Keeping the Pressure on…
DRO’s “real-world” Project Car
Words and photos by Jok Nicholson
If there is one constant for every drag car it is the need for steady oil pressure. Drag racing tests your oil pan and pick-up system for performance at both ends of the drag strip. Hard acceleration presents one problem and then hard braking creates another problem the oil system has to deal with. Most race pans have baffles or trap doors to keep the oil around the oil pickup to prevent loss of oil pressure during the launch and in the shut-down area. Some work, some don’t.
Dragsters have their own set of problems that are a bit different than door cars but the problems and the cures are about the same. On a dragster you can’t have a very deep oil pan sump for obvious reasons (low ground clearance) and on door cars the pan can usually be deeper but since the chassis can move more it can create a problem as well with oil sloshing around and getting away from the oil pump pickup tube.
Our project dragster, “Back-2-Basics”, has always struggled with maintaining oil pressure in the shut down area. It will go from 75 lbs. at the finish line to 0-10 lbs. in about 2 seconds as we get stopped. We have tried different pans, swinging pickup with external pickup hoses running to the oil pump and it did the same thing. Is this the best it could get? NO.
Moroso has the answer for this problem, the Accumulator. It is available in a 3- quart capacity and a smaller 1.5- quart capacity. If space is available I would recommend the larger one for most V-8 racing applications. If you are running an import with 4 or 5 quart capacity the smaller version is likely your best choice. We went with the smaller one on “Back-2-Basics” mainly due to space limitations.
The engine had already been raced one weekend and all was well (at least it ran OK)! We started the engine and the pressure built up in the Accumulator to match our cold oil idle pressure of 80 p.s.i. We have our Accumulator wired similar to an electric fuel pump, power for the solenoid on the Accumulator is only available when the ignition is “on”. If you don’t want the Accumulator to turn on when the ignition is turned on there is a toggle switch you can leave in the “off”
We got to the track last weekend and used the Accumulator to “prime” the engine before we started it. Simply turn the ignition on and flip the Accumulator switch to “on” and youhave 80 p.s.i. of oil pressure going through the engine. The pressure falls off pretty fast but that is because it is being forced through the oil galleys. We then started the car and the Accumulator builds back up to the 80 p.s.i. as the engine idles and warms up.
We wanted to experiment a little so we made the first pass with the Accumulator switch in the OFF position. In this position the solenoid will not let pressure out if the oil pressure drops. We made a normal run and sure enough the pressure dropped to about ZERO and stayed there several seconds during shutdown. The next run we made we turned the Accumulator switch ON and left in that position so whenever the ignition switch was ON the valve was open on the Accumulator.