In The Race For Off-Track Vehicle Development, BimmerWorld Shifts Into High Gear SPEED Touring Car team takes the engineering lead; gets closer to bringing the new BMW 325i to victory circle. Building, preparing, and running a racing car...
In The Race For Off-Track Vehicle Development, BimmerWorld Shifts Into High Gear
SPEED Touring Car team takes the engineering lead; gets closer to bringing the new BMW 325i to victory circle.
Building, preparing, and running a racing car in a professional series is a never ending process of clawing and scratching for ways to improve that car. The rapid pace of development and improvement for teams within the SCCA SPEED World Challenge series is no different.
BimmerWorld Racing of Dublin, Virginia faces the unique challenge of not only having to keep pace with their factory-backed rivals in the SPEED Touring Car series, but are also challenged to lead the charge to extract and engineer the maximum performance from their unique new generation BMW 325i racers.
While the older BMW 3-series E46 chassis is still a popular car to race, BimmerWorld chose a familiar path for the company, opting to build, develop, and race the new BMW E90 chassis in-house.
The BimmerWorld E90's racers debuted in 2006, and despite them showing a lot of potential in the hands of driver Seth Thomas and BimmerWorld owner/driver James Clay, the entire team understood it would take some time for all of E90's potential to be realized. With a number of starts from the top-5 in 2007, and a best finish of 5th, it's clear that the development path to deliver the E90 to victory circle is getting clearer race by race.
To catch us up on where BimmerWorld has led the E90 racing development path from the end of the 2006 season through the last race at Toronto, James Clay opened the doors to discuss some of the unique mechanical attributes and innovations his BimmerWorld crew and partners have employed to date.
James--can you walk us through the major mechanical, drivetrain, and engineering updates to the BimmerWorld E90's going into the first race of the 2007 season at Sebring?
"Weight was one big focus. We did a lot of work in that area over the winter. It's amazing -- we put more than 400 hours of labor into each E90 shell when we first built the cars, focusing intensely on weight reduction. This past winter, we still somehow managed to pull out another 50 pounds. All of our E90's now easily meet the mandated minimum weight.
"The next concentration was on the suspension geometry. With a little help from BMW Motorsport, we corrected some issues induced by lowering the stock E90 suspension more than four inches. From this, and most importantly, the rear of the car now handles and works the way we want it to, and uses reasonable spring rates so we have some compliance to get us out of the turns quickly.
"Another focus was the driveline and gearing. We switched transmissions to a BMW Motorsport H-pattern 'dogbox.' This box gives us better gear selection and quicker shifts - an upshift now takes a little over a tenth of a second. We had a bit of a learning curve with the new transmission; compared to the stellar race starts we've had in previous years with the old 'box, it's taken a bit of experience to get the same great launches with the new unit. Diffsonline also came through with a new limited-slip differential carrier assembly that is very smooth and easy to modulate. It's really helped us to improve and focus on our rolling speed through the corners."
What was developed after Sebring in the two month gap between races?
"We really didn't have a lot of development work to do in this stretch. We were super busy over the winter and it was nice to just relax a little and catch our breath! We were still doing some fine-tuning on the driveline, but really, the cars were fast and ready to race. Our BimmerWorld crew members work incredibly hard--it's important to keep pushing to improve the cars, but it's also important to pause every now and then, review what can be done better, and charge your batteries to make the next steps in development.
"Racecar development runs in a cycle--first you conceive an idea or ideas in our case, fabricate and implement those changes on the cars, test those ideas on the track, and based upon the results of those tests, be it in a race or on a private test day, you develop a list of new developments to pursue, and a list of improvements or tweaks to the development items you just tested. It's a never ending process, but one we welcome and love.
With a lot of new parts and pieces on the cars, we decided that more track testing was the best development focus for us after Sebring--we were able to get some additional testing in at Road Atlanta, as well as Watkins Glen and a day in Reno to refine the setups, learn more about the chassis, and prepare us for the rest of the races in the season."
BimmerWorld then hit upon a busy patch of races at Miller Motorsports Park in Utah, Lime Rock in Connecticut, a double event at Watkins Glen in New York, and then in Toronto last weekend. How have the E90's developed over this five week span?
"Well...to put it gently, we were able to find the weak links in the cars. Since our first Watkins Glen outing in testing, we've had an engine oiling issue arise. We saw the problem very lightly last year and thought some changes to the bottom end had resolved the issue, at Watkins Glen last month we were right back where we started. The up-and-down nature of the track is unique, and exposed the oil feed issue like we hadn't seen at the other tracks this year.
"In this short time period, we've gone through several iterations of oil pumps and pans. BMW has a very crafty variable pressure pump that is great for the complex N54 engine in normal use, but it means a long recovery delay to the oil pressure if or when pressure drops.
"After re-engineering this, we were left trying to keep oil in the pickup. We added Accusumps, which also added weight to the car. We then added more and more baffles, and trap doors were then added to the stock steel pans. Then we finally went to a larger sump aluminum pan for Toronto with extensions, about 6 baffles, and several more trapdoors. The result still left us low on oil pressure."
Toronto last weekend was obviously a frustrating one for you--you've mentioned some big improvements for the upcoming Mid-Ohio round that should hopefully stem the oiling issues that knocked you out of Toronto. What are those changes, and I also hear a rumor that those developments will be carried out in a new E90 chassis?
"It's amazing. A wet sump system may not be the best oiling system, but it can usually be made to be functional. In the SPEED Touring Car E90's, and after multiple engine issues and an aggressive development program (which unfortunately, must be conducted on-track with realistic G loads) we are choosing to abandon the wet sump oiling configuration. The wet sump is simply not supplying the oil the E90's engine needs at all times and under any running condition. It's time for something different.
"We are going to implement a dry-sump system which will provide a constant supply of oil to the engine. I feel that at this point without a dry sump, we are really gambling on whether or not our engines will last; with the dry sump, we hope to have bulletproof engine reliability. We've taken the wet sump development as far as it can go in our E90's, so it's on to something new and improved for Mid-Ohio and beyond.
"With only 8 shop days between races this time, we are very rushed to make this unplanned change. I had hoped to be in a new E90 chassis we've been building to debut at Mid Ohio, but there simply is not time to make the modifications required on all three cars."
What can we expect from James Clay and BimmerWorld as the season moves toward the finish line?
"We have a new driver that has signed onto the team for the remainder of the season. Since I am not in the points battle this year, I will have to watch from the sidelines until after Mid-Ohio when the new dry sump will be installed in my new chassis. It's a one-race hiatus for me, but in my role as team owner and team manager, I have to put my energies into getting our new dry sump configuration implemented and sorted out immediately. With that done, and my new car done, we're looking to aggressively attacking the last three races with a VERY formidable three car BMW E90 team."
With the announcement of BimmerWorld's new driver early next week, the team's plans for the rest of 2007 will be even more clear: to unleash the winning potential of the BimmerWorld E90's with the best crew and drivers possible.