2008 Chevrolet Silverado lift kit

Don't make me come over there and slap you! No suspension and alignment specialist will destroy your truck by installing these modifications. The only shops that might do it are those more interested in your money than all the other problems you could run into. First of all, don't even think about altering the suspension geometry. That will adversely affect braking, handling, and tire wear. It can also land you in court.

Do a search for "scrub radius" and learn what it is and how it affects a car or truck. I can guarantee you lawyers and insurance investigators know what it is and how to use it to their advantage. They will convince a jury that you were partly at fault for the crash when the other guy ran the red light because you were less able to avoid it, and they will be right. They love to find those kinds of modifications on the other guy's vehicle.

Raising the body raises the center of gravity. That makes the truck less stable on high-speed corners, and it causes a higher weight shift to the front when braking. Your truck has a "proportioning" valve built into the brake system, and the diameter of the wheel cylinders and / or caliper pistons are chosen to provide balanced braking front to rear without causing easy rear-wheel lockup. Most trucks have rear-wheel anti-lock brakes to prevent that lockup. To do that they have to reduce brake fluid pressure and that increases stopping distances.

I've had a lot of '70's Chrysler muscle cars with easily adjustable torsion bars, and now that I understand the ramifications of altering ride height, all of my cars sit exactly as they were designed. There is obviously a market for these products, but with the automotive industry as competitive as it is, you can be sure the manufacturers would have offered a lift package if it could have been done without compromising safety.

I recently helped a friend in his shop lower a guy's Dodge Ram diesel back down to where it was supposed to be. Restoring drive shaft angle brought his fuel mileage up from 15 to 23 miles per gallon. The owner liked how it looked when he bought it that way, but now he really likes the improved ride quality.

Be aware too that alignment shops won't align your truck or they won't offer a warranty on their work because there are so many factors out of their control. Some shop owners won't even allow the truck in their shop for any repairs or service because of the possibility of becoming a party to any future lawsuit, even if it involves things they never worked on. They could be charged with negligence for not restoring the truck back to its proper ride height, and there's no way for them to prove they warned you of the problems it could cause. Most guys who alter their trucks do their own service and repairs. You'll need to be prepared to do the same. With all the insane computers today, you'll need lots of diagnostic equipment and the training to use it.

You won't have perfect tire wear either. The wheels can be adjusted "to the rack", meaning the numbers on the computer screen look good, but that only applies to the truck when it's standing still. The suspension geometry is shaped to allow the wheel and tire to move up and down over bumps with minimum sliding back and forth sideways as the control arms move through their arcs. That results in reducing one component in tire wear. If you look at the upper and lower control arms from in front of your truck, you'll see the lower one is perfectly parallel to the ground but the upper one is angled down. THAT was designed in for best possible tire wear. Don't change it.

I can share some observations but I've never used them myself. The friend I spoke of has a body / repair shop and he specializes in rebuilding smashed one and two-year-old Dodge trucks. He had one of these boxes on a '99 dually diesel that he rebuilt. He was already using it to pull a three-car hauler to transport cars he was rebuilding for another business about 250 miles away. He also used it for plowing snow in the winter for local businesses. As it was, he left it in two-wheel-drive and just idled across the parking lots to push the snow. No real need to get a running start or use 4wd. The power was amazing but he had a bug that told him he needed more. After installing the chip, with more power, of course he "needed" to use it, and he promptly tore up the transmission. He bought a professionally rebuilt and beefed-up transmission and a special torque converter to handle the horsepower, but now the truck just sits because he has two newer ones that he rebuilt.

The next one was a '96 that came out of Salt Lake City. It was hit so hard in the front end, it pushed the engine back over a foot into the firewall. My job was to rebuild the crushed heater box, and I helped him, (learned how to), weld in a new firewall and straighten the frame. This is another dually diesel, and he wanted me to install a chip in this one too. My strong suggestion was to let me fix the smashed plugs for the under-hood computer and get the engine running first, THEN put the chip in so there's not so many variables if it didn't run. Nope; had to do it right away to make him happy. The first night he took it out for 20-minute test drive he came back with this stupid grin on his face, then he took us out to eat. (That's my pay for the hours of hard work). I've driven a Viper a few times after changing the oil, and I got a ride in one once. That was nuts, but this truck will almost keep up to that. Later he took it to a local fuel injection shop and they determined the truck already had an over-size turbocharger and over-size injectors, and now it has that chip. They estimated it is pushing around 700 horsepower and 700 foot-pounds of torque. This truck has a six-speed manual transmission, and the clutch is the weak link in the chain. Dual rear wheels are hard to break loose, so it's the clutch that slips if he really gets on it. The truck can easily get 23 miles per gallon, but adding speed or load cuts that by quite a bit. He recently moved his sister from Texas back here to Wisconsin, and he built a huge box onto his 32 foot goose neck trailer, then severely overloaded it with all her personal stuff and three horses. That trailer was bottomed out on the axles, one wheel separated, and he broke all the lug nut studs on two pairs of wheels. Took him a day to drive down there but three days to get home with all the expensive repairs on the side of the road. We've estimated he was pulling 38,000 pounds of trailer. For the first time he was limited to 55 miles per hour, and he was down to 9 miles per gallon, but he made it home.

