The World Rally Championship leaders will be battling on unfamiliar terrain as the competition returns to Turkey after an eight year break.
"The Rally of Turkey is a leap into the unknown for everyone," said Thierry Neuville, the championship leader who drives for Hyundai.
The Belgian, and his closest rivals Sebastian Ogier and Ott Tanak, will battle over open roads and rocky tracks on which none of them has ever driven.
Frenchman Ogier finished fourth the last time the Turkish rally was run in 2010, but this edition will be based, for the first time, around Marmaris at the southwest corner of Turkey. It is the 10th of the 13 legs is this year's championship.
"This is the first completely new event for a long time and, even though I contested the rally in 2010, (the) event will be completely different," Ogier, of M-Sport Ford, told his team's web site.
Teams have tried to prepare by practising on similar roads in Portugal, Greece and the south of France, but they are still unsure of how to set up their cars and choose tyres.
"We do not know much about the stages, even though we've watched some videos," Neuville said.
The Belgian, who, along with co-driver Nicolas Gilsoul, has extended his contract with Hyundai until the end of 2021, said "our focus is on completing this current season in the strongest way possible."
The jarring terrain and temperatures over 35 celsius could shake up the field.
"No one really knows what to expect," said Ogier a the five-time world champion, who is 23 points behind Neuville.
"The loose gravel will make it a challenge. We'll be the second car on the road and there will be a lot of fast drivers benefiting from a cleaner and faster road behind," Ogier told his team's web site.
Tanak (Toyota), the winner of the last two rallies in Finland and Germany, is third, 36 points behind Neuville.
"It is difficult to have any expectations for Turkey as we don't have a lot of know-how about the rally," the Estonian said on his team's site. "Everybody is talking about it being a rough event. We certainly know that it will be hot."
The rally starts Thursday evening with a stage round the seaside resort of Marmaris before heading inland into rougher terrain and higher temperatures.
On both Friday and Saturday, the cars will drive twice round three-stage loops. Both days include two stages more than 30km long which will test car management. The rally returns to Marmaris on Sunday where it ends with a power stage.
The Rally of Turkey was first run in 2000. It joined the WRC calendar in 2003, when Spaniard Carlos Sainz (Citroen) won in Kemer, near Antalya. It was last run in 2010, when it was held closer to Istanbul.