Everyone makes mistakes when car tuning now and again, and perfectly good cars can be ruined by small mistakes. So to help prevent these, here’s our essential guide to what NOT to do when tuning…

  1. DOING THINGS IN THE WRONG ORDER
    Doing things in the wrong order can be divided into two categories: ones that look bad, and ones that will hurt your wallet. Fitting bigger wheels without first lowering the suspension looks ridiculous – often worse than standard. And buying skinny wheels then fitting your wide body kit is both stupid looking and expensive to sort. Engine tuning is where doing stuff in the wrong order can really hurt you though, and this can range from doubling your already expensive labour costs, to buying an expensive part then deciding you want more power than it is capable of. Plan upgrades carefully.
  2. SILLY MISTAKES WHEN PUTTING THE CAR BACK TOGETHER
    You could have made all the best choices possible when tuning your car, but you are still at the mercy of the stupidity of whoever has re-assembled the car. When doing something, especially with the anticipation of trying out your new parts, it’s all too easy for something to go wrong. From huge fuel and oil leaks, to driving down the road without your wheel nuts done up, it’s all easily done and can be pretty terminal, so double and triple check everything once you have finished tuning!
  3. WRONG BRAKE PAD COMPOUND
    Most aftermarket brake pad manufacturers sell various compound pads ranging from fast road to full race use. And just like most car parts, going for the most hardcore choice is rarely the best plan. Heavy cars and hard used track cars can justify full race pads as they need to cope with the heat that would destroy normal fast road pads, but for your average tuned road car is best off with fast road pads as more hardcore pads do next to nothing until they are hot, something that may never happen on the majority of road drives.
  4. STRIPPING YOUR CAR TOO MUCH
    Lightening your car is a great way of increasing performance for very little money. But doing it then remembering you need to take the missus shopping and the kids to school is not a wise move. Removing the heater/blower setup seems a good idea in the summer, but come winter it’s a living nightmare, and if your car is a daily, the extra noise created by stripping will piss you off in no time. On a weekend warrior or track car, rip out as much as you like, but on a normal road car, don’t go too far or you may regret it. Especially when it comes to reselling, so keep all those stripped off parts somewhere safe!
  5. PASSING THE WEAK POINT AROUND
    Spending a fortune fixing a weak point on your car usually just sends the problem elsewhere, so be careful. A weak clutch might just be masking a weak gearbox, which could be hiding a weak diff, which could be hiding weak driveshafts, and so on. Do some research, as especially with 4WD cars it can be a slippery and expensive slope…
  6. TRENDING CAR PARTS
    Tacky parts are everywhere and many people don’t realise how stupid they look. Most tacky “mods” were cool for a few weeks, but those few weeks were usually a decade ago. But somehow these things still sell well. It’s bad enough when fitted to a rubbish car, but some good cars are ruined by Lambo-style doors, chrome spinners, and a skull-headed mermaid airbrushed on the bonnet. If an upgrade doesn’t enhance the performance or the look of a car, it’s probably best avoided.
  7. HUGE WHEEL SPACERS
    While never as good a solution as having wheels with the correct offset in the first place, decent quality bolt-on spacers are perfectly safe and acceptable as long as they aren’t too big. But big slip-on spacers, especially on a car that has wheel bolts rather than nuts. Aside from needing longer wheel bolts to keep things safe, it becomes a royal pain in the arse when it comes to fitting and removing wheels as it’s bloody hard to line the bolt holes up. When there is no real money to be saved by doing it this way, why do it? So don’t even think about it, okay?
  8. MORE POWER BUT NO CONTROL
    You can have all the power in the world, but unless you can use it, it’s pointless, but lots of people fall down here. 500bhp cars with open diffs and skinny tyres that spin the wheels in every gear; cars with big power but such abysmal brakes and suspension they are slow on all but the longest straightest roads – the list goes on and on. As your power increases, you will need better grip, handling, and stopping to match if you want to be truly quick and not catch death.
  9. RACE GRAPHICS AND FULL INTERIOR
    The decision to have graphics on a stripped out racer is all yours. However, one thing that is universally rubbish is a normal road car with a full interior with race graphics. The main culprits are Subaru drivers, often in base model estates, covered in full WRC graphics, but the effect is seen everywhere, from Mondeo BTCC replicas to cars covered in awful ‘drift style’ graphics. Unless your car is a caged-up race monster, don’t make it look like one from the outside.
