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-   -   Oil+ cooling (https://www.miataturbo.net/engine-performance-56/oil-cooling-99904/)

Joe Perez 04-22-2019 03:49 PM


Originally Posted by hornetball (Post 1531896)
Valve springs? R U serious?

It's not implausible.

Find a piece of metal which is thin enough for you bend it easily. Bend it back and forth rapidly until it snaps. Did it get warm before it snapped?

Now imagine doing that to sixteen pieces of metal strong enough to resist Hustler's mom standing on them, 58 times per second. Each.

I can totally see the valve springs being a major contributor. I'm having trouble with the assertion (in the other thread) that the oil pump itself creates more heat than the valve springs, pistons / rings, bearings, etc.

DNMakinson 04-22-2019 04:17 PM

Joe. Not a good example. In your case, the material is yielding, thus work is being done. In a valve spring case, operating in the elastic area, the energy is stored and released. Only hysteresis is involved in a well designed spring. I would anticipate very little loss in the springs themselves.

sixshooter 04-22-2019 06:10 PM

Point of reference, NASCAR uses sprinkler systems to get oil onto the valve springs to keep them cool to promote longevity. They typically run between 6 and 8000 RPM for extended periods of time. I'm not sure what other forms of racing implement strategies like this.

DrPoke 04-22-2019 08:24 PM

So- RPM is the primary source of heat input to oil.
Unless breaking my engine by remaining at the rev limiter on the street is my actual goal, I won't need to cool the oil (probably). Adding power will add much more heat to the coolant, but not much more heat to the oil.

Google tells me that ATF has a viscosity similar to 5W20, so I don't think the amount of tubing would end up being too flow restrictive, especially with less overall distance to the lower portion of the radiator than to go around it as most oil coolers are mounted. Another possible advantage to this setup is that the whole system could hold more oil, resulting in a larger effective heat sink.

Another thread on this forum said it would be possible to use the oil cooler from a 1.8 in a 1.6. I like the idea of having a water-cooled oil cooler, since it aids in warmup initially and keeping the overall temp down, but adding another heat load to the coolant system seems a good way to encourage overheats.

Joe Perez 04-22-2019 08:48 PM


Originally Posted by DrPoke (Post 1531962)
Another thread on this forum said it would be possible to use the oil cooler from a 1.8 in a 1.6. I like the idea of having a water-cooled oil cooler, since it aids in warmup initially and keeping the overall temp down, but adding another heat load to the coolant system seems a good way to encourage overheats.

That is exactly what I wound up doing on my turbo '92. (Remember to also get the longer threaded pipe to match, and the nut that holds it on.)

With only a modestly sized radiator and no re-route, I never once overheated the car in spirited driving in the California desert. (Eg, climbing Palomar Mountain at felonious speed.) It only started to overheat after I moved to Florida and got stuck in stop-and-go traffic in August, and a reroute cured that nicely.

HarryB 04-23-2019 03:47 AM


Originally Posted by DrPoke (Post 1531962)
Another thread on this forum said it would be possible to use the oil cooler from a 1.8 in a 1.6. I like the idea of having a water-cooled oil cooler, since it aids in warmup initially and keeping the overall temp down, but adding another heat load to the coolant system seems a good way to encourage overheats.

https://www.speedflowshop.co.uk/lami...lers-174-c.asp

You may also wanna check that. Joe, do you have any idea about the heat exchange surface area of the OEM oil to water heat exchanger? Just by looking at it, it looks quite small to me, especially when given the relatively small delta T between oil and water.

sixshooter 04-23-2019 07:06 AM

Auto trans cooler in radiator will not flow enough volume. The restriction will starve and destroy your engine.

z31maniac 04-23-2019 08:10 AM


Originally Posted by DrPoke (Post 1531962)
So- RPM is the primary source of heat input to oil.
Unless breaking my engine by remaining at the rev limiter on the street is my actual goal, I won't need to cool the oil (probably).

Yes. If you have an oil cooler temp sensor. Just grab a few gears and hold a steady speed, at high RPM on the highway..........oil temp builds quickly.

Gee Emm 04-23-2019 06:34 PM


Originally Posted by HarryB (Post 1531995)
https://www.speedflowshop.co.uk/lami...lers-174-c.asp

You may also wanna check that. Joe, do you have any idea about the heat exchange surface area of the OEM oil to water heat exchanger? Just by looking at it, it looks quite small to me, especially when given the relatively small delta T between oil and water.

