BrianCunningham

Or does it?

The turbos can be supplied oil from the engine. The trouble comes when mounting them down low. The oil stays in the turbo and eventually the seals go.

I've read/seen that Callaway Twin-turbos have a separate oil pump built into the belt tensioner. Do they run a completely separate system as well? tank? cooler? If all they do is a separe pump, how does it get the oil out of the sump.

Can the stock pump be used if the return line is above the oil level so the vacuum is broke?

What about using a one-way valve?

Thanks

WashingtonRacer

Playing with Oil flow is not something to even think of taking lightly when it comes to turbo's. If you can mount the turbo higher than the oil level in the oil pan, then you should be okay, But you should make sure the oil flow out of the turbo is at least flowing the minimum amount. I don't recall what the flow requirments are for each kind of bearing housings. but that can be found easy. If the turbo is mounted lower than the pan, then yes an external pump is what is needed. Now I believe that in that setup, you actually can feed the oil into the turbo via a main line from the engine, then you mount a pump on the outlet side to pull the oil back up to the pan. Now I believe you need to have a adiquate line coming out of the turbo into the pump, with enough area to take up the the area in the turbo. So when the pump does stop, any remaining oil will drain out of the turbo and sit in the outlet line. Besides that, if you run an electric pump"which would be better" you can have a delayed stop time in it so it will continue to pump the oil out after the engine has stopped.

I believe what I have said is true, but if not I am sure someone here will correct me. Like Monty perhaps..

Twin_Turbo

For low mounted turbos you'll need a seperate small oil sump lower than the turbos for them to drain into and have a pump pick it up from the sump and route it back to the oilpan.

Callaway used 2 seperate sumps (which were connected to eachother) on their early TT's and one single larger one on the later (I think 87 and up)

The pump callaway used was at first was a piggyback pump driven from the back of the Power steering pump but they later chaned to a pump which is incorporated into a serp. belt tensioner.

There was one on ebay a few days ago and it went for 105 bucks

This is the pump:


Mounting the turbos up high will eliminate most of the oil problems, there's room if you're planning your setup carefully. I don't know why callaway opted for low mounted tubos and the intercoolers above the exhaust manifolds (possibly the worst place).

Things you should keep in mind is that the oil return has to be big, like a -12 line, there can be no low spots in the return line where the oil can accumulate and last the oil needs to be drained in the pan above the oil level

Marck


[Modified by Twin_Turbo, 8:59 AM 12/3/2002]


[Modified by Twin_Turbo, 9:36 AM 12/3/2002]

HunterRose

I must admit that a dry-sump oiling system would be ideal for low mounted turbos. Probably would have to be a 5-stage sump pump and use a scavenge on each turbo. That way the oil is quite literally sucked out. You'd also have the added bonus of running higher crankcase vacuum.

Tony