Ford SVT Thunder - Performance Trends

What's Hot:* It's big, black and Lightning fast* Burnouts are cool in a huge SUV* 440 lb-ft of torque

What's Not:* Ford has no plans to put the Thunder into production-bummer

Performance TestFord SVT Thunder ExpeditionWhen this Ford Expedition-based 'ute looms behind you in the rearview, it seems ready to suck you off the tarmac like a funnel cloud. Tom Scarpello of Ford's Special Vehicle Team describes the Thunder as "authoritative" and even uses the word "intimidating."

But unlike the limited-production Lightning, you won't find the Thunder in Ford dealers anytime soon. It's an experimental "what if" screwed together by SVT project manager Al Suydam, with engine and suspension parts snatched from the Lightning. Unfortunately for performance fans, SVT told us that "other more pressing performance projects" have bumped the Thunder off the to-do list.

Underhood, the Thunder's rumble is provided by the same supercharged 5.4L SOHC V-8 used in the Lightning, which pumps out 360 hp and 440 lb-ft of torque. With virtually zero wheelspin, the short hop to 60 takes just 5.6 sec. (A stock Expedition needs 9.2.) Thunder, then somehow ignoring aerodynamics laws, gobbles the quarter mile in 14.4 sec at 95.8 mph. That's the same performance ballpark as a Boxster.

The Thunder is more than a monster motor in search of a decent chassis. This truck changes highway lanes with the precision and low roll of a good sport sedan. SVT borrowed the Lightning's giant P295/45ZR18 Goodyear Eagle F1 GS tires, 9.5-in.-wide five-spoke aluminum wheels, lower-rate front and rear coil springs, Bilstein monotube gas shocks, and stiffer front and rear anti-roll bars. We found a huge handling advantage on our test track, and it felt crisper around town and stopped shorter than stock, thanks to the upgraded brakes.

Start your letter-writing campaign today. Let Ford SVT know you want the Thunder Expedition in dealer showrooms and you want it now. -Jack Keebler

What's Hot:* Viper-like acceleration with an automatic transmission* Easy burnouts and power oversteer slides* Looks great

What's Not:* Two hundred grand for an SLK?* Suspension mods need more development* Impossible to use full throttle in first gear

Brabus SLK V-8The Mercedes-Benz SLK is an attractive, sprightly sports car, but when even the new SLK320 V-6 five-speed only runs 0-60 mph in 6.6 sec, you can't call it blazingly fast. This all changes when German tuner Brabus bolts in a 6.5L DOHC V-8. This pushes the Brabus SLK to 60 mph in 4.5 sec, while the quarter mile goes by in 12.9 sec at 110.6 mph. Severe tire spin kept all the power from getting to the ground; otherwise these numbers would have been better.

Think of the SLK V-8 as a rolling catalog for Brabus (which has a California division). The tuner offers everything from engine and suspension modifications to eye-catching bodywork and interior enhancements. And this SLK V-8 has it all-at an as-tested price exceeding $200,000.

The conversion begins with an aluminum block borrowed from an E420. A long-stroke crankshaft, lightweight pistons, ported cylinder heads, and high-lift camshafts are then added. The result is 450 hp at 5700 rpm and 488 lb-ft of torque at 3800 rpm, according to Brabus. Their engineers found few engine compartment mods were needed to accommodate the compact V-8 engine. Power is routed through a strengthened S-Class four-speed automatic and an SL differential. Brabus claims a top speed of almost 190 mph.

Included in the modifications is a new braking system with four-piston calipers and larger, slotted rotors. The new setup stopped longer than stock, but provided better fade resistance. A stainless steel high-flow exhaust system was also added. Traction is improved thanks to the 255/35ZR18 Michelin Pilot Sport tires wrapped in Brabus Monoblock IV modular alloy wheels. Suspension modifications include special gas dampers and uprated progressive springs that drop the ride height by 30 mm compared with stock. However, in the slalom test, the SLK V-8 was skittish on the edge compared with a stock SLK showing that it needs a little more suspension development.

The interior upgrades are highlighted by Mastick leather throughout and two polished stainless steel rollover bars that emphasize the classic roadster look. However, with the throttle down in the 3350-pound SLK V-8, the world rushes toward you in a real hurry-a result many classic roadsters didn't have the power to produce.-Mac DeMere

Source:Brabus North America949/797-0177 www.brabus-usa.com

Shopping For MufflersPurchasing a performance muffler can increase your engine's horsepower by decreasing backpressure. But understanding a few simple terms will keep you from ending up with a muffler that's too loud or unsuited for your application.

1. Inlet/outletMufflers come in many inlet/outlet sizes and configurations. You can find models that feature a center inlet and offset outlet, while some units have both the inlet and outlet offset. Be sure to check your application to determine to proper orientation. Inlet and outlet sizes also vary and you'll need to make sure they match with the exhaust pipes. A common misconception is that very large diameter exhaust pipes are better. Typically, increasing pipe diameter by 11/44-11/42 in. over stock is sufficient to increase flow.

2. Size/shapeMufflers come in all sizes and shapes-oval, round, and even rectangle. It's important to ensure that the muffler you've chosen fits into the space under your car. This sounds simple, but many people have problems with this.

3. Material/constructionTypically, stainless steel is the best for mufflers, but there are many mild steel mufflers that'll last just as long. Welded-on end caps are better than crimped-on ends (seen on most stock mufflers). The new breed of carbon-fiber mufflers are great if you're into the look of carbon or need the weight reduction it offers, but they doesn't come cheap and many don't last that long.

4. PriceBuying an expensive muffler doesn't mean it will last a long time and buying a cheap one may not be the best bet, either. A good muffler built from mild steel may just be better than a cheap one constructed with stainless steel.

5. SoundThis may be the single most important aspect of shopping for a muffler. Unfortunately, it's impossible to test drive a muffler. However, you can ask around. See if anyone you know has the muffler you're looking for on his vehicle. But be warned. Several things affect sound, including engine size and modifications, muffler placement, and pipe length.