Sunday 30 September 2012

CHOOSING RIGHT ALLOY WHEELS FOR YOUR CAR

SIZE OF THE WHEEL:

 If you are buying a new set of alloys but do not wish to change your tyres then buy alloys that are the same size as your rims and you can use your original wheels. So if you have 15-inch steel rims then you need to buy 15-inch alloy wheels. If you are willing to change your tyres as well then maintain the specified wheel and tyre combination

PCD?

PCD or pitch circle diameter is the distance between the wheel bolts and the center point or axle of the wheel. It also takes into account the number of studs that you have on the rim. For e.g.: A PCD of 5×160 indicates that the rim has a 160 mm diameter on which the 5 evenly spaced bolts are located. If you don’t match the PCD exactly to what the car came with, you won’t be able to fit your alloy on the car’s wheel hub.

OFF SET?

Some people play the offset on purpose to make the alloy wheels stick out of the wheel arches. That is high negative offset while positive offset means that the wheel hub protrudes out further, when compared to the rest of the wheel. Most alloy wheels come with zero offset or slight negative offset.
It is best to stay within 1-inch of deviation from the stock setup. Negative offset aids handling while too much offset puts pressure on the hub and axle. This can even cause breakage of these parts.

RIMS WIDTH?

Take care that the alloy rim that you are buying is not too wide. Apart from having to buy new tyres, wider rims can also foul with the fender, steering rod or suspension components. The width of the alloy wheel is denoted by numbers such as 6.5 J, 7 J, 8 J etc, where 6.5 is the width in inches and J is the shape of the rim lip .

UPGRADING THE SIZE OF THE TYRE?

You will need to get wider alloy wheels if you upsize your tyres. The overall diameter of the tyre and alloy combination should stay the same. If this is not done then the reading on your odometer will not be correct and your car’s handling will suffer.
Reduce the profile size of the tyre based on the increase in the tyre’s width. Upsizing is essentially increasing the diameter of your wheels and reducing the profile of your tyre to accommodate the tyre and maintain the rolling radius.

SOME OF THE WAYS TO TUNE A PETROL CAR



When you decide to modify your car for more performance, be warned that many of these modifications can affect your warranty, so preferably don’t do some of these modifications with a new car.


High-flow air filter
You can get high flow air-filters from K&N or Green Cotton. These come in two kinds. Stock replacement filters fit directly into the air filter slot in your car. These are oil-coated mesh filters that allow more air into your engine, allowing the car to “breathe” better. Other universal cold air intake kits are more expensive and need some plumbing. Stock replacement filters cost between Rs. 3000-Rs.7000, while universal filters will cost between Rs. 10,000 and Rs. 15,000.

Free-flow exhaust

With a car that breathes better, it needs to let the gases out equally fast. Modifying the exhaust to a free-flow exhaust allows for more gases to escape faster. A free flow exhaust needs to be fitted in entirety from the “headers” or exhaust manifold that comes out of the engine head, to the muffler and tail-pipe. Some will only add a muffler that makes more noise but gives not significant performance gains. The catalytic converter may have to be removed for full performance gains, but then your car won’t meet emission norms. This modification will cost between Rs. 10,000 and Rs. 30,000.

Engine oil

If you plan to increase performance of your car, it will likely see a lot of high-rpm driving. In which case it would be better to switch to a synthetic engine oil instead of a mineral oil. This will allow for better lubrication and longer engine life. Synthetic oil will cost you about Rs. 900-Rs. 1000 a litre. 

Tyres and wheels

One of the most important factors in extracting maximum performance from your car is to upgrade the tyres and wheels. Go in for low-rolling resistance tyres and light-weight alloy wheels. If possible you can widen the tyre size a little, but reduce the profile height accordingly. Also read: 

Performance spark plugs

For constant high-rpm driving and better tolerance to heat build up, you will need to replace your spark plugs with performance plugs (iridium tipped plugs). These spark plugs will cost between Rs. 1000-Rs.4000 a set.

High-voltage plug wires

To ensure there is no loss of current it would help to upgrade the plug wires to a performance wiring set. This will ensure you get the best possible spark at all times, without misfiring. This will cost about Rs. 2,500-Rs.3000.

Suspension upgrade

The car’s suspension will need to be stiffened for performance driving. One of the easiest ways to do this is to install high-performance shock absorbers such as Bilstein or Koni kits that will add that extra stiffness to the suspension. These cost about Rs. 12,000-Rs.15,000 a piece.

Strut braces

To add more rigidity to a car’s body you will need to add strut braces. This is a bar that connects the two suspension struts across the top and prevents the car’s body from flexing (especially in monocoque designs), adding rigidity and giving better handling. This mod will cost about Rs. 5000-Rs.6000

Roll cage

Once you’ve got most of your performance upgrades done, it is a good idea to consider additional safety for your car. Installing a roll cage (like a rally car) will ensure that in the event of a crash you are more likely to step out unharmed. A roll-cage will cost about Rs. 50,000 and will require extensive body work (cutting and refitting of the body).

Performance brakes

Keeping safety in mind, another very important performance modification is the braking system. If you give your car 20% more power, you will need 20% more stopping power as well. You will need to upgrade the disc size and the brake pads and calipers. A brake upgrade can be expensive, with cost ranging from Rs. 8000-Rs.50,000.

Tuning chips

Diesel tuning boxes are now a common performance modification for diesel cars. There are tuning boxes available for petrol cars as well, which function in the same way. They “piggyback” with the car’s ECU and modify some engine parameters to fool the car’s ECU into injecting more fuel for a given rpm range. Tuning boxes cost between Rs. 20,000 to Rs. 35,000.

Clutch upgrade

If you plan to use your car for rallying, it would be a good idea to upgrade the clutch as well, as constant high-rpm driving will involve a lot of clutch wear. Upgrading the clutch, however, can affect day-to-day running of your car as it won’t be as smooth as you want it and will respond only to rough use. This will cost between Rs. 15,000 to Rs. 50,000 to upgrade.

Upgraded camshaft

The camshaft is what controls the opening and closing of the intake and exhaust valves in the car. Upgrading this to a performance (or high-lift) camshaft will allow the engine to breathe better and take in more fuel. However, day-to-day drivability will be affected. Camshaft kits from Piper etc, cost about Rs.30,000-Rs.45,000.

Polishing heads

Polishing the cylinder head will add a little more breathability to the engine as the ports for the intake and exhaust valves become bigger. This is not a task for the fainthearted, as it involves opening up the engine and refitting it. This will cost between Rs. 12,000-Rs.20,000 depending on the car.

Turbo-charging

Normal petrol cars can also be turbo-charged to make them even more powerful. Installing a turbo-charger would also mean changing the other parameters in the car. The cost of turbo-charging a car can vary between Rs.1 lakh to Rs. 2.5 lakh depending on the kind of turbocharger used.