well we just got a 04 yukon denali XL with the 6.0 in it. this engine is weak. it suck down the gas and can barly get out of its own way. is there any ideas as to how i can get a some pep out of it?

Also those who have them how can you tow with them? when i was in massouri it had trouble pulling it self up a hill.

The 6.0L is an LS1 based motor. There are quite a few items to "waking" it up. I think there is a section on LS1tech.com for the truck motors that may be able to help you out.

I have a o3 2500 hd and the 6 litre has been more then enough to get the job done. I has pulled 5 tons of hay, up and down hills, hauls 550 gallons of water , pulled stuck farm machinery out and more then enough stumps. It also has run with some of the best, so as far as sucking i dont see it, compared to a diesel though there is a difference.

I agree the 6.0 sucks, very disappointing especially compared to a Duramax. I had to tow my friends truck 250 miles this weekend and I couldn't wait to get home after that. As much gas as it drinks it should have a better power range. One upgrade is a PCM (westers, nelson) that changes shift points & timing specified to your needs. I dont have one yet but am seriously considering getting it if i cant sell this truck first. 6.0 is ok for everyday driving other than the fuel mileage issue but when it comes to towing it really struggles. I'd try a PCM for your Denali, but don't expect it to pull like your Duramax because it won't even compare

Add me to the "6.0L is disappointing" crowd. I will say in defense of the 6.0, you have to get the RPMs up before it actually wakes up. Also, I am used to driving my '01 Duramax and the oomph is right there off-idle. My wife loves her '04 Sub 2500, but I am unimpressed. I think I should have opted for the 4.10s and I think this would have helped the 13.5 mpg around town issue. I like the idea of 87 octane so programmers for power are out....for me anyways. Maybe a set of long tube headers and an exhaust, but I would hate like he11 to pay upwards of 1500 to 2000 bucks to get 10 - 15 hp especially when it doesn't show up until 5000 RPMs!! I think GM could've done better with where this engine makes it's power in the RPM range...my $.02 worth. I guess I'm sayin' I wish the DMAX would have been available in the Sub last year....:(

JP

Guys...2 totally different things...6.0 and the Dmax....I have the 6.0 and yes it was gutless until I put in a tuned PCM. Mind you , it is definitely not a DMAX as far as performance, but it is much better than it was. Peppier and a lot smoother. Better shifting by far. The 6.0's are choked up by GM's Torque Management. The PCMs remove this and that annoying "bog" is gone. Still not the motor the DMAX is, but it is what it is. I'm OK with mine...

i agree it is hard to justify the millage for the lake of power. if they put an 8.1 in it i would be all over that. but i love the denalli i just hate the motor

tmg115 & Heartbeat Hauler,

Both of you have Suburbans.

One a 3/4 Ton, one is a 1/2 ton both are 3 ton trucks with the capability to haul a lot of "extras" making these some of the heaviest vehicles with the 6.0 engine.

Then, and this is a biggie....you both have 3.73 gears. These engines NEED 4.10's. Slap on 265's and you should really have 4.56's.

All this combined with very heavy torque management in place, and they can become rather sluggish. Especially to someone comparing them to the Duramax.

tmg115 & Heartbeat Hauler,

Both of you have Suburbans.

One a 3/4 Ton, one is a 1/2 ton both are 3 ton trucks with the capability to haul a lot of "extras" making these some of the heaviest vehicles with the 6.0 engine.

Then, and this is a biggie....you both have 3.73 gears. These engines NEED 4.10's. Slap on 265's and you should really have 4.56's.

All this combined with very heavy torque management in place, and they can become rather sluggish. Especially to someone comparing them to the Duramax.

I think your point is well taken and it's kinda what I was saying. I was also saying that it would be nice if the 6.0L made it's power (TQ) about 1500 RPMs lower and about 600 RPMs lower for HP. But I am spoiled by my DMAX and think it would be way better than even the 8.1L in my SUB. I think that the new DMAX rumored to make about 250 hp and 400 or so ft lbs. will be better than the 6.0L because that power will be available at a much lower RPM. I also said that in hindsite, I should have gotten the 4.10s, but I thought the highway mileage would have suffered. I am probably wrong in that way of thinking.
JP

This is a complaint I hear almost every day about the 6.0

We have been doing the STS turbo upgrade for the 6.0 and have had feedback from customers saying they are getting on average 3 mpg better mileage.

The system boosts horsepower and torque in all parts of the power band, but especially in the midrange. (Go to ststurbo.com to see dyno sheets.)
The reason people are seeing better mileage is in part because you no longer have to downshift out of overdrive and get the RPMs up to make power.
In fact allot of people say it rarely downshifts at all unless they are pulling BIG hills.

The 6.0 system adds about 130 HP and 140 Ft lbs to the wheels.
This system can be installed in less than 4 hours by just about anyone.
We have special pricing and can drop ship anywhere in the country.

I tried a Westers PCM "upgrade", but it really didn't do all that much (unless you call pinging an advantage). Some of the other companies might be able to do better with their PCM tuning, but I don't have any experience with them so I can't really say.

Perhaps you should have the dealer check your Denali out. I have the 6.0 with 4:10's in my CC, and I really haven't noticed the sluggishness you have. Yes, it's a gas pig -- I get around 12MPG -- but it seems to be pretty responsive. I tow a trailer and backhoe combo that weighs around 8500 pounds, and it does a quite good job with it.

I own a 2001 1500HD with the 6.0 and I have towed my 5er weighing in at 8500 dry over 2000 miles yes drank a fair amount of gas but worked very well each time I hve towed. I am upgrading to a 3500 Duramax at the end of June though and can't wait.

From reading this thread, and from personal experience, it sounds like the key difference between those that are dissatisfed with the power of the 6.0, and those that are sastisfied, lies in the rear gear. The 3.73'ers are unhappy. The 4.10er's are pleased.

Looks like 4.10 must put the 6.0 up to the right rpm level for power.

By comparison, Ford tuned their rear end to 4.30 to get the most out of their 6.8L V10.

A 4.30 gear would really be nice in the 6.0 trucks too.

Would help those that slap on 265 or 285's to bring the power loss back.