What to do with oil cooling?

[grelland]

Gentlemen,

The traffic seems a bit slow on this forum, but I try anyways as there are some very knowlegdable people here that have helped me a lot earlier.

I have a couple of threads in here from building and fixing my 2110cc oxyboxer, and currently, after another failure, I have it up an running quite nicely.

The issue I have now, is related to oil cooling.

I am running without a doghouse cooler; just an external one (not a very big one either) mounted under the car, next to the gearbox. A friend of mine made a drawing where he indicates that the air flow under the car goes something like this:

ghia.jpg

The red line indicates how mine is currently placed.

What I experience is that at idle I have good oil pressure, 3-4 bars at idle, that rises approximately 1 bar per 1000 rpm.

But after some 20-30 min on the road, the oil temp has risen steadily to about 230°F, and it keeps rising. I do not know if my temp guage is 100% accurate, but the temp keeps rising, and at this point, the idle pressure is around 0.7 bar, and it goes down as temperature goes up.

I am using a sandwich plate between the case and the filter with a thermostat. I also tried removing the thermostat so that all oil flows through the cooler always.

I have bought aother cooler, that I was planning on installing on the other side of the gearbox, but this time maybe lying down, and using a scoop on the underside to direct air flow. Something like this:

lie down.jpg

There are other options, like placing a cooler up front under the bumper, or even in the spare wheel well, but I am trying to minimize body work hatching.

Any proposals as to what I can do to improve this?

I am very happy with the engine apart from this. Good low end torque and a decent sting at the top. I want to keep improving the engine, especially with better heads, but I want to get this issue under control first.

Here are som quick specs on the engine
-Stock, balanced crank
-Scat I-beam rods
-Wiseco 94mm pistons
-FK 8 cam
-Thorsten Pieper lifters and bushings
-CB los Panchitos 043 heads
-Pauter 1:1.3 rockers
-Oteva 90 springs
-38mm VW speed parts throttle bodies
-Microsquirt ECU

[andy198712]

what oil cooler is it?

i have mine in the same RED line position as you and not had any issues (in a beetle though) done a few hr trips on main roads, its a setrab cooler which isn't huge but apparently quite effective.
i'm using the mocal thermostat plate too with AN10 lines between it.

[Ol'fogasaurus]

Suggestion: Before you change anything do the cotton yarn trick that people use to see what is going on with the airflow around the body. In this case it is hard for a friend to video you as you drive so, if you have a GOPRO or similar camera mount it under the car in the area(s) are curious about. Take a bunch of lengths of cotton yarn and tape to the to the underside of your pan and other areas where the air flow potentially could affect your cooler mounting location or angle then get out and drive... at various speeds. Watch the video then it might give you some ideas of what is going on under your car.

Spoilers can also change the under car flow pattern so be aware of that.

[sideshow]

What is preventing you from using forced air cooling? I am assuming your shroud still has the cavity that fed the oil cooler so why not reduct (like OPP/DTM hose) that into you cooler?

[Ol'fogasaurus]

Sideshow, sounds like a viable option but I still think I would like to know what is going on under there before I tried a few different things. Dead air spots, swirls from the pan or fenders causing opposing air flows could (conceivably) change things no matter how you tried to do other options. Even the height off the road he is set at can affect what is going on. Since he probably doesn't have a wind tunnel to try it it should be the second easiest thing to try .

I don't think rigging up a compressed air setup would tell him enough especially if air flow turned out to change at different speeds... or maybe it doesn't but I would want to know before I invested too much time or money on dead end solutions.

On the horizontal cooler and scoop the same reasoning would apply... maybe even more if the scoop's location turned out to be critical. The yarn trick could be used to find workable locations with a temp mock up and yarn at the outlet side of the pickup.

A very interesting question to say the least.

[grelland]

What is preventing you from using forced air cooling? I am assuming your shroud still has the cavity that fed the oil cooler so why not reduct (like OPP/DTM hose) that into you cooler?

No my shroud does not have the doghouse. It is quite crowded behind the shroud as I have 4 LS2 coils there also

[grelland]

Suggestion: Before you change anything do the cotton yarn trick that people use to see what is going on with the airflow around the body. In this case it is hard for a friend to video you as you drive so, if you have a GOPRO or similar camera mount it under the car in the area(s) are curious about. Take a bunch of lengths of cotton yarn and tape to the to the underside of your pan and other areas where the air flow potentially could affect your cooler mounting location or angle then get out and drive... at various speeds. Watch the video then it might give you some ideas of what is going on under your car.

Spoilers can also change the under car flow pattern so be aware of that.

Good idea, I have three boys in the "right" age, so we have numerous gopros available

[grelland]

What is preventing you from using forced air cooling? I am assuming your shroud still has the cavity that fed the oil cooler so why not reduct (like OPP/DTM hose) that into you cooler?

I will try forced air cooling in the form of a scoop, to see if that has any influence.

[grelland]

what oil cooler is it?

i have mine in the same RED line position as you and not had any issues (in a beetle though) done a few hr trips on main roads, its a setrab cooler which isn't huge but apparently quite effective.
i'm using the mocal thermostat plate too with AN10 lines between it.

The one I have right now is this;

44313.jpg

I believe it is mocal brand

The other one I plan on maybe adding is this:

Capture.PNG

[grelland]

Preparing for some gopro-filming

19656953_10213788926467550_3044021206207882822_n.jpg

[Ol'fogasaurus]

This is going to be interesting to see. This might be the first time anything like this has been posted here. By-the-way, the underside of your car looks so clean and nice. Good job!

[grelland]

The video became too dark, but you get an idea... The piece mounted on the IRS arm is almost directly in fron of the radiator, so from what I can tell, I should hav plenty of air going through the cooler...


[BBvideo=560,315]https://youtu.be/t5AFk5U_m_M[/BBvideo]

Turn the volume up I went to about 120 kph here, and the cruise at the end is about 80-90 kph

[grelland]

I had one piece monted in the middle of the cooler also, and I managed to capture a frame where the light was better, and it seems that the thread is flat against the cooler, but opinting out to the side:

Image2.jpg

[grelland]

This is going to be interesting to see. This might be the first time anything like this has been posted here. By-the-way, the underside of your car looks so clean and nice. Good job!

Thanks

[Piledriver]

#1 rule of airflow through cooler cores etc:
If it can go around easier than going through, it will (mostly) go around.

The #2 rule is you gotta keep 'em separated (hot/cold side air) when using a fan.
Just like the big engine cooling fan, it it can re-circulate hot used cooling air, it will.

That needs some ductwork and/or a 12v Muffin fan.

The T4 "fan idle booster" blowers move a lot of air as well, saw someone use one ducted over a T4 oil cooler recently with reported great results. These push decent pressure as well, much better than an axial fan.