Car Use: Track + autocross, only driven on the street to get to events
Motor: M20B25, 10:1, 284/272 cam, VAC springs, intake, 20lb injectors, long tube headers, 2.5" straight exhaust, chip tuned
Oiling: New oil pump, I-J crank scraper, VAC oil pan baffle, 19 row oil cooler, motor seems to have been built to "tight" tolerances
Prior to installing the oil cooler I was running Rotella T6 5w40 synthetic just because I had it and it was cheap. My oil would go up to 230* just cruising on the highway (4k RPM with a 4.10), so I knew I'd need an oil cooler. Oil pressures were around 22psi at idle and about 75-80psi at redline with that oil. The motor idles around 900-950 rpm.
When I installed the oil cooler, I switched over to Redline 15w50 synthetic. Oil pressure went up a bit across the board, but keep in mind also my temps dropped a good 20*+. My idle is now about 28-31psi and at redline I am at about 85-90psi.
Side note: My oil pressure gauge is an Innovate unit that has a resistance-type thermistor. With the engine OFF, the gauge reads 9-10psi, so keep in mind my pressures may not be that accurate (could be off by 10psi?). I just use it as a point of reference and to make sure the shit is not hitting the fan while on track. Innovate says this is normal behavior, so I have no idea.
During my track day yesterday, my temps averaged 220-225*F and the max temp I saw was 232*F. Pressures were solid, never dipping 60psi or so, even on sustained left hand corners which are tough on M20's. Water temps were always good, in the 185-190*F range.
Even if you deduct 10psi from my pressures, I'm still on the strong end of what you normally see in M20's. I've read that thinner oil can shed heat better, and I don't want to be putting unneeded strain on the motor and oil pump if this oil is thicker than it needs to be. On the street the oil only gets up to 180-185*F, and I think it's going to be tough to keep it that hot at autocrosses.
Based on the data above, would you say this oil is just what the doctor ordered, or should I give Redline 5w-40 (or 10w40 or 15w40) a try on my next fill? I have not been able to find much information on determining if oil is too heavy, just that if oil pressure is low heavier oil can bump it up. I'm comfortable with the oil getting up in the 230* range, but wouldn't want it getting a whole lot hotter than that.
Any feedback would be appreciated. Thanks in advance.
Motor: M20B25, 10:1, 284/272 cam, VAC springs, intake, 20lb injectors, long tube headers, 2.5" straight exhaust, chip tuned
Oiling: New oil pump, I-J crank scraper, VAC oil pan baffle, 19 row oil cooler, motor seems to have been built to "tight" tolerances
Prior to installing the oil cooler I was running Rotella T6 5w40 synthetic just because I had it and it was cheap. My oil would go up to 230* just cruising on the highway (4k RPM with a 4.10), so I knew I'd need an oil cooler. Oil pressures were around 22psi at idle and about 75-80psi at redline with that oil. The motor idles around 900-950 rpm.
When I installed the oil cooler, I switched over to Redline 15w50 synthetic. Oil pressure went up a bit across the board, but keep in mind also my temps dropped a good 20*+. My idle is now about 28-31psi and at redline I am at about 85-90psi.
Side note: My oil pressure gauge is an Innovate unit that has a resistance-type thermistor. With the engine OFF, the gauge reads 9-10psi, so keep in mind my pressures may not be that accurate (could be off by 10psi?). I just use it as a point of reference and to make sure the shit is not hitting the fan while on track. Innovate says this is normal behavior, so I have no idea.
During my track day yesterday, my temps averaged 220-225*F and the max temp I saw was 232*F. Pressures were solid, never dipping 60psi or so, even on sustained left hand corners which are tough on M20's. Water temps were always good, in the 185-190*F range.
Even if you deduct 10psi from my pressures, I'm still on the strong end of what you normally see in M20's. I've read that thinner oil can shed heat better, and I don't want to be putting unneeded strain on the motor and oil pump if this oil is thicker than it needs to be. On the street the oil only gets up to 180-185*F, and I think it's going to be tough to keep it that hot at autocrosses.
Based on the data above, would you say this oil is just what the doctor ordered, or should I give Redline 5w-40 (or 10w40 or 15w40) a try on my next fill? I have not been able to find much information on determining if oil is too heavy, just that if oil pressure is low heavier oil can bump it up. I'm comfortable with the oil getting up in the 230* range, but wouldn't want it getting a whole lot hotter than that.
Any feedback would be appreciated. Thanks in advance.
Comment