Tuning Performance and Fuel Requirements - Ok, so I purchased this truck about 2 months ago. I love it, 2004 Silverado 2500HD. Not a Z71 or an SS package so ...

Ok, so I purchased this truck about 2 months ago. I love it, 2004 Silverado 2500HD. Not a Z71 or an SS package so I'm assuming it's the LQ4 motor. Previous owner says it needs to run 91 octane. First on a stock motor I'd call BS all day, even at 10.1 on the higher performance LQ9 with todays heads and casting technology 87 octane isn't hurting or predetonating the motor.

However he did the hypertech tuner and turned it up, I suppose my questions is could he have advanced the timing to a point where 91 is a necessity? Or am I just lighting up money and burning it as fast as the fuel i'm replacing. (mind you I'm lifted on 37s so my economy is averaging 10mpg)

Also, volant cold air intake and there's a flowmaster exhaust system both of which don't really effect octane ratings but I was also curious as to any other easy instal items that will help push a little more down to the wheels.

what kind of changes have you seen with Throttle body (aka bbk throttle body) Throttle body spacers and performance MAF Sensors

if he used the hypertech on the truck it is possible that he set it for the premuim fuel tune. so that would require 91 octane

The LQ9 not only has higher compression but advanced timing and other changes to the tune that require 91+. It's like the different levels of Diablo's tunes, they have a 87 that will run on everything, 91 and then the Diablo Tune (93 only). If you run lower octane gas you will probably only lose power becuase of knock retard but it could cause worse damage.

OK, anyone have feedback on the other mods

do NOT get an aftermarket MAF sensor...

keep the stock GM MAF sensor... they're good for 550/600+ hp anyway, so there's no need to change it... and keep the screen in it too if it has one...

And the throttle body spacer for fuel economy?

Those things are just about as good as the 80 dollar "Chips" which are just a resistor that messes with you MAF reading and do more harm than good.

Thank you for the good advice

The spacers don't actually hurt your motor but they do nothing and usually cause fitment issues with intakes if you choose to get one or already have one.

It has volant right now, I think the next real step will have to be gears to take the load off the motor. Or hope a supercharger can be tuned to save a little.