5.3L to 8.1L

Well we figured this winter we are looking to make a change. right now we have a 5.3L turbo, fun to drive around town etc, but looking to do something different. So we picked up an 8.1L. Figure we would shoe horn this in there with a turbo or blower.
Has anyone made this swap happen. What I am concerned about is the electrical stuff. Can we take the truck computer and just tell it its a 8.1L with proper tables etc.? Or is this going to be a fun headahce making project?
Any help would be great pm or drop a line.

Rick

ive seen it, but the 6.0 is just as good and fits alot easier!

And the 8.1 is such a gas hog, 8-9 mpg.

do it b different.....

I think motor mounts might be differant. I think Quick may know for sure.

Big motor 2 big twin turbos.

Not worried about gas milage etc right now, I have a truck for that. This is a test truck and lets test some stuff. The 5.3 is great I could figure out this surging crap. I already have a tire roasting set up, just surges in the upper rpms.
Looking at expanding the line up and see how it is already setting in the garage I figured I would try to make something happen over this winter.
We are looking at twin 76s or maybe a blower. It will be different thats for sure.:)
We have a 6.0L here as well but really want something different...

should be a beast, but I don't know how hard it will be to find a blower cam for that thing, or headers or most anything elsefor that matter.

it has been done before
http://image.automotive.com/f/featur...ngine_View.jpg

in this truck.
http://image.automotive.com/f/featur..._Side_View.jpg

Any data on the truck. was that a 1/2 ton or did it start off as a 3/4 ton. He is missing the turbos or blower I am thinking. LOL

I am not too worried about finding the other items, mainly the computer stuff is got me on a little edge.

The beast,, maybe thats what we will call it... thanks;)

theres a guy on PT.net thats got a 8.1 L twin turbo'd or at least turbo'd in the projects section, its pretty wicked looking, i would like to see it done, i think it would be cool. thats a big motor. I think one problem that might be there is i heard somewhere that they don't rev up as high as the 5.3L or the 6.0's, has anyone else heard this? Since i was watching one of Mic's videos of his truck where it was on the dyno and was at just under 3k and then 3k and boost like crazy, if the 8.1L doesn't go farther than 4500k then that might be a problem for high end boost.

just a thought, if you do it i want plenty of pictures.

worst comes to worst you will just need to pick up an 8.1l computer. wiring is another story but should be rather easy, easier then my truck anyways..

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Originally Posted by Turbo6.0L

Any data on the truck. was that a 1/2 ton or did it start off as a 3/4 ton. He is missing the turbos or blower I am thinking. LOL

I am not too worried about finding the other items, mainly the computer stuff is got me on a little edge.

The beast,, maybe thats what we will call it... thanks;)

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i dont know, i just searched google images to see if i could find anything...i searched "8.1 swap" i think

Got the PCM and all harness's with the swap. I went to upload and it will not allow me to log in. Changed password, no luck.:(
I will be taken lots of pictures.

Yea that was the half ton and 3/4 ton truck. It was a tire roaster on trucks with mr DAVID

none of the usual tuners support the 8.1 computer, like say nelsons or S&P?


With the rpm peak comments and parts issues, I think ur confusing folks, they dont understand torque. :D Personally, I think this is the beginning of the slickest project on this site.

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Originally Posted by banker099

it has been done before
http://image.automotive.com/f/featur...ngine_View.jpg

in this truck.
http://image.automotive.com/f/featur..._Side_View.jpg

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Actually that particular truck was not an engine swap. They did a body and suspension swap. I have that issue of truckin' right here. It is however a swap that I would like to do

Can you scan and send me a copy?

I figured it would be a little work inthe fab area to make it happen. And since I find little data on it (not a good looker uppper) I am betting its a fun one.
A little cutting, a little welding, alot of sweating a touch of hammering and it fits. LOL
Thinking old school, big engine in a 1/2 chassis. Usually the 3/4 stuff is lifted, and beefier. So instead of a 454SS.. Build a 496 BEAST.:)
Hopefully by the time this is done I am a little ok alot more versed with HP tuners...

how much hp does an 8.1 come with stock

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Originally Posted by DuBbLe C

how much hp does an 8.1 come with stock

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I think it's around 340hp/455tq.

