4l80 went through changes over the years. So the earlier ones had some issues then the middle ones had some issues and they got most of the issues solved by the later years
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Anyone have an 8.1L in your Blazer?
- Thread starter colbystephens
- Start date
4l80 went through changes over the years. So the earlier ones had some issues then the middle ones had some issues and they got most of the issues solved by the later years
COCHEV
1/2 ton status
as much as i love big blocks, I'd say the 5.3 is the perfect K5 blazer motor. I've owned the 8.1, 6.0, currently have 5.3 in my tahoe, plus i've had several 454s in various rigs. For the wheeling that i've seen you do in your threads and the road trips you mentioned, I think the 5.3 is a nice blend of power and economy in the k5 platform
I apologize, my son got a hold of my phone
I was thinking maybe you were having a brain tumor too...
then I saw your avatar...
8.1 pad!
Colby, just gotta convince me to drop the BBC into my 03 Tahoe and then you'll have a 5.3L drivetrain instead :P
My experience has been that the 8.1L averages around 14 - 15 mpg on the highway at 62mph in my site truck. Thats with a light foot (company truck, no flooring it!) though.
My experience has been that the 8.1L averages around 14 - 15 mpg on the highway at 62mph in my site truck. Thats with a light foot (company truck, no flooring it!) though.
y5mgisi
1 ton status
Subscribed.
454Sub
5/8 ton status
Headers plus full exhaust, tune, XR270R cam, roller rockers, head and intake porting, valve springs and some other crap I cant remember = 18 MPG in the factory 2500HD 4WD extended cab truck.
Plus the thing will shred any tire you put to it with just about any gearing you ask of it. But this one in particular runs 4.10s and 33s.
Im slightly buzzed, but Im sure I have a build thingy mcbob in here somewhere with all the info on how I built it. BTW, the tuning on these is the major problem, not the motor itself.
And anyways, a TBI 350 isnt going to touch 13 with a lift and tires, so why not add a 8.1 that gets 12 or 18ish if your willing to do the extra labor like I did and will run circles all day over a turd tbi 350?
Plus the thing will shred any tire you put to it with just about any gearing you ask of it. But this one in particular runs 4.10s and 33s.
Im slightly buzzed, but Im sure I have a build thingy mcbob in here somewhere with all the info on how I built it. BTW, the tuning on these is the major problem, not the motor itself.
And anyways, a TBI 350 isnt going to touch 13 with a lift and tires, so why not add a 8.1 that gets 12 or 18ish if your willing to do the extra labor like I did and will run circles all day over a turd tbi 350?
mr250twostroke
1/2 ton status
I was thinking maybe you were having a brain tumor too...
then I saw your avatar...
8.1 pad!
Tapatalk, Sudafed and a sick 3 1/2 yr old :sly: he was drunk typing sorta...
5.3l all the way. 8.1 makes no sense for your application imho.
454Sub
5/8 ton status
An 8.1L never makes sense, but neither does drinking them last drinks before going home to the impending trouble the wife has already implemented. But, as well all know, it seems to happen and in my case, at that particular time, its worth it. Sometimes, you just have to say Keep Calm Chive On (basically F*CK IT) and rock the 8.1L.
mr250twostroke
1/2 ton status
Ummm, if I can make 18 MPG with a big block for a price similar to the 5.3 swap, then that's the route I'll take.
I'll have to look for your build thread.OR:
Russell: Here's me convincing you to put the BB in your rig: Do it.
I am conflicted.
I vote 8.1. But I also have no room for logic and reason in my life.
Go big or go home.
big reaper
1/2 ton status
Since I have to be different than everyone else I say put a twin turbo v6 in there.
But honestly I would go BBC if I had that option. I'm sure with the right gearing and a light foot you could get decent fuel mileage. Then again I called the 8mpg I got in my old truck decent mileage.
But honestly I would go BBC if I had that option. I'm sure with the right gearing and a light foot you could get decent fuel mileage. Then again I called the 8mpg I got in my old truck decent mileage.
