The one thing you've probably missed whilst watching the SSC Tuatara record
You've certainly noticed the top speed it reached, but did you observe how it got there?
I'm almost certain that you've seen the clip of SSC Tuatara reaching an incredible speed of 331mph. Even though it all happened few days ago, it still amazes me, as it is a truly mind-boggling record and an astonishing engineering achievement. If you still haven't seen the clip, here it is. I will be referring to it a lot throughout the article:
Initially, the acceleration was... sluggish
If you watch the speedometer carefully, you will notice that initially the acceleration wasn't that incredible. Getting to 100kph took about 8-9 seconds, which is a lot slower than you would expect from 1700HP engine. 100-200kph? Another 12-13 seconds. Newest BMW M5 Competition can do 0-200kph sprint in about 11 seconds, despite being nearly 50% heavier and having one third of the Tuatara's horsepower. How come it is the Tuatara that holds the top speed record?
VTEC kicked in, yo!
I would like you to pay special attention to this part of the clip. In this part of the video, the Tuatara slowly climbs to 320kph (200mph) and then BOOM! Turbochargers spool up and the car skyrockets past the previous Guinness record. Acceleration from 320kph to 420kph took about 10 seconds, which is shorter then it took the car to accelerate from 100kph to 200kph, despite the exponentially greater air drag at higher speeds. Something does not match up here.
VTEC kicked in so hard even a photographer couldn't take a photo fast enough!
Not giving it the beans
I've googled the actual performance of the Tuatara and the results were massively different. One site claims it can do 100-200kph acceleration in just 2.5 seconds. Another one states it will take the same time to do 0-100kph sprint. If both of the figures are correct, I would mean that 0-200kph acceleration should take about 5 seconds, not over 20 it took in the video. Thus, it is clear to see that the driver didn't gave the car all the beans. This was likely scripted, as the team likely wanted to minimize the risk of something going wrong. 5 seconds is about what we would expect from the four-digit horsepower car, I would even argue that we should expect an even faster time than this, but there might be some limitations to that.
SSC Tuatara - An astonishing showcase of human ingenuity
You can't defy the laws of nature
Tuatara's acceleration is impressive to say the least, but so is the acceleration of BMW M5 Competition. SSC's newest creation is 33% lighter and has nearly 3 times as much horsepower as the M5, yet it can only accelerate twice as fast to 200kph (if both of the aforementioned figures are correct). This is because the car is likely significantly traction limited.
In the simplest terms, acceleration can be limited by one of the two factors: traction and power. If a car has enough traction to accelerate faster, but doesn't have enough power to do so, then the acceleration is power limited. However, if putting more power down is impossible, as the car would start spinning the wheels and losing traction, then the acceleration is traction limited. Acceleration could also be electronically limited to prevent the damage to the internal components of the car, but I will skip over it.
Tuatara is likely traction limited during its initial acceleration. Much heavier and less powerful cars (like some special editions of Ford Mustang, I don't remember exactly which ones) are already traction limited, so you would expect the Tuatara to have the same problem. However, as lack of grip stops being an issue, the Tuatara can show what it is made of and fight off the air resistance with an incredible ease. However, to achieve such results, engineers had to make a crucial decision, which I do not 100% agree with.
The monstrous engine powering this beast
Big turbos - BIG problems
When I heard of the Tuatara's 1700HP engine, I was a bit sceptical. You see, in order to make a lot of power, you need to burn a lot of fuel. To burn a lot of fuel, you must provide the engine with sufficient air supply. To do so, you need to use big turbochargers that will be able to push all of this air into the engine. And big turbochargers require a lot of energy to spool up, which means you will have big turbo lag and a rather sluggish performance at lower RPMs, when turbos aren't spooled up. Basically, Tuatara might have the same problem as 90s supercars, as presented by Jeremy Clarkson on The Grand Tour. And whilst the sudden acceleration in a bit unexpected fashion can be quite thrilling (it is basically why the roller coasters are so fun), it can be quite annoying on the race track and even a bit dangerous.
Everything will likely turn out all right
However, my worries are probably unjustified. SSC has a whole bunch of great engineers that have likely used all of their skills and knowledge to prevent turbo lag from happening. To see whether they've succeeded, we will have to wait until an usual bloke Doug DeMuro reviews the car and gives us the insight about its driving experience. The run itself was organised to beat the top speed record, not to see how quick can the car accelerate to this speed. To see the true acceleration of the Tuatara, we have to wait until SSC smashes 0-400-0 record, currently held by Koenigsegg.
I hope you enjoyed the article. If you did, you can leave a like and read my other articles. Till next time!