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February 2007 Off-Road Notes

Posted in Features on December 26, 2006
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A recent survey by SEMA showed that the first aftermarket parts vehicle purchasers are likely to acquire are air intake systems, exhaust systems, wheels, and tires. Wheels and tires were no surprise, but the strong showing of air intake and exhaust systems was surprising - until we thought about it.

In the "good ol' days," it was easy to improve on the stock OE air filter and restricted exhaust. The air filters were cheap and poor, and the exhaust systems were usually not mandrel-bent and afforded plenty of restriction through plugged mufflers. Later, early catalytic converters did nothing to help flow. As time went on, competition in the marketplace changed this. OEM engineers designed freer-flowing air filters and air intake plumbing. Exhaust systems received the same attention with freer-flowing, larger-diameter pipes and less restrictive catalytic converters and mufflers, resulting in higher horsepower numbers and much better performance out of the box. This is especially noticeable in the diesel market, where there has been a remarkable surge in horsepower and torque figures, helped by these well-engineered systems.

So, why buy an aftermarket air or exhaust system if the OEs are doing so well? There's still room for improvement. Remember, the OEMs are in business to make a profit, so many pieces of our new vehicles are not the highest-performance parts, just the most cost-effective ones. The most glaring example of this is shock absorbers. On new vehicles, the shocks can Always be improved, usually along with the suspension system. But, we're not talking about shocks here, so let's get back to intake and exhaust.

Aftermarket air intake and exhaust companies have spent a lot of time engineering systems that truly improve performance, with little or no tradeoffs. Air systems bolt in easily and use much improved filter mediums over stock. Aftermarket performance exhaust systems are, in many applications, stainless, mandrel-bent, and always freer-flowing than stock. Performance catalytic converters are no longer restrictive and keep the air clean too. We use performance cats on all our gasoline-fueled projects. In a nutshell, aftermarket intake and exhaust systems offer real performance gains over already good stock systems. We recommend them.

We read a report on wheel purchases in the latest issue of SEMA eNews. It came as no surprise to us that many of you are choosing larger wheel sizes, especially 20-inch wheels. We used 20-inch wheels on our F-150 and they worked great on the street, but not as well as 17-inch or 18-inch ones that, with the same tire diameter, afford more flotation off-road. With 40-inch tires, it's a different story, but smaller tires need smaller-diameter rims, in our opinion.

Since many of you don't agree with us, we won't argue. Trucks with 20-inch rims look good (as long as at least 35-inch tires are mounted on them) and we'll start featuring more of your vehicles with 20s on them. By the way, can you guess how many new truck buyers purchase aftermarket wheels? Seventy-nine percent of them do! That's a phenomenal number and is probably the reason we see new foreign wheel manufacturers on every corner at the SEMA Show.

You're the people who drive our industry in your quest for better vehicular performance. Thanks for your dedication and thanks for reading Off-Road magazine!

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