Heads cam and intake you can get over 500hp.

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Originally Posted by ramair2002

I think it's around 340hp/455tq.

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i dont htink its that much. its one reason why they dropped the 8.1 cause the power of the 8.1 vs 6.0 along with mileage wasnt that much difference

Gas & Diesel Chevrolet & Ford Engines - Truck Trend

just going off this site. may not be 100% accurate though...

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Originally Posted by ramair2002

Gas & Diesel Chevrolet & Ford Engines - Truck Trend

just going off this site. may not be 100% accurate though...

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i stand corrected, i was thinking the 300hp from the diesel

I agree though, the 6.0 seems to be a much better platform overall

It is but 8.1 are pretty crazy! Me and a buddy form high school tried to put one in his 2001 rcsb but it didnt turn out well and we had some computer problems and its half together in a storage unit :( maybe one day it will run
http://i25.photobucket.com/albums/c9...r/DSCF0502.jpg also i belive whipple makes a blower for th 8.1

I figure alot of people go to a 427 or larger out of the LSX block. Keep in mind not building for any one reason other then because I thnk it woudl be cool. :) Not sure how long if it will work out, and if it doesn't then it doesn't no big deal. I think the 6.0is a great step up I have one of those laying around as well. But the 8.1L is more wow then a 6.0L I think.
Already talked to my engine builder, with some good pistons, cam, and a port job on the heads, he thinks the engine will be a freakn beast.
But thats months away for today.

Quote:

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Originally Posted by ramair2002

Gas & Diesel Chevrolet & Ford Engines - Truck Trend

just going off this site. may not be 100% accurate though...

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Nice find, I am looking forward to this and another project we have been working on.

Doesnt the 8.1l use big block chevy parts and not lsx as far as aftermarket goes?

yeah its like a 7th gen big block i think and its nothing like an LSx and apparently different form the 5th and 6th gen big block as far as block construction but i feel sure internals are the same.

I helped (just a little welding) a customer with his twin turbo rear mount on his 8.1L 3/4 ton. He's running 10psi, pump and larger injectors. The allison takes quite a bit of the power, but
It's pretty fast and lots of torque, but i think a 6L would stay with it.

Sounds like a neat project!

good luck
allen

I would look at it in the perspective of future profits. How many small block to big block conversions do you think people will be doing? Are you going to be gaining customer sales on such a miniscule niche market? Why not work on a setup for a more popular vehicle like 73-87 or 88-98 1/2 ton 2wd chassis trucks with the LSx based engine conversion? Make it a bolt in kit for those that don't have fabrication skills or access to a welder.

There is hardly a mileage difference between a 6.0L 2500 and an 8100 2500 stock because the 6.0L has to work so much harder to do the same work....and the 8100 has a 5-speed auto (or six speed manual).

The 8100's all get horrible mileage but so does a stock LQ4 in a 2500 truck pulling loads. The 8100 didn't make the cut because it didn't sell. It didn't sell because it cost a little more to operate than a 6.0L but a lot more on the sticker (mostly because it was extra cost and the 6.0L was standard)....and although a lot less than a diesel on the sticker and operating cost, it was still too much money when compared to the capability of the Duramax.

It's not a bad engine at all....it's just really large by external dimension, very heavy being almost all iron, gets poor mileage (bad excuse not to use one), and has hardly any aftermarket support because of its relative rarity. Vicious cycle...

Man yall are thinking way to hard on this.LOL
The reason to it is
because its there.
Not for profit, not for gasmilage, not even for power.
Just wanted to see if we can.
We already can kill the tires @ 45mph.

TrickPerformanceProducts, builds alot more 1 off type pieces for customers then we do mass production stuff. Sure the electronic are mass produced, and the turbo its are somewhat mass produced. But any really laid outfab work is usually limited to a handfull of customers, and the really wild stuff is limited to even less.
Thats ok with us, it allows us the opportunity to build what our customers want and to always be working on something a little different.
Mass production stuff is boring to me, did it for almost 9 years @ a nitrous company.
I strongly believe if someone is looking for gasmilage they should have never bought a truck. I have a daily driver that makes pretty good gas and is the all around parts getter. This is a test truck to test new things, new ideas, and different ways to do things. It is used a bunch in the electronic development of our products. back on track.

