Oil control on track is a weakness of a stock Toyota-powered Lotus. Our baffled oil pan, the gPAN has been a reliable solution that has kept many, many cars safe with good oil control when subjected to 1+g loads. We initiated a serious dry sump effort to develop the next level in oil control but continued to look at the gPAN to see if slight improvements could be made. Both our dry & wet sump solutions are discussed in this post.
A wet sump solution like the gPAN is truly the best option for most owners as it remains street friendly. I cut my engineering teeth at Pontiac Fiero where continuous improvement was part of our daily mission and expectations. In the 90s, I worked with the Japanese OEMs, while working at 3M Automotive, and saw it applied at all areas of their business. From the Japanese I learned that small improvements, done continuously, can have a big impact over time.
The new gPAN2 is an example of a product that we have been able to improve through small design changes. Our latest improvements are horizontal ledges in the side of the pan. The chart above shows oil pressure data measured from two of our Elises(Nirvana & Blue Car). They were equipped with basically the same modifications: Nitron 46mm Triples, Hoosier A6s, SJ Racing wheels, RACEunderAero, titanQR and KATANA265. The Blue Car had our new ULTRAliteLINES vs. stock oil cooler lines in Nirvana, which may account for the slightly higher average oil pressure. The data is from the Lotus Cup events at Laguna Seca in 2010 & 2011, with yours truly doing the driving. We took laps that were close in time and also compared the g loads (over 1g) to insure we were loading the cars equally. The data is shifted a bit as our Start/Stop point were a bit different for each car so the peaks and valleys don't correspond perfectly.
The variation between the two pans is the most striking difference. Both gPANs do a good job with keeping the oil pressure in an acceptable range - the gPAN2 simply controls the variation better. Will this make any difference to wear and tear on the engine? Hard to say as we don't have the ability to test longevity. The engineer in me says that it must be better as it varies less. Though there would be added cost of material and labor for welding the ledges, I felt it would be an improvement worth incorporating. It was also a big enough improvement that a new name was in order. So we put on our creative hats and came up with... gPAN2...8^)
Dry sump development continues in earnest. We took Blue Car to Spring Mtn racetrack two weeks ago to test her. We first ran her on a dyno to insure we had a working solution then made the trek out to SMMP. The oil tank in our solution is a modified tank from Peterson. Ryan spec'd a design and had it built. He wanted to see how well the solution would work so installed a temporary clear top on the tank so we could view the oil in action. The Dailey pump that we choose includes the air separation stage as external oil pumps can add a ton of air into the oil causing foaming. His separator works amazingly well as shown in our video: Tank in action
We recruited our friend Jack to drive the car at the track in 105deg F weather. He ran the car under specific directions from Ryan so we could check various issues. Oil pressure readings were excellent once we determined the correct oil level. The two issues that we experienced were our breather set-up and low hot idle oil pressure. The breather plumbing from our tank was not adequately shielded from the incoming oil under high revs, so too much oil was getting into our catch tank. You can see a bit of this in the video above. We're now making a change to the vent design. The hot idle pressure required that the pump be removed and tweaked by Dailey. The pump was adjusted after we returned and the tank is now getting modified. We should be ready for testing again soon.