This is hypothetically speaking of course, in a situation where you must pick, because, if you can upgrade both, better to pick both.
However, if for some reason you’re limited when it comes to engine upgrades, is it best to compensate for its flaws or augment its advantages? Cams seem to add more bhp than forced induction, but they almost don’t add torque. Turbos are more balanced and positive displacement superchargers give more torque than horsepower. Centrifugal superchargers on the other hand actually have good synergy with cams.
Taking the 1999 Viper ACR for example, the amount of torque is truck-like, but way less horsepower than other engines, whereas an S2000 would be the opposite relatively speaking.
The goal here would be for high speed tracks mostly, as I feel an engine that already has big torque when stock would benefit more from the extra oomph at high revs.
Going for the turbo/supercharger would be your first priority over any other upgrade. cams actually come last on my list of priorities, which you can view here https://forums.forza.net/turn10_postsm698511_HOON-tunes--Updated-OP-and-tuning-tutorial-post--20.aspx#post_698511
One thing I will say that isn’t in the tutorial yet is the centrifugal supercharger may actually be the best option because of where the torque is distributed in the curve. It gives max torque at a much higher rpm than anything else, putting it in the rpm range you actually use in racing. More car specific testing is needed to see if the PI difference is better used elsewhere in the tune or not.
Sometimes I make naturally aspirated cars just for fun (M3 E30 for example), but usually when going turbo I follow your guide and save cams for last. I was building a turbo Viper ACR and I verified that the extra bhp from the cams did not have that much of an impact in performance, but then I wasn’t using the most competitive parts either.
Another thing I’ve seen is that cams may boost power by increasing the rev limiter but sometimes the rev limiter is moved to a range where the engine has already begun to lose power, forcing me to short shift. This makes the cams not so interesting as an upgrade IMO, precisely because there’s no numeric data on the max power and torque range (only the graph, which I don’t find very accurate).
Displacement charger isn’t very competitive, then? It’s heavy and boosts torque more than horsepower, so…
displacement supercharger is plenty competitive in most cars. Its the ones that you have trouble upgrading other parts of the tune because you run into the PI limit. I generally try to increase torque just as much as HP because that’s what you tune the gear ratios with, not HP. I find more torque helps acceleration, while top speed is more dependent on HP.
You want the best useable powerband through a corner to prevent unessecary mid corner shifts. Cams usually make the powerband peak longer and become more predictable. Short burst of acceleration are no good through corners.
