DIY Cold air intakes:
This is not really a cold air intake in the truest sense of the word, but doing this mod will still net you a few extra horses.
Most of the benefit will come at wide open throttle, but it will still enhance a few miles to the gallon out at cruise speeds. You *need* to match a cold air intake to your engine *after* you have gotten an aftermarket exhaust in the truck. Putting this together wastes time and effort if you do not have a cat-back system installed. I have had to bore out my catalyst on my last trip down to Florida, it was plugged and cooked badly from a pre-existing condition the previous owner had fixed. (The truck would not be running today if it was not addressed) Usually a fuel regulator or injector "nut kit"(that's the plastic fuel supply and return lines from the internal fuel "rail" inside the upper intake on VIN "W" '95 Blazers) on these CPI fuel injected engines will puke itself up and get to leaking something badly, dumping raw fuel in your upper intake and plenum. This of course enriches fuel, makes the truck run awful, dilutes your oil and plugs up the catalyst terribly. I will not go into the oddball nonsense it does to your oxygen sensor(s) on top of all of this. However, a Carsound performance catalyst was added to a mandrel bent, stainless steel exhaust system with a Flo-Pro 750 muffler under the belly of the truck. (It lost 65 pounds of steel in the process, the OEM muffler is huge, quiet, and power robbing!) But without further ado, I present the "Ghetto Cold Air Intake" which allegedly, is "impossible" to do with an engine of this type from this model year. It works, trust me:
First you need to get your Sawzall out, with a stout metal cutting blade. Go at the slowest pace as possible. The plastic the intake and airbox are made of is very tough. Going too fast will either loose you a finger when partially molten plastic grabs hold of the blade and tears the works out of your hands; or you make a mess of the plastic when the saw bounces out of the slot you are cutting. First, using the small, square breather hole in the airbox, use the right hand side of it as a guide to make your first cut. You want to cut inside the airbox hole to remove all of the plastic to the right of this hole, leaving merely the upper lip to act as a seal when you clip the box back together around your air filter. Make another cut, following just behind the lip of the seat and "skeletonize" the box by leaving only the left hand side of the airbox hole and the airbox material in place. This serves two purposes: 1) A heat shield on the side that faces the radiator so you are not sucking in heated underhood air. Heat bad - lower intake temps makes a naturally denser air flow which will "trick" the truck's computer into adding more fuel to the air mix. Denser, enriched fuel mix gives you more power out of the hole, and most certainly as you approach top end and wide-open-throttle. 2) You still have the left hand side to slip back into the airbox's retaining slot to keep it stable and it restores the geometry needed to plug your PCV air supply back into.
Next, remove the tank "bellows" sticking out of a hole in the rubber boot by your airbox. This is a resonant chamber, tuned to cancel out induction noise. They engineered this engine to run as silently as possible, like it was going to be parked on red velvet in a rich guy's house. Come on, it's a compact light-duty sport-utility with one of the largest and most powerful V-6's ever made by GM. Free up those ponies and treat it rough - it wants it, and just sucks it up! But anyway, once that is removed, you are going to need to plug it up with something to keep unfiltered air from entering the intake and your plenum. What works is using a baby food jar lid stuffed up into the hole, and then sealing it snug and tight with a stainless steel radiator hose band.
Further up, if you have removed the intake completely from the truck, you are going to find another resonator cavity that sits atop of the fan shroud. It is anchored through a rubber grommet and a barbed connector at the passenger side of the fan shroud. Pop the works up and pull it out. Get your Sawzall out again and get to work. Chop it as close as possible to the intake's main tube as possible. Remove all sharp edges when done with a rasp or file. Now don't get lazy here! This is going to leave a big, gaping hole in the side of your intake tubing. Wash and let air dry the entire assembly. It's clean when water does not bead, but streak off of the hard plastic and wants to spread on it's surface. Once air dried, layer on duct tape. Yep, duct tape here is being used for EXACTLY what it was made for. Cut strips long enough to go around the intake, overlapping at first one side of the hole by 2 inches. Overlap the tape in strips that covers half of the last piece of tape you put down. Keep doing this until you are 2" away from the other side of that gaping hole. Once that is done, repeat with Aluminum duct tape. This is not only more abrasion resistant, because one part will touch the top of the fan shroud; but adds an extra layer of protection, heat shielding, and makes it airtight under vacuum.
