Quote:
Originally Posted by aerohead
So far,I think that 20-21% drag reduction maximums have been reported for caps.
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What were the mpg improvements @20-21%drag reductions??
This is why I am asking for help in finding "facts"about what actually happened to improve FE from 18.237us mpg average up to 23.067 average a 26.458% increase. The only time I've had the cap off in the last 10,000mi I had a load on or severe weather
I anxiously awaiting the specifications for small diesels. As I would like to be able to publish reliable statistics.
Source for 2:1
Secrets of Better Fuel Economy
The Physics of MPG
pg 4 ph2
https://www.google.com/url?sa=t&sour...D_FWTQjBg3_j1A
Thire is a 2:1 drag(drag = Cda correction may be necessary ) to mpg on over the road diesels semi
Quote:
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Originally Posted by aerohead
So far,I think that 20-21% drag reduction maximums have been reported for caps.
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I will take this as a compliment that my design is slightly above average especially for a blind shot in the dark with a 18 year old(as in 1998) idea from high school. Thankyou Aerohead.
A 26.458% gain on FE at any raito evan 1:1 is well above 20-21%cda avrage gain ,for a cap.
My last 3 trips to Helena Montana from Anaconda,Mt 200 mi roundtrip over 2 passes Have averaged 25.095mpg. 1 ea. 60mph (27.705mpg) 65mph(24.27) and 70mph(23.11) . With 1200lbs in tools in back under cap (the reason i haven't completed a Terminal Velocity Test the junk in my trunk will yield an invalid test )
Quote:
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Originally Posted by Aerohead
Hucho shows a different CdA/MPG relationship for Diesels compared to gasoline vehicles.I don't have his book with me.Perhaps a member can help us out on this one.
These relationships are predicated upon steady-state highway cruise mpg,not coasting or coastdowns.
Also,we have no idea what the engines BSFC is doing with the modifications,and all the relationships presume a constant BSFC,or gear-matching to achieve a constant BSFC which may not reflect reality.
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Agreed gas vs diesel
the cost down( terminal velocity test is what i meant) was in reference to me wanting to do more testing. Mpg alone has been and will always be an unbelievable test hear@ ecomodder and in reality/life .
I am aware that a terminal velocity test will not give me the stock cda. However terminal velocity aba test ,I believe and correct me if I'm wrong, give the % improvement. And will not involve the motor in neutral.
This is my proposed test site
https://goo.gl/maps/ufJoDps6hcN2
stock sealed injection pump
a 16sq cm housing
Exhaust manafuld and turbocharger wrap
End of list
Full list of mods to motor
GraysGarage has showed that he has the necessary equipment to print the correct1:10 modle. Reference. Watch "Automotive Aerodynamics Ep. 7: Spoilers and Gurney Flaps for Racing" on YouTube
https://youtu.be/vzMe1e9fE50
This with the 1:43 model and some basic measurement angle of body ground clearance and I'm shure a couple more. Should be able to gert some reliable specifications. Thank you as your input is helpful