Track Day Prep: Carbon Fibre Upgrades That Save Real Weight
There's a saying that gets thrown around in motorsport circles: "adding power makes you faster on the straights, but losing weight makes you faster everywhere." It's one of those lines that sounds like a bumper sticker, but it also happens to be true. Every kilo you strip off your car improves acceleration, braking, cornering, and even tyre life. If you're prepping for a track day or just want your car to feel sharper on a weekend blast through the hills, weight is the first thing worth thinking about.
But here's the thing. Not every carbon fibre part saves meaningful weight. Some of them are primarily cosmetic, and there's nothing wrong with that, but you should know the difference before you start spending money with performance as your main goal.
Why Weight Matters More Than You Think
Let's put some numbers on it. A typical mid-size performance car like a Kia Stinger GT or a BMW F80 M3 weighs somewhere between 1,600 and 1,900 kg. Dropping even 10 to 15 kg doesn't sound like much on paper, but that weight reduction compounds across every single corner, every braking zone, and every exit. Your suspension works less hard. Your brakes run cooler. Your tyres last longer. It all adds up over a full session.
The reason carbon fibre is the go-to material for weight saving is simple: it's dramatically lighter than the steel and plastic it replaces, while being just as strong or stronger. A well made carbon fibre panel can weigh 60 to 70 percent less than its factory equivalent. That's not a marginal gain, that's a serious difference.
The Big Wins: Where Carbon Fibre Saves the Most Weight
If performance is your priority, you want to focus on the largest panels first. Bonnets, boot lids, and roof panels offer the biggest weight savings per part because they replace large, heavy factory panels. A carbon fibre bonnet alone can save 10 to 15 kg depending on the vehicle, and because it's high up on the car, that weight loss also lowers your centre of gravity slightly.
Engine covers are a bit of a nuanced one. If pure weight saving is all you care about, the most efficient move is to just remove the factory engine cover entirely and not replace it. That costs nothing and drops a kilo or two straight away. But most people want something under the bonnet that still looks good, especially if they're popping the hood at meets or in the pits between sessions. A genuine carbon fibre engine cover gives you the best of both worlds, lighter than the factory plastic while looking substantially better. We carry them for the BMW F80 M3 and F82/F83 M4 as well as the VW Golf MK7 GTI and Golf R, both currently on sale.
Spoilers and aero pieces are worth considering too, though the weight saving is more modest. The real value there is aerodynamic. A properly designed rear spoiler adds downforce at speed, which means more grip through high speed corners. Our carbon fibre rear spoiler for the Kia Stinger GT weighs noticeably less than aftermarket alternatives made from ABS plastic or fibreglass, and it actually does something useful above 100 km/h.
The Honest Truth About Smaller Parts
Mirror covers, grille trims, fender vents, shifter surrounds: these are all genuine carbon fibre parts and they're built to the same standard as the bigger pieces. But I'd be lying if I said they save significant weight on their own. A pair of mirror covers might save 100 to 200 grams. A grille trim, maybe a few hundred grams at most.
Does that mean they're pointless for a track car? Not at all. Every gram counts if you're serious about it, and these parts add up when you combine several of them. But more importantly, they replace factory parts that can fade, crack, or look tired after a few years of sun and stone chips. If you've already done the big weight saving mods and you want to keep going, the smaller pieces are a natural next step.
I deal with this question every week. Someone building a track Stinger or a Golf R asks me where to start. My answer is always the same: start with the parts that replace the heaviest factory pieces, then work your way down to the detail items once the big gains are locked in.
Material Quality Matters on Track
This is where a lot of people get caught out. Cheap carbon fibre parts, the kind you find for suspiciously low prices on certain marketplaces, are often not real carbon fibre at all. They might be fibreglass with a carbon fibre vinyl wrap, or ABS plastic with a hydro dipped pattern. On the street, you might get away with it for a while. On track, where temperatures are higher and forces are greater, those parts can warp, delaminate, or crack.
If you're not sure how to spot the difference, we wrote a detailed guide on how to tell real carbon fibre from fake that's worth reading before you buy from anyone. The short version: look for visible weave depth, proper clear coat, and consistent layup quality. If the seller can't tell you whether it's wet layup or dry carbon, that's a red flag.
Speaking of which, we also covered the differences between dry carbon and wet layup carbon fibre in a recent post. If you're chasing every last gram for competition use, dry carbon is the lighter option, but wet layup with vacuum bagging and heat curing still produces excellent results for the vast majority of track day enthusiasts.
A Practical Upgrade Order for Track Days
If I were building a track day car on a budget and purely chasing weight, here's the order I'd personally upgrade in:
- Bonnet, boot lid, and roof panel. These are the biggest wins by far. A carbon fibre bonnet alone can knock 10 to 15 kg off the car, and a boot lid is usually good for another 5 to 10 kg. If you can only afford one upgrade, this is where your money should go.
- Aero pieces like a rear spoiler or front splitter canards. The weight saving is more modest here, but you get a double benefit: less mass plus genuine aerodynamic improvement at speed.
- Engine cover. As I mentioned above, you could just remove the factory one entirely for a free weight saving. But if you want it to look right, a carbon fibre replacement is lighter than stock and far better looking. Quick swap, no drama.
- Exterior and interior trim like grille surrounds, fender vents, mirror covers, and shifter surrounds. Individually the savings are small, but they add up across the car and they resist heat and wear better than factory plastic under hard driving.
We don't carry bonnets or boot lids at the moment, but that's coming. Right now we focus on the pieces further down this list, and I'd rather be upfront about the upgrade order than pretend engine covers and trim are where the biggest gains live. They're still worthwhile, just not where you start if weight is your only metric.
The exact order depends on your car and what parts are available for it. If you want to see what's in stock for your specific vehicle, the shop by vehicle page is the easiest way to browse.
Don't Forget Maintenance
Carbon fibre is tough, but it's not invincible. Track days mean higher temperatures, more road debris, and harder driving. If your carbon fibre parts have a proper UV-resistant clear coat, they'll handle it fine. But you should still clean them properly after each event and keep an eye out for stone chips that could expose the raw fibre underneath. We put together a guide on how to care for carbon fibre car parts that covers everything from washing technique to long term protection.
The Bottom Line
Carbon fibre upgrades are one of the most effective ways to shed weight from a performance car, but not all parts are equal when it comes to the numbers on the scale. Focus on the big panels first, make sure you're buying genuine carbon fibre that can handle the demands of track use, and then fill in the details as your budget allows. The cumulative effect of several quality carbon fibre parts across your car is more than the sum of its parts, both in terms of weight and the way the car feels to drive.
Browse the full range at RB Innovations, or get in touch if you've got questions about which parts suit your build.