Tim McCreary

Does anyone know how hot the oil is after leaving the turbochargers? The reason I am asking is because I am thinking of isolating the turbocharger from the engine oil supply and setting up an external electric pump. I converted my automatic over to a 5 speed and currently have the transmission oil cooler available. I was thinking of installing an electric pump, reservoir, and a supplemental small fan. I was going to set it up to circulate the oil (100% SYNTHETIC) through the turbos and back to the tranny cooler. I would also have it set up to run after the engine is shut off for several minutes to continue to cool the oil.

Removing the turbo from the oil loop should also help the engine oil maintain a cooler temperature and make the engine last longer.

Separating it also has advantages determining whether turbos are leaking oil or engine leaking oil.

Any thoughts on this? The reason I need a temperature is due to the limitations of the oil pump that I have found.

Thanks in advance,
Tim McCreary

FormerPorscheGuy

Your about to do a lot of work for very little return. Why not just get a second oil cooler and a turbo timer.

The problems that I see with what you are proposing deal with space, capacity, and efficiency. First, you are going to have to install a new system complete with reservoir, filter, and pump somewhere under your hood and design it to work from scratch. This will be like running a dry sump oiling system for your turbos and a wet sump for your engine.

A second oil cooler will probably accomplish what you want at half the price and work.

Tim McCreary

The idea is to isolate the turbos from the engine. This way, troubleshooting and cooling the turbos would be much easier. I do have the R1 setup, but I think that there would be much better benefit from running just synthetic through the turbos alone and standard oil in the engine alone. This way, the cost of oil changes drops drastically at 3K miles versus using all synthetic. Space is an issue, but with all the crap that people put in the engine bay, I am sure I can find a place for it. As far as efficiency, I would hope to be able to cool the turbo fluid to a much lower temperature separately versus having it tied in with the engine. I could also control the pump either separately using an aftermarket turbo timer. This way I could park the car with the tranny in gear and have the turbo oil cool down without worrying of the car drifting off a hill. Not that this is a common occurrence, I just don't like leaving a car out of gear when parked.

Tim

Kento

Even though you're only proposing running the oil through your turbos, you're going to need a very efficient (and fairly powerful) pump, because it will be circulating a high viscosity fluid through some very narrow passages. There's a reason why oil pumps are usually driven off the motor.

FormerPorscheGuy

You still have the problem of setting up a complete dry sump oiling system while still running a wet sump for your engine. I am not saying that this can't be done but the benefit you are looking for won't happen with your proposal because your turbos will still heat up the same due to their position on the receiving end of the exhaust ports.

You will also be stuck with changing two oiling reservoirs every 1500 to 2000 miles and not just one. That is assuming that the oil in the dry sump turbo system will degrade at the same rate as the engine oil.

If you are worried about oil benifit, run a full synthetic in your engine. I do with no problems.

Tim McCreary

I did not realize that 10W30 was high viscosity oil? I am talking about a variable pump used for transmission and rear end oil applications. It is a continuous pump rated at 150C and capable of 250C intermittent temperatures.

Also, changing 5 quarts of dyno and two quarts of synthetic is much cheaper than 5 quarts of synthetic. With the compression gasses separate from the turbocharger oil, the synthetic oil will last much longer and will need less frequent changes. (Just for example, how often do you change rear end oil or tranny oil? Since they are a nearly sealed system, introduction of dirt is extremely low and the oil lasts much longer). Remember, it is not the thermal viscosity breakdown that kills the oil (as touted by a popular oil manufacturer), it is the contamination of the oil that does the most damage. Blowby gasses and unburned fuel degrades the oil quickly, whether it is synthetic or dino oil. Thermal viscosity breakdown can only degrade 10W30 down to SAE10W. A small amount of unburned fuel can degrade the viscosity way far below that. Separating the oils has much more advantages than you might initially think. Remember, a rebuilt engine is much cheaper than a new set of turbos any day of the week. I contemplate getting a 99 spec turbo in the future, so having the separate oil systems plays a much larger part than you would think.



Tim

PS I know there might be a lecture on 20W50 being the oil of choice, but I beg to differ. Asking an oil system designed around 10W30 oil to pump fresh 20W50 through those tight passages in the engine is asking for trouble. If you use 20W50 because it thins out quickly, then you have problems with your engine, mainly blowby gasses and unburned fuel contaminating the oil. By letting this happen, you are letting your oil quickly degrade to the point that it so thin that it does not adequately protect the moving parts. If you use it because of thermal breakdown, then you have not read up on the viscosity modifiers in the oil. The further the two numbers are apart, the higher the viscosity modifiers are added and the more likely it will break down quickly to the base oil. 10W30 is the most stable and consistent of all oils and uses the least amount of viscosity modifiers, so as long as there is no contamination, it is the best choice.

