Project Turbo 914 begins..., (yes, I know you can't turbo a 914) Options

[ottox914]

Just a little teaser on this winters project. Last winter I dug into this little update:

http://www.914world.com/bbs2/index.php?sho...c=53733&hl=

This winter will be phase 2. This photo will show some of the goodies under the tree, which will soon be under/on the car. The WRX intercooler has one round inlet on the back, and 2 smaller oval outlets under the opposite end tank. These will each exit and attach to some CB performance turbo "hats" for the ITB's that have 2" tubes welded to them. Some silicone elbows, and we're good. The intercooler will mount on braces running across the engine bay to support the intercooler as close to the GT lid as possible. I'll see how it goes, and probably do some yarn tuft testing to see about airflow in and around that lid, but I could always use the SDS computer to switch on either a puller or pusher fan below the intercooler based on boost, if needed. The turbo will mount on a custom flange/adaptor to be built to connect the turbo to the collector of the Kerry Hunter exhaust system. The turbo is a small Garrett VNT. The compressor map looks like a good match for this motor. I'm expecting the VNT turbo to give good low rpm thorttle response. Starting out at 5-6 psi, I'd be happy to see 10 when I'm done, but will tune to run safely on 93 pump gas and see where we end up. Off the back of the transmission, where the factory exhaust hanger mounted, I'll mount a similar hanger to support the turbo and exhaust system. A Tildon differential pump will return the oil to a willing valve cover. Oil will be taken from a "T" at the pressure sending unit on the case. There is a blow off valve to be added to the intercooler, and a mocal thermostat/sandwitch plate adaptor for the oil cooler, which has a thermostat controlled fan. I'll be adding an ignition switched relay for power to the fan and scavenge pump, so both will have power when the key is on. The pump will run continously, the fan when the thermo switch tells it to. Add some pressure side stainless or aluminum tubing from the turbo, thru the back engine tin, into the round inlet on the intercooler and we're done. Except for another trip to the LSE dyno, for some additional tuning. I'll keep posting as progress would warrent.

[ottox914]

Brian- the engine oil is pressurized, and I am tapping into that to supply the top of the turbo bearings w/oil. As these are bearings, and not a pump, gravity is the only force trying to move the oil out the bottom of the turbo once the initial pressure supplied by the engine is "used up" getting the oil into the turbo. So you're mostly right. The engine pumps the oil to the top side of the turbo, gravity drops it out the bottom, and now my scavenge pump sucks it out and sends it back to the engine. Thats why you want the oil in/out to be as close to verticle as possible, and to mount the turbo higher than the oil pan if possible. I chose this mounting system mainly to save the $$$ and effort of a custom exhaust.

Which brings me to chappy.

I have been talking with Corky Bell, author of "Maximum Boost", and he suggested a line directly to the pump, although his book shows some low mount turbos with a small sump as you suggest. His reasoning was that if with the VNT feature of the turbo, I couldn't get a verticle oil drain, the draw of the pump may be more important to keep the turbo bearings flowing well, and this design concern may overrule the conventional set up of a small sump. He noted the main purpose of the sump was to allow a drain for the oil in the line to the turbo, and in the turbo, after shut down, and that the de-foaming of the oil in the sump was a happy side benefit. I'll be trying things as they are, and I can always turn the key to "on" and let the scavenge pump run a second or 2 prior to starting the car, to suck the lines clear, and also leave the key "on" a second or 2 after shutting the motor off, again to clear the lines and allow some room for draining. Supposidly the pump is self priming, and has some crazy verticle draw, but the thought of having the de-foamed drain oil ready to enter the pump can only make is last longer, rather than to start out dry each time the car is run. I still may contact you for that little sump you made if the godfather of turbos isn't 100% correct on this one.

The wonders of a one off install never cease to amaze and confound me.