VorTecxas
American Nightmare
I dynoed my pretty much stock 1996 Sierra SLE last weekend. No, I'm not making crazy power, no, I didn't do it so I can brag about numbers. I simply wanted to see what difference I had made on my 350 with what little I did to it before I swap in the L29. And, it was free. So, for all of you looking for free or cheap "mods", here is what I've done and the results
A little background on the truck-
1996 GMC Sierra SLE ECSS (pictured in my signature)
227,787 miles as of today (about 227,500 on dyno day)
Everything drivetrain wise is original (L31 350/4L60E/3.42 rear)
Out of 4 pulls, my maximum output to the wheels (I still have a 98MPH limiter)
is 219.47 HP@4400 RPM and 286.71 ft-lbs@3300 RPM
With a 24% drivetrain loss (which is what I was told by the tech running the dyno), that comes out to 272.14 HP and 355.52 ft-lbs. About 17HP and 25 ft-lbs over stock specs (255@4600 and 330@2800)
Here is the list of alterations (I wouldn't really call them "mods") I have done, mainly because I had the time or the parts already laying around. I'm not saying any one of these individually will really do anything significant, but as a whole they made a small difference, especially in throttle response (I've put 25,000 miles on this truck in the past 13 months, please don't try and tell me it's "mental" or I'm using a "butt-dyno", I know my truck and how it drives extremely well).
-Straight air intake (or Cold Air Intake, if you want to call it that). Just a generic 4" tube style, nothing fancy. It was on the truck when I bought it, but you can pick one up at AutoZone or Oreilly for about 35-40 bucks.
-Cone Gauze-type oiled air filter (K&N, Spectre, etc.). I have the Spectre (again, on the truck when purchased) mid-length size with the open end. It's mounted straight to the MAF. If you just pick one up from AutoZone or Oreilly they're about 25 bucks and work just as well as a K&N, I've had both on the truck and noticed no difference between the two. Kind of like having a blonde and then a brunette. They're different, but they all do the same thing for you.
-Descreened MAF. I've seen arguments both ways on descreening the MAF, I have had no issues. The screen simply pops out. I used emory cloth and sensor cleaner on the inner surface to clean the housing up a bit (take it apart and remove the sensor itself first), it was pretty nasty. And then I painted it red. Because I can.
-Cap the noise box hole. The big box that says "Vortec" on your throttle body hat is just a noise suppressor, I removed it and used a 2" plumbing pipe cap to block it off. About 3 bucks at Lowes or Home Depot, I already had one in my toolbox. Makes the truck sound a little meaner at WOT too.
-454 Throttle Body. Off of a '96 or later L29 or L21 454. The 8.1L one might work too, i'm not sure. I got it for 10 bucks at a local boneyard. It's the same size all the way through instead of tapering like the L31s, and it doesn't have that foot on the bottom of the throttle blade. You will need to modify it slightly to work with the throttle cable. If you're going to do this, see the "BBTB" notes at the bottom of the post for all that I did to it. If not, don't see the notes at the bottom of the post. And suffer the consequences.
-Exhaust. I have the stock tubing (cats deleted and straight pipe run) to dual Flowmaster 40s, I got them used for 30 bucks. Had a local hole-in-the wall shop do the work, cost about 120 bucks. Then dual pipes run out under the fender directly behind the tires to 2nd Gen Trans Am splitter tips. That part has nothing to do with the performance, I just think it looks good and sounds awesome.
-Cooling system. Electric fan. I pulled mine off of a Texas State Trooper Crown Vic. It can suck the air out of a blimp. I also have a 4 core radiator from a '99 3500 and removed my shroud and clutch fan. If you run e-fans its best to use a thermostatic switch instead of a flip switch or key power. It's much more consistent and doesn't rely on you maybe forgetting to turn them on after having a few at the local Hot Gals With Big Boobs Serving You Beer joint.
-170F Thermostat. May not be necessary for some of you. I live in Texas. It gets really damn hot. It helps.
-Tune-up. Plugs, wires, cap, rotor, PCV valve (yes, it is important), and fuel filter. I had done all of this about 8,000 miles before the dyno.
And that's it. I'm sure there is more you could do for free or cheap, but that's all I have and there are numbers to go with it.
BBTB notes-
You will need to use the throttle shaft from your 350 unit for your cable to work on the 454 TB. It's easy to remove. These instructions are the same for both units. You will have to remove it from the truck to do this, obviously.
-First, remove the throttle blade. Its two torx screws and then rotate the shaft to pull it out. It can only come out of the top of the TB. Depending how much crud is there you may have to wiggle it. Clean it while it's out.
-Second, position the TB on its side where you can drive the shaft out. I wrapped my TB in a rag and lightly clamped it in a vice with the TPS facing up.
-Third, remove the TPS and you will see the end of the throttle shaft. There is a ring holding the shaft in the housing. Using a hammer, easy but firm strikes, and common sense (don't be a dumbass!) (I used a 3 lb. sledge with a shop rag as a buffer), drive the shaft out of the housing, if possible without damaging the ring (though it's not extremely necessary, the blade will hold the shaft in place once it is reassembled).
Repeat to remove the shaft from the other TB. Then, put the 350 shaft in the 454 body and re-install the retaining ring (again, no big deal if you can't) and 454 throttle blade. I used a 10 or 11mm socket and a hammer to reinstall the ring. Don't forget the return spring, use the 350 one, the 454 is too soft and it sucks trying to drive in traffic with it. (Toe on the gas= HOLYCRAPHOLDONHEREWEGOHEYTHATCARSTOPPEDHOLYCRAPWEREGONNADIE!)
