September 27, 2004
Adding the MagnaFlow exhaust to Avalanche
Two weeks ago, Steve added the MagnaFlow Performance Exhaust to the Avalanche to top off the tuning. The manufacturer says 9hp and 11fp gain. The really cool part is the sound though. It is a straight through system, but since you still have the cat, there is some muffling and it is not an obnoxious roar. Just a slight noticable throatyness. You can hear the sound here. It is a fully stainless system as well that looks great sticking out the side. So the stock is a 3 inch exhaust. The MagnaFlow bumps it up to a 4 inch.
I didn't notice any real performance difference after the supercharger and the reprogrammer. The biggest difference was the sound. I am going to take it to a dyno next week and see what it is pushing. I am thinking it is over 500hp.
December 2, 2003
Whipple supercharger review...
So I have had my North Face Avalanche for 30,000 miles (over two years). About a year and 15,000 miles longer than most of my vehicles. The problem is that I love it. There is no other truck as versatile. It hauls Harleys, surfboards, a family of five, and construction materials for a remodel. So instead of getting something new, I decided to upgrade it. Basically more power.
Friday I picked it up from my pal Steve Huff who slapped on the Whipple Supercharger for me. The company claims 90 hp bolt on! The supercharger fits in-line to the fuel system. You get a new air flow system, a new air box (more air flow), two new injectors, new plugs, a new pulley, some new hoses, and a new computer in-line with the factory computer. The supercharger basically mixes the air and gas better and shoves the cylinder full of an optimal mixture so you get a bigger bang. Normal fuel injection systems fill up about 60% of the engine cylinder volume with normal air pressure and the downstroke of the piston pulling in the air/fuel mixture. The supercharger crams in the mixture, filling 100% of the volume with the perfect mixture. The computer controls when the thing is on and when it is off. Basically when you stomp your foot on the gas, it kicks in and pulls like a banchie until you reach the motor's rev limiter. When you are just driving around normally, you don't get any boost and the thing only takes 2HP for the pulley. There is no change to the hood or the exhaust or anything visable on the truck. The only thing you may notice is the whine of the supercharger when you stomp on it. A very satisfying feeling actually.
Now I had the Porsche Turbo for a couple years and the accelleration was amazing. Snap your neck fast. I knew that wouldn't happen with a truck that weighs three times as much. Certainly the handling would still be like and SUV. When I first hit the gas I was totally blown away. My Avalanche launched off the line like the Turbo. Nearly as much force snapping my neck back. I haven't put it on a dyno to see how many HP have been added, but plenty. And because it is automatic, it just keeps pulling all the way up. The computer shuts down the engine around 100mph. There is an upgrade I can get to bypass that, but don't think I will do it just yet.
In summary, I LOVE IT! My favorite part is the little sticker they give you for your dashboard:
DO NOT MAINTAIN WIDE OPEN THROTTLE WHEN FUEL LEVEL IS BELOW 1/4 OF A TANK. YOU MAY DAMAGE THE FUEL PUMP.
Gotta love it.