Money saving tip, don't over-octane your Raptor!

[Akmike]

If I order svt Prius what's average wait time..

 

[justthebest]

I would like to see this comparison run on a relatively broken in truck (+2000 miles).

 

[Deinonychus]

Filled tank 1/16/12 with 3,664.5 miles

Refilled and calculated mileage:

• 1/24/12: 17.112 gals, 250.4 miles, calc 14.6330 mpg, computer 15.0 mpg
• 2/1/12: 17.729 gals, 260.2 mile, calc 14.6785 mpg, computer 15.0 mpg
• 2/8/12: 15.038 gals, 221.5 miles, calc 14.7294 mpg, computer 15.0 mpg
• 2/17/12: 20.219 gals, 301.3 miles, calc 14.9018 mpg, computer 15.0 mpg
• 2/29/12: 22.365 gals, 330.5 miles, calc 14.7776 mpg, computer 15.0 mpg

Average difference between calculated mpg and computer mpg was 0.26 mpg.

Considering only five samples, the 95% Confidence Interval of the average (mean) is between 0.13 and 0.39 mpg worse than the computer mpg

All fillups were done at the same station, but not necessarily the same pump (not practical if I valued my waiting time). All fillups were to the auto-cutoff hose lowest click. Driving consisted of highway (less than 65mph) and suburban areas, where driving with optimal mileage in mind (occasionally a quick acceleration)

 

[cage1993]

I know your talking about the 6.2, but an FYI on the 5.4, the published 320 HP & 390 TQ numbers are based on E85! That kind of thru me for a loop when I first realized it. Gas with no ethanol added will drop HP by about 8-10 but improve MPG by 1 to 1.5 MPG on those trucks - not sure on the 6.2 - I'm trading my '10 5.4 for a '12 6.2 this week, so does anyone know offhand if the 6.2 is designed to run on E85, regular, etc. (besides the obvious 91 octane rating per OP)?


edit - would be interested to know if the published MPG on the 5.4 was based on E85? - wouldn't be surprised if they based MPG on regular (non-ethanol) and HP, TQ on E85 to get the best of both worlds!

 

[Humvee21]

I know your talking about the 6.2, but an FYI on the 5.4, the published 320 HP & 390 TQ numbers are based on E85! That kind of thru me for a loop when I first realized it. Gas with no ethanol added will drop HP by about 8-10 but improve MPG by 1 to 1.5 MPG on those trucks - not sure on the 6.2 - I'm trading my '10 5.4 for a '12 6.2 this week, so does anyone know offhand if the 6.2 is designed to run on E85, regular, etc. (besides the obvious 91 octane rating per OP)?


edit - would be interested to know if the published MPG on the 5.4 was based on E85? - wouldn't be surprised if they based MPG on regular (non-ethanol) and HP, TQ on E85 to get the best of both worlds!

The 6.2 is not designed to run E85. The 6.2's HP and Torque ratings are based off 91 octane.

 

[K-9]

I had not heard about the octane sensing. i did a little digging and came up with this on the V6 Mustang from MM & FF:

"Ford also worked outside the engine to make the package a better fit for the Mustang. The powertrain ECU has been upgraded with a very aggressive deceleration cylinder shutoff for fuel economy, coupled with very rapid tip-in for street performance. On the flip side, the ECU has been reprogrammed with adaptive-knock spark control. If the two knock sensors embedded in the cylinder block don't hear knocking, the ECU will keep advancing the spark until it does.What this means in performance terms is that, if the owner uses premium or race gas on weekends, the engine should make considerably more power and torque than the numbers quoted here, which are the product of standard SAE dynamometer laboratory testing procedures and not real-world driving"

This would lend to the thinking that there is not a cap at the 91 octane but I suppose there could be a limit as to where the timing can be advanced in the tune...Maybe one of the tuning pro's will chime in. This is an amazing advancement in my mind.

 

[Reptar]

If I order svt Prius what's average wait time..

SVT Prius = Tesla? Pretty badazz!

I would like to see this comparison run on a relatively broken in truck (+2000 miles).

I'll update with my results long term, I always keep track of my mileage. But pretty confident the instantaneous nearly 1 mpg jump on the digital readout wasn't from a magic mileage of suddenly being broken in. Over the month I've owned it the mpg has slowly improved gradually over time, but as soon as it had 91 in it over 93 it was an instant increase in the running average. Almost a full week now on 91 and still hovering right at 14.9 on the readout.

I know your talking about the 6.2, but an FYI on the 5.4, the published 320 HP & 390 TQ numbers are based on E85! That kind of thru me for a loop when I first realized it. Gas with no ethanol added will drop HP by about 8-10 but improve MPG by 1 to 1.5 MPG on those trucks - not sure on the 6.2 - I'm trading my '10 5.4 for a '12 6.2 this week, so does anyone know offhand if the 6.2 is designed to run on E85, regular, etc. (besides the obvious 91 octane rating per OP)?


edit - would be interested to know if the published MPG on the 5.4 was based on E85? - wouldn't be surprised if they based MPG on regular (non-ethanol) and HP, TQ on E85 to get the best of both worlds!

As Humvee said it's rated for 411 hp on 91 octane, and the truck should not be ran on E85. I believe the manual states you shouldn't exceed E15? Majority of stations are all E10.