His latest project is a 2011 Dodge Mega Cab that he is extending. Those only came with a six-foot box. He bought a frame that came from an experimental truck right from Chrysler and used the rear half of it to extend the truck 20" so he could put an eight foot box on it. My job so far was to repair the crushed wiring and extend it to the rear, and modify the brake line, fuel lines, and fuel filler pipe. He's painting the front of the truck today and I'm headed there shortly to help him hang panels on it. He wants a chip put on it too. Most importantly, he removed the ridiculous exhaust system our stupid politicians demanded it come with. That should increase his fuel mileage by five miles per gallon.

One thing I've heard from a number of people is if you have a Traveler Computer that shows your average and instantaneous fuel mileage, that reading will be wrong. Most people say your mileage WILL increase, but not to what is displayed. These chips alter some of the sensor readings the Engine Computer uses to calculate fuel metering and it's those calculations that it uses to determine the miles per gallon to display. One fellow with a gas engine in a Dodge said he was getting 19 miles per gallon but the display showed 28 mpg. I don't know what is original fuel mileage was but from what I've heard, 15 to 17 was typical.

Also be aware all of my buddy's trucks are diesels which respond to fuel quality more than gas engines do, and he does other modifications like installing 5" diameter exhaust systems to help them breathe. One other thing he is a stickler for, and not to rehash my previous reply, but makes sure they're exactly at the proper ride height, then takes them to his favorite alignment shop. Being a suspension and alignment specialist, I can't help but look at the tire wear patterns on his stuff every time I go out there, and the wear is always perfect. Proper alignment when the truck is in motion is a big contributor to good fuel mileage. The very poor suspension designs on Ford products, especially the miserable twin I-beam suspension, are a big reason Fords can't compete when it comes to fuel mileage, and they will never get decent tire wear. Your truck will have the upper and lower control arms which keeps the tires in proper alignment as you bounce down the road. That, and drive shaft angle are two of the biggest contributors to good fuel mileage, more power transferred to the road, and minimum drive line vibration.

One last comment has to do with warranties. All manufacturers will not honor engine or drive train warranties if a mechanic at the dealership finds a chip on the truck. Some owners remove them before taking the truck in for repairs, but we have one well-known chain tire shop in town that does a lot of work on heavy trucks and farm machinery. If a newer truck comes in there with a chip, they will call the dealer and inform them. Apparently they are getting some type of financial incentive or reward for this, then some dealers use that information to deny warranty service. I don't know if this takes place anywhere else but it is something to consider if your drive train is still under warranty.

My job yesterday was to add rear air bags to the suspension and a pump and gauge to his 8' box Mega Cab project. Today I'm headed there shortly to install the chip. We got the engine started last night, now it "needs" more modifications.

I'll ask him about the muffler you mentioned. One thing I can tell you is if you install a loud muffler, it will sound cool for a little while, then you'll get tired of the noise, especially if you drive more than five miles to work each day. If you want to go to a more free-flowing true dual exhaust, not the single exhaust pipe that splits into two mufflers and tail pipes, you will get a nice mellow rumble with a pair of stock mufflers. That is assuming you have a V-8 engine.

The reason for that is if you look at the firing order of the cylinders, (Chrysler and GM use 1, 8, 4, 3, 6, 5, 7, 2), you'll see that 8 and 4 are next to each other and are on the same side of the engine, then 5 and 7 are next to each other on the other side. Each side of the engine has two cylinders that fire one right after the other. That makes a larger puff of exhaust gas, then there's a dropout when the same thing happens on the other side. That's where the rumble comes from.

The guys who install the kits that split a single exhaust pipe into two still have that small pipe for a restriction to breathing, and those puffs of exhaust gas are combined and steady, so instead of the rumble, you just get half the flow through each tail pipe, and it looks neat, ... I guess.

Usually the original tail pipe is on the right side. When you add the dual system, watch the orientation of the left tail pipe as it will pass right under the rubber brake flex hose which will likely have a wire attached to it for the rear wheel speed sensor for the anti-lock brakes. I had one where that wire was melted. It wasn't due to the pipe installation. It was from the wire being pulled out of the clips that held it to the relatively stiff hose, then it fell down onto the hot pipe. It would have gone unnoticed and would have continued to work fine if that pipe wasn't there.

Also be aware you will have a front oxygen sensor on each side of the engine, then most likely a catalytic converter and a rear oxygen sensor on each side. Don't try to mess with that arrangement as it will lead to all kinds of running and emissions problems, and the Check Engine light will always be on, then you'll never know if a minor problem is detected that could turn into a serious one. Look for a kit that has you cut the Y-pipe after the rear oxygen sensors, or it has provisions to install those sensors right after the two converters. Your Engine Computer will insist on seeing the signals from all four O2 sensors, (3 on some applications).

Yes, the exhaust will sound different if some cylinders are turned off because they'll only be pumping air and won't be producing any power pulses.

