4.8 light towing

[nate3531]

Guess I will be first since no one else will post here.

Truck is a 2000 Silverado, 4.8 now I know these engines have the torque band pushed higher into the RPM curve than the older tbi and vortec engines, but the raw stats suggest a 4.8 should tow a light load as well or better than any of those older engines. However mine will not. It is about as weak as any truck I have ever driven. Load is a 14' single axle with a John Deere D130 mower on it. Shouldn't be more than 1500lbs total. This truck shouldn't even notice that load.

My current suspects of my lack of power are faulty clutch fan, clogged cats, and just general sucky torque from a baby v8.


Opinions and suggested course of action accepted.

 

[2003tahoe]

swap to efans and get high flow cats

 

[nate3531]

I considered both those options. plus maybe a laptop tune...

 

[RAGMC]

Id start with the basics like a tune up and fixing whats wrong that 4.8 should tow that much weight fine stock.

 

[nate3531]

Yea, I may try that first, something is definitely wrong. I have only got 11.9 mpg the last 2 full tanks of gas. When I first got the truck it was getting 14.6-15.1 every tank. Suddenly dropped off tank before this one.

 

[RAGMC]

I would also service the trans and while you where down there Id install a corvette servo. IMO one of the cheapest mods you can do on these trucks that you will see an dramatic improvement.

 

[nate3531]

Transmission was just rebuilt in Feb, I had him use upgraded parts, and a shift improver kit. Would a better servo not been part of that?

 

[nate3531]

Took the intake tube off and cleaned the crap out of the throttle body, it had a lot of carbon buildup. Went ahead and removed the EGR tube from the intake and cut it down flush with the intake wall, changed the oil and filter. Drove a lot smoother and seemed more responsive. Going to replace the air filter and plugs tomorrow probably.

I could tap the catalytic converter with my fist and hear a rattle. I'm not sure it was the internals or just the case rattling. Thinking if I can get my local muffler shop to do universals I may get some from summit and a new muffler all installed at once.

 

[2003tahoe]

The shift improver if it was a transgo wouldnt be in it but it is good to install for only $20 sometimes cheaper i still need to put the transgo in but i have to wait 6 more months been in my room for 2 or more years so far

 

[Nasty02Avalanche]

If the guts went sideways in the cats - you will not get any airflow through them.

I would suggest that you take it to a GM garage and have the problem diagnosed.

First 10 years / 100,ooo miles, the exhaust is covered under warranty.

 

[nate3531]

Truck is 15 years old with 152,xxx miles. Warranty is out of he question. Truck is running a lot better with a fluid change, tune up, and modding the EGR tube that obstructs the throttle body. I also cleaned the crap out of it with carb cleaner while I had the intake tube off. It had a good 1/16th build of up carbon on the lip of the butterfly blade. it still feels so much weaker than I'm used to with my trailer hooked up. Around town driving is a lot better now though.

 

[silverado13]

e fans is probably next on my list, already got the tune for it

 

[silverado13]

dont bother with a tune for a 4.8, my tuner said that 6.0s and 5.3s are de tuned from the factory so you can get some juice out of them but the 4.8s......well not so much

 

[2003tahoe]

Find a 5.3 and put the 4.8 pistons in it and bump the power up a little

 

[silverado13]

Wouldn't you need new rods too?

 

[2003tahoe]

not from what we do i think the l33 is the same way as 4.8 pistons and 5.3 block but pistons are coated with graf.... something that i cant spell

 

[silverado13]

Which would make up for 1/2 a liter?

 

[2003tahoe]

just bumps compression up a little

 

[nate3531]

Well it was my clutch fan, I bought a new one for $57 from Autozone and installed it tonight, took it for a test drive and wow, she is a different animal now. Ass dyno says I'm in a LS engine and not a 4 cylinder now. This weekend I will load the mower up on the trailer and go for a test drive just for a direct comparison. I may still do efans and keep the clutch for backup. Think I will also get a Diablo predator to remove torque management. My transmission is fresh with a shift improver kit and should be able to handle the extra stress.

 

[silverado13]

i hate clutch fans, they rob so much when they come on