Has anyone attepted to mount there turbo's lower in the vehicle. i know theres a new kit for the 05 stangs that mount them low, under the car, but Im curious myself as to how to get the oil return back if your too low and gravity wont do it for you. Id like to do the same idea as that 05 setup for my truck but am worried about the oil return. The truck is a 55 F100 so theres plenty of room up top or down low. Id prefer down low first. I love the old incon systems, but they unfortuanatley went out of business, and no one that I know of makes a manifold like that. I basicly dont want the turbo's mounted up front of the motor, going for a super clean stealthy appearance here.
Here is a copy of the my post on this subject from turbomustangs.com forum. BTW, while the Ultimate Racing kit looks fantastic, they will have problems with the oil system.:
Given the issues I have had running low mounted twins and the many phone calls with racing engineers that have worked with pump scavenged turbos, I can humbly say that I have now become an expert on this topic. With that said there are many issues to consider and many sub-optimal ways to accomplish the task.
First consideration is the physical system. Even with a pump, a small scavenge tank is recommended by 100% of the people I have talked with. The consensus being that a 20 cu. inch tank is sufficient for all but the largest turbos. The reason for the tank is two fold. 1. This gives a buffer to the scavenge pump. 2. This allows you to easily plumb a vent line for the scavenge system. The reason for this is that you should not run a large vacuum on the turbo. The senior engineer at Garrett I spoke with said to run no more than 2 inches of vacuum on the GTBB turbos I am running. I would guess that the same would apply to a varying extent to all turbos.
This is a good place for this: Rule: If you are running twin, low mount, non-gravity feed turbos and want an effective long term scavenge system you will need two pumps. Once a single pump starts pulling air from one turbo (usually the one mounted the highest) you will quickly back up the other. This is particularly the case if the pump is not below the turbos.
The second consideration is the pump. Diaphragm pumps have difficulty with high temperature fluid. This becomes application specific as many variables effect fluid temps. With that said, the Weldon 9200 gear pump will be more durable if high temps (>270 deg.) are common.
Third, these pumps don't like to pull oil against gravity. If this pump can't be mounted as low as the turbo then you will have problems. Also remember that g loads aren't static to a performance car and sustained cornering, acceleration and braking can dramatically effect the scavenge systems efficiency. This is particularly the case for a road racing car like mine.
Fourth, watch your supply! Most turbos don't like a ton of pressure. Make sure that they either have a built in restrictor or a add one to the feed line. Also, oil can pool in the turbo if the feed line is downhill (as most are that require manual scavenging). On my application the oil would feed back out of the oil filter, down the line and fill the turbo and drain line (this was prior to adding scavenge tanks). Trust me, turbos don't like to be pooled with oil - think insect fogger on startup. The fix for this is to use an in line residual pressure valve on the feed line close to the turbo(s) - 2psi is plenty as long as it seals well (most don't).
Lastly, there is only one way to really do this right - Use a Belt Driven Pump. They create much more vacuum, follow the flow curve of the oil pump, and are totally unaffected by oil heat.
Having learned these lessons the hard way, I am now using a five stage dry sump pump that had two .6" stage sections that individually scavenge each turbo via a -8 line that is connected to a 2" diameter x 6" long scavenge tank. This tank has a -4 vent line that then runs up to the valve covers to prevent excess vacuum. The feed line has a 2 psi residual pressure valve and each turbo has a .035 restrictor. BTW, the twin turbo Audi RS8 Le Mans Prototype car is using the exact same oil system.
96 Cobra American Iron Extreme
Griggs, Jerico, Wilwoods, Motec, Incon 4.6 Twin Turbos, and an absolute mininum of stock parts
Hmmm, I am running a modified (larger wate gate and turbo combo, front mount intercooler) low mount kit from Turbo Engineering with no issues, buddy used to run the same kit back in 1990 and once we installe a hi temp impeller in the oil return pump it worked fine.
2015 Ecoboost Perf Pak
I was thinking of making a system with low mount turbo's using block hugger style heads for engine swaps-I think they were 351 swap headers. They stay close to the block,and look identical to the Incon headers (minus the turbo flange).