I hope to be at the dyno this week with the 5.3 and then I can pull it out and start shoe horning this monster in. :)

OH on side note, If we had a kit that gave you 700-900whp that would be a bolt in that would be cool too. :)

This all reminds me of my build. 1998 Vortec 454 into a 1989 K-1500

LINK

any updates on this, this will an awesome swap!

Nothing new, we had to figure out what was wrong with the 5.3 first. thought is was electrical and did not want to have a new set up with an old electrical problem. Probably start tearing the 5.3 out within a week. Had to get back to work on some big projects we have been waiting on parts for.

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Originally Posted by Quik

to fit 8.1 youll need the front frame clip since the rails are shaped differently. wouldnt be a direct swap. best to start with a 3/4 ton 2wd truck

anything can work if bust out the torches and welders

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I don't understand why would you need to do any frame work to fit an 8.1L in a GMT800 half-ton 2wd? The 8.1L has the same mounting as the old 7.4L, 5.7L and 4.3L V6. Being the 4.3L was an option in the GMT800, I don’t see why it wouldn’t bolt right in.

If you are thinking the A/C compressor would contact the frame, it just might. Just use GM medium duty truck, 2000-2002 3500HD or Workhorse Custom Chassis accessory brackets and move the A/C compressor to the driver’s side top of the engine and alternator to the passenger’s side similar to the L29 7.4L brackets. Same with exhaust manifolds. Any BBC exhaust manifold will fit the 8.1L. You would think one of them would fit the frame if the original 8.1L manifolds posed an issue in a halfton.

I dropped a 2002 8.1L into a 1978 K10 a while back and was surprised how easy it actually was. Used the same engine mounts, clutch and pressure plate from the 454HO that was removed as well as exhaust manifolds although I did use a specific 8.1L flywheel. The 8.1L is pretty much a direct bolt in. Mine is running on a Delphi MEFI-4 engine controller similar to the RamJet engines and marine engines. I may change it over to a MAF system sometime but so far I am happy with the speed density MEFI-4 system as it a much less intrusive wiring harness to deal with. This ’78 running a MEFI-4 controller on a custom calibration would run circles around the 454HO it replaced and definitley has a lot more nut than my stock 2001 Silverado 2500HD with an 8.1L.

http://farm4.static.flickr.com/3092/...95dec50dbb.jpg


A few YouTubes.
YouTube - Dirty Engine

YouTube - 8.1L mild launch

YouTube - Westcliff Stuck again

Install pictures is my sig.

I bet it would fit but a 900 didn't come with a 7.4 or an old school 5.7 either. The factory 8100 trucks have a 2" body raise over a half ton....and the frame is different. Just need some custom engineering. The 73-87 bodies did come with 454's in half ton form in the 70's.

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Originally Posted by GasGuzzler

I bet it would fit but a 900 didn't come with a 7.4 or an old school 5.7 either. The factory 8100 trucks have a 2" body raise over a half ton....and the frame is different. Just need some custom engineering. The 73-87 bodies did come with 454's in half ton form in the 70's.

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I was a sales technical liaison to the Silverado/Sierra Brand Teams in 1998 during the launch of the GMT800’s so I am well aware the GMT800’s did not come with a 5.7L or 7.4L although they did come with 4.3L V6’s. My point is the 4.3L has common engine mounting as the 5.7 and 7.4L (6.5L diesel too), which is exactly the mounting the 8.1L uses.

While the HD frame is different from a LD frame, as it has a much taller frame channel to achieve a higher section modulus for increased GVWR. The taller frame was used for added strength to the hydroformed frame rails and contrary to popular belief, was not designed taller for the Allison, although it does help with fitment.

Regardless, HD or LH frame, I still see no reason why an 8.1L won’t fit in a GMT800 or even GMT900 half ton. Look at the GMT800 Suburban and Avalanche. They came with 8.1L and the Suburban/Ave frame has more in common (channel height) with a halfton frame than a HD frame so the taller frame to fit a 8.1L is a mute point. I would be curious to see the article on the truck in post #8 where someone said the orange halfton truck had a body swap.