I've got the 8.1 in my Avalanche and my 2500 HD...both have about the same lift and similar tires. The Avalanche has a super charger and quite a few other mods and gets about 8 mpg. The HD has more modest mods (exhaust/air intake/programmer) and gets about 10 mpg. The stock Tahoe has the 5.3 and gets about 20 mpg.
The 5.3 will work just fine...but damn, the other two are way more fun to drive!
The 5.3 will work just fine...but damn, the other two are way more fun to drive!
Colby keep this in mind, the FEDERAL law says you can go with the same size engine or LARGER but you CANNOT install a smaller engine than was original to your vehicle. With that being said the 5.3 is not an option but the 6.0 would be and would definately be what I would choose over the 8.1 engine. There is a TON of aftermarke support for the 6.0 versus the 8.1 and there is alot more fuel economy to be had with a 6.0
Also keep in mind that your first emission test after the engine swap MUST be done at a referee station who will then attach a tag to the door jam which states what emissions are required on the vehicle then future emissions testing can be done at any test station.
Also keep in mind that your first emission test after the engine swap MUST be done at a referee station who will then attach a tag to the door jam which states what emissions are required on the vehicle then future emissions testing can be done at any test station.
I thought that was Cali rules?
I dunno about NV smog rules, do they follow CA rules?
I just remember the size thing being a CA only rule. I have been known to be wrong though.
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Colby, the reality it is your money and your truck. Go with whatever fits in your budget and wants. Another reality is when playing with trucks like this the fuel mileage is a moot point. If fuel mileage is a big concern, you’re in the wrong hobby
All that said, you really can’t go wrong with any of the engines you mention and each one would certainly be stronger than a TBI 5.7L and as you can already tell it doesn’t take much to look around and see the 8.1Ls are often overshadowed by the Gen III LS engines just due to their sure abundance and popularity legacy build upon generations of older small blocks. There is nothing wrong with Gen III LS small block engines, they just are not up to task of propelling large heavy vehicles well in my opinion. The LS engines are low torque/ high HP engines where their happy spot runs at high RPM’s, which is exactly the opposite of what you want in a built tail rig. If you get behind the wheel of a LS engine it doesn't take long to notice they don’t build any real usable torque or HP until you spin the snot out of them where as an 8.1L is already making over a 100 lb. ft. of torque at IDLE! Think of the 8.1L being more like a diesel engine than a gas engine where it is a high torque engine at low RPM’s. I’ve only spun my 8.1L to 5,000 RPM on a handful of times in 5 years and 30,000 miles. The Gen III in my wife’s ’13 Tahoe spins to 5,000 RPM daily just to merge on the interstate. Low end torque is what you want in a trail rig. HP, not so important.
It amuses me to see a lot of people, such as 4x4High, often comment on the lack of aftermarket support for the 8.1L….Okay, seriously, let’s think about that for a minute, what do you really need from the aftermarket to bolt on a bone stock engine that is already capable of 425 HP and 550 lb. ft. with only ECM work and bump in fuel pressure? Any power needed above that is more for a race vehicle, not a trail rig. The best and worst thing about the 8.1L are most people know nothing about them.
I think you would be pretty disappointed in the 5.3L shortly after you go through the hassle of installing it. I was often surprised how much power our 2002 and 2004 Tahoes didn’t have when backed by the 4L60E transmission and 3:73 gears. Other hand, our 2013 Tahoe with the VVT 5.3L has considerably more power but that power doesn’t come up until you spin the hell out of it as I mentioned above. This Tahoe runs well but it sounds like the pistons are swapping holes just to get some oommfff out of it.
A 6.0L or 6.2L would be much better than the 5.3L but when it comes down to it you will find the 6.0L and 8.1L fuel economy is hardly mentionable once you start working the 6.0L hard to move a large truck. A few years ago I bought a 2005 Silverado 2500HD in total shambles for dirt cheap for the sake of fixing and flipping it. During the time I had that 6.0L Silvy and my 2001 Silvy with the 8.1L along with my ’78 K10 with an 8.1L it became very obvious the smaller engine in the 2005 had to work its ass off to do the same work. Around town the 6.0L Silvy was quite fast and athletic, probably helped by the fact it was the only automatic of the 3 trucks, but you load the 6.0L down with a car trailer and quickly it became a thirsty gutless pig that actually drank more fuel than the manual trans 8.1L trucks.
