DAYTONA BEACH, Fla. -- NASCAR's attempt to eliminate tandem racing for the season-opening Daytona 500 remains a work in progress.
The governing body made five changes to the cars prior to Thursday's first day of a three-day test session, made one more involving in-car radio communication before the morning session and then changed three more things on the car following the afternoon session.
The morning change mandated that drivers and spotters will not be allowed to communicate with other drivers over their in-car radios with the hope it will be more difficult for teams to work together.
After the afternoon session in which some teams ran in pairs, NASCAR told crew chiefs they were enlarging the restrictor plate by 15/16ths of an inch, reducing the cooling pressure by five pounds and closing the front grill by one inch on each side.
Sprint Cup series director John Darby said the changes were made after cars were able to stay locked nose to rear bumper for as many as two laps without swapping and offset for as many as eight laps.
The hope is to increase the likelihood of cars overheating when paired, and increase speeds to the point where drivers will feel more in control in large packs than in pairs.
Darby said teams will be asked to try pack racing in the Friday afternoon session to see if the changes work.
Dale Earnhardt Jr., who was skeptical that changes made before Thursday would fix the two-car phenomenon, was even more skeptical after the afternoon session.
"Nothing's changed,'' he said. "I don't know what they need to do. The changes were a good effort. They're not really affecting it as much as I thought they would. I thought it would be a little different. Sorry.''
Changes implemented for this test were:
" Radiators reduced from a five-gallon capacity to two.
" The overflow tank shrunk to a capacity of half a gallon.
" The radiator inlet moved closer to the front center bumper area.
" Springs made softer.
" The rear spoiler shortened.
" The restrictor plate made 1/64th of an inch larger.
The changes made overheating more of an issue, but drivers worked around that by pushing offset more and swapping positions more.
"There's a tool there now that the drivers have learned that they'll never unlearn it,'' Darby said.
AJ Allmendinger said his water pressure heated to the danger level of 240 degrees after one lap of pushing nose to tail, but said with the offset he and new Penske Racing teammate Brad Keselowski could stay together for three to five laps.
"We're still going to push,'' Allmendinger said.
Carl Edwards expects Friday's pack session to be "wild.''
"At the end of the day, NASCAR walks a fine line, I believe they do, of making the cars hard enough to drive that they're not in a giant dangerous pack,'' Edwards said. "They've got to make then hard enough to drive so when we drive in the corners we aren't sure what the cars are going to do.
"And they don't want to make it so hard that one guy runs away from the field and it's no exciting for the fans.''
All the changes have come because a large number of fans, according to DIS surveys, have become increasingly unhappy with the tandem racing.
"The situation of running two-, three- and four-wide is wild enough,'' Bowyer said. "I don't understand making the cars not handling good to make it a better race.''
The communication change was made for all races, not just restrictor plate events where some drivers had the capability to communicate with more than 20 other teams.
The communication allowed spotters and drivers to coordinate what cars would pair up and to help drivers switch from the pusher to the "pushee."
By eliminating the communication NASCAR hopes teams will have a tougher time making deals and staying in pairs. The driver pushing especially needs that communication because he has little to no visibility.
It was so refined that one spotter would communicate for both drivers even if one of the drivers wasn't with his organization.
Teams already were trying to find ways around that with hand signals.
"If I had to guess,'' Earnhardt said, "I'd guess (the Daytona 500) is going to look like last year's race.''
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org