Or did you mean to sell the AUG call and buy the SEP call?
Yeah, typically on a Long Calendar Call Spread you sell the close to expiration call and buy the further call. However, note that typically those Calls have the same strike, which means it's most suitable for stocks whose prices you expect to remain stable. What Acmykguy's talking about is a mix of strike prices and expirations. So, you get some of the Bull Call Spread behavior (limited risk and limited upside) and some of the Calendar Spread behavior. That might work for TSLA, but it's pretty darn complicated, and I don't see Tesla as the kind of stock you invest in to make some money off of Time Value.
With both spreads, if you think the stock is going to shoot up, you simply buy back the sold call and then you have a purchased call with unlimited upside. However, to really profit from that, you need to make that decision when the stock dips because that's when the sold call can be bought back for less than you sold it for. Thats exactly the opposite of what your instinct will tell you to do, so it'll take guts. If you wait until the stock starts to rise before buying back the call, you'll pay more to buy it back than you sold it for, in which case you'd have been better off only buying a call in the first place.
EDIT: Just a note to those not familiar with a Bull Call Spread. It's roughly equivalent to buying the stock and then selling a Covered Call. Selling Covered Calls are considered a "safe" strategy since you can only lose money you've already spent (no margin calls). With the Bull Call Spread you've spent less money than if you were to buy shares, so it's even less risky. With Tesla pushing all time highs and some people having fear of it dropping below $100 (or lower), then a BCS will let you enjoy some run up from here without the risk of the stock tanking to half it's current value.