That about sums it up. I hope I helped at least one person. It would make all this damn typing worthwhile.
A little background on the truck-
1996 GMC Sierra SLE ECSS (pictured in my signature)
227,787 miles as of today (about 227,500 on dyno day)
Everything drivetrain wise is original (L31 350/4L60E/3.42 rear)
Out of 4 pulls, my maximum output to the wheels (I still have a 98MPH limiter)
is 219.47 HP@4400 RPM and 286.71 ft-lbs@3300 RPM
With a 24% drivetrain loss (which is what I was told by the tech running the dyno), that comes out to 272.14 HP and 355.52 ft-lbs. About 17HP and 25 ft-lbs over stock specs (255@4600 and 330@2800)
Here is the list of alterations (I wouldn't really call them "mods") I have done, mainly because I had the time or the parts already laying around. I'm not saying any one of these individually will really do anything significant, but as a whole they made a small difference, especially in throttle response (I've put 25,000 miles on this truck in the past 13 months, please don't try and tell me it's "mental" or I'm using a "butt-dyno", I know my truck and how it drives extremely well).
-Straight air intake (or Cold Air Intake, if you want to call it that). Just a generic 4" tube style, nothing fancy. It was on the truck when I bought it, but you can pick one up at AutoZone or Oreilly for about 35-40 bucks.
-Cone Gauze-type oiled air filter (K&N, Spectre, etc.). I have the Spectre (again, on the truck when purchased) mid-length size with the open end. It's mounted straight to the MAF. If you just pick one up from AutoZone or Oreilly they're about 25 bucks and work just as well as a K&N, I've had both on the truck and noticed no difference between the two. Kind of like having a blonde and then a brunette. They're different, but they all do the same thing for you.
-Descreened MAF. I've seen arguments both ways on descreening the MAF, I have had no issues. The screen simply pops out. I used emory cloth and sensor cleaner on the inner surface to clean the housing up a bit (take it apart and remove the sensor itself first), it was pretty nasty. And then I painted it red. Because I can.
-Cap the noise box hole. The big box that says "Vortec" on your throttle body hat is just a noise suppressor, I removed it and used a 2" plumbing pipe cap to block it off. About 3 bucks at Lowes or Home Depot, I already had one in my toolbox. Makes the truck sound a little meaner at WOT too.
-454 Throttle Body. Off of a '96 or later L29 or L21 454. The 8.1L one might work too, i'm not sure. I got it for 10 bucks at a local boneyard. It's the same size all the way through instead of tapering like the L31s, and it doesn't have that foot on the bottom of the throttle blade. You will need to modify it slightly to work with the throttle cable. If you're going to do this, see the "BBTB" notes at the bottom of the post for all that I did to it. If not, don't see the notes at the bottom of the post. And suffer the consequences.
-Exhaust. I have the stock tubing (cats deleted and straight pipe run) to dual Flowmaster 40s, I got them used for 30 bucks. Had a local hole-in-the wall shop do the work, cost about 120 bucks. Then dual pipes run out under the fender directly behind the tires to 2nd Gen Trans Am splitter tips. That part has nothing to do with the performance, I just think it looks good and sounds awesome.
-Cooling system. Electric fan. I pulled mine off of a Texas State Trooper Crown Vic. It can suck the air out of a blimp. I also have a 4 core radiator from a '99 3500 and removed my shroud and clutch fan. If you run e-fans its best to use a thermostatic switch instead of a flip switch or key power. It's much more consistent and doesn't rely on you maybe forgetting to turn them on after having a few at the local Hot Gals With Big Boobs Serving You Beer joint.
-170F Thermostat. May not be necessary for some of you. I live in Texas. It gets really damn hot. It helps.
-Tune-up. Plugs, wires, cap, rotor, PCV valve (yes, it is important), and fuel filter. I had done all of this about 8,000 miles before the dyno.
And that's it. I'm sure there is more you could do for free or cheap, but that's all I have and there are numbers to go with it.
BBTB notes-
You will need to use the throttle shaft from your 350 unit for your cable to work on the 454 TB. It's easy to remove. These instructions are the same for both units. You will have to remove it from the truck to do this, obviously.
-First, remove the throttle blade. Its two torx screws and then rotate the shaft to pull it out. It can only come out of the top of the TB. Depending how much crud is there you may have to wiggle it. Clean it while it's out.
-Second, position the TB on its side where you can drive the shaft out. I wrapped my TB in a rag and lightly clamped it in a vice with the TPS facing up.
-Third, remove the TPS and you will see the end of the throttle shaft. There is a ring holding the shaft in the housing. Using a hammer, easy but firm strikes, and common sense (don't be a dumbass!) (I used a 3 lb. sledge with a shop rag as a buffer), drive the shaft out of the housing, if possible without damaging the ring (though it's not extremely necessary, the blade will hold the shaft in place once it is reassembled).
Repeat to remove the shaft from the other TB. Then, put the 350 shaft in the 454 body and re-install the retaining ring (again, no big deal if you can't) and 454 throttle blade. I used a 10 or 11mm socket and a hammer to reinstall the ring. Don't forget the return spring, use the 350 one, the 454 is too soft and it sucks trying to drive in traffic with it. (Toe on the gas= HOLYCRAPHOLDONHEREWEGOHEYTHATCARSTOPPEDHOLYCRAPWEREGONNADIE!)
That about sums it up. I hope I helped at least one person. It would make all this damn typing worthwhile.
j/k
