Some deep thinking on getting Best MPG in a VAN

[racprops]

Originally Posted by freebeard

Because you want to make your expensive engine-work less effective?

Concentrate on the front wheelwells and Moon disks.

Yes because I feel my van is fairly streamlined as it is, and nothing less than radical major changes will make much difference, and feel these changes if done will only add about 10 to 30%.

Where as the total engine mods, with its tuneablity with the add on computer board that includes a lean burn cruse mode and with the 8 speed transmission AND rebuilt low gear ration will provide the most possible improvement and stuff many can also convert their vans/cars to.

VERY Few are willing to do the areo body changes.

Rich

[Ecky]

I suspect you're vastly overestimating what you're going to get out of an engine swap.

[racprops]

Well when I consider how bad the TBI system is, that a TPI stock is rated to give 30% better MPG which if true that works gets me to 18.2…on a bone stock engine, now add in my changes to a new strong 383 tuned for lower RPM Torque, add in the modified PCM with a lean burn cruse, I think I will hit 20+ MPG.

NOW add in the 8 gear auto and the high rear end with a 2.14 to 2.23 I think I will be able to see much more…

Rich

[freebeard]

...these changes if done will only add about 10 to 30%.
[snip]
VERY Few are willing to do the areo body changes.

So your saying V[ery] few people will accept 10 to 30% improvement? And are you saying 10 to 30% in Cd or MPG? There is a rule of thumb inbetween.

The balance between thrust (applied to the contact patch of the rear tire) and drag determines your forward progress (velocity or acceleration).

A site search for "NASA van" returns 196 results.


https://ecomodder.com/imgs/knox/nasa-van-z.jpg

If you go back to Permalink #54, your van is closer to the orange and white poptop than the bubbletop.



How would you feel about a sun visor, peep mirrors and fender skirts?

[racprops]

That is sure a ugly bus....

Here is the only profile picture I have of it.

But it rises in front on a nice tapper and drops in back.

To my eye it is closer to the blue and white that the other vans.

Rich

[racprops]

"How would you feel about a sun visor, peep mirrors and fender skirts?"

For the front no for the rear perhaps..mirrors are smaller than I would like, but they are OK and with power adjustment good. And the are slightly aero. See?

Would not a sun visor create more drag..

I would also consider a cover that covers the wipers.

Rich

[Galane]

Originally Posted by racprops

That is sure a ugly bus....

Here is the only profile picture I have of it.

But it rises in front on a nice tapper and drops in back.

To my eye it is closer to the blue and white that the other vans.

Rich

Tape some bits of yarn on the back corner and on the back, then have someone video them as you drive. See if those vortex things actually do anything.

[racprops]

I cannot drive it as it has a frozen motor, which is why I am posting al of this to try to figure out the best course with the replacement motor.

Personally I do not think they work, I have not noted any change from before them and after them.

I will say that the back of the van does not seem to get any dirtier than any other part of it.

I would think that suggests there is less a pocket/vacuum behind the van.

Rich

[freebeard]

The vortex generators create counterrotating vortices that promote reattachment of the laminar flow to a surface that isn't there. You could peel them off and put them further forward.

..mirrors are smaller than I would like, but they are OK and with power adjustment good. And the are slightly aero. See?

No I don't. Ignore the mirror and look at that big chrome base between the door hinge and door handle. Consider modern practice on any new bus or fire truck. Technically a peep mirror, it is moved forward of the A-pillar — one of the most problematic areas.



Trends in bus aerodynamics

That is sure a ugly bus....

Proof of concept. In that thread at Permalink #10, KamperBob posted the graph that relates to corner radius.



What's your frontal area? Assume six feet squared and 4" radius on the front edges. Find 0.055 on the dotted line.

[racprops]

Very interesting..So your saying the mirrors are OK but their bases are bad??

As I am 70 I can only handle simple normal everyday math.

So I can see something of what was said at the other post, and as the work was for a trailer behind a towing car or truck, it is not a clear how much would applies to my van.

PS someone posted that the mirrors were moved more to prevent hitting people on the streets NOT to improve aero...

None the less I am interested in some improvements if they are simple to do.

And I placed the vortex generators as close to where the instructions said to.

Rich