I’m going to take a moment to deviate a bit from the turbo sizing as Project Evo X is a good example of how to do a quick and dirty power estimation for an engine based on boost pressure. It’s really quite simple; multiply the horsepower of the engine if it were naturally aspirated by the boost pressure ratio. For example, my old Nissan SE-R put down about 140whp naturally aspirated with bolt-ons and a tune. I dyno’d the car with a T25 turbo at 7.5psi and it made 215whp. So, the math to determine the pressure ratio is (boost gauge pressure + ambient pressure)/ambient pressure. 14.7psi is the ambient air pressure at sea level. So, on my SE-R, the PR was (7.5 + 14.7)/14.7 = 1.51. So I take that PR and multiply it by the horsepower the car made naturally aspirated, 140whp x 1.51 = 211whp. Pretty gosh darn close to the 215whp and really within uncertainty.
Now let’s look at Project Evo X again. With most of the bolt-ons with the stock turbo at 7000rpm and ~16psi, the car made about 310whp. So that is about a pressure ratio of 2.09 which means the car would make about 148whp naturally aspirated. With all the bolt-ons and the bigger turbo, the car is running ~23psi of boost at 7000rpm making about 375whp or so. (23 +14.7)/ 14.7 x 148whp = 380whp. Pretty darn close again. So that’s how you do a back of the envelope calculation on how much power an engine will make. This does assume a similar state of tune and modification (so intake, exhaust, similar fuel, etc) and similar volumetric efficiency which requires proper turbo sizing. It is by no means perfect but it gets you in the right ballpark.
For an example of a drag car dyno chart, you’ll have to look elsewhere. Sorry, we don’t have any drag cars in the MotoIQ stable.