I didn't drive the 2006 truck before it was chipped. I had to take the timing gear cover off to replace a broken power steering pump bracket, and we pulled the engine and transmission out to replace the firewall. The bodywork and paint were done, AND the chip was installed before we started the engine. I have driven the truck a few times since then but I drive like there's an egg under my foot. Also, it has a six-speed manual transmission which is made for power, not speed-shifting. My friend can get around really quickly with it when he's in a hurry, but I'm not familiar enough with it to drive like that.

I did remember to ask about the muffler yesterday, but my e-mail was acting up last night. It's going through all kinds of changes, ... Again. According to my friend, he did use a Flowmaster muffler once and was rather unhappy with it. The sound was terrible and it was extremely over-priced. He pointed out that if you pull a trailer, the sound will echo off of it and give you a headache. He won't use dual exhaust anymore for that reason. He has three Dodge diesels and all have a larger 5" single exhaust on the passenger side. We put on a new stainless steel system two days ago on his current project, and the muffler was a straight-through design with a chamber around the pipe, and small perforations between the pipe and chamber. There's no other muffler or resonator in the system, and we thought it was going to be really loud, but it actually sounded fine. You can still tell it's a diesel but they're a lot quieter than years ago. You could stand right next to the tail pipe and have a normal conversation without having to yell.

As far as telling the difference before and after, he services a lot of Dodge trucks for many of the farmers in the area so he knows what "normal" is. This chip is supposed to add 175 horsepower. I'm sure there's a difference to be felt. The 2011 Mega Cab hasn't been on the road yet. We just started it two days ago but we're waiting for a new radiator and bumper.

The larger exhaust applies to diesel engines because they are wide open to air flow. They don't use a throttle blade. Engine speed is controlled strictly by fuel volume. Even at idle speed air flow is so huge that the larger exhaust has benefits.

On gas engines air flow is restricted at all speeds except wide-open-throttle. The exhaust diameter is designed to handle severe driving conditions already, so the gains from a larger exhaust would only be noticeable if you drove near wide-open-throttle for long periods of time. Also consider that pipe diameter is chosen to tune the engine response. That's why race engines don't automatically assume larger is better. If you look at the headers you'll see all the tubes are exactly the same size and length and they aren't real big. That forces the exhaust gas to go fast enough to get out, and that momentum contributes to a "scavenging" effect which has to do with how well all the spent combustion gases get cleaned out of the cylinders. Larger header tubes result in slower exhaust gas flow so there's less momentum.

The diameter of the exhaust contributes to setting the points of highest power and torque. It's one of the variables an engine designer uses to shape the personality of an engine. A good example was Chrysler's 440 c.I. From the '70s. It was used in highway police cars and large motor homes. Those were two totally different applications. The motor home needed very high low-speed torque to pull away from stop signs to get going. That was accomplished by retarding valve timing and other changes like the exhaust manifolds. The police car, (I had one), would start out at low speeds like it had a puny engine, but it would "come alive" above 60 mph. You couldn't squeal the tires but at higher speeds it just about tore the seats off the hinges. The same was true of the larger GM engines. Transplanting an engine from one application into another could leave you disappointed or amazed. To see the power or torque in the speed range the engine package was designed for, you had to have all the parts of that package. Simply changing camshaft timing, for example, might move the power curve to a different range of engine speeds and that may change the transmission's optimum shift points and things like that.

The exhaust diameter plays a role in that tuning too. There is a chance you could improve performance in the type of driving you do most often by going to a larger diameter system, but it's probably more likely you won't notice any difference at all. I suspect it's pretty unlikely you would notice a decrease in power with a larger exhaust.

As for that echo my friend mentioned, I don't know where his pipes came out. I just wanted to point that out as something to be aware of before you have to learn it from your own experience. On his diesels the pipe exits at the right rear corner of the box but it's pointed more to the right than the rear. I went on a three-hour road trip with him yesterday to a car show. It was easy to hear the exhaust, but I could have slept if it wouldn't have been for that miserable garbage can-banging noise he listens to on the radio!

Very sorry to ignore you for so long. I just accidentally found a bunch of automated e-mails in my spam folder.

Changing tire size doesn't accomplish much. By the time you raise the ground clearance to amount to anything you'll have to contend with the tires rubbing on the inner fenders when you turn. You'll also have to visit the dealer to have the speedometer reprogrammed. Usually they only have a list of standard tire sizes to select from on the program menu.

The most important thing to look at is whether you'll be changing scrub radius. Taller tires will do that and wheels with a deeper offset will do that. What will NOT change it is going to wider tires and wheels that keep the center in the same point. They can only add about a half inch to the inside before something will rub on the suspension parts. If you also add a half inch to the outside, scrub radius will stay the same. I've never seen a chart or any reference material indicating which wheels and tires would be acceptable, and 90 percent of the tire salesmen you talk with won't even know what scrub radius is or how it affects your truck's handling.

The truck is painted and has been on the road for about three weeks. Rode along on a four-hour trip dragging a grossly overloaded 32' goose neck trailer to deliver his sister's stuff to their new house. He used the truck to move her from Austin, TX to western WI. It rides really nice.