Wind fairing

[rbryan4]

Originally Posted by Jubal

Lead was added to gasoline to lubricate the valve train. Valve guides and seats.

Right. Lubed valve guides and seats means no knocking (or reduced). It actually helped the engines of that time. Ethanol? Not so much.

[Donna D.]

Originally Posted by Brian B-P

This is a lot like the use of lead in gasoline. When it was first eliminated there was a genuine concern for older engines. Now, decades later, those racers and aircraft engine manufacturers that say they still need lead have no excuse and should just upgrade or retire their old crap.

NOT Likely!

[rbryan4]

Originally Posted by Donna D.

NOT Likely!

Nice Fastback. Yours Donna?

[Donna D.]

Ah no Robert. I have one.. actually two. The one in the garage is a 1967 Fastback like the picture... only in pieces! Like the interior needs to be put back in. Can't afford to drive it. That 390 really sucks the fuel! AND, it needs lead... you know that old crap that needs it...

[rbryan4]

Originally Posted by Donna D.

That 390 really sucks the fuel! AND, it needs lead... you know that old crap that needs it...

....a 67 GT, even in pieces, could never be called 'crap'.

[Brian B-P]

Although I actually didn't mention non-racing cars in my comment, it applies almost as well to them, too. The engines of classic Mustangs and other vehicles can be rebuilt with modern materials in valves and valve seats (and guides?) so that they no longer need lead in fuel - that the "upgrade" I mentioned. Premium pump gas has enough octane for old stock engines. If an owner doesn't think that the upgrade is worthwhile, then perhaps the vehicle is good only for static display.

Racing cars certainly don't need lead, although in some styles of racing it is still used - particularly those using outdated engine designs. Formula One hasn't used lead for two decades and even NASCAR doesn't use it any more; if they don't need it, clearly no one does. Those still running it should be proud to be at the same level of advancement as Algeria and Iraq.

Certified aircraft engines are a little different. If the engine needs 100LL fuel, the owner isn't free to modify it; in that case, the engine manufacturers who have ignored reality and done no development for decades are to blame. There is still no excuse for spewing lead into the atmosphere to run an engine... in my opinion, of course!

[Donna D.]

Oh just admit it, you stuck your foot it in Brian . No way the 390 in my Fastback will ever be "upgraded to modern materials," at least not while there's lead additives available. Even suggesting such a thing to a gearhead is blasphemy. If I said such a thing to my hodrod buds, they'd run me out of town on a rail...

[ATHiker]

I use an apt on my phone, Free Gas, to locate stations that offer non ethanol gas, which is all that I use in my boat.

[DeadEyeDan]

Originally Posted by J Mac

This brings up an interesting point. Does premium gas give better MPG when towing?

On our truck, Ford recommends Premium for towing, says regular is OK when not. I don't think premium gas does you any good on a vehicle that is recommended for regular, could even do worse.

One exception could be on a vehicle with high miles on it, that has carbon build up in the combustion chamber. This effectively raises the compression ratio which could cause detonation (knocking) on regular gas.

Modern engines have knock sensors that will change the timing to prevent knocking, so you won't hear it, but there potentially is a loss of mileage and power under that condition.

If you suspect that, you can try a tank of premium and track the mileage.

[rbryan4]

Originally Posted by DeadEyeDan

On our truck, Ford recommends Premium for towing, says regular is OK when not. I don't think premium gas does you any good on a vehicle that is recommended for regular, could even do worse.

One exception could be on a vehicle with high miles on it, that has carbon build up in the combustion chamber. This effectively raises the compression ratio which could cause detonation (knocking) on regular gas.

Modern engines have knock sensors that will change the timing to prevent knocking, so you won't hear it, but there potentially is a loss of mileage and power under that condition.

If you suspect that, you can try a tank of premium and track the mileage.

Spot on.

[padlin]

Dan and Robert or anyone else with the Ecoboost, do you use premium when towing? I have not and haven't noticed any issues.

[rbryan4]

Originally Posted by padlin

Dan and Robert or anyone else with the Ecoboost, do you use premium when towing? I have not and haven't noticed any issues.

Ford says 87 Octane or higher, but they don't specifically recommend Premium. Around here, that's regular gas. On our trip north, especially in the Rocky Mountains, 87 was mid-grade or higher. I've never put anything in but 87, and it runs like a top. The variations in octane levels sold in certain states for Regular, Mid-grade and Premium vary quite a bit with altitude. Here it's up to 93. In some places they top out at 88 or 89.

