Looking for good low-cost engine performance improvements?

[Eggert]

I am looking for advice and examples of past experience, good or bad.
My 2001 Yukon XL K2500 with the 6.0 liter engine and 4.10 rear end will be towing 9,000 lbs soon.
Will I become a traffic obstacle going up hills?
My gas mileage is 10 city, 14 highway.
How low will this go? Is expecting about 6 mpg reasonable?
Are there reasonable improvements (not the $6,000 supercharger) ?
2 things I hear are K+N air filter and computer re-programming chips that require high-test gas.
Any advice is greatly appreciated.
Take care, Eggert

[tonytone]

Westers PCM may be something to look into, although how much of a performance increase you might be able to get from it may be debatable, given your statement that you plan to do some serious towing. Notwithstanding the previous comment, specifically the part about towing--if there is one single performance mod that doesn't involve taking the engine apart or the addition of a supercharger which will offer the most improvement, performance-wise...the Westers is it. Put it another way--I'm not saying that everyone who's bought a Westers was completely satisfied with it, but I can say I've yet to see anyone who has tried both a Westers and a handheld programmer (e.g., Hypertech) claim that the handheld programmer offered the better performance gains.

[Vroom2]

I'd definitely recommend a cold air intake kit - either the K&N FIPK, Volant, or some other reputable brand, as well as a more free flowing muffler. You don't have to go loud - Flowmaster makes a 70 series 'big block' that provides happier airflow without a big increase in sound. (Probably obvious, but if you go with an exhaust system, be sure to have the pipe(s) exit out the side since you'll be towing.

Tony's recommendation of the Westers PCM is great advice. I'd agree - for $600 you simply cannot find a better performance mod.

Regarding traffic - I doubt you'd be an obstacle on hills, but 6mpg may be optimistic on anything more than nice flat terrain. It'll be interesting to see your results though - good luck!

Take care,
Jerry

[Eggert]

Thanks, Guys. I appreciate your advice.
I did order the K&N FIPK.
I looked at Flowmaster's web site, they do not have a 70 series big block exhaust for me - my system has 2 separate cats on 3 inch pipes.
The muffler has dual 3 inch pipes come in and out.
After that they have a Y to get from 2 to 1 pipe, still at 3 inches.
My muffler is 9" high, 12" wide, 24" long.
This is similar to the flowmaster dimensions.
Could this be a 'free enough' flowing muffler?
It does sound pretty hollow and roomy.
I did look at Western's web site, and their chip programming is very customized and detailed.
I do not want to pull/replace my chip, so I may go with the Hypertech programmer that connects to the diags port.
It costs 1/2 the price, and I hope that it is good enough.
They do show some encouraging Dyno pics.
Thanks again for your advice.
Please post any thoughts on this.
Take care, Eggert

[tonytone]

Eggert--yeah it's hard to ignore the fact that the Hypertech can be had for roughly half the price of a Westers. However...if you ever decide to get a different GM truck, odds are that you'll have to get another Hypertech (assuming that you like it enough to do so); whereas with the Westers, you get full credit towards another one--which could mean that ideally, it might not even cost you anything to get another one except S/H.

Bottom line--if you want the most power available just from tweaking the tuning tables, the Westers is the way to go; OTOH if you're looking more for the ability to switch between stock and modified programming, with the ability to change certain parameters (e.g., tire size) easily, then the Hypertech is your best bet (and yes, it'll retreive and clear codes too--a nice bonus...IF you know what to do with them).