Tim McCreary

Currently my engine and turbos are running with one oil cooler. If one cooler was sufficient for the turbos and engine together, one should be more than enough for just the turbos. Yes they will heat up the same, but I can cool the oil down much quicker and more efficiently with a separate cooler.

Tim

Kento

I said high viscosity fluid, not oil. You're talking about circulating a fluid that is highly viscous in nature through multiple small passages (turbo oil lines, bearings, then through the lines to the myriad tiny passages in the oil cooler) using an electric pump. I'd think you would need a very specialized electric pump that will be able to maintain the necessary pressure (and will probably need a good amount of amps to run). It takes some power to force oil through all these passages, and that's why oil pumps (for the engine) are usually driven off the engine itself. If there was an easy way to do this, I'd think an auto manufacturer would have done it already, as it would free up the parasitic power losses from a conventional oil pump.

I'm not saying it can't be done. And I would be interested if you could make this work.

reza

the turbo known to whip the oil into foam, that is why you have big tube coming out of turbo into the oil pan...
Think about this too..It will not be all fluid running in your tubes, you need to separate the air and oil. Its done in the regular Oil Pan. plus the oil pan has a lot of oil to go around just in case the foam has not settle down.

Tim McCreary

What other FLUID would be pumped into an oil line to a turbo other than OIL? Enlighten me. If it has to be oil, it is the same oil going through the same passages now, right?

Tim McCreary

Do you think that 2 quarts would not be enough with a reservoir system? Seeing as how there is 5 quart in the whole system right now.

Thanks for the advice. I did not think of this.

Tim

Kento

Tim, man, no need to get defensive here. You were implying that I was saying the 10W-30 you were going to use is a high viscosity oil-- all I'm doing is specifying what I was saying: that you're going to using an electric pump to force motor oil (a viscous fluid) through a lot of small passages, and that creates a lot of resistance. If you've got an electric pump that will do this without requiring a lot of current draw and will maintain sufficient pressure, more power to you. I just haven't seen one that will do all this efficiently.

Hell, if you can make this work for a reasonable cost and construction, I'd be interested.

maxcooper

The oiling system is pretty good as-is. You don't hear about many (any?) oiling problems on these cars besides the occasional plumbing problem. The bearing journals are large and rarely show any damage when people get their engines rebuilt. You can buy a lot of full synthetic oil changes for the cost of setting up (and debugging) a separate oiling system for the turbos. Plus, by staying with the combined system you avoid a bunch of weight and complexity that a separate system would bring.

-Max

Tim McCreary

I beg to differ. How many turbos have needed rebuild or failed. My understanding is that the bearings wear out. Why? Lubrication. Yes, many housings crack, but usually the turbo still runs with cracked housings. I have seen many turbos for sale needing "REBUILT with minimal cracks". Most reputable turbo reman places state that the turbo should last as long as the engine given the fact that the oil is maintained clean and given time to cool down.

Also, the oil cooler is already in place, I just need to install a pump, reservoir, add a fan, and connect the lines. Not much there other than the planning and execution.

Weight is not my concern. An extra 20# give or take, I can stand to lose that much weight. Reliability and long term cost effectiveness is my goal. Call me **** retentive if you want. Just trying to engineer a better mousetrap.

Tim

KevinK2

You would need a high pressure vane or gear pump, with a relief valve. BB turbos could use a low pressure pump. Not worth the effort, complexity, and new stuff to fail and really trash turbo bearings.

Run coolant thru xtra cooler if compelled to do something. For oil, switch to R1 set-up. If you don't do driver ed events, 2nd cooler is not needed.

rotary-tt

I would think you'd need a 'positive displacement' pump (gear, vane, etc.) capable of handling the temp, pressure, and viscosity ranges. You would also have to have an idea of the flow rate. A good manufacturer has these parameters available graphically (pump curve, forget the actual name). Be nice to tap into the oil supply lines and get the temps and pressures. Pressure should be no higher than the crappy oil pressure gauge (if accurate and working). Flow rate is going to be tough. If you know the pressure, diameter, temp, and viscosity I believe you can get the flow rate. Good hydraulics catalog would help...

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