Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere. * Colin Chapman
Having decided on a Caterham 7, there are still many decisions to make before purchasing.
The first decision is which base model to select. There are five Caterham 7 base models to choose from. In 2019, these were the 270, 310, 360, 420, and 620. The numbers roughly correspond to the horsepower per metric ton of weight. For comparison, a 2019 Mazda Miata MX-5 has 181 horsepower and weighs 2,337 pounds (or 1.06004 metric tons). This is about 170 horsepower per metric ton, and would correspond to something like a Caterham 170.
Each model is designed around a specific use; the 270 and 310 are mostly for leisure driving with some track racing. The 360 is about in the middle. It\'s at the upper end for power, useful when just driving around, but it\'s not specialized for track racing. The 420 and 620 are designed for more serious racers and are a bit much for the average leisure car.
Of course, with each model increase, the base price increases. After considering what I would be using this car for, and my budget, I decided on either the 270, 310, or 360. The 270 is the entry-level Caterham and comes with a Ford 1.6 Litre Sigma engine. The 310 has the same Sigma engine as the 270 but includes some upgrades to increase performance. The 360 has a Ford 2 Litre Duratec engine.
Since this car will mostly be used for driving around on weekends, and with a limited budget, I narrowed it down to either the 270 and the 310. As both of these cars have similar performance and similar specs, I decided to go with the 270. It was the cheaper of the two, and it is supposed to be a project car - if I want more performance, I can upgrade the engine myself.
If budget was not a consideration, the 360 would have been my pick!
The next big decision was which chassis to buy. The 270 comes in two sizes of chassis - a Standard and SV (large). The advantage of the SV chassis is that it is four inches wider and six inches longer. And it has a wider pedal box, which would be nice for my wide feet. But it costs $3,200 more.
Since everybody who will be driving the car frequently will be able to fit in the standard chassis, that was what I chose. The extra space that the SV offers would have been nice, but not worth the 3,200 extra dollars.
The next few decisions relate to driving performance.
My first performance-related decision was whether or not to get a limited slip differential. A limited slip differential prevents power from being transferred to a wheel that has lost traction. This would be helpful on the track as to keep both the wheels with power around tight turns where the inside wheel has less traction. Since I wouldn\'t be driving on the track frequently or seriously, I decided to save money and skip the limited slip differential. If lack of a limited slip differential turns out to be a problem, I can always add an aftermarket limited slip differential.
My second performance-related decision was whether or not to get the rear anti-roll bar (i.e anti-sway bar). This helps keep the car level and increases traction around turns. Since I plan on doing lots of driving up canyons, the extra traction may be helpful. And because the anti-roll bar is not too expensive, I decided to get it.
The last performance-related decision was whether to upgrade to the Trackday Roll Bar. This replaces the standard roll bar with a taller and stronger roll bar. I decided to spend the extra money to have a taller, safer roll bar in the Caterham.
The next set of decisions relate to cosmetic and ease of use items.
First, I had to decide between the four point harness or the standard three point seat belt. If this car is built to be used in canyons with tight turns, then it would be nice to not slide around as much. So I decided to upgrade to the four point harness.
Second, I had to decide whether or not to get the side screen armrests. These are attached on the door to act as half doors/armrests. This decision was made purely for comfort for the driver and passenger. They were not too expensive, so I decided to get them.
The third decision was if I should add the half hood. Since rain in the Colorado mountains is intermittent and hard to predict, I decided that having something I could quickly put up to keep a light drizzle out of the car would be perfect. I decided to get the half hood.
After all the performance and cosmetic options, there was still one major decision: the color.
Caterham offers a large selection of colors ranging from standard to exclusive. After much debate and polls from friends and family. I decided on an Arancio Argos with black 270 with black triple stripes and black pinstripes.