You are now ready to secure your new, Ghettoized cold air intake into place. Before you do that though, these engines are prone to having a mild idle problem caused by a slightly plugged Idle Air Control Valve. These trucks idle like shit when that gets all goofed up with crud that collects over time. Get yourself a can of throttle body cleaner (cheap, under $2 no matter where you go - make sure you use one with a chlorinated solvent!) and a replacement IAC valve gasket. I went with a top shelf Felpro rubber and steel seal. Knock your IAC off with a #15 Torx wrench and a tap with a screwdriver after removing the servo motor's control wire. Scrub the seal area on the engine upper intake and the valve's body with seal remover and a wire brush, but do not physically touch the tip of the valve's pintle. (The round part that looks like a needle hat goes into the valve's housing on the upper plenum) Once it's clean, flush with the carb and intake cleaner and let air dry. Spray the area where it goes with a healthy dose of the carb/intake cleaner too and scrub it with a small, soft children's toothbrush. Douse it again when done scrubbing to flush the brown and black crud you knock off out of the valve seat. Stick the works back together with your Torx wrench again, being mindful to install the gasket with the striped side facing out. (Towards the IAC valve itself) Then push the throttle open with your thumb on the cam that connects to the accelerator cable and flush the interior of the valve body out and hit both sides of the butterfly valve. Once that is all clean, put your Cold air intake into place, mindful to connect your Intake Air Temperature sensor (IAT). Put the tube from your PCV breather back into the hole just behind the airbox, and seat that puppy back into place. Tighten the stainless band until snug, not tight. Tight will get the rubber boot of the intake split and then where will you be? That's right, waiting for two week until your GM/AC-Delco replacement arrives at your local parts counter or worse - you swallowed a shitload of sand and dust and ruined your engine. But this is what it looks like when it's back in place:
Reset your computer and wait for the last of the carb/intake cleaner to evaporate out of your intake bore. Resetting the computer involves removing the negative battery terminal from it's post, then go inside the truck to the driver's side fuse panel. Pop out your T/L-CTSY, RDO, ECM-BATT and ECM-IGN fuses. Smoke a cigarette, flirt with the cute blond next door - make a sandwich. This is going to take a little bit. After 10 minutes, pop your fuses back in and then reconnect your battery terminal. Now, she is going to be really hard to start. Your intake's going to be full of solvent vapor, not air. It's going to have to suck out the bad stuff to make with the good stuff. I got a false start, where she cranked and kicked over, but then sputtered and died. Waiting for the fuel pump to prime again, I then cranked and she came right to life. She idled roughly as she burned off the rest of the vapor, but when the clean air hit, she idled just fine. Hold the RPMs at a fast idle for 30 seconds (1500 RPM) then let her go. Note the nice black/gray cloud coming out of your exhaust - that's the last of the solvent burning off. She will clear up and idle fine on her own in just a minute. Once that is done, put her into gear (drive) but hold your foot on the brake. Do not touch the gas, just let her idle for 2 minutes to let the computer figure out how to idle with a free breathing IAC valve and the denser air mixture you are getting from the cold air intake. Then take her for a spin! Mix your travels a little. I went for a lazy, winding romp down the highway to Lake Weddington to a little patch of off-road goodness there that leads to the outdoor shooting gallery. (Sorry guys, it is closed at this time) Popping her into 4-wheel high, I took her for some fun in the rocks and gravel - let me tell you, there is a noticeable amount of perkiness at low engine speeds when you are crawling through the rocks with the intake modded out like this. Shaking the dirt off, I took her for a spirited jaunt back down the highway - without the resonators and the filter being exposed to suck up any available cold air under the hood, she ROARS. Damn near spun the wheels all through second gear on dry, level pavement. I will follow up in a month's time with whether or not it is saving me gas, but she has tons more power with this modification under the hood and Flow-Pro 750 single baffles under her ass for the exhaust. This project is complete, and looking *smart*.
