* Nikkei rises 3 pct, adding to Wednesday's 3 pct rise
* Data sparks optimism about US economy, autos race ahead
* Elpida surges, Taiwan Memory may take stake
By Rika Otsuka
TOKYO, April 2 (Reuters) - Japan's Nikkei average climbed 3 percent on Thursday, adding to its hefty gains the previous day, as exporters such as Sony Corp <6758.T> climbed on growing optimism about the U.S. economy and a weaker yen. Toyota Motor Corp <7203.T> and other carmakers rallied after U.S. auto sales data for March met or beat Wall Street's dismal expectations, sending a bit of light into the sector. [
]U.S. stocks climbed broadly on Wednesday as factory and home sales data raised hopes the economic downturn is moderating. [
]"Investors are feeling some relief about the U.S. economy as signs that the worst may be over have started to appear in the housing and auto sectors, which have been struggling the most," said Masayoshi Yano, senior market analyst at Meiwa Securities.
The benchmark Nikkei <
> gained 251.58 points to 8,603.49 a day after it jumped 3 percent.The broader Topix advanced 3.2 percent to 819.52.
The dollar edged up 0.3 percent against the yen to 98.80 yen <JPY=> on Thursday.
Big exporters such as electronics companies and automakers have made business plans for the January-March quarter based on estimated dollar/yen exchange rates around 90 yen.
They may be more profitable than they expected if the yen stays weaker than that.
"Both the stock market and corporate earnings have likely hit their bottom," saidSohichi Yamazaki, chief analyst at Fukoku Capital Management.
"On the other hand, uncertainty remains over how much further the market could rise because Japan's economy is not yet strong enough to justify more stock gains."
The Nikkei has surged since hitting a 26-year closing low just above the 7,000 level in early March.
Market players said the Nikkei may stay near 8,500 in the afternoon on caution about the outcome of a gathering in London of leaders of the Group of 20 developed and developing nations.
ELPIDA, AUTOS EXTEND RALLY
Elpida Memory Inc <6665.T> surged nearly 13 percent after the world's No. 3 DRAM chip maker said on Thursday it was thinking about letting new partner Taiwan Memory Co buy about a 10 percent stake in it. [
]Shares in the auto sector shot up across the board, boosting the market. Toyota Motor rose 5.8 percent to 3,460 yen, gaining 10.9 percent in two days.
Honda Motor Co <7267.T> was up 8.9 percent to 2,690 yen, and Nissan Motor Co <7201.T> climbed 9.6 percent to 422 yen.
Other exporters advanced, with electronics giant Sony rising 8.7 percent to 2,310 yen and electronic device and office equipment maker Kyocera climbing 2.6 percent to 6,760 yen. (Reporting by Rika Otsuka; Editing by Hugh Lawson)