I also find the 8.1L to be an easier swap as it is a direct bolt into any older BBC or SBC, the 8.1L will accept any exhaust manifold or header from any old BBC and there are OEM accessory brackets available to move the A/C compressor up high so the frame doesn’t need to be hacked to death for the compressor clearance. Like an LS engine, you do not have to run electronic throttle control on the 8.1L.
I put together THIS thread to help people with 8.1L questions as I get bombarded with emails and PMs from people almost daily wanting to know how to do an 8.1L swap.
In the end, go with whatever engine you want, can afford or have access too. You can’t go wrong with any of them but some are better than others. It is very unlikely you will ever see anything under the hood of any of my toys with less than 7.4 liters. Actually, I am gathering parts now for second 8.1L swap…this time into the Polar Bear.
For the fun of it here is some real world fuel economy numbers on my 1978 K10 with the 8.1L......
The truck has a NV4500, 4:56 gears, 35” tires and weighs 8,000 lbs when loaded for long distance off-road excursions around the Desert Southwest. Last year, it delivered 11.72 MPG on a 1,555 mile trip around Utah, Western CO and back home to Southern CO. This trip was a mixture of desert wheeling, high mountain trail riding (Emogene, Red Cone, etc) with lots of highway in between. The fuel mileage was figured by adding the total the gallons consumed vs. total miles driven over the entire trip.
This year on the Death Valley trip my MPG numbers got skewed because I accidentally pumped a lot of gas out of the main fuel tank when I forgot to turn off the transfer pump a couple times. I know for a fact we never dropped below 10 MPG on that trip. Had I not lost so much fuel, my guess is we would have come in closer to 11 to 12 MPG again this year. Again, these numbers are on an 8,000 lb. truck with the aerodynamics of a drive in movie theater screen. A lighter truck would deliver much better results. My driving style is also more of an old man where I shift this thing between 1,200 and 1,500 RPM. Typically I am already in 5th gear around 40 MPH. The big block has enough low end torque where you can drive it like a Cummins.
Can you post some details of this Federal Law you speak of? I’ll have to call bull**** on that statement until some facts are shown.
All that said, you really can’t go wrong with any of the engines you mention and each one would certainly be stronger than a TBI 5.7L and as you can already tell it doesn’t take much to look around and see the 8.1Ls are often overshadowed by the Gen III LS engines just due to their sure abundance and popularity legacy build upon generations of older small blocks. There is nothing wrong with Gen III LS small block engines, they just are not up to task of propelling large heavy vehicles well in my opinion. The LS engines are low torque/ high HP engines where their happy spot runs at high RPM’s, which is exactly the opposite of what you want in a built tail rig. If you get behind the wheel of a LS engine it doesn't take long to notice they don’t build any real usable torque or HP until you spin the snot out of them where as an 8.1L is already making over a 100 lb. ft. of torque at IDLE! Think of the 8.1L being more like a diesel engine than a gas engine where it is a high torque engine at low RPM’s. I’ve only spun my 8.1L to 5,000 RPM on a handful of times in 5 years and 30,000 miles. The Gen III in my wife’s ’13 Tahoe spins to 5,000 RPM daily just to merge on the interstate. Low end torque is what you want in a trail rig. HP, not so important.
It amuses me to see a lot of people, such as 4x4High, often comment on the lack of aftermarket support for the 8.1L….Okay, seriously, let’s think about that for a minute, what do you really need from the aftermarket to bolt on a bone stock engine that is already capable of 425 HP and 550 lb. ft. with only ECM work and bump in fuel pressure? Any power needed above that is more for a race vehicle, not a trail rig. The best and worst thing about the 8.1L are most people know nothing about them.
