4x4 Tindfjallajokull
Finally a great opportunity to go off roading. Weather forecast looks promising with the wind coming from north. Going out to taste some snow and fresh air!

Formula Off Road 2007 Calendar
Dates and at least some locations have been set in the first draft of the Formula off road calendar. Check it out and see if you have the opportunity of attending one of the events.

BIG Suburban - 49 Inch Tires and Atlas Gears
Go Big - Go Suburban - Go Suburban AND fit 49 inch tires! - That's BIG! Kristjan Kristjansson - Stjani - has done just that. After spending countless hours and days in his garage his 49 inch modified Chevrolet Suburban is now street legal.

4x4 OffRoad Gadgets
Perhaps you have noticed a small Google gadget on the home page of 4x4OffRoads.com (it's also the one you see above). It shows a random picture of a 4x4 in action - all from offroad articles and 4x4 readers rigs. You have two possibilities if you want to take advantage of this gadget.


 

ARTICLE
 

Engine Choice
Most 4 wheelers are stuck with the engine already in their trucks because swapping it out takes a lot of time and effort.

Somehow it seems you always want slightly more power. Fuel economy is naturally high on your list of improvements. Under similar load - fuel consumption is mostly related to the weight of your rig. A typical two ton petrol truck uses about 15 liters of fuel pr 100 km while a three ton truck uses about 22 liters of fuel for the same distance. A smaller engine may in some cases be less economical because it is working under more strain. A bigger engine may also use more fuel because you drive it in a more aggressive way.

Petrol engines
Petrol engines have traditionally been lighter and give you more horsepower. The fuel efficiency is not too good. The petrol engine works under less pressure than diesel engine and are therefore less costly to maintain.
Petrol engines are best if you have to rely on yourself for fixing the engine someplace far from home. Select a petrol engine if you use it only for shorter tours, need short spurts of high output power and if you can afford to spend more on fuel.

Diesel engines
Diesel is just a little bit more popular than petrol as fuel for the trucks. Diesel engines are more economical, have higher torque in lower RPMs and have been getting lighter in the last years. Older diesel engines where big and heavy and could run for hundreds of thousands of kilometer (or miles) without any maintenance. The newer lighter ones need more service and are not as durable. The biggest drawback to the newer diesel engines is the cost of maintenance and the need for expert mechanics.
A diesel engine is better for long and extended tours and when you are driving your rig through difficult areas for long stretches.

More air
A combustion engine is basically an air pump. To increase the power you have to get more air through the system. The major methods to get more air are:
 - Turbo – is especially popular in diesel engines. It pumps more air into the engine and therefore allows more fuel to be used. An intercooler is often used in conjunction with the turbo to lower the heat of the incoming air and since cold air takes less volume than hot you can increase the air by up to 20% - an added benefit is that colder air makes the engine last longer.
 - Blower – works in a similar way as the turbo. It is an electronic air pump that automatically comes in after a certain number of RPM is reached. It is more popular in petrol engines.
 - Exhaust headers – are designed to eliminate the manifold's back pressure. Instead of a common manifold that all of the cylinders share, each cylinder gets its own exhaust pipe. The individual pipes are cut and bent so that each one is the same length as the others. By making them the same length, it guarantees there is no back pressure generated by the cylinders sharing the single collector. In petrol engines exhaust headers can give you a 10% increase in power.
 - More open exhaust pipes – are a relatively simple option to reduce resistance in the exhaust air flow - especially in addition to more open mufflers. Turbo enhanced engines make good use of the reduced resistance and will kick in at lower RPM.
 - Hot chips – may be your only option if you have made other changes to your engines air flow – like a turbo, exhaust headers or more open exhaust pipes. If not they are hardly worth the cost and may shorten your engine life as well as increase fuel consumption.

Thrandur Arnthorsson is a 4 wheeling enthusiast and the webmaster and owner of 4x4OffRoads.com.