well if i was a tree hugger then i would have not bought a truck. number two if you have nothing productive to say why post in the thread?

 

Reality is though, that HP/TQ comes with a pricetag. My MPG dropped about 2 or so if i dont get on it. Problem is........I haven't figured out.

 

i am asking this becasue those are my goals for mods, and a friend of mine did almost the same setup on his 99 yukon and he gets alot better mpgs. But i have also learned that some mods react differently to the lsx motors compared to the older tbi v8s.

 

Your sig says you want 300 at the wheels. That will take some serious $ and you will undoubtably lose economy.
If i wanted better milage i would start with intake, catback, a real good tune and proper gearing for your terrain/style of driving. Anymore than that will cost you MPG.

 

well i have a decent intake. and my exhaust helped a little when i got it on. but i have heard of alot of guys getting alot better with a cam designed for lower end power. Did anyone put a cam in for between 1500 to 6000 for power range and lose gas mileage?

 

My cam is set up for 2000 to 6200. You are thinking of this wrong. The cam/valve/rocker set up is designed to provide lift and timing of lift on the valves. In most cases a person going with a cam change is looking for additional lift which means more air. More air means more fuel. More fuel means more horsepower. More horsepower means more foot travel to feel afore mentioned horsepower. I know of no one who has added a cam and claimed better fuel economy. If you are trully looking for additional horsepower but better fuel economy I suggest you get a custom tune. Allen can get you 20-30 horsepower and 3-5 MPG with just a tune. He did it for me prior to adding my bolt ons. Once you add a cam, IMHO you will lose fuel economy due to loss of vacuum, more airflow/fuel flow, and human nature.

Hope this helps....

 

Ok that makes since, but if the came had an increased vacum then economy could possibly go up right?

 

i guess 4.8's vs 5.3's really is a big difference...

 

My stock Vacuum before cam was -20" and even with the supercharger installed with stock motor I was getting 16-17 mpg on the highway. After head/cam/rocker/LT mods I see about -16" vacuum at idle. Granted with the cam my idle is higher, from 550 to 750, but my MPG around town is 10-12 and hiway at 65 is around 14.5 to 15.5.

Again, I suggest a good tune. It will easily provide 50 to 60% of what you would expect to pick up with a cam only as far as horsepower. The fuel trims and timing on the custom tune will be far superior than factory and will gain you 3-5 MPG.

Otherwise I think you will find the cam will increase your horsepower and decrease the mpg. It will all depend on the tune and your driving habits.

Hope this helps. Call Joe at Vinci. I think he will tell you the same. He also posts on this forum so maybe he will chime in....

 

Ok that makes since. They advertrise it as a good fuel economy cam though. When me and my dad worked on his 79 camaro we put in an early 70s lt1 cam and it got alot more power and better mileage, but that wwasnt the newer gen 3 motors too. I emailed nelson to see what they offered and thought about my goals and such.