Question about oil return for 3.2 Turbo

lr172 · 07-16-2009, 07:56 PM

I am in the process of converting my 3.2 to a turbo. I will be going with a std. journal bearing turbo and now planning the oil routing. First, I cannot get a 90* fitting on the drain plug becausle the oil hard line is in the way. I prefer not to get the new pipe, as I am trying to stay on a budget. I called BAT and my only option is to get a banjo fitting to go in the drain. The problem is it will be $60 for the banjo fitting. What do you guys think about tapping into the chain case, like protomotive does? I have read someone's post about their build and they indicated that this method increased the oil temp. This doesn't seem logical, as it appears that the chain case dumps directly to the sump, where the drain plug is.

Second, it sounds like I need a parallel thread, not NPT, fitting for the tee that goes before the oil pressure warning sender (for the oil feed line) What have you guys used successfully for this? I could find too much in archive. Also, can this be a -3 or does it need to be a -4?

Thanks for your assistance.

Larry

gsmith660 · 07-17-2009, 06:54 AM

I would go with the banjo (-12) on the drain fitting the lower you drain the oil back the better and that is the suction of scavenge pump so that is all the better. You need -4 and you need a little more than the a tee there is a check valve assembly that is back there and a banjo.

911st · 07-17-2009, 11:07 AM

Just my opinion but I like the return into the chain housing a lot better than to the bottom of the case.

What turbo are you using? If it is a ball bearing you need to restrict oil flow to it or it may blow past the seals.

That is about all I know.

juan ruiz · juan ruiz's Garage

What do you guys think about tapping into the chain case, like protomotive does?

If I had to do it all over again I stay away from the chain case

gsmith660 · 07-17-2009, 12:16 PM

I like the tap into the bottom plate what I would like to do is put a system one oil cartridge filter on it just in case of any coking on the oil out of the turbo.

911st · 07-17-2009, 12:24 PM

I am not up on turbo draining but I belive it is suposed to be non restricted and not be dumped below the oil level.

At the chain housing it seem easyer for the oil to drain out of the return line and might reduce the chance of coking.

When running and the turbo is receiving oil pressure, probably not much differance as the oil is going to end up in the bottom of the motor and be pumped up through the oil filter and back into the tank. (Did I get that right?)

gsmith660 · 07-17-2009, 12:40 PM

The lowest pressure in the case is right at the suction of the scavenge pump, I dont know for a fact but some have said there may be some foaming in the chain housing from the chain.

911st · 07-17-2009, 01:44 PM

Just thinking out loud.

When running there is positive oil pressure pushing the oil out of the turbo so it probably dose not mater from that point if the drain is under watter or dumps in above it. (Dose fluid that is dumped into the bottom of a vessel flow faster or easer than if dumped from above the fluid line? I do not know.)

The crank, rockers, and chain are already agitating the oil to a significant degree. This is why motor oils are designed to be low foaming. Further the oil tank has separators built into it for that purpose.

My only thought is when the motor is shut down, the oil from the oil tank flows back and wants to fill the crank case. The oil in the turbo line then may back fill and or be more inclined to not drain as fully out of the turbo if it is dumped in the bottom of the case.

At the chain housing, it may have more of a chance for the return tube to stay above the oil line and even drain down and away from the hot turbo.

Both system seem to work fine. Protomotove is one of the best Turbo builders that has been has been able to make more reliable HP out of a Porsche than most so using my limited common sense as it relates to mechanics and this, I lean toward dumping into the chain housings or lower rocker covers.

Draining into the bottom of the case seems a relatively new approach to me (Ben at M&K being the first I had seen). However, I have not heard of anyone having any issues doing it this way. I would just pick what is the easiest and fits your build.

One last thought, It may be a low probability but on top of that, you now have an oil line exposed on the bottom of the motor that can get damaged in an off road or with something getting kicked up. I once took a short cut over the berm at Laguna Seca into the cork screw that I know would have riped that style of attachment off.

lr172 · 07-17-2009, 09:35 PM

Thanks for the input guys. It would seem, from a draining stand point. that both would work. I also feel that the greater the incline the better. However, the advantage with the chain case method, is the very short distance of the the drain line. I also saw a post from Jbrinkly, I think, stating that the engine ran cooler with the drain plug method over the chain case. Has anyone else experienced this?

