super08

I will have to get back to you. I plan to use it this summer (I drive a winter beater now). I will be able to tell pulling and empty. I have been curious too.

STingray1300

After reading these posts, I was curious, so I was on the freeway today and here's my results:

I am tuned (HyperTech), and when I put the cruise control on at about 67 mph, my Roush boost gauge was reading 6 in/HG of vacuum.

So the comment about being tuned having anything to do with when the boost kicks in is lost on me. Am I missing something?

FYI, you don't have to actually be getting boost to hear the turbos spool up. Maybe that's what is being talked about (?)

Also, if you're in high gear (6th) and start getting a little boost registering, like in a head wind or going up a grade, watch what happens if you shift to 5th gear! The rpms will increase slightly, but the boost will drop - yielding better mpgs. Check it out!

Manuellabour247

[MENTION=34229]k-stater88[/MENTION] I drive from Wichita to Hays once a month. I have a SCrew 5.0 with 3.55's. Up to Salina I get abou 19.5 to 20.7 with cruise set at 78. (20.7 was with a 7mph tail wind). Going from Salina to Hays I get 15.3-17.8 with cruise set at 78.(Again 17.8 was tail wind). I haven't driven my buddies eco that way but I don't think it would be too far off. (At least by the numbers he's given me....but he has kind of a heavy foot. lol)

When I had the 3.31's I got a best of 21.4 going to Salina and a best of 17.9 to Hays. The hills west of Salina are about like around Manhattan. So that would be my little input. I've gone to Riley a couple times and the headwind didn't take my mileage too far. about 1.5 to 2.5mpg less. And I don't usually drive with a heavy foot.

k-stater88

Thanks, that is valuable info. Most of my highway mileage is from Salina to Wichita, and i've never averaged better than 15, but then again mine is 4x4.

hobbesnmina2001

You can get get an Elm327 blue tooth adapter that reads the ECU and use the android app Torque. You can set up gauges for cat temps, boost, etc. You'll find out that the turbos are sized right there, what I mean is with no boost hit the gas and no lag! 420 ft lbs of torque @ 2500 rpms, 90% at 2000 and you have torque at an rpm no Naturally aspirated 5.0 or 6.2 can match for towing.
My 2003 Silverado 2500 HD 6.0 ltr was rated at 365 ft lbs at 4200 rpms but that thats not the rpm we tow at. My Silverado using HP Tuners I could log delivered torque and towing we were in the 2000-2400 rpm range the engine torque output was in the 220-230 ft lbs range.

Carlos

Howler

For most the break even point is about .90 difference.

So E85 needs to be 0.90 cheaper a gallon just to break even.

hobbesnmina2001

Technically a naturally aspirated the engine cruising (unloaded) should be 10-12 " vacumm, maybe 16-18" at idle. When seeing 6" means the turbos are working which equal boost. Just because we're not seeing positive lbs of boost doesn't mean we are not in boost. When towing heavy weights I see boost plenty which is why the mpg is more like a 6-7 ltr engine.
A 3.5 ltr motor with ~14.7 boost breathes like 7.0 ltr, rough rule of thumb.

STingray1300

What I am talking about specifically is the poster that said he sees 6 lbs of boost (in the positive) while doing 65mph in cruise control on a flat road.

THAT is a big difference to what I realized under similar circumstances. Which would make a huge difference in mpgs.

Wanted33

@k-stater88, I have the '13 5.0L w/3.31's in a Crew Cab 5'5" bed. It averages 19-21 hwy at 70 mpg's interstate with rolling hills/flat land. It has been as low as 18 with a heavy headwind or steeper hills. Around my small town with a stoplight at nearly every intersection, and too damn much traffic it will average between 15 - 16.5 mpg's. With 9060 miles the overall avg. is at 18.1 mpg's by the computer thingy. That is as good as my previous '11 in the same set-up with the 3.7L & 3.73. gears that had an overall avg. of 17.9 mpg's with a bit over 18000 miles. I drive normally, without much pressure with the right foot most of the time. It seems all the engines (after reading many thread on mpg's) when compared to the same set-up are so close in mpg's the difference becomes a moot point. That of course is without towing. In my mind without towing heavier loads the choice is a matter of preference. I say get the one that makes you smile the biggest, and don't look back. Good luck on your decision.

71_340

How true, could not have put this any better!


What difference does it make when/how much boost there is.....bottom line is you have power when you need it. And what is the big deal with the fuel mileage? It is a full size truck, out-towing most V8s, almost like a diesel. If one wants an economy cruiser don't buy a truck.