Hi all. Picked up the mag for the first time over the weekend and enjoyed it quite a bit. I am looking to increase the horsepower and torque of my 02 Avalanche. Did some towing over the weekend and i just am not happy with it's performance for higher speed passing and climbing at more than 4% grade. I really don't want to get into anything that requires too much work; and have been reading a bit about. Intake systems; cat back; computer chips and injectors. Plus a few other systems that could be "snake oil" so to say

I am looking for recommendations on proven; reliable upgrades to accomplish this; and I am guessing I am looking to boost it by 50-100 horsepower and a likewise %increase in torque. I think mine is the 4.8 but i doubt it matters much for what I am trying to accomplish.

Thanks for any input
Mike  

Hi Mike! Welcome. As far as I know, I think all the Avalanches are 5.3 or higher. A 50-horse gain might be achievable with bolt-ons, but 100 will likely require a supercharger or more dramatic measures. I would recommend a programmer like Hypertech or Superchips for a quick increase that should get you 10-15 horse. The rest will be incremental gains from headers, intake, and cat-back exhaust. JBA makes smog-legal headers, and there are a number of good intakes out there on the market. I know a lot of people have said they've been happy with AEM's Brute Force line.

If you're looking for some major gains, you're almost going to have to go with a supercharger. For the GM trucks, I've been most impressed with the Magnacharger, but Whipple and several others make kits as well. Personally, I'd stick with a Roots or screw-type supercharger if you go that route, as it makes the most noticeable difference in low-end torque. I am not a huge fan of the somewhat peaky power delivery of centrifugal superchargers. Hope this helps. Let us know if you have any other questions.  

Wow Thanks for the quick and informative post. You are correct on the engine size. I must have been that under impressed with it's towing over the weekend.

I would imagine that the biggest gains from bolt on's would be with intake, chips, ignition and injectors. Not necessarily in that order. Would this be a mostly correct assumption?

The real issue is holding speed at an incline of more that 4 degrees or so; unless I am driving at unsafe speeds.

Also passing with or without boat in tow at highway speeds is not "adequate".

I do not want to spend a ton of money; nor do I want to modify it much. Yes a ton is relative. The real problem is I really do not know how much horsepower will be "adequate"

I do wonder about the systems out there that supposedly create hydrogen and mix that into the system. Theoretically a win situation; with the added bonus of a reduced temp burn. Any experience with that?

Thanks
Mike  

Mike, injectors on a normally-aspirated engine with just bolt-ons would probably be superfluous. You've got to think of an engine as an air pump. The main thing you want to improve is the airflow into and out of an engine. Therefore, I'd probably do intake, exhaust, headers, chip/programmer. Bigger injectors on the same size engine with a stock cam will probably only increase fuel consumption.

One thing you can do with pushrod engines that almost mimics the effect of a bigger cam is putting different rocker arms in it. I know SLP offers different-ratio rockers for the Gen III and IV GM V-8s.

Actually, SLP offers a package deal. It's not exactly "cheap" at $2,700, but the company is claiming 350 horsepower total. You can check it out here. It consists of an intake, headers, cat-back exhaust system, new rocker arms, and a programmer.

Aside from putting a supercharger on it, that's probably your best bet.