Online tool: shows aerodynamic drag, rolling resistance, power required & est. MPG

[orange4boy]

Thanks. That's about what I get with my Previa 2.4L when warmed up. I would have loved to do those load tests before and after but I only got my mpguino lately.

[MetroMPG]

Thanks for the input, guys. I imagine this is going to be a work in progress for a while.

I chipped away at the basics a little more this evening: you can now enter weight & A in either Metric or Imperial units. Added a few more explanations & links to the notes as well.

[MetroMPG]

I've made a new page "EcoModder tools". The aero/rr/power/mpg calculator is now linked there as well as a units conversion tool (for mpg --> L/100 km etc.)

You can access it via the "Tools" link in the navigation at the top of every page.

Expect the toolbox to grow & evolve to include more stuff.

[Daox]

I likey. Now they just need icons/pics.

[MetroMPG]

Functionality first, then fancyness.

[Big Dave]

If this spreadsheet is valid, I must be doing a bang-up job of improving my aerodynamics and improving engine efficiency by slowing down engine RPM.

Last summer I went to Nashville, TN and back. Slightly cool weather - roughly 70 degrees F. Out and back to same fuel pump so delta y = 0.

I had the full aero treatment: "fastback" bed fairing, air dam, and side skirts.

The trip was entirely an Interstate run and set the cruise on 1700 RPM (70 MPH).

Thev truck weighs 7000 lb. Figure Crr of 0.011 for worn 235-85x16 E-Rated tires pumped up to 100 psi Estimate frontal area at 41 sq. ft. 95% drivetrain efficiency for an overdrive manual. Summer No. 2 diesel.

I got a documented 28.1 MPG over that trip of 600 miles. Playing the variables to duplicate that performance says my Cd is 0.30 and my engine efficiency is 35%.

Am I that good? I figure a open-bed pickup to have a Cd of 0.45 and a diesel engine to have 33% efficency.

[MetroMPG]

Originally Posted by Concrete

I'm up for anything as long as there is a field for a flat load fudge factor
GPH, like I used is probably not appropriate

watts or Horsepower is probably more acceptable
- what do you think?

Got your PM - haven't forgotten about this.

I'll work it in this weekend, probably as watts to start. (Can always do conversions to other units, if people want.)

[Concrete]

Darin,
Thanks
looking forward to it!


Big Dave,
from what you describe and some of Aeroheads data
I bet you are really doing that well

those are great results & it seems you are in the ball park on your numbers
of course it is hard to argue the particulars without a test facility
but even matching +/- a few percent in each entry is good work

[Funny]

Perhaps you could also utilize this online tool for gear calculations and adjustments. That is for those of us who are interested in swapping transmissions and gears.

Gear Calculation Tool

I am so excited with all these numbers! God, I am such a nerd!

[Blue Bomber Man]

I thought I should point you towards an existing spreadsheet that is the culmination of years of research (I believe it is someones PhD thesis) that is availible on the web.

Just search for Pamvec on google, it should turn up an excel file. It is extremely customizeable for many things that you have already included but also for things like: various drivetrains (hybrids, electric etc), driving models, can specify design goals, or just input known variants. When I used it to model my current car it nailed its MPG rating and I used it to model hypothetical cars.