Dyno Sorcery: how less total power can make for a faster car
If you've seen the latest episode, where the 180SX hits the Haltech dyno (CLICK HERE) then you will have heard Tuning Fork talk about why peak power isn't as important as having a good amount of llamathrusts "under the curve". We don't want to harsh anyone's vibe, so here is your MAHOOSIVE SPOILER ALERT!!11onejuan
When it comes to race cars, peak power is very important. If you're new to dyno-babble, "peak power" is the maximum power a car can produce at or near the top of the rev-range in a gear.
However, street cars don't actually spend much time at that magical point; you're more likely to be lower in the RPM range as you accelerate the car towards peak-RPM. This is where the fabled "mid-range" power is important, as you climb from low-RPM through the middle part of the car's powerband, into the screaming top-end.
You'll hear many experts, like Tuning Fork, talk about steep power curves (sometimes referred to as "ski jumps") and this relates to cars which have all their power hit suddenly like a blow from a hammer. In several hundred RPM they can go from slugs to like someone lit the afterburner!
Instead, what you want in a street car is a nice, gradual power curve that won't bomb tyres or be too difficult or unpredictable to drive. This way you always have a good amount of power available, no matter what gear you're in, and this is important when you want to go for a drive in the twisties or have some fun on track.
Y'know those SPOILER ALERTS I mentioned? Well that big, fat spoiler is below so WATCH THE NEW EP HERE before reading any further. Otherwise, you'll see MOOG's museum-piece 180SX is tuned for serious fun.
That green line is the powerband, and it shows that MOOG's SR20 is making most of its power early in the rev-range - simply put it makes a decent chunk of power over a lot of RPM. That green curve is the line of llamathrusts and everything underneath it is their skiddy paddock they prance around in.
This green curve makes MOOG's 180 a fast car, because of how wide the overall powerband is. A much bigger turbo will result in more power but in a much narrower powerband, as the power comes on much higher up and is then cut-short by the mechanical limitations of a 2.0-litre four-cylinder and the SR20's valvetrain.
Think about it like this: MOOG can jump on his 180's accelerator above 2500rpm and have a good slice of power to hand, whereas the more outright powerful car would have to get to that narrow RPM window and build its boost.
So, while the Internet loves to froth over million-kilowatt street cars, the best ones to drive are actually the ones with the nice, gradual curves.
