https://github.com/bitcoincandyofficial/bitcoincandy/blob/master/src/pow.cpp

cdy need to change follow function :
LwmaCalculateNextWorkRequired


// Keep t reasonable in case strange solvetimes occurred.
if (sum_time < N * N * T / 20) {
    sum_time = N * N * T / 20;
}

to

// Keep t reasonable in case strange solvetimes occurred.
if (sum_time < N * N * T / 200) {
    sum_time = N * N * T / 200;
}

You can change 200 to 500~600. It will make block time 2 minute faster under hash pumpping.
If cdy change upper function, it reduce block time flucuation.  Check my blog :
https://steemit.com/cdy/@bluejaytodd/18-5-1


581683block  9:17
581646block  9:08   8.2 faster block time

581645block 8:08
581624block 7:53    2.8 faster block time

581623block 7:21
581567block 7:12    12.4 faster block time