Anyone have an 8.1L in your Blazer?

[6.2Blazer]

The only comment I have is regarding the MPG numbers people give between the 5.3, 6.0, and 8.1 engines in factory trucks. You need to keep in mind that you are not comparing apples to apples as there are more variables than just the engine. All the 5.3 MPG numbers come from 1/2 ton (1500) trucks which have more emphasis placed on fuel economy numbers and daily driving. They are lighter overall, generally have higher gears (usually 3.42 or 3.73 axles or higher and the 4L60E has a higher OD ratio), and less rotating mass (smaller trans, t-case, axles, driveshaft, etc...). All of the 6.0L (except for a small handful) and 8.1L engine MPG numbers are all from 3/4 or 1-ton trucks that are heavier, have lower gearing, and much more rotating mass (the 4L80E and 14FF soak up a lot more power than a 4L60E and 10-bolt).

I'm not saying that the 6.0L and 8.1L get better fuel economy than the 5.3L, just that you need to take into consideration that the 20 MPG from the 5.3L and 13 MPG from the 6.0L is not all from just the differences in the engine. If you take the 1500 and 2500HD side by side and swap engines between them I'm sure the MPG difference gets a lot smaller.

 

[rob h]

That is very true, I just looked over weights on a 03-06 ext cab short bed in the difference between the two..

1500 curb 4,925 gross 6,400

2500hd 5,600 9,200


Decent difference, in the gas trucks the hd only came in 3:73-4:10. Both are super close in hp rating tho..The hd trucks didn't have e-fans either, just clutch fans.


That should tell you some with the fuel mileage, sorry to add this bull to your thread....its prob not needed at all but my vote is small block, I like the 6.o....mine has been good to me.

 

[Larry]

Also keep in mind, us folks living in high altitude already suffer from roughly 15 to 20% power loss on a naturally aspirated engine vs. the sea level guys. How an engine runs in the Midwest or even PA (PA isn’t really high altitude and doesn't have real mountains either, PA has hills ) is considerably different than how one would run here in CO or at Colby’s place in Reno. Reno is around 4,500 ft.

Altitude alone is one main reason I always opt for the largest engine in anything I buy or swap. I noticed a huge power gain a few months ago while playing around Death Valley then noticed the power continually getting lower the closer I got to home, especially climbing over Wolf Creek Pass. Out here in the West is it nothing to drive over 7,000 ft. in elevation in one day. Leave home at 5,000 ft. and cross over the continental divide to camp/fish a few hours later where it is 13,000 ft. If there is any good excuse for a big block, altitude is a good one

Altitude changes is where a diesel, or any turbo engine for that matter, really shine as altitude doesn't affect forced induction engines as badly.

In Death Valley a truck loaded to 8,000 lbs with an 8.1L runs like a rapped ape burnout.

At 13,000 ft. not so much....an 8.1L runs more like a 5.3L. Just imagine how those little engines feel when playing in the extreme altitudes

 

[modernbeat]

...Altitude changes is where a diesel, or any turbo engine for that matter, really shine as altitude doesn't affect forced induction engines as badly...

I can tell you that our turbocharged Subaru hillclimb car looses about HALF of it's power between the start line and the summit of the Pikes Peak hillclimb. The naturally aspirated service car can barely make it to the top. The 2002 Duramax and the 2009 Dodge Cummins both made it easily, but you could still feel the power loss at that elevation. My 6.0 2500 had a hard time going over Monarch Pass last year.

On mileage, my last two trucks:

2003 2WD 2500 standard cab, long bed with the 6.0, 4L80E, 4.10 gears and 265/75-16 Goodyear Silent Armor tires got 12mpg at it's best and normally about 10-11 whether it was city or highway, towing a light open trailer with a racecar (3500 lbs total) or empty.

2002 4x4 2500HD extended cab, short bed with the 8.1, Allison 1000, 4.10 gears and 285/75-16 Goodyear Duratrac tires gets about 15mph on the highway and 13mpg in town, loaded or empty.

Both speedos are corrected for the non-stock tire sizes.

 

[kennyw]

Colby, when the shop starts the emission testing part of the test is to make sure that the engine that is in the vehicle belongs there (in your case a conventional old school SBC and nothing else). If they see a BBC or even an LS engine they will now send you to a referee station to have it tested the first time.

That is California rules... every state is different and I doubt many of them have a visual inspection. Washington and Oregon do not do this. I don't know anything about Nevada however.

 

[dhcomp]

This thread is killing me. Another vote for Not a TBI 350 like i did

 

[colbystephens]

I found a .pdf file of the training manual for certification of a NV smog shop. It does in fact say that the emissions test has to be performed to the spec of the make and model of the engine. That's no problem.

I still don't think that smog shops actually check this, though, because most of them aren't mechanics and wouldn't know the difference.

 

[ashman]

decided which way you're going to go yet?

 

[colbystephens]

No. Not yet. But, I am more and more interested in the big block...

 

[GMCbigblock]

No. Not yet. But, I am more and more interested in the big block...

Very interesting discussions.....It took me some time (with fun) but I noted the viewpoints made by all with due respect (it's evident that “Relativity Theory” has strong presence; besides the logic).


Well.....Having gone thru the '89 posts', this post #90 firmly votes for 8.1; given not only my application but also the personal-experience; which left me no room to live with anything smaller than 8.1L displacement.


I believe the "CK-5" was born & built with a misssion.....and it has to continue holding it as strong as possibly achievable!


Honestly, I can't imagine for a minute driving my Blazer with even "8.0L Engine"! Good luck making the "best-fit decision"....but make it right once.