vf171

I bought our '02 2500 4WD 8.1L mainly beacuse of brute towing power. I have a small tractor I like to haul around and play with and this thing does it perfectly.

I have a question about the engine though. How in the world is it only rated for 325 hp??? I have a 5.3L in my 1500 Silverado and it has the same hp rating. I realize the torque is way better with the 8.1L but come on. There has to be a way to unlock the potential hp in the 8.1. Anyone have any links or experience doing it?

ZX1100F1

Nothing that would really "unlock the potential hp in the 8.1" this side of a blower but it is rated at 340 hp not 325.
The 8.1 is built of the old 454ci block and head design, the new 5.3 is of new technology.

With that said there are a couple of things that you can do, the internal pipe in the muffler is necked down so a muffler or exhaust system upgrade helps this engine is a great place to start, also junk the stock thermostat for a 180 degree unit.

tasturbo86

I don't claim to fully understand the relationship between torque and horespower, but the 8.1 was designed for TORQUE.
TORQUE is whatpulls the trailer.
Compare the torque number between the motors and you will see the difference.

vf171

I didn't relaize the 8.1 made so much more torque. I knew it would be a bit but the numbers I found indicate almost 125 ft-lb more. That's an increase of around 40% with an increase of almost 6.5% in horespower. Looking at it like that sheds new light on it for me.

I realize torque is what gets the work done but horespower is a measure of how quickly the work get's done. But, being that the 8.1 is capable of doing 40% more work in a slightly shorter amount of time I don't think there is much room for complaint on my part. Granted the energy consumption is generally about 40% more so ain't nothing free, I know.

2004urb

The formula for HP is Torque X RPM'/, Constant 5252.
The 8.1, based on head design, cam, design, timing, etc. delivers peak torque at a lower RPM, hence lower HP rating.

Kerr

The answer is how much moeny do you want to spend.

on the 8100 you can expect around these numbers. Of course it depends on price and who maked the part.

1) Intake, abour 20 hp 20 lbtq. $300
2) headers 30hp 45 lbtq $500-2K
3) Cat back exhaust, 15 hp 20 lbtq $500-1500

You can also have some go into the computer and turn off the torque management on the 4L80E and you will get all the hp the truck has. On the other forums people have logged the TM while driving and GM pulls as much 60% of the power threw fuel and timing when you go wide open. They say its safer.. I bet it will just cause you do big burnout

If you really want to have some fun, ( what im looking into) Is a head & cam swap. Run you from $3K + depending on how much you want. Ryler claims there head and cam package makes 425 hp on regular fuel. Crawler also makes some cams... IF you have high milage you could go all out with a board block, pistons, new crank, then the head and cam, but that would probably $8K... should be good for 550hp..

As far as forced induction you have Nitrous, turbo and blower.

Ive see a few truck with a 150 shot of spray but i would not go that way.

Whipple. make a intercooled blower that take it to 450hp and 800lbtq ( those are crank figures) its about $6500. a few years ago a guy had this on his and he burb was running low 13's at the track...

STS is also an option.. There rear mounted turbo ad 125 hp and 150 lbtq. I havent done one on a 8100 but we have done it on a 5.3 silverado.. made little over 300 wheel hp also did one a stock camaro Z28 it made 403-410 wheel hp ever pull...


My plan is this.

1) Intake, cat back
2) Long tube headers
3) ecu work to remove the tq management.
4) cam ( got have some thump thump thump with 496ci)
5) heads
6) blower on down the road...

VenomTT

I agree with Kerr, it is the same information that I have. Plus this link. for 525 HP with cam change.

http://www.cranecams.com/?show=newsLetters&no=31

I'm planing on Twin Turbo Vortec 8.1L, I took it from a 2003 Avalanch, with a 1999 camarao ECU without electronic accelerator, TH700 transmission from Monster Motorsports for 650 HPso that's the plan at the fly wheel. 10 psi, 48# injectors, turbocharged cam and water injection. It is a copy from nelsonperformance. And it is in a '55 chevy.

http://www.nelsonperformance.com/avalanche.htm

And here is some results on how much power this engine can handle. I took this results from the internet, not sure if ti is true. It is from a turbochargedand N2O.

This is on a stock Vortec 8.1L so you can see how much power this engine can handle.

??? Psi boost 400whp 440wtq = 470-530hp depends on .75 or .85. at the wheels. 525-585ft/lb

with N2O[/b] 550whp 618wtq = 650-735 HP depends on .75 or .85. at the wheels 727-824ft/lb

that’s a minumum of 650 HP and 727 ft/lb.


I'm sending this information even that it is an old post, just to share my two cents.

Regards.