Most of the benefit will come at wide open throttle, but it will still enhance a few miles to the gallon out at cruise speeds. You *need* to match a cold air intake to your engine *after* you have gotten an aftermarket exhaust in the truck. Putting this together wastes time and effort if you do not have a cat-back system installed. I have had to bore out my catalyst on my last trip down to Florida, it was plugged and cooked badly from a pre-existing condition the previous owner had fixed. (The truck would not be running today if it was not addressed) Usually a fuel regulator or injector "nut kit"(that's the plastic fuel supply and return lines from the internal fuel "rail" inside the upper intake on VIN "W" '95 Blazers) on these CPI fuel injected engines will puke itself up and get to leaking something badly, dumping raw fuel in your upper intake and plenum. This of course enriches fuel, makes the truck run awful, dilutes your oil and plugs up the catalyst terribly. I will not go into the oddball nonsense it does to your oxygen sensor(s) on top of all of this. However, a Carsound performance catalyst was added to a mandrel bent, stainless steel exhaust system with a Flo-Pro 750 muffler under the belly of the truck. (It lost 65 pounds of steel in the process, the OEM muffler is huge, quiet, and power robbing!) But without further ado, I present the "Ghetto Cold Air Intake" which allegedly, is "impossible" to do with an engine of this type from this model year. It works, trust me:
First you need to get your Sawzall out, with a stout metal cutting blade. Go at the slowest pace as possible. The plastic the intake and airbox are made of is very tough. Going too fast will either loose you a finger when partially molten plastic grabs hold of the blade and tears the works out of your hands; or you make a mess of the plastic when the saw bounces out of the slot you are cutting. First, using the small, square breather hole in the airbox, use the right hand side of it as a guide to make your first cut. You want to cut inside the airbox hole to remove all of the plastic to the right of this hole, leaving merely the upper lip to act as a seal when you clip the box back together around your air filter. Make another cut, following just behind the lip of the seat and "skeletonize" the box by leaving only the left hand side of the airbox hole and the airbox material in place. This serves two purposes: 1) A heat shield on the side that faces the radiator so you are not sucking in heated underhood air. Heat bad - lower intake temps makes a naturally denser air flow which will "trick" the truck's computer into adding more fuel to the air mix. Denser, enriched fuel mix gives you more power out of the hole, and most certainly as you approach top end and wide-open-throttle. 2) You still have the left hand side to slip back into the airbox's retaining slot to keep it stable and it restores the geometry needed to plug your PCV air supply back into.
Next, remove the tank "bellows" sticking out of a hole in the rubber boot by your airbox. This is a resonant chamber, tuned to cancel out induction noise. They engineered this engine to run as silently as possible, like it was going to be parked on red velvet in a rich guy's house. Come on, it's a compact light-duty sport-utility with one of the largest and most powerful V-6's ever made by GM. Free up those ponies and treat it rough - it wants it, and just sucks it up! But anyway, once that is removed, you are going to need to plug it up with something to keep unfiltered air from entering the intake and your plenum. What works is using a baby food jar lid stuffed up into the hole, and then sealing it snug and tight with a stainless steel radiator hose band.
Further up, if you have removed the intake completely from the truck, you are going to find another resonator cavity that sits atop of the fan shroud. It is anchored through a rubber grommet and a barbed connector at the passenger side of the fan shroud. Pop the works up and pull it out. Get your Sawzall out again and get to work. Chop it as close as possible to the intake's main tube as possible. Remove all sharp edges when done with a rasp or file. Now don't get lazy here! This is going to leave a big, gaping hole in the side of your intake tubing. Wash and let air dry the entire assembly. It's clean when water does not bead, but streak off of the hard plastic and wants to spread on it's surface. Once air dried, layer on duct tape. Yep, duct tape here is being used for EXACTLY what it was made for. Cut strips long enough to go around the intake, overlapping at first one side of the hole by 2 inches. Overlap the tape in strips that covers half of the last piece of tape you put down. Keep doing this until you are 2" away from the other side of that gaping hole. Once that is done, repeat with Aluminum duct tape. This is not only more abrasion resistant, because one part will touch the top of the fan shroud; but adds an extra layer of protection, heat shielding, and makes it airtight under vacuum.
