Hello Trackites,

I was doing a weekend at Road Atlanta last year for a BMW DE. My instuctor, a 350Z owner who is the CEO of a firm that preps race cars suggested that I use 15/50 Mobil 1 in my Z to keep oil pressure up with track use. He has switched to this oil in his Z with lots of track use. He also added that this would be helpful since I have the "Dougie Do", that is the full bolt on package from our own Mad Z Professor, Doug Crawford. With the intake, plenum, headers, high flow cats, exhaust and a re-chip to 7200 RPMs. By the way I spotted the mad professor grinding away in his laboratory on some new dohickie he tells me will need to be under my Xmas tree this year. I have tried the 15/50 oil and it sure helps oil pressure at the track. It is hard for me to ascertain if I am loosing power from the heavy oil.

Anybody got an opinion on 15/50 in a track prep Z?? Anybody else try it??

Tomzz

 

Is your oil pressure low at the track ?

 

Oil Pressure low at track?

It was almost 0 at idle during the track day at Road Atlanta - (Spring 75 degrees) when I had time to look at it. I did not look at it during the track sessions being that Road Atlanta is the #1 track for DE crashes. He told me he had the same "problem" with his Z on the track, and that 15/50 "worked great" to incresae his oil pressure. I would guess that too much oil pressure can be a bad thing?

 

Oh. Well, 0 psi can’t be good that’s for sure!

But before SpacemanSpiff finds this post, I’ll say “I don’t know” lol

Oil pressure is not a direct measurement of how well the engine is being lubricated. I do use it to have an idea of how hot things are in there. I don’t remember seeing my pressure below 60 psi during a 25 minutes track session with Mobil 1 5W30 oil. Minimum operating pressure is 43psi according to the manual.

I guess it’s a matter of finding out how well the oil holds up to higher temperatures. Being more fluid (less pressure) might not mean it’s losing its film on the parts.

I’m curious to hear other peoples opinion, since I have a couple of gallons of Mobil 1 15W50 at home, with no car to put it in…

 

Okay, I just went for a stroll to talk to the guys from the race team here and asked.

Answer:

I can’t hurt and it will give more protection. In your case with very little pressure at idle, yeah go for it! For me, the 5W30 seems to be holding on pretty well (I change it before every week-end). I might use the 15w50 I have in my garage, just not to waste it.

You will loose power thought. More drag in the engine, it will rev a bit slower.

 

Almost 0 psi at idle is not good thing. The Service Manual states 14psi min at idle, and IIRC ~30psi min at 2000 rpm and ~43psi min at 4000 rpm.

I use Mobil1 5w30, and the oil pressure is at 30psi at idle. When I added the oil cooler, the oil pressure stayed the same.

Maybe your oil pump is going bad?

I called Redline Oil a while back, and they recommended their 5w30 for the 350z, even for track days in 100F+ temperature.

 

Good input folks,

well, maybe I will do the scientific thing and do some readings at the track day in Sept. with the fresh 15/50 I have, and then do a 5/30 test for the Oct track day and see what the numbers are on thinner oil, and what throttle response is with both.

 

Are you measuring your oil pressure with the stock gauge? I have found that my stock gauge reads 0 at idle when the motor is hot. Obviously I was concerned about this, so I hooked up an autometer mechanical gauge and found out the pressure was actually around 15psi at idle. YMMV.

-Rob

 

I have been running the 15w50 for over a year on the street, but I am TT'ed. No problems here.

 

tom
I have also question if the oem oil pump is adequate for cars that had raised redline to 7200 and tracked at those rpm's consistently.
i wondering if the rev-up engine oil pump my provide better pressures at high rpm's.
i also know that some racing 350z's were using 20/50 oil.
regards

 

I wouldn't rely on the stock oil pressure gauge for an accurate reading. Oil viscocity needs on a race track are generally no more then what the OEM recommends if you're doing open track or driving events where the sessions are around 20 minutes.

If you're racing in longer sessions, an accurate oil temp guage is important and will probably indicate the need for an oil cooler. Keeping the oil temps under 230 for regular and under 270 for synthetic is more important then increasing viscocity to see the pressure gauge needle a little bit higher on the scale.

 

john
good points.
any thoughts on a better oil pump (either nismo or rev-up engine oil pump)?
regards

 

I'm not an engine guy so I would leave that up to the VQ experts. Jim Thompson at Sunbelt (770) 932-0160 is a person to call.

IMHO, based on a number of different cars I've prepped for racing, a larger pan with a trapdoor sump and a windage tray would be something I would do before upgrading the pump. Make sure the oil you have stays around the pickup and doesn't foam.

 

So lets look at the action plan relative to the great inputs.

Some "Race" Z's use 50 oil
My stock oil pressure gauge may read zero but it might really be 10-15


So my Action plan to do some track day measurements with 15/50 and then to test the 5/30 might offer the clues I am looking for (oil pressure and throttle response.

Is it also possible that the 15/50 oil will not effect my throttle response, nor offer any greater protection, but does no harm?