Looking to build a show car? Or simply want your engine bay looking the best it can? Here’s our guide to the best engine bay modifications you should make.

Your engine is there to do a job, that’s obvious. You chuck a load of air and fuel in one end, some sort of fiery witchcraft happens inside, power explodes out all over the place, then some smelly gases escape out the back. Simple. But there’s more to it than that, of course. When you lift your bonnet at a show, you don’t want people seeing a dirty mess, or a sea of grey plastic covers. It’s got to look cool under there, alongside the rest of your car modifications. So where do you start? Well, our guide to the best engine modifications is a good place to start.

Ford Focus RS Mk2 engine tuning

Silicone hoses

It makes sense to start this best engine bay modifications guide with an obvious and easily replaceable part, silicone hoses. Engines have a lot of hoses, and they can all end up looking like a dirty pile of spaghetti. So it can really liven up your engine bay to replace all of those tired old rubber pipes with some premium quality silicone hoses.

These are available in a wide variety of colors – even upgrading to a subtle black set will improve the aesthetics no end, or you could choose a bright color to match some other color details across the car, or something to wholly contrast with your paintwork. And they’re not just about the looks either – silicone hoses are designed to take the higher pressures and temperatures of tuned engines, and they’re far less prone to splitting or degrading than standard OEM-fit items. There are off-the-shelf kits and upgrades for loads of different cars from the likes of Samco Sport, Pro Hoses or SFS Performance, or you can get a specialist to make up a bespoke set.

Be sure to check out our guide to silicone hoses for more information. 

Ford Focus ST Mk2 Tuning engine bay modifications

Hydro-dipped covers

Without wanting to sound old and haggard, you used to be able to actually see engines rather than them being covered up with acres of plastic. But you can use this to your advantage with newer cars, and there’s a more elegant solution than simply unbolting and binning the covers. Hydro-dipping opens up a plethora of aesthetic opportunities. This is a process of water transfer printing whereby your engine cover (or battery cover, fuse box cover, and whatever other covers you may find lurking in there) can be reimagined with practically any design.

It’s a simple process whereby a specialist company will smooth and prime the surface, transfer the chosen design, then lacquer it. And the sky’s the limit when it comes to designs – tartan, carbon fiber, movie stars’ faces, flames, skulls, clouds, Rubik’s cubes, Scrabble tiles, it can be literally anything. It also isn’t overly costly, either, making it one of the best engine modifications for the price.

Pure Turbo BMW M4 with engine bay modifications

Strut brace

Technically this is more of a chassis mod than an engine dress-up mod – but when you lift the bonnet, a strut brace will be one of the first things people notice, so it actually combines function with form very effectively.

Strut braces are a supremely smart mod, as they tie the tops of the suspension turrets together to promote improved handling by stiffening everything up. It’s one of those mods that’s directly derived from motorsport, which was then adopted by manufacturers for sporting road cars, and the aftermarket is simply awash with strut brace options. They come in all sorts of finishes, from polished to anodized to powder-coated to carbon; entry-level prices are highly affordable, and they’re very simple to fit. It makes sense on all levels!

Alloy header tank

Upgrading your coolant system’s header tank can be good for a number of reasons. If you’ve got an R53 Mini, for example, the stock plastic header tank sits above the exhaust manifold, which is silly as it splits with the heat and drips on the hot manifold. Steamy! On many a car this upgrade is a good way to ensure the longevity of an otherwise potentially perishable part. But most importantly, alloy header tanks look cool. Tidy little splash of bling for your bay, and a functional bit of future-proofing to boot.

k20 engine in modified fk2

Upgraded caps

You might not pay a lot of attention to your oil filler cap, or the various other caps in your engine bay, but you’d be surprised what a visual difference it makes to upgrade them. There are a couple of different ways you can do this. Firstly, there’s the polished alloy route – there’s a whole bunch of companies on the aftermarket who can sell you shiny polished caps for your engine. Secondly, it’s fun to try a bit of OEM+, by which we mean fitting the parts from a higher model in the group: so if you’ve got a Golf, for example, you could find yourself a set of Lamborghini Gallardo caps. A tasty little easter egg for those in the know.

Dress-up bolt kit

This is one of those engine bay modifications that’s a bit of a no-brainer. Because you know what they say, the devil’s in the detail. If you pop the hood at a show and people can see that all of the tiny detail parts are gleaming, it speaks volumes about your attention to detail throughout the rest of the car. So an engine dress-up bolt kit is a simple and effective way to create a lot of impact. Replacing those rusty old fixings with fresh anodized aluminum bolts and washers will really freshen things up – and once you’ve found yourself elbows-deep in the details, you may well end up going a step further with anodized hose separators, manifold studs, battery tie-downs and all sorts.

screamer pipe on Modified Ford Focus ST Mk2

Exhaust heat wrap

This is a real #becauseracecar mod, and it’s something that’ll look wicked in your engine bay. This is a modification born of pure function, because if you heat-wrap your exhaust manifold, it’ll mean that the system works more efficiently – and the added bonus is that under-bonnet temperatures will be reduced (which can pay dividends if your air intake happens to be nearby!), and any nearby componentry will be exposed to less heat.

There are a number of different types of exhaust heat wrap, including titanium weave and carbon, and you can apply some reflective gold-wrapped glass cloth to nearby areas for extra bling points too. It’ll make your engine look super serious, making it one of the best engine bay modifications.

Billet dipstick

One might argue that you’ve run out of things to modify if you find yourself upgrading your dipstick. After all, it’s just a stick – or so your mum might tell you… although in fact, in an attractively detailed bay, this is yet another opportunity to add a little style and uniqueness. And it’s not as frivolous as it might seem either, it’s actually quite a practical upgrade; dispticks are often either made of plastic or have some manner of plastic element attached to the metal stick, and plastics are prone to degrading in hot environments. It’s really annoying when your dipstick snaps, but a billet one shouldn’t do that.

Engine bay of Sean's AWD Focus ST

Custom rocker cover

This is a mod that’s as old as the concept of modifying itself. It’s fair to say that some engines are naturally more attractive than others, and some came as standard with really cool-looking rocker covers (like the Cosworth YB, for example). And assuming your engine isn’t obscured by plastic shrouds, the rocker cover is basically the first thing you see, it’s the most prominent bit. So how do you zhuzh it up?

Well, there are two key ways to go about it: firstly, you can fancy up your existing rocker cover with some high-temperature paint, a healthy dose of powder-coating, or a thorough buffing up on a polishing wheel. Secondly, you can do a bit of research and see what alternative rocker covers have been offered by aftermarket tuners over the years; this generally applies more to old-school motors, and there are some real gems out there – like the Power Engineering cam covers for the Ford CVH, or the Schrick items for Mk2 Golfs and the like.

clean Modified VW Rabbit Pickup engine bay


You can make a massive improvement without changing a thing. All you need to do is source the right products and apply a bit of elbow grease. It’s a pretty simple process, it just takes some effort: with the engine cool, you remove the plastic covers (they can be cleaned separately), protect any electrical components such as the battery and ECU with plastic bags, then spray everything with degreaser. Give it a good scrub with a synthetic brush, then rinse it off with the hose (double-checking that all the electrics really are fully protected first). Dry it all off with a cloth, replace your freshly cleansed covers, and bosh – one much tidier-looking engine bay.

There’s a wealth of products for this on the aftermarket from all the usual suspects – Meguiar’s, Auto Finesse, AutoGlym, Gunk, Holts, you name it. A clean bay is a happy bay. It also happens to be the easiest, and arguably cheapest of our best engine bay modifications.

Need more advice? Visit our step-by-step guide on how to clean your engine bay