How to Modify Your Car for Better Performance

1

Determine whether to upgrade your existing car or to purchase a new car just to make into a "sleeper" (a car that is powerful under the hood but looks stock):

• If you are planning to go N/A (natural aspiration) rather than the turbo route, your best bet is changing the bore, stroke or compression ratio,for example a Nissan skyline GT-S R33 has a compression ratio of about 9.5 to 1, the 9.5 represents the air/fuel mixture in the cylinder before compression, the 1 represents what it's being compressed to, so in this case raising it to 10.5 to 1 would give a nice increase of power over the low end of the RPM band.
• If you go with a turbo you don't need a very high compression ratio because you already have forced induction. But be wary of changes of more than 2.5 over factory settings, too high compression ratio could send your spark plugs through the hood. (Not literally but you get the point.) You could use a small car with a large engine installed. For example a Ford Mustang V8 forced into the body of a little Ford Focus. Keep in mind that a heavier engine will likely change the front-rear weight ratio. This change could significantly affect handling, traction and braking.
• Consider a common conversion like a Chevy LS-1 and Ford 302 (5.0L) powered Mazda Miata. It’s a pretty easy swap and pretty cheap too for the performance these motors can be made to deliver.

Do some basic research on your car to determine what kinds of upgrades are possible and how much they may cost both in time and money.

3

Determine if you can do the work yourself or need to hire a professional. You won't be paying the full price of a Benz, Corvette, or Beamer (BMW) but you will be paying. Expect to pay upwards of up to $3,000 for an h22 motor swap to an Accord chassis, possibly more if you're not using the 4th gen. due to mounting issues and other complications.

4

Choose to:

• Install a turbo kit.
• Go with N/A (natural aspiration), install a small bottle of nitrous (before installing nitrous oxide in a used car, get a compression test) and upgrade the transmission but also be sure to install forged pistons, it is not a must but it will help to stop internal damage. More than likely, keeping a car naturally aspirated will cost a lot more than a turbo set-up; however, this makes for the best kind of sleeper.

Purchase tools and parts. You will need many tools and parts including but not limited to:

• Plumbing

• An inter-cooler
• An oil return line for lubricating the turbo.
• Possibly a better intake manifold.
• A boost gauge
• A turbo management system. And even after all that, there will likely be more.

• Install a cold air intake and an after-market exhaust. The reason for this is if you want power, you need to be able to move more air than the stock system will allow.
• The intake option may be removed in favor of an inter-cooler set-up once you've decided to go turbo as opposed to N/A route. If you would rather stay N/A but can't afford the amount of fabrication needed to drop a V8 in your import, there are other options such as port and polishing your intake manifold, installing performance cams with overlapping grinds and the use of high compression pistons just to name a few.

7

Research options for chipping (reprogramming) your current ECU (Engine Control Unit) or replacing it with a good one that can be chipped. Look for these features in an ECU:

• Make sure you can log data.
• You want the ability to program your own fuel maps
• Include a sophisticated dyno (engine diagnostic tool for measuring performance including horsepower). The current dyno attached to your ECU probably will not be adequate for measuring your performance after modifications you make to turbo-charge your car.

Understand that this kind of tuning may not be applied to a carbureted engine (static fuel map), however, carburetors have the higher torque potential. If this is a N/A track application, consider four independent motorcycle carburetors per cylinder. This should specifically be restricted to the track as this kind of set-up creates a nasty amount of power.

9

Upgrade your tires to make sure this new power can make it to the ground without unnecessary wheel spin and over/under or torque steer. You will most likely need:

• Sticky tires that will last at least 1,000 miles (1,600 km).
• New bushings for your control arms.
• New ball joints
• Stiffer shocks with shorter coils.

TIPS

• Don't use nitrous if you don't have to. The turbo maybe causing more than enough stress on the engine and using nitrous should be restricted to the track anyway. If you're going to go beyond 10 psi or possibly 20 psi, it is absolutely necessary you build a better motor. You don't necessarily have to replace the whole engine, but new camshafts, cranks, pistons, connecting rods, and maybe a better head wouldn't hurt.
• Nitrous isn't all bad. For example, if with a stock small 4 cylinder engine, a "Dry" system would be better suited than a wet single or wet direct port nitrous system. Small-shot Dry systems also have a very low chance of damaging an engine versus a wet shot with upwards of 200-400 hp gain would. Leave wet systems for larger engines.
• Nitrous also is the best application for HP gain in terms of cost for parts and labor. You can get a Dry shot system with purge kit for under $1,000.00 depending on the shop.
• There is far more to performance than engine/exhaust mods. All performance cars (even dragsters) need good tires and properly tuned suspension. And sometimes the best performance parts are not the coolest-looking; five-inch mufflers, overweight 19" rims, and under-lighting do nothing good for your lap times.
• horsepower costs money. If you want to get an idea of how much power you can make your car put out, look at how thick your wallet is.
• Spark plugs and wiring can also do a good job if you are on a budget.
• Nitrous oxide is not as bad as it is made out to be by some people.

There is a lot of hysteria surrounding N₂O (nitrous oxide),things like "it will blow up your engine" and other myths. N₂O can ruin your engine but that is only if engine can't handle it or if you use a to high level of PSI. N₂O isn't just good for power but running it through your intake will lower temperature because of how cold it is when it leaves the bottle (the Boiling effect). Get a compression test and if your car is used check the state of your engine.

• Don't use nitrous as your accelerator. Save it for when you need it.
• Contrary to common belief torque steer in an FF is not an example of horsepower, but a badly aligned vehicle, uneven length drive axles and a discrepancy in the road's surface. Of course increasing horsepower will increase the effects.
• If you plan on racing the car then build up a big engine for huge amounts of power.
• Installing nitrous into a stock engine isn't always a good idea. Slowing your cam timing a little is a good idea with nitrous to stop you ruining your engine.

Remember for every action there is a reaction. you can't just put a huge turbo under the hood and be done, turbos mean forced induction, forced induction means more air, more air means you need more fuel. So basically installing a huge turbo means you need to upgrade the fuel pumps and fuel lines -- otherwise you will be starving your engine of fuel.

• Advancing the ignition timing and running high octane fuel is the cheapest thing you can do to increase hp.
• Turbo is much more expensive than nitrous, with the average being 3,000.00 non inter-cooled and 4,000.00 with an inter-cooler. Installation is also expensive with the average time of 22 or more hours for install. So spending over $1,500.00 for installation alone might be too much for someone with a budget crunch.

WARNING

• Buy a Radar detector if legal. This is illegal in the Netherlands, many European countries, parts of Canada and elsewhere.
• Turbo charging a vehicle isn't as simple as bolting on a kit. Along with the complexity of installing it there's the risk factor in damaging valves, heads, pistons, manifolds or even totally blowing your motor and cracking the block.
• Racing on the street is illegal in almost all places.
• Do not treat one item as more important than the other. In other words, do not go out and buy every tool in the shop and then realize you needed metric instead of SAE or vice versa.
• Be Careful-too much torque can twist your frame and cost 3 times more than trying to "fix up" your car
• A lot of insurance companies consider performance mods as a liability. Expect more expensive charges and possibly them dropping you.
• Adding Nitrous to your vehicle is dangerous. You can destroy your motor running large shots. Start conservatively, reinforce your motor, and slowly dial up the shot until your running the amount you want. This will prevent you from blowing your pistons 10 feet (3.0 m) under.
• All work should be done under the supervision of a professional or if possible, by a professional.