Waste of time, my 7.4Vortec got 11mpg around town, my diesel gets 20mpg, and the .60cents difference wouldn't come close to even in fuel.I wouldn't take one if you gave it too me, unless you supplied the fuel too.
I thought the 8.1 was 502 cubic inches? I have a 2002 2500 HD GMC and it tows great! I have a 2004 360RK Open Road 10800 lb dry and the GMC has no problem with it. At 75 mph I get about 6 mpg (I know, I know). After blowing some chinese tires, I slowed down to 60-65 mph and I now get 8 - 9 mpg. I've gotten as high as 9.5. I try to keep the 8.1 at about 2,000 rpm, but, it seems to have more torque at about 2,400 rpm. I'm amazed at the mileagee difference I got by slowing down. I'd like a newer truck to get the integrated brake controller, but, I'd like another 8.1. I guess I'll just stay with what I got. If GM won't give the customers what they want, it's no wonder they had to shut-down some truck plants.
By the way you guys are right. They do not make 8.1 chevy engine anymore. In the past they did have in 3500 series truck. A friend of mine he said he thinks they stopped making 8.1 in 2004 or before. So I guess that is something for me to think about diesel. I just found out that Dodge and Ford have a special promotion. They offer 4500 - 5000 dollars off if you buy a new truck. That sound not too bad. I know diesel is about dollar more but 5000 dollars off (avg price for diesel 7000 dollars). Thanks for your sharing your thought or input.
I have a K3500 w/496 (8.1L) and an Allison. I have towed 10,000 quite regularly and would run at 66-67MPH in a 70 zone and 62-63 in a 65 zone. At the higher speed I get a constant 9 MPG overall average and at the lower speed I got 9.75 MPG. However in the city, empty, I usually get 8.0 MPG. Empty at highway speeds, the best I have ever got was 11.5 MPG, but usually 10.5.
The only thing that I really like about this gasser is that it towes head and shoulders above the previous diesels that I have had in my other F350 and 3500 series. Up to 10,000# being towed, I usually don't have to select tow/haul mode except in the long hills, Like I-77 WV T'pike or west of the Mississippi. With the couple of trailers that were around 14,000#, I do use the T/H mode.
I find that the 8.1L is an excellent TV, but very poor daily driver.
"Doc"
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It's gone because it didn't sell well, would sell even fewer with expensive gasoline prices, would kill GM's future CAFE numbers and is too expensive to build as a stand alone unit. The 6.0 shares the same manufacturing process and many parts with the other v8 GM engines and can be built alongside them. The old 8.1 just can't deliver fuel mileage that the smaller engines do and won't perform the work like today's diesels do. Kinda like ole Great Uncle Herschel's plow mule. It's day has come and gone.
It's still manufactured for the Workhorse Class A Chassis, and will stay in that chassis through 2010, and then the (anticipated and much guessed about) V-10 will take it's place.
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Yeah they still make it but, it's not sold in 2500 or the 3500 class trucks. They sell to RV makers, Boat engine manufactures plus the 4500,5500 class trucks, I have one in a 2007 2500 GMC love it for the work it can do. and it is a truck that carry's weight and tows 100% time. It's a pure work hard truck engine not made for fuel economy. If I run a lighter truck I'd go back to the 6.0. 8.5 MPG aver. city / highway
Bob Shaw wrote: I thought the 8.1 was 502 cubic inches? I have a 2002 2500 HD GMC and it tows great! I have a 2004 360RK Open Road 10800 lb dry and the GMC has no problem with it. At 75 mph I get about 6 mpg (I know, I know). After blowing some chinese tires, I slowed down to 60-65 mph and I now get 8 - 9 mpg. I've gotten as high as 9.5. I try to keep the 8.1 at about 2,000 rpm, but, it seems to have more torque at about 2,400 rpm. I'm amazed at the mileagee difference I got by slowing down. I'd like a newer truck to get the integrated brake controller, but, I'd like another 8.1. I guess I'll just stay with what I got. If GM won't give the customers what they want, it's no wonder they had to shut-down some truck plants.
The 502 was never put into a production vehicle. It was based on the Gen 5 and Gen 6 blocks.
The 8.1 (496 ci) is based on the Gen 7 block and was first offered in 2001.
Actually, IIRC, a larger part of the reason for the 8.1's demise (in pickups) had to do with new emission laws that came out a couple years ago.
Bottom line was, GM could not make the big block engine conform to the newer emission standards. Ford was able to with their V10 and V8, and GM could with the 6.0, due to (in part) the cylinder size being so much smaller. Had to do with them being to control the burn rate more efficiently with smaller cylinders. Big block V8s generate great low end torque, but they are horribly inefficient, and not the most clean burning engine. That was as I recall, the main reason for its demise.
Might have also had to do with cost cutting measures/demand as well. Cost a lot to keep/maintain a big block like that, since all its parts were specific to that one engine. So, when demand went down some, they may not have been able to justify keeping it 'cause of all the parts specific to that engine.
Ford kinda 'ate their lunch' in that dept, by building the modular V10. Doesnt matter how low the demand for the V10 gets, Ford can keep it around for a looong time, due to its modular design, and the fact it shares so many parts with other Ford engines. I've heard rumors that GM learned from that, is eventually going to do the same thing and come out with a V10.
Up until recently, they (GM) were still offering the 8.1 in marine applications. Seem to recall they stopped even that, which is a cryin shame, 'cause that doesnt leave boat buyers many good choices.
Now, whats really entertaining, is to watch the same GM folks that for years told us 'there's no replacement for displacement, 8.1 rules, beats Ford's 6.8 V10 hands down'. NOW, those same folks are talking about how powerful GM's smaller displacement 6.0 V8 is. Some even try to suggest it can compete with a Ford V10, LOL. I guess there *IS* a replacement for displacement, as long as its a GM engine? Hahahahaha!
Will
* This post was
edited 05/12/08 01:15pm by willald *
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