  10. MATCHING YOUR CLOTHING/ LIFESTYLE WITH YOUR CAR
    If covering your lightly tuned road car with rally graphics wasn’t bad enough, dressing like your car takes it to a whole new level of bad. Subaru and Ford owners seem to be the main culprits, but it crosses the whole tuning spectrum. A whole family decked out in Subaru rally gear, including caps, jackets and umbrella while walking their dog called Scooby Doo is not a good look. As much as we love cars, dressing like one is taking it way too far for us.
  11. POOR WHEEL SIZE AND OFFSET
    Nothing makes or breaks a car’s look more than wheels being the wrong size or offset, and it can do a good job of ruining the performance too. Wheels sitting too far in the arches kill the looks, while it’s amazing how a really ordinary car can look fantastic with the wheels fitting just right. Oversize wheels is a trend that has thankfully died out in the UK. Big wheels on a small car not only look pants but increases unsprung weight and slows acceleration. If you are unsure what size to run, look at race versions of your car. Generally small cars run 15s, medium cars run 17s, and larger cars run 18s, you won’t see many GT cars rocking 22s at LeMans…
  12. BEING OBSESSED WITH PEAK BHP FIGURES
    “Target: 1000bhp” is a common thing you see on car forums when people are starting the epic build of their new project car. But most of the time they want these numbers for internet bragging rights, not because its any use on the road. It’s all too easy to think you need 1000bhp when you are surrounded by big power cars in magazines and on the internet, but in the real world, how much do you need? On the road you can pretty much be assured that a car with 400bhp per ton will rarely come across anything that can keep up; that’s enough to waste the vast majority of supercars and bikes. To put 1000bhp to the ground in the lower gears needs a slick-shod full race car; so, tell us again, why do you need a 1000bhp road car? Now go and sit in a dark room…
  13. INCORRECT FUELLING/IGNITION/MAPPING
    We probably say this every single issue, but the main killer of engines is things blowing due to detonation, and that is generally because the fuelling or ignition is wrong, either because the parts cannot cope, or it hasn’t been mapped correctly. You can have the strongest parts in the world but if the fuelling and ignition isn’t sorted its life will still be short.
  14. DRUNKEN EBAY PURCHASES
    Something that seems a good idea after a white wine spritzer and a twelve pack of Tenants’s Super is not always a good plan the next day. This doesn’t just apply to bedding your friend’s mother; you can make huge tuning mistakes too. Drunken eBay bidding is your main culprit, from buying seized up and pretty crappy engines to whole cars. When it’s possible to bid more than your yearly wage in one drunken click, bad stuff can happen. It might actually make financial sense to invent and fit a breathalyser to your phone or computer!
  15. IGNORING THE RESTRICTION
    Engines are only as powerful as the most restrictive part, but people often forget this. You can have an engine capable of 1000bhp, but if the turbo is rated to 350bhp, all you will have is 350bhp. It’s not just turbos either, you can have an F1-spec bottom end on your car, but if the other parts cannot produce that power you wont get anywhere. It doesn’t matter if you’re Usain Bolt, if you let your fat mate run the last leg of a relay race, all your other hard work will be wasted (he’ll probably spill his chips, too).
  16. TUNING THE WRONG CAR
    The saying “you can’t polish a turd” is a myth, as you can make anything good with enough work. But it’ll cost a hell of a lot more to get a low-spec of a car performing well, than it would if you started with something with more potential in the first place. There are many sub-£5k cars that you could spend £10k on and have the performance to out-accelerate supercars all day long. But if you decide to base your project on a Ssangyong Musso your life won’t be so easy…
  17. RUINING AERODYNAMICS
    You might think your enormous rear wing or bonnet scoop looks good, or you may think going spoilerless and subtle is the way forward, but both ways could seriously mess up your performance at speed. Massive spoilers and scoops can add huge amounts of aerodynamic drag, noticeably slowing acceleration knocking significant amounts off the top speed. Conversely, most performance cars have rear spoilers and front splitters for good reason, and without them the car can be dangerously unstable.
