Dyno Graph Discussion

[Bender Rodríguez]

I'm just opening this up for opinions but I want to understand some of the concerns in using a larger turbo setup on a track driven car. I’ve never really been into or interested in autocross but I could always understand how drivability could be compromised if once your coming out of a turn or corner your at a lower rpm and the vehicle has little to no power. A large scale turbo with lots of inertia would be a problem, someone with better low end power has a definite advantage. Doing some comparing of dyno graphs of several 2ZZ FI cars, anywhere from typical high power turbo Celicas to various Lotus Supercharger kits. I noticed that at around 3000-3500 rpm is where you start to see gains or equivalent power and torque to the smaller setups. Does anyone have some idea on how low engine speed goes our car goes when doing aggressive cornering? I know that overall using a 4 cylinder overhead cam engine is typically better at higher rpm’s and the gearing should reflect that to some degree. Obviously if it’s around 2,000 rpm there is no way you would ever want to try something that large.

[ace996]

Usually, unless you are using something WAY too large for the application, you're fine whilst on track - you're usually in the upper RPMs so lag is less of a concern. During an autox, however, low-rpm turns are not uncommon and that is the issue and when a smaller turbo (or supercharger) would give faster throttle response/spool.

Good luck,
TomK