Let me put it this way, if you made 2-4 more MPG, would you care if you had to use 93?

at $2 a gallon for 87 and 25 gallons it would cost $50 a tank and we'll say you get 12 mpg. You'd get 300 miles for $50, that's 16 cents a mile

at $2.50 a gallon for 93 and 25 gallons would cost you 62.50 and lets say you get 14 mpg on higher compression. You'd get 350 miles for $62.50, that's 17 cents a mile. If you got 15 mpg you'd get 375 miles a tank and cost 16 cents per mile.

If you can get an additional 3 mpg your gas cost would be the same price per mile on 87 at 12 mpg as it would on 93 at 15 mpg

A 3 mpg increase is not far fetched. I gained 2 mpg by switching to 93 and a tune on my 2004 5.3, I gained close to 4-5 mpg from a tune, intake and exhaust on my 2014. And that's even with turning off the 4 cylinder mode. I'm not the only one that's seen these results. It's happened many times.

 

 

When I had my truck tuned, the tuner grumbled about me using 87. I asked what the benefit of 93 would be, he said 1-1.5 MPG at best. Hence why I say no thanks and stuck with the 87 octane swill. If I could for sure get 2.5-3 MPG - I could be swayed. He also wants me to switch to a 160 degree thermostat, currently have a stock one. (187 degree I think?) I currently get 15 MPG consistently, a lot of rural and stop & go. The price difference between 87 and 93 around here is about $0.60 - $0.70 per gallon on average.

 

 

 

LMAO x2. On the forums the opinions > math & logic kills me. It's like everyone would rather assume than actually crunch some numbers.

I don't doubt any of that at all. As for the 706 head being the best, I would say if you're looking to just slap a head on a LQ4 I would agree. If you're able to do a little touch up (milling) the 243 is superior. The intake valve size is a key area of concern, but with a 4" bore the 243 valve is still going to be unshrouded and flow very well. But seriously nothing wrong at all with slapping some 706's on there.



The way I saw it was it's a hell of a lot more fun for an additional $10-$11 a tank BUT I also got some extra day of driving out of it. So when you crunched numbers it was only actually costing me about $3-$4 more per tank. Who gives a **** about $3-$4 a week (was my view). I understand things are tight sometimes and a few bucks is a few bucks, but if that were the case I doubt you'd be considering doing a head swap etc.

Believe it or not, a free-er breathing setup opens up a little MPG too, you wouldn't think so but headers help a little, good flowing exhaust a little, good tune a little, higher octane letting you run higher timing and compression a little. And ALL of that adds to more hp, torque, and MPG. There's a few other things too that open up power and MPG.

I think you'd really be surprised how much different and better the truck will feel with some compression and timing in it on 93. It's far snappier, more powerful and fuel lasts longer.

I have gas stations around me too that sometimes charge up to $0.70 or so more per gallon, and other stations charge .40-.50 more. Just try to find the ones that aren't ripping off the premium fuel users.

It's your truck, but if you want to use 706's prepare to up the fuel, you may get by with 89, not sure, ask your tuner what he thinks.

 

If you did the small chamber heads and 93 octane I wouldn't be surprised if you picked up 4-6 mpg.

If you tighten up the quench a little with those .045 gaskets that I posted you could run the timing up a little hair more and that also contributes to hp, tq, and MPG. Or you could leave timing and have a little extra safety margin on detonation.