You are now ready to secure your new, Ghettoized cold air intake into place. Before you do that though, these engines are prone to having a mild idle problem caused by a slightly plugged Idle Air Control Valve. These trucks idle like shit when that gets all goofed up with crud that collects over time. Get yourself a can of throttle body cleaner (cheap, under $2 no matter where you go - make sure you use one with a chlorinated solvent!) and a replacement IAC valve gasket. I went with a top shelf Felpro rubber and steel seal. Knock your IAC off with a #15 Torx wrench and a tap with a screwdriver after removing the servo motor's control wire. Scrub the seal area on the engine upper intake and the valve's body with seal remover and a wire brush, but do not physically touch the tip of the valve's pintle. (The round part that looks like a needle hat goes into the valve's housing on the upper plenum) Once it's clean, flush with the carb and intake cleaner and let air dry. Spray the area where it goes with a healthy dose of the carb/intake cleaner too and scrub it with a small, soft children's toothbrush. Douse it again when done scrubbing to flush the brown and black crud you knock off out of the valve seat. Stick the works back together with your Torx wrench again, being mindful to install the gasket with the striped side facing out. (Towards the IAC valve itself) Then push the throttle open with your thumb on the cam that connects to the accelerator cable and flush the interior of the valve body out and hit both sides of the butterfly valve. Once that is all clean, put your Cold air intake into place, mindful to connect your Intake Air Temperature sensor (IAT). Put the tube from your PCV breather back into the hole just behind the airbox, and seat that puppy back into place. Tighten the stainless band until snug, not tight. Tight will get the rubber boot of the intake split and then where will you be? That's right, waiting for two week until your GM/AC-Delco replacement arrives at your local parts counter or worse - you swallowed a shitload of sand and dust and ruined your engine. But this is what it looks like when it's back in place:
Reset your computer and wait for the last of the carb/intake cleaner to evaporate out of your intake bore. Resetting the computer involves removing the negative battery terminal from it's post, then go inside the truck to the driver's side fuse panel. Pop out your T/L-CTSY, RDO, ECM-BATT and ECM-IGN fuses. Smoke a cigarette, flirt with the cute blond next door - make a sandwich. This is going to take a little bit. After 10 minutes, pop your fuses back in and then reconnect your battery terminal. Now, she is going to be really hard to start. Your intake's going to be full of solvent vapor, not air. It's going to have to suck out the bad stuff to make with the good stuff. I got a false start, where she cranked and kicked over, but then sputtered and died. Waiting for the fuel pump to prime again, I then cranked and she came right to life. She idled roughly as she burned off the rest of the vapor, but when the clean air hit, she idled just fine. Hold the RPMs at a fast idle for 30 seconds (1500 RPM) then let her go. Note the nice black/gray cloud coming out of your exhaust - that's the last of the solvent burning off. She will clear up and idle fine on her own in just a minute. Once that is done, put her into gear (drive) but hold your foot on the brake. Do not touch the gas, just let her idle for 2 minutes to let the computer figure out how to idle with a free breathing IAC valve and the denser air mixture you are getting from the cold air intake. Then take her for a spin! Mix your travels a little. I went for a lazy, winding romp down the highway to Lake Weddington to a little patch of off-road goodness there that leads to the outdoor shooting gallery. (Sorry guys, it is closed at this time) Popping her into 4-wheel high, I took her for some fun in the rocks and gravel - let me tell you, there is a noticeable amount of perkiness at low engine speeds when you are crawling through the rocks with the intake modded out like this. Shaking the dirt off, I took her for a spirited jaunt back down the highway - without the resonators and the filter being exposed to suck up any available cold air under the hood, she ROARS. Damn near spun the wheels all through second gear on dry, level pavement. I will follow up in a month's time with whether or not it is saving me gas, but she has tons more power with this modification under the hood and Flow-Pro 750 single baffles under her ass for the exhaust. This project is complete, and looking *smart*.