Read the manual when you get the truck. There actually is some pretty interesting information in there for features you wouldn't even realize. It would have taken me months to accidently realize the front headrests tilt forward. And I never would have figured out you can actually calibrate the factory compass, and there's actually geographical zones and you should update your compass settings to be the zone you live in for the most accurate readings. I'm about 2/3rds of the way through the manual, then I still have the Nav book to go through after that.

---------- Post added at 02:00 PM ---------- Previous post was at 01:50 PM ----------

I had not heard about the octane sensing. i did a little digging and came up with this on the V6 Mustang from MM & FF:

"Ford also worked outside the engine to make the package a better fit for the Mustang. The powertrain ECU has been upgraded with a very aggressive deceleration cylinder shutoff for fuel economy, coupled with very rapid tip-in for street performance. On the flip side, the ECU has been reprogrammed with adaptive-knock spark control. If the two knock sensors embedded in the cylinder block don't hear knocking, the ECU will keep advancing the spark until it does.What this means in performance terms is that, if the owner uses premium or race gas on weekends, the engine should make considerably more power and torque than the numbers quoted here, which are the product of standard SAE dynamometer laboratory testing procedures and not real-world driving"

This would lend to the thinking that there is not a cap at the 91 octane but I suppose there could be a limit as to where the timing can be advanced in the tune...Maybe one of the tuning pro's will chime in. This is an amazing advancement in my mind.

And I think that last part in bold is essentially it. The fuel tables and timing map are only programmed to a certain extent, so I'm sure Ford probably coded it for adjustment between 87 and 91, but didn't continue with mapping fuel tables and timing for higher grade fuels, since you can't always get higher than 91 everywhere. It probably stops at a certain max timing that is ideal for burning 91. Putting in 93 when the timing and fuel maps are only optimized for 91, since higher octane burns slower, you're wasting money on unburnt fuel, and does explain the behavior observed from my switch from 93 down to 91.

 

[IRONMAN]

I was afraid it might be to small. Maybe someone might be able to make it biggger so it is readable.

I tried to make it bigger but it's just a big blurrrr.

 

[cage1993]

appreciate the info on the 6.2 and E85guys, when the new one comes in, I'm gonna be too busy ******** around with it to read the manual!

Manuals? Manuals? We don't need no stinking manuals!

 

[K-9]

From one on my Mustang forum that knows a lot more about this stuff than I do....He does not subscribe to my theory of it can't be fixed with a hammer it's an electrical problem Sorry to hi-jack, I just really found this interesting:

"There are torque limits baked into stock tunes for various reasons so that would still have to be dealt with if making substantially more power.

Cars don't measure ocrtane per se -- typically a knock sensor (or sensors) are used since it's not just octane that matters, but conditions and cylinder pressures, so a knock sensor detects when the threshold is reached regardless of conditions/tune/CR/dynamic-cylinder-pressures, etc and then the engine management logic (in conjunction with a proper tune) uses various strategies to prevent crossing into serious detonation (timing/fuel). The 5.4 Shelbys up thru 2010, I believe (iron blocks) have no knock sensors, so good tuning practices are even more critical. The alloys have two (one on each bank) snesors and, along with wideband O2s, enable 'riding the edge' quite accurately and dynamically under most all conditions and so, for the same reasons, those engines are more friendly to adding boost and octane variations in terms of getting the most out of it without further tuning -- but still within any limits intentionally set in whatever proper tune is installed ...and certainly assuming within other capacities (e.g. pump & MAF).

Appraoching your Q from anotehr angle: could the factory have installed a tune on an 11-up that would permit *exploiting* more boost, race gas, headers, and other optimizations with no further tuning? Absolutely -- tho possibly not a wise warranty thing to do. ...it also likely implies making the knock snesors much more than just a safety net.

To some extent there is some octane-range exploitation built into several Ford engines today (e.g. those that say x HP on 93 octane but y HP on 87 octane) but x and y only vary by a few percent of total output -- likely because Ford wants to keep the **** sensors as a safety net and not have to ride them all the time (full-time dynamic timing) while at lower octane, which would be implied to *exploit* 110 ocatane but permit 93 and 87 ...probably just too risky a strategy since it only takes a cylinder to seriously detonate once to make its rod into pretty wall art.

But, in therory, it's doable, imo ...it might imply more robust detonation sensing (or, better still, direct cylinder pressure sensing) and likely much higher frequency computers that can run full analyses on instantaneous conditions for every cylinder firing (that's 28K passes thru the logic/sec at 7K rpm) with 100% reliability. There's also an inherent problem in using the O2s (even widenbands) since's a delay between a cylinder firing and it's results passing the O2 ...a delay that makes it impossible to adjust for the very next cylinder to fire because it's already been fueled and is compressed, if not already fired. So it implies (to me anyway) real-time in-cylinder pressure sensing to truly *dynamically* *exploit* (vs just accept) a wide rnge of fuel octanes with 100% accuracy (0% risk of wall art) without changing the tune. Even today you can put in higher octane gas and the car will run fine, but you won't make materially more HP ...unless you would have hit the knock sensor on less octane but now didn't ...but you would have still made similar HP on lower octane under conditions that would not kit the **** sensor, so that' snot *exploitation* which I think is what you're looking for if I'm reading your intent correctly.

My net: it's potentially doable but would take some invention to broadly exploit it relaibly with the same tune. "