The Speed Up Factory is an item upgrade building that allows you to convert your current speed ups into larger speed ups once a certain timer has occurred. It works much the same way the Vault building does with the Gold.
The Speed Up Factory has 10 levels and in order to be upgraded, requires golden stopwatch items which can be found via in-game purchase(s). In order to unlock the Speed Up Factory you will need a Speed Up Factory Blueprint which is found in certain in-game pack purchases.
Conversions per Upgrade level
The amount of speed ups you can earn at one time depends on the level of your Speed Up Factory building. Here is the details of which speed ups you need to put into the Speed Up Factory and the returns you get back.
The Variety of speed ups you can get from the Speed up Factory increases as you upgrade the building. At level 1 you have 2 different options, by the time you reach level 10 you have 8 different options for speed up conversions.
The value of speed ups you can convert also increases as the building is upgraded. At level 1 the highest return you can make is a 30 minute speed up, by level 10 its a 350 day speed up.
The value of speed up that is required in order to convert to a higher value does not change as each level is upgraded.
The Speed Up Factory is an excellent way to turn lower leveled speed ups into larger ones which is valuable when completing researches etc. Picking values to convert to that you will use the most will be of the greatest benefit to growing your base. It is worth noting however that in order to keep converting speeds you will need to first have the required deposit to use which could become a bit more tricky once you want to start using the bigger speed up conversions.
This building is probably the most useful building in your base as it allows you to create a solid flow of speed ups that are relevant to your level of growth (for example: 7 day speed ups every two hours for troop training) Although this building takes items only found currently in packs to upgrade: which means it costs to upgrade, its well worth the investment and is a building every player should look to acquire.