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MikeJinCO · Posted: Tue Jun 23, 2020 11:02 pm Post subject: Oil Cooler

Got in my first short runs a week ago, unfortunately short because I have a vacuum leak at the manifold so it ran poorly and then exhaust system broke, more/better hangers required.

At any rate I changed out the oil cooler last winter replacing the 15,000 BTU B&M unit with the 20,000 cooler. My oil temperature which was 250+ last summer dropped to 215/220 in 95 degree outside temps, right where my motor guy wanted(water+30).
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

Cedric · Joined: 27 Aug 2004 Posts: 2608 Location: Sweden

How is the oil cooler located, 250F is closer to what a standard car get up to on track without oil cooler, though yours might have a bit more power than the 125 std ponys. 220 range sounds more healthy, great upgrade! My turbo creeps up a little bit above 250 on a hot day on track, i hope it will be better with the new setrab cooler, we'll see . Its not really an issue but ads to the risks and brake down the oil quickly.
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1980 924 Turbo
www.instagram.com/garagecedric/

924RACR · Posted: Wed Jun 24, 2020 3:47 am Post subject:

Yeah, that's a super-happy number, borderline too cold. I'd be comfortable with around 230-235 on a hot day.

It really comes down to engine longevity; while the oil itself is OK at those higher temps, the engine durability definitely suffers.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

MikeJinCO · Posted: Wed Jun 24, 2020 1:28 pm Post subject:

I have the cooler mounted in front of the radiator, but not touching it. With the front end I have it is directly in the air stream. I now have a 1/4" wire rock screen in front of everything. I expect the oil temp will creep up a bit when the car gets longer runs.
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

safe · Joined: 18 Mar 2017 Posts: 586 Location: Sweden

To have a radiator in free air isn't necessarily the best way, air tends to take the easiest route and it will be around the radiator if possible.
It would be better to mount an oil cooler flush against the water radiator than to have a gap between them.
You also want some form of funneling/border so the air doesn't flow around the radiator.
I you look at factory cars the openings in the bodywork isn't huge, that's not only a design thing, you want to take fast moving air and slow it down so it will pass the radiator easier and transfer the heat more efficiently. (The less air you get under the car the better, unless you have under body venturi tunnels.)
Ideally the opening in the body should be 1/3-1/2 the size of the radiator, if I don't remember incorrectly. Look at the Porsche 944 turbo intercooler ducting.

924RACR · Posted: Fri Jun 26, 2020 12:57 am Post subject:

We actually put ours off to the side, in front of the LF wheel - so no overlap of rad cooling air supply. It gets enough air fed through the gap between the bottom of the bumper and the top of the front lower valance panel to cool well, even without the slots on the Turbo (we're not allowed to run that bodywork per the rules).

We do have some degree of ducting on it, but not as much as we could.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

MikeJinCO · Posted: Mon Jun 29, 2020 12:53 am Post subject:

Hopefully I'm posting a picture of my cooling setup. The oil cooler is the dark block behind the bug/rock screen. Moving it would be a major re-plumbing job. All the info I had said not to mount it to the radiator so that neither one influenced the other. My water temp with a stock thermostat stays a solid 180 under all conditions so far.

You might notice the extra aluminum angle for the screen and the brace by the tow hook is a homemade kevlar/fiberglass strap I had around, lighter than the aluminum and stiff enough. Above that are my homemade bumper mounts, wood reinforced with similar composite reinforcing. The bumper weighs about 2lb so it is purely decorative. I don't have cooling ducts back to the front brakes yet an haven't needed them so far. Maybe next winter I'll work on that, the high temperature ducting is quite expensive although I'm not sure it is needed and the aftermarket cooling inlets a unbelievably expensive for little bits of sheet metal. I'd have to figure out how to make them.[img]https://imgur.com/Sy7q2Dn[/img]https://imgur.com/Sy7q2Dn
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

MikeJinCO · Posted: Mon Jun 29, 2020 12:55 am Post subject:

obviously I'm not quite sure how to get the image up.
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

924RACR · Posted: Mon Jun 29, 2020 6:25 am Post subject:

I will mention - we've never found the need to add brake cooling ducts to our 5-lug setup, even running at Road Atlanta and Mid-O. You'd probably have to be making quite a good bit more power than stock/us to be in need...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Fifty50Plus · Posted: Tue Jun 30, 2020 2:54 am Post subject:

Ditto on no brake ducts. Running Summit Point, NJMP (both tracks), Pocono and VIR. But I found it necessary to change my fluid at the beginning of the season. Forgot in the spring of 2018 and SURPRISE!

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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car