That is what I used (middle size). Quickly got oil temperature up at freezing ambient, no oil or water overheating at 40*c (atmo race car, 8k rpm) on MSM radiator. I'd want a bigger radiator, and good radiator ducting, on a turbo.

The factory version obviously does something, but not enough in my situation (track). Anecdata (eg Joe) seems like it works in mountain driving, but looking at size of water lines, and volume available, it obviously is limited compared to the Laminova.

Joe Perez 04-23-2019 07:04 PM


Originally Posted by sixshooter (Post 1531939)
Point of reference, NASCAR uses sprinkler systems to get oil onto the valve springs to keep them cool to promote longevity. They typically run between 6 and 8000 RPM for extended periods of time. I'm not sure what other forms of racing implement strategies like this.

Fascinating stuff, indeed. Built right into the valve cover, somewhat like the VVT supply in the later NB engines.

http://www.grumpysperformance.com/12519_4_.jpg





Originally Posted by Gee Emm (Post 1532138)
The factory version obviously does something, but not enough in my situation (track). Anecdata (eg Joe) seems like it works in mountain driving, but looking at size of water lines, and volume available, it obviously is limited compared to the Laminova.

Oh, absolutely not sufficient for a sustained high-RPM track car. And in fairness, I'd probably describe it as more of a warm-up-improver for street-driven cars which otherwise don't require substantial oil cooling.

Savington 04-23-2019 07:44 PM


Originally Posted by sixshooter (Post 1531939)
They typically run between 6 and 8000 RPM for extended periods of time.

NASCAR motors are designed to spin out to something like 10,500rpm. I have seen in-car video with data from Sonoma where they would spin the motor that high into T11. On the ovals, NASCAR specifies the rear end ratio, and they typically park the engines in the high 8k range, so the teams optimize for that, but if given the choice, I think they'd spin them higher on a regular basis.

NASCAR engines are absolutely fascinating to me. At one point in recent history (last 10yrs or so) they had a higher BMEP than any other motorsport engine, F1 included.

tomrev 04-23-2019 08:37 PM


Originally Posted by Savington (Post 1532162)
NASCAR motors are designed to spin out to something like 10,500rpm. I have seen in-car video with data from Sonoma where they would spin the motor that high into T11. On the ovals, NASCAR specifies the rear end ratio, and they typically park the engines in the high 8k range, so the teams optimize for that, but if given the choice, I think they'd spin them higher on a regular basis.

NASCAR engines are absolutely fascinating to me. At one point in recent history (last 10yrs or so) they had a higher BMEP than any other motorsport engine, F1 included.

I agree; I have no interest in NASCAR racing, the cars, or the drivers; seems more like a soap opera, with cars, but how well they have developed the 1950's V8 design, the power level they are getting with reliability just amazes me! About 20 years ago I bought an open wheel car from a guy who at the time owned a NASCAR team with Bobby Allison. Just for grins he, and a very experienced engine builder from Toledo, Ohio spent a month on a dyno, down in N. Carolina, trying to see how much more HP they could make with a team engine that was fuel injected, instead of carbed. The full tilt, injected engine never even matched the simple carb motor's output, and they finally figured out that so many guy's had spent so much time optimizing the rule legal engine, that it couldn't breath any better than it was on the carbs, and the advantages of injection couldn't be taken advantage of. That a pushrod V8 can spin the revs they currently do, and live, is pretty damn tits!

ATX. 04-24-2019 09:01 AM


Originally Posted by sixshooter (Post 1532001)
Auto trans cooler in radiator will not flow enough volume. The restriction will starve and destroy your engine.

This is an answer I need. Whats the smallest size oil cooler we can safely use and get adequate flow? I could not fit my 25row setrab, so as a quick work around I installed the type 103 bar and plate cooler from silicone intakes. It is very small, but uses the same M22 size ports, so I assumed it was rated for similar flow, but unfortunately no flow sheet was provided. Im worried now that it will prevent adequate flow, even with my BE stage 2 oil pump. Any thoughts other than to man up and mount the 25 row more creatively, which is the eventual goal

Socals14 10-29-2021 01:54 PM

Meant this post for oil tech thread.


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