[DeadEyeDan]

Originally Posted by padlin

Dan and Robert or anyone else with the Ecoboost, do you use premium when towing? I have not and haven't noticed any issues.

I typically use regular, and use premium when towing. I beleive that is what is recommended, but now that you mention it, I cannot remember if I read that in the manual or not.

[Klem]

Back to aerodynamics, take a look at this site: Aerodynamics 101 | ATDynamics – Fuel Efficiency Aerodynamics Technology for Tractor Trailers saving over 10% with TrailerTail and Side Skirts our Escape trailers are a miniature version of the tractor trailers and this gives us 'food for thought' on how we can improve handling and performance by smoothing out the airflow.


The contribution to fuel burn can be divided into five elements:

[yardsale]

Interesting. Reducing the low pressure in back of the trailer is as useful as manging high pressure in front. Still probably not practical for Escapes I suppose.

[Brian B-P]

Yes, there is potential in changing the trailer shape. I've seen a few attempts to make travel trailers in shapes that are more curved in various ways, but very few that look like there was any significant understanding of aerodynamics involved. One theme is creating a rounded end that is promising for the front, then using the same shape at the rear where it is a poor choice.

The Escape shape is a development of the classic Trillium 1300 and 4500 shape of the 1970's; the Escape models are enlarged but otherwise essentially unchanged in shape from those originals... except the 5.0 and 5.0TA which are a little different in front. I'm just guessing, but I don't think aerodynamics was the primary consideration in any of the designs. To me, the important changes are not the aerodynamics, but instead design features in floor and the much-improved joint between the top and bottom sections.

Although features such as a long tapered tail are impractical, some changes would be quite practical to build, but of course reasonable dimensions and proportions are still needed for a workable travel trailer.

The side skirts that have recently become common on transport trailers are not particularly applicable, since travel trailers (especially Escapes) are not box bodies perched entirely above the tires. On the other hand, the gap between the tug and trailer is more significant to us, and that's what a deflector on top of the tug would address.

[Brian B-P]

Originally Posted by Donna D.

Oh just admit it, you stuck your foot it in Brian .

No, I meant what I said. We just disagree.

Originally Posted by Donna D.

No way the 390 in my Fastback will ever be "upgraded to modern materials," at least not while there's lead additives available. Even suggesting such a thing to a gearhead is blasphemy. If I said such a thing to my hodrod buds, they'd run me out of town on a rail...

I'm not talking about sticking some wimpy or inappropriate engine in - just a mod. Lots of gearheads and hot rodders fit appropiate exhaust valves and harder seats... but apparently not Donna's crowd. By the way, the additive may not be lead at all - there are lead substitutes for this purpose.

The only relevance of the lead-in-gasoline discussion is that it is an example of a changing situation (environmentally, technically, and legally) requiring a change in the fuel that is used. We may not agree with justification for these changes (I share some of Robert's concerns about ethanol), but will need to accomodate them. Ethanol is likely in your future...

Back to aero.

[Donna D.]

Originally Posted by Brian B-P

Although features such as a long tapered tail are impractical, some changes would be quite practical to build, but of course reasonable dimensions and proportions are still needed for a workable travel trailer.

The Bonair Oxygen was one such trailer. It's totally cool! Too bad the company went bankrupt after building just a few.

[Brian B-P]

Originally Posted by Brian B-P

I've seen a few attempts to make travel trailers in shapes that are more curved in various ways, but very few that look like there was any significant understanding of aerodynamics involved. One theme is creating a rounded end that is promising for the front, then using the same shape at the rear where it is a poor choice.

Originally Posted by Donna D.

The Bonair Oxygen was one such trailer. It's totally cool! Too bad the company went bankrupt after building just a few.

Yes, that's one that I had in mind.

For those not so familiar with the Oxygen (this is an Escape forum), I've attached the floorplan (from a 2002 Bonair brochure). The outline of the protruding tail lamp fairings is just visible on the tail end; ironically, it would probably be better aerodynamically if the whole body was that shape.

If anyone wants to try things on their Escape such as nosecones or tail fairings, just keep in mind that the considerations for each end are very different.

[gbaglo]

I saw a used or demo Oxygen at the RV show where I looked at the Escape and a stickie.
Viewing it from outside, I guessed that it was quite weird inside to accommodate the lines, and narrow too.
Have to admit, I didn't bother looking inside.

Edit: appears that I saved myself a couple minutes from BP's floor plan.