Sync two SQL Server database
As you plan to update location Y, you should consider merge replication but it isn't simply a case of turning it on and you may need to make some changes to your DB or application. 

You do have other options.


Reduce database chatter. Minimise the number of calls to the database to reduce the impact of latency. If you're talking between London and Hong Kong, you'll pick up 250ms of latency with each packet (round trip). Four packet would accumulate 1 second of latency, so batch your queries up and use stored procedures to reduce the overall size of your queries.
Split reads and writes. The reads could talk to the local DB (Y) and the writes sent back to the master (X). This could enable you to use AlwaysOn Availability Groups, Log Shipping or other forms of replication like Snapshot and Transactional.
WAN optimization. Most firewalls have a WAN optimiser option (usually a bolt on). This would compress the traffic, reducing the latency of larger payloads. Or look at Windows Server BranchCache.