pump is barely able to keep up.. Is your oil cooler plumbed using the internal pump pressue or the scavenge. People have had luck using scavenge to push the oil through the oil cooler then to the tank , then back to the internal pump.

What is the oil pressure you are seeing?

topmover

Im thinking both you guys may be onto to something here with the pump, so far as the cooler the car acted the same way before AND after the addition of a dedicated oil cooler first time out it was running through the Dewitts.

My problem isnt the oil pressure coming off the track as I'd be ok with 19psi at low rpm coming off the track..........in fact my 2010 zr1 comes off the track at 22psi.

My problem is that the previous motor would drop to 18psi at high rpm on the track and the new set up drops to below 15psi on the track at high rpm which clearly is problematic.

exracer28

Can you go over your dry sump pump setup. How many stages and line size.

Maynor29

Sounds like a possible issue with the o-ring on the pump inlet. I was at VIR this past weekend as well in a dry-sumped LS2 (in a BMW). Dedicated oil cooler, 50 wt oil and smoking hot ambient temps etc. Oil pressures never dropped below 45 psi anywhere on track with Hoosier R6s. Same thing at Summit.

At VIR, turn 1-2 and oak tree were oil pressure killers when I was wet sumped. With the ARE scavenge only set up and stock pump, no issues.

On edit, I'm running -16 lines to the tank which is trunk mounted. -14 or -12 everywhere else.

John

topmover

It was very hot although I didnt get to be around for much of it.........didnt even make the BBQ. Thanks for your suggestion.

JMURF28 I thought I replied to you yesterday on my blackberry but it looks like it didnt go through. My system is 2 stage so far as the size hoses I cant tell you off the top of my head however they are the same size as the ones I had on a 4 stage 1500hp top sportsmen drag car a few years back, so sufice to say the're large.

2000BSME

Over a quarter inch of clearance? 0.28? Yeah that a problem I don't think heavy weight oil will solve.

topmover

Clearly that was a typo