The extra power afforded by the C drive must just be pushing my heat load beyond what the current oil setup can handle.  Stay tuned for more fiberglass fun.

 

Ed, have you noticed any of this temp increase?  Also, what was the size of your oil inlet again?  I know you have a much more ideal duct shape than I do, which is probably helping quite a bit.  At the moment, I'll settle for brute force cooling if it actually works.

 

Rusty (joining John with my "tired of this" attitude)

 

 

Yes, Rusty.  I have noticed that both oil and coolant elevated once I went to the C drive turning more engine rpm (and producing more Power).  My coolant intake area is currentl a total of 28 sq inch for both - with 10 sq inch on the left core and 18 sq inch on the right core.  My oil cooler inlet is 24 sq inches.  When I reduced my coolant inlet from a total of 48 sq inch to 28 sq inch oil temp remained the same but coolant went up 5F (this with the B drive).

 

But, I could run WOT (approx 6100) and coolant would stay around 180-185F as did the oil.  However, when I went to the C drive I noticed that at WOT (approx 6400) and 11.5 gph that my oil and coolant both were pushing 200F at 6500 MSL.

 

My conclusion is my current 28 sq inch for core inlets is a bit on the small side for the C drive and high RPM/power.  I intend to increase it to a total of 38 sq inch from the current 28 for coolant but leave the oil at 24 sq inch. 

 

Giving how cool your coolant is your oil temp problem might be even worst if your coolant was not helping to carry some of the oil heat load.

 

I am using the stock mazda oil cooler which might be the difference.  With the old Earl oil cooler I eventually ended up with a 5" dia hose feeding it air with is approx 19 sq inches - that made the oil temp barely cool enough to fly as long as the OAT was not over 80F.  But, at that time I was probably not producing much more that 120-130 HP.That was the 4th mod.  The 5th mode was installing the stock oil cooler and my chin scoop for it.

 

I would say that if you enlarge your oil inlet to 38 sq inch and still do not get the relief from your oil temps that you might reconsider the use of the core for the oil cooler.  38 sq inch should provide plenty of air for the oil cooler.

 

I did go flying Saturday and got the engine up to 6600 rpm at 3500 MSL. 

 

Tomorrow off comes my "intimitator" mufflers and my new design to see if I can quite the exhaust bark without killing the performance.  My take offs are not getting pretty smooth now that I am able to anticipate the amount of rudder to put in at left off.

 

Ed Anderson