I have forked **`Litcoin 0.8v`** to make my own costomized coin(learning purpose), with some changes in parameters:

    1. Total no of coins to be mined = 270,000,000. 
    2. Block formation time = 15sec. 
    3. Time for halving = 2 years. 
    4. Life span for mining = 20 years. 
    5. Mining reward coins per block for first 2 years = 32.16899445. 
    6. Total no of coins to be mined in first 2 years = 135264187.8669276

Every thing is working ok but blockgeneration time seems to be too slow. Though conformation time of 15 sec is just an avg value but in my case i am getting conformation in every 2 to 3 min which is far beyond expected

*Edit:I have set my difficulty to be as low as possible which is around 0.002 and retargeting time is set to  10 min, but even after of 3 days of minning i got somewhere around 3400 blocks,and also its difficulty is same in every block though i am doing number of transaction within nodes.* 

    {
        "version" : 80705,
        "protocolversion" : 70002,
        "walletversion" : 60000,
        "balance" : 17474.98800000,
        "blocks" : 3407,
        "timeoffset" : 0,
        "connections" : 2,
        "proxy" : "",
        "difficulty" : 0.00024414,
        "testnet" : false,
        "keypoololdest" : 1516853983,
        "keypoolsize" : 102,
        "paytxfee" : 0.00000000,
        "mininput" : 0.00001000,
        "errors" : ""
    }