On the oil supply line, I am not sure that I can source the check vavle that is used on the 930 setup. Do I need this. I have seen several post their builds with simple tee's. Does anyone the thread size of the fitting/sensor?

Thanks,

Larry

gsmith660 · 03:59 AM

You can get the check valve housing (18mm) and the through bolt (14mm) that the sender screws into from pelican by getting the partnumbers in the PET or parts diagrams dont forget the new sealing washers as for the 9mm ball Ben got his from the hardware store I was going to have to order one from the internet, I got my banjo fitting (14mm to -4an male) from BAT inc. IMHO this is a cleaner install than the tee and has the check valve that from what I have read is needed for a street car to stop oil flow to the turbo but some have taken it out for track cars. Maybe someone else can elaborate on this because we are draining back to the case and not using a scavenge pump the oil cant pool up in the turbo housing and cook as even when you shut down the motor it takes time for the oil to drain back to the case from all the various locations in the motor and therefore not likely to back up into the turbo and coke up right away. What I would like to do is put a check valve in the drain line to prevent oil from backing up and flooding the bearing housing and working it way past the seals so I dont get a puff of smoke every time I start up the car in the morning never any other time.

gsmith660 · 07-18-2009, 04:01 AM

Does anybody know how high the oil gets in the case when it sits overnight?

mb911 · mb911's Garage

on a 3.2 most folks use the drain plug and buy the adapter fittings from BAT INC and run the drain in there . the oil level can get real high in the engine over night depending on a few factors.

I have tried the following solutions

drain to chain cover (drains poorly IMHO)
drain to sump plate (drains good though is somwhat exposed)
drain to drain plug on a 3.2 (great solution though bit more expensive)
drain to tank and use 930 scavange pump(cleaner butno better then solution 2 and 3)

as for running the feed line that is pretty simple as I know what turbo you have larry you can simply use a -3 line 36" long and 1/8NPT male/female/female T fitting and the standard feed flange you can buy off ebay for $20 for turbo feeds. no check ball is required for your setup as I have a friend with the same setup

gsmith660 · 07-18-2009, 04:56 AM

Thanks Ben, so draining to the chain housing verses the sump plate would not prevent the oil from pooling in the center section?

sjf911 · sjf911's Garage

Does the stock 930 pump the oil scavenged from the turbo directly to the tank unfiltered?

gsmith660 · 07-18-2009, 07:19 AM

Quote:

Originally Posted by sjf911

Does the stock 930 pump the oil scavenged from the turbo directly to the tank unfiltered?

Yes that is why I have the punch list to add a system one filter to my drain

spence88mph · 07-20-2009, 10:12 PM

I drain to the 3.2 drain plug, works great....

But..... If you park the car on a hill, point it downwards as the oil will slowly make it's way into the turbo, I had the front of my car on stands for a few days, when I put it back down and fired the car, I filled the street with smoke. I thought the engine must have somehow disolved it's rings and pulled the headers, no wet exhausts ports... pulled the turbo, full of oil. If the car stays level, you're all good, maybe my seals ain't the best though.

911st · 07-21-2009, 06:34 AM

I suspect that you can add a filter after a 930 scavanging pump.

However, is one us using a gravity drain, I do not know if it would be a good idea to add any restriction in the return.

Somthing to look into.

Dose a factory 930 have a seperat hose attached to the oil tank that bypasses the normal oil filter?

Draining into the case (chain or motor bottom) I would think would run the oil through the stock oil filter on its way back to the oil tank.

gsmith660 · 07-21-2009, 07:09 AM

Quote:

Originally Posted by 911st

I suspect that you can add a filter after a 930 scavanging pump.

However, is one us using a gravity drain, I do not know if it would be a good idea to add any restriction in the return.

Somthing to look into.

Dose a factory 930 have a seperat hose attached to the oil tank that bypasses the normal oil filter?

Draining into the case (chain or motor bottom) I would think would run the oil through the stock oil filter on its way back to the oil tank.

You are right upon looking at pics of the inside of the tank the scavenge pump either goes to the filter or the oil cooler then to the filter and when cold the oil would be more likely to have coke in it and would go to the filter first. Thanks.