Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Full-boat-tail trailer with gap-fillers for Toyota T-100 pickup

aerohead · 08-15-2011, 07:23 PM

Saturday night light winds were forecast for Sunday,so Sunday I went for it.
Test#5 was with Viking.
NOAA @ start: dew point 72F,R.H.76%,Baro 30.00" steady,75F,wind N@5mph,rho 0.0023074 slugs.
NOAA @ finish: dew point 71F,R.H.60%,Baro 30.02" rising,85F,wind N@5,rho 0.0022665
*Result: 104 miles,3.557 gallons,ave.63 mph= 29.074 mpg.
I was very disappointed,thinking back on the 33.24 I'd pulled before.
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I live 4-miles from the station where I top off,so I high-tailed it to the house,dropped the trailer,and returned to the same pump for a back-to-back comparison.
It was within the same hour so my NOAA start is essentially the #5 finish.
NOAA @ finish of #6: dew point 68F,R.H. 43%,Baro 30.00" falling,93F,wind variable @ 3 mph,rho 0.0022323
* Result: 104 miles,3.325 gallons,ave 63 mph,31.278 mpg.
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So with the 2009 damage,incomplete trailer,incomplete diffuser,and no hood blister,the trailer creates a 7% mpg penalty.It cost me 85-cents in extra fuel to pull it 104 miles.It pulls like it isn't there and statistically it is close to being invisible at the pump.
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If Hucho is correct,and the gap-fillers are good for up to a 10% mpg increase,it is possible that when finished,the trailer will cause a net gain in mpg.That relationship is for 'normal' trailers,I have no idea what it will mean to Viking.
Had the panels been in place,I might have seen 31.981 mpg on Sunday.Not exactly a rocket booster but I'll take it.I should have done a back-to-back the time I pulled 33.24.
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Anyway,I felt better about the whole thing after the #6 test and I'll keep grinding away at the project.I may do a 70 mph run to look at possible BSFC affects.
------------------------------------------------------------------------- As to Miles question about urban use,I would only consider this trailer to be of real benefit when on the open road.Unless you can eradicate traffic and un-synchronized traffic signals.Too much inertia.

08-15-2011, 07:23 PM	#186 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 16,228 Thanks: 24,375 Thanked 7,357 Times in 4,757 Posts	RESULTS:Road Test 5 & 6 Saturday night light winds were forecast for Sunday,so Sunday I went for it. Test#5 was with Viking. NOAA @ start: dew point 72F,R.H.76%,Baro 30.00" steady,75F,wind N@5mph,rho 0.0023074 slugs. NOAA @ finish: dew point 71F,R.H.60%,Baro 30.02" rising,85F,wind N@5,rho 0.0022665 Result: 104 miles,3.557 gallons,ave.63 mph= 29.074 mpg. I was very disappointed,thinking back on the 33.24 I'd pulled before. --------------------------------------------------------------------------- I live 4-miles from the station where I top off,so I high-tailed it to the house,dropped the trailer,and returned to the same pump for a back-to-back comparison. It was within the same hour so my NOAA start is essentially the #5 finish. NOAA @ finish of #6: dew point 68F,R.H. 43%,Baro 30.00" falling,93F,wind variable @ 3 mph,rho 0.0022323 Result: 104 miles,3.325 gallons,ave 63 mph,31.278 mpg. ------------------------------------------------------------------------- So with the 2009 damage,incomplete trailer,incomplete diffuser,and no hood blister,the trailer creates a 7% mpg penalty.It cost me 85-cents in extra fuel to pull it 104 miles.It pulls like it isn't there and statistically it is close to being invisible at the pump. ------------------------------------------------------------------------- If Hucho is correct,and the gap-fillers are good for up to a 10% mpg increase,it is possible that when finished,the trailer will cause a net gain in mpg.That relationship is for 'normal' trailers,I have no idea what it will mean to Viking. Had the panels been in place,I might have seen 31.981 mpg on Sunday.Not exactly a rocket booster but I'll take it.I should have done a back-to-back the time I pulled 33.24. ------------------------------------------------------------------------- Anyway,I felt better about the whole thing after the #6 test and I'll keep grinding away at the project.I may do a 70 mph run to look at possible BSFC affects. ------------------------------------------------------------------------- As to Miles question about urban use,I would only consider this trailer to be of real benefit when on the open road.Unless you can eradicate traffic and un-synchronized traffic signals.Too much inertia.