The Ultimate Car Modification Guide

"Modify your car and choose the correct car mods"

Whatever car you have you'll find each requires a similar approach when modifying it for performance gains.

Getting the right mods and applying them in the right order can maximize your power gains and keep your investment outlay as low as possible.

Read our Top Ten car performance modifications and explore our tips and 'how to' articles.

Here are our top 10 performance modifications and links to articles that cover them in more detail. Each tuner has their own preferred mods and on different engines you'll need to employ a slightly different approach but this is general common sense guide.

Just because a modification is popular it does not necessarily mean they're effective, or that they are truly a performance modification, so we're sticking to the tried and tested power gain methods.

Please browse our many articles for our unbiased opinions and tips on all aspects of car tuning and car modification. Feel free to join our forum to discuss tuning mods in more detail.

1) Turbo upgrades. Adding a larger capacity turbo or adding forced induction to a NASP engine provide the largest power gains.

Adding a turbo to a NASP engine is a major engineering feat and will cost a small fortune. But without a doubt is one of the best ways to get a significant power gain.

Read our guide for more information on this. Twincharging is also becoming popular (the addition of supercharger and turbo).

Upgrading an existing turbo is relatively easy and there are bolt on direct replacements around. For larger gains you could go with a big turbo conversion but this will require a lot of work.

2) Remaps and Chip tuning. Changing the timing parameters of the engine and altering the fuelling and boost bring large power gains. On turbo engines in particular you can see power gains of around 30-40% without compromising reliability.

NASP engines do not respond as well to new engine maps and will usually only gain around 10% more power. Read our guides to chip tuning, tuning boxes and remaps

3) Fast road cams. A new camshaft will dramatically alter the intake and exhaust durations and can also make a large difference to your engine power. There are some catches though, as this mod will typically push the power up into the top end of the RPM band.

Choosing the right cam is an art and should ideally take into account any other mods you have performed. Setting this up with a vernier pulley gets the maximum power from it and puts the power where you need it.

4) Intake and Exhaust upgrades. Improving the airflow through the engine will usually result in a power gain. The larger the engine and the higher it's RPM range the more dramatic the power increase will be.

Large capacity engines and turbo engines will respond well to induction kits, performance air filters and performance sports exhausts but there are many pitfalls and things to note with this mod.

Exhausts are fitted with catalysts or particulate filters which usually degrade performance. Looking for performance alternatives to these can often free up some of this lost power but most drivers will need to keep their car street legal.

5) Porting, polishing and valve seat angles. Getting as much air into the engine and doing this efficiently by Porting & Polishing will generally allow the engine to burn fuel more efficiently. If you are, in fact, running rich (lower than 14.7:1 A/F ratio), then you ideally want as much turbulence as possible. Turbulence aids in atomized fuel dispersion into the A/F mixture while entering the combustion chamber during the intake stroke. Turbulence is so sought after, that automotive manufacturers are engineering the engine blocks now to encompass a turbulent phenomenon known as squish.

DIY porting, polishing and grinding rarely offers any gains. This is an operation best performed by a professional with a flow bench and computerized tools.

This is a complex area and depends much on the engines characteristics and whether you are dealing with a NASP or Turbocharged engine.

6) Fuel upgrades. Larger injectors and performance fuel pumps are useful modifications, if you have done other mods and fuel starvation is proving to be an issue.

Additionally, a fuel pump with a faster flow rate will change very little, if anything at all. A beneficial alteration to a fuel delivery system that can correct a lean condition is by increasing the fuel pressure (By changing your fuel pressure regulator AND check valve), THEN attempt to feed more fuel to the engine. Just Installing a fuel pump with a flow rate of 100 liters/seconds by itself would never help considering that your fuel pressure regulator will only ever allow a predetermined amount of fuel to flow at any given time.

More fuel requires more air to maintain the essential ratio of fuel to oxygen so it is vital to get the fuelling right.

7) Major engine upgrades. These would including balancing, reboring, cryo treating and a crank grind and polish.

As this requires a strip down and rebuild of the engine it is not a mod for the faint hearted. Although power gains through internal engine mods are relatively modest you have a more reliable engine and can exploit much higher RPM levels. When pushing power beyond 50% of standard a major rebuild and strengthening modifications are essential.

8) Handling Modifications. Uprating the suspension and getting it correctly aligned/adjusted can totally transform a car's handling.

Avoid the common cliché that a lower and harder ride is better because in reality, performance suspension modifications are a lot more subtle than that.

A lower center of gravity can improve cornering. Going too low limits the suspension travel requiring stiffer suspension and if the suspension is too stiff the wheels will skip over the road rather than bedding in and gripping the road surface.

9) Brake Upgrades. Being able to stop the car more quickly makes sense. Too many people overlook the importance of braking.

Bigger brake disks are more efficient at dissipating the heat generated and will not only stop the car more effectively, the brakes will last longer before heat related brake fade kicks in. A cheaper option to increasing your braking includes high friction performance brake pads or replacing the standard disks with vented and grooved ones.

10) Transmission modifications. Power comes from the engine and arrives at the wheels after traveling through the transmission.

Power losses arise through the clutch and within the  Standard gearboxes are designed for comfort (low noise) and fuel economy.

Going with different ratios can improve your acceleration and going with a dog box (straight cut) you avoid many transmission losses at the expense of a notchy gear change and more gear noise.

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Your Constructive comments on this article

One Response to “Guide to the best car mods”

  1. shaun says:

    Good article, engines have changed a lot since I used to buldmy own pintos X fLOWS AND THE ODD NAT ASP COSY, Had a mk 1 escort, 2.1 rl1 cam skimmed ported polished grp 1 valved vernier, balanced crank, VP lead indium bearings, duplex valve springs, twin DCOEs nice exhaust, with Ans twin pie oulet. 175 bhp and all the porting work done by myself and the strip down and build, miss than days. so im looking at a kit car with a pinto and dcoes alread in place then a total rebuld, oh the brakes on the escort were done, and leda adjustables and uprated springs, 140 mph at 8ooo rpm 354.1 diff and 4 speed RS 2000 box. loved it still love it, now ride a hayabusa aged 61 ;-))

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