I have a 2012 Mazda3 s (manual transmission, base engine) to which I'd like to begin adding more performance-oriented parts once the OEM parts begin to degrade. However, I am not the kind of person who would like to do everything at once. However, I also don't want to do something in the incorrect order.

What I'd like is tight handling for mountain driving, as well as more responsive acceleration when I'm already over 50-ish mph. Where should I begin to look for opportunities for improvement in these areas?

  • What is the altitude of the "mountain driving" relative to mean sea level?
    – Bob Cross
    Nov 19 '13 at 12:49
  • 5k-11k ft above sea level
    – swasheck
    Nov 19 '13 at 16:13
  • You should put those numbers in the original question - at that altitude, there aren't a lot of minor engine modifications that are going to help you (e.g., intake + exhaust => very little noticeable gain). Forced induction will help but that's a serious endeavor. Removal of weight and drag always helps, though, no matter where you are.
    – Bob Cross
    Nov 19 '13 at 17:39

Doing incremental upgrades is a very wise move - not only does it spread the costs, but it also gives you a much better idea of the effect of each change you make.

For mountain driving (and, in fact, for any situation), the first things I would look at are the brakes and tyres. The tyres are vital, as they're the only things keeping you on the road! The particular choice will depend on your location, the size of tyre you're using, and the weather you're expecting to drive in, but whatever you choose, make sure it's a good brand. Don't go for low-profile tyres - they might be good for smooth highways, but they'll give you an awful ride on potholed mountain roads...

The first upgrade with the brakes will be the pads. Uprated performance pads are usually not much more than standard - but buy 'fast road' pads, not 'race' ones - the latter will be designed to work very well when hot, but can be poor when cold. Vented or drilled/grooved discs (rotors) can then follow.

Moving on to suspension, on an older car I'd always suggest poly bushes, but on a nearly-new car they won't need replacing for years. Stiffer shock absorbers will tighten up the handling, but again the OEM ones ought ot be good for a few years yet! Many aftermarket shocks are adjustable, so you can tweak them to suit your driving style.

The engine is always the last thing to look at - and on many modern engines a chip or remap is the only feasible upgrade without major work. regular maintenance to keep it in tip-top condition, and high quality parts (e.g. spark plugs) are of course vital. If you're doing a lot of high-altitude driving then a more free-flowing air filter might make a little difference.

  • "little difference" is right: check the altitude listed above.
    – Bob Cross
    Nov 19 '13 at 17:39
  • 1
    +1 on tires first! I would add that most cars are biased for understeer from the factory, and that adding a stiffer rear swaybar can give a huge handling boost by dialing out some of this understeer bias.
    – mac
    Nov 19 '13 at 17:44

The only thing that will make a big difference on an economy car motor (ie, more than a placebo effect) in terms of acceleration is forced induction. Having been down this road myself, I feel I should warn you now:

  • once you start doing serious modifications, you're going to be maintaining your car a lot more. Get a spare car.
  • best route is probably to get a programmable ECU like a megasquirt and tune the car with bigger injectors in preparation for turbocharging. You can actually get quite a bit of power from timing advance in some mazda engines (my experience is in the BP engines), since they're generally tuned for 87 octane rather than 93 and you're not going to want any 87 octane left in your tank once you add the turbo. Then organize the turbo bits and install everything in a weekend and then tune it, set up the boost control, etc. You need a wideband, you need an EGT probe at the turbine inlet, etc. Don't cut corners while doing the tuning. If you don't know what I'm talking about, you should probably not go this route. This stuff takes time to learn and it's very expensive if you do it wrong.
  • No matter how cheaply you do this, it will cost several thousand dollars. Assuming nothing goes wrong.
  • You need to get on a forum dedicated to your car and find out if it is actually worth modifying. Every make and model of car has weird quirks that will affect your decisions. You may find there is no real performance aftermarket for your car. You may find that adding boost to your car blows head gaskets or breaks oil pumps or bends rods.

As for suspension and braking mods, there are tons of traps here. There are a huge variety of cheap coilovers and suspension packages available that are garbage (they'll work great for about 3 months and then fail). You're best off doing lots of research to find out what the actual competitive drivers use (assuming your car is raced much, which it might not be). Be prepared to spend over 2k for a decent coilover package, be very suspicious of anything under 1k USD. Barring that, your best bet is probably to just get better shocks and tires.


Before you go fast, you need to be able to slow down. That means better brakes and tires and possibly uprated suspension components (springs and shocks). And strut braces if you don't mind shortening the life of your tires.

With that out of the way, as far as making the car go faster, I always work from back to front, meaning I make sure that the things downstream can handle any power increases upstream. I assume you're not going to put a turbo on your Mazda. If you are, please tell me because not all of the following would apply:

  1. fit a larger performance exhaust. Not too large, or you'll actually lose power. Basically because the exhaust gases won't flow at a fast enough rate.
  2. fit a performance manifold. There's no use having a larger exhaust if the manifold is still old hat.
  3. Install larger intake and exhaust valves, or have the current ones "ground". This allows for more air to be pushed into and out of each cylinder.
  4. Have the engine's top gasflowed. I think this is also called "porting and polishing". This allows air to enter and exit the engine more efficiently.
  5. install a more aggressive camshaft with higher lift and duration. A more aggressive camshaft will push your peak power further up the rev range, so keep in mind that the car will feel slightly less alive at slow RPM. Note I said "slightly". It's not noticeable most of the time. This may also require the installation of a vernier pulley, but the cost isn't that much.
  6. Get an ECU remap, or if you don't have a Flashable ECU, get a piggyback system or custom ECU installed and programmed with a performance map.
  7. If you're still in the mood to spend money, increase the engine capacity by having the cylinders bored out. This will require you to install new, larger pistons and may also require you to pay for some of the other things again. Get a few quotes.

But for mountain driving, nothing beats a nice supercharger. You can find one that was fitted to a Mini Cooper S relatively cheaply on Ebay. You'll have to get a custom ECU, exhaust, intake manifold and intercooler too, so it won't be cheap and doesn't really speak to your question, but it's worth mentioning.

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