  18. BIG POWER BUT OPEN DIFF
    This has been touched upon elsewhere, but is so important it’s worth mentioning in its own right. The myth of FWD being useless with any more than about 200bhp comes from many running open diff’s and so on, as big power cars generally are pretty useless without them. It’s not just restricted to front drivers either; tuned RWD and 4WD cars suffer just as badly. Trust us here, the difference is huge. Massive. BIG!
  19. OVER THE TOP COMPONENTS
    This is the exact opposite of people ignoring a huge restriction, but even more common and can ruins a car even more significantly. A restriction just means the car is less powerful than it should be; it would still drive nicely. But when you fit OTT parts like wild cams and huge turbos it can make the car drive like poo. Crazy cams and giant turbos might get you high peak power figures, but a poor powerband will make the car slower overall, so be careful…
  20. POOR POWER BAND
    Again, this is something that has been touched upon already, but it’s so important it deserves its own section. Getting power is easy – even a trained monkey could bolt on the biggest and strongest parts and double or even triple its power. But if it drives like crap with no power till high rpms it will actually be slower than it would be with less power but more drivability. It takes real tuning knowledge to make a car powerful AND drivable, but the effort is more than worth it; even at well over 200bhp per litre a car can be very drivable, if tuned correctly.
  21. GETTING TOO TRIGGER HAPPY WITH THE BOOST/NITROUS…
    Power is addictive, and when huge amounts of extra power is merely the push of a button away, it’s incredibly tempting. But unless the car is set up to handle the extra boost or nitrous, this will end in expensive engine rebuilding tears before too long. Contrary to popular myth, it’s very rarely the extra boost or the extra power that kills engines; it’s the fact the fuelling and ignition hasn’t been modified to match, ending in head gasket blowing and piston melting.
  22. LOTS OF TAILPIPES
    If an exhaust is a single pipe to the back, it only needs a single tailpipe, simple as that. But sometimes even standard cars split to two, or even four tailpipes at the back for visual reasons. Whether you like that look or not is up to you, but adding lots of tailpipes to totally inappropriate cars is a great way of making perfectly good car look cack. There’s not a set rule to this, but overall, if your tailpipe is more than an inch bigger than your exhaust diameter, or you have more tailpipes than exhaust pipes under the car, then you need to take a step back and have a word with yourself. Tailpipes are like limbs: if you have more than four people will look at you funny.
  23. SILLY TUNING GIMMICKS
    Trust is a terrible thing. It makes you believe people when they tell you a piece of junk will make your car faster when it does precisely nothing. Preying on the trust and lack of knowledge of people is bad, but it happens unfortunately. Electric superchargers, fuel magnetizers, and super spark plugs, and so much more, they are everywhere, and (most) do nothing but make your wallet lighter.
  24. INCORRECT SUSPENSION GEOMETRY
    Your fully adjustable arms, big money coilovers, and road legal slicks won’t do a thing for your grip and handling if the geometry is all over the place. A few degrees either way can turn a car from an ill-handling pile of dogger to a front running car, not to mention help tyre wear, so it’s well worth shelling out for a pro to do your geometry. Go on then, what are you waiting for?
  25. INCORRECT TYRE PRESSURES
    Tyre pressures really do make a huge difference to handling. On the road the difference is big, but on track people really take things to the extreme. Some run less than half the pressure most road cars run, often due to the huge pressure increases that happens naturally as the tyre heats up while on track. If you’re serious about your performance, do some testing to see what settings you prefer.
  26. OVER THE TOP TRANSMISSION AND CLUTCH
    Fitting a drag racing sequential air-shifted gearbox to your car may seem a great idea at the time, but having no downshift capability and only able to shift at full throttle isn’t ideal for the daily commute. Even on a less extreme level, don’t let the number of tuned cars you see in magazines and on the internet with dog ’boxes and triple plate clutches make you think they are nice to drive on the road, but they are complete bastards! They are fine on the open road and track, but in stop start slow traffic you will want to get out and walk within ten minutes.
  27. CHEAP CARBON FIBRE PARTS
    Yeah yeah, we know, carbon is super-light and amazing. Well, it’s not that light when backed with fibreglass for extra strength like a lot of cheap carbon is. In fact it may be just as heavy as the metal original! Some cars have lightweight alloy bonnets and boots as standard too, so think twice before you decide to replace them trying to save weight.