I think you would be pretty disappointed in the 5.3L shortly after you go through the hassle of installing it. I was often surprised how much power our 2002 and 2004 Tahoes didn’t have when backed by the 4L60E transmission and 3:73 gears. Other hand, our 2013 Tahoe with the VVT 5.3L has considerably more power but that power doesn’t come up until you spin the hell out of it as I mentioned above. This Tahoe runs well but it sounds like the pistons are swapping holes just to get some oommfff out of it.
A 6.0L or 6.2L would be much better than the 5.3L but when it comes down to it you will find the 6.0L and 8.1L fuel economy is hardly mentionable once you start working the 6.0L hard to move a large truck. A few years ago I bought a 2005 Silverado 2500HD in total shambles for dirt cheap for the sake of fixing and flipping it. During the time I had that 6.0L Silvy and my 2001 Silvy with the 8.1L along with my ’78 K10 with an 8.1L it became very obvious the smaller engine in the 2005 had to work its ass off to do the same work. Around town the 6.0L Silvy was quite fast and athletic, probably helped by the fact it was the only automatic of the 3 trucks, but you load the 6.0L down with a car trailer and quickly it became a thirsty gutless pig that actually drank more fuel than the manual trans 8.1L trucks.
I also find the 8.1L to be an easier swap as it is a direct bolt into any older BBC or SBC, the 8.1L will accept any exhaust manifold or header from any old BBC and there are OEM accessory brackets available to move the A/C compressor up high so the frame doesn’t need to be hacked to death for the compressor clearance. Like an LS engine, you do not have to run electronic throttle control on the 8.1L.
I put together THIS thread to help people with 8.1L questions as I get bombarded with emails and PMs from people almost daily wanting to know how to do an 8.1L swap.
In the end, go with whatever engine you want, can afford or have access too. You can’t go wrong with any of them but some are better than others. It is very unlikely you will ever see anything under the hood of any of my toys with less than 7.4 liters. Actually, I am gathering parts now for second 8.1L swap…this time into the Polar Bear.
For the fun of it here is some real world fuel economy numbers on my 1978 K10 with the 8.1L......
The truck has a NV4500, 4:56 gears, 35” tires and weighs 8,000 lbs when loaded for long distance off-road excursions around the Desert Southwest. Last year, it delivered 11.72 MPG on a 1,555 mile trip around Utah, Western CO and back home to Southern CO. This trip was a mixture of desert wheeling, high mountain trail riding (Emogene, Red Cone, etc) with lots of highway in between. The fuel mileage was figured by adding the total the gallons consumed vs. total miles driven over the entire trip.
This year on the Death Valley trip my MPG numbers got skewed because I accidentally pumped a lot of gas out of the main fuel tank when I forgot to turn off the transfer pump a couple times. I know for a fact we never dropped below 10 MPG on that trip. Had I not lost so much fuel, my guess is we would have come in closer to 11 to 12 MPG again this year. Again, these numbers are on an 8,000 lb. truck with the aerodynamics of a drive in movie theater screen. A lighter truck would deliver much better results. My driving style is also more of an old man where I shift this thing between 1,200 and 1,500 RPM. Typically I am already in 5th gear around 40 MPH. The big block has enough low end torque where you can drive it like a Cummins.
Can you post some details of this Federal Law you speak of? I’ll have to call bull**** on that statement until some facts are shown.
I am somehow convinced I need an 8.1 in my K5 now.
He's real good at that I've noticed
Fubeca
1/2 ton status
I don't think federal law says this. Federal law basically says you can only switch to something else that is certified for the chassis (http://www.epa.gov/compliance/resources/policies/civil/caa/mobile/engswitch.pdf)
However, it is a little hazy about something newer if installed with all of the certified emissions equipment from the newer vehicle.
I think you will have basically no way to pass federal law with a new engine - however, as long as it is running clean and looks complete - I bet most state places will pass you - especially if they have to do a sniff test and it passes.
Just make sure it looks clean, professional and runs clean with the OBDII stuff intact.
There may be an argument that the 5.3 is in the current version of the chassis (tahoe) but I don't think a EPA lackey would go for it - and they would require every component of the emissions equipment that is a part of the newer vehicle to be installed and functional on the older vehicle.
