This was sort of an accidental experiment, but I will post the results anyway. Today is take your kids to work day, so I had to take the Prius.
In one corner, the 1993 Honda Del Sol, 2400 lbs with passenger and cargo, $5000. In the other corner, a 2004 Prius, 3200 lbs with passengers and cargo, $24,000.
Conditions were mid 40'sF and dry, the route was my daily route to work, no one on my tail, and made all of the critical lights, exactly the same conditions for my drive to work on 4/18/06 with the Del Sol.
1993 Honda Del Sol, 71.1 MPG
2004 Toyota Prius, 72.5 MPG
One note of interest, the Prius is much more sensitive to ambient temps than the Del Sol. If the temp was above 70F, the Prius would have been 10 MPG higher. The Del Sol would only get 1 or 2 more. So for approx 8 months of the year, the Prius and Del Sol would get nearly the same FE. During the other 4 months, generally during the Summer, the Prius shines.
Now if I need to carry more than 2 passengers, well, my choice would be Prius at 72.5 or the Outback at 33. No brainer.
Re: New Tech vs Old Tech, which yields the best FE?
Originally Posted by MetroMPG
Originally Posted by krousdb
the Prius is much more sensitive to ambient temps than the Del Sol. If the temp was above 70F, the Prius would have been 10 MPG higher.
you've mentioned this before about the prius, and you also once suggested it may be a factor that affects my car more than others. but i never asked why that is. can you explain?
I can't explain why it is that way. Most likely has to do with the emmissions. To make sure that the catalyst is always at top efficiency, the engine is forced to run longer. There seems to be a threshold of around 65F that FE increases dramatically.
All cars should show gains as temp rises due to lower frictional losses in the drivetrain and tires as well as less dense air/ less aero drag.
Were your driving techniques exactly the same? Do you do engine-off for coasting with the Prius as well?
As close to being the same as possible. I have th EV button which forces the engine off at speeds below 34MPH. I use forced EV to get me over small hills that separate two long coasts, thereby turning them into one coast that is twice as long. With the Del Sol, I have to bump start in between.
At speeds over 41, the Prius engine must (has to do with overspeeding the MG sets if it doesnt) run so the Del Sol wins for engine off coasting at higher speeds.
I'm thinking that if you were to, say, hit every light red, then the Prius would probably win-out with the electric motor doing most of the work, especially if forced-to. Out on the open highway, I'd put my money on the Del Sol, but if stops are required in high numbers, then the "New Tech" takes over and wins. But also consider that "New Tech" also employs better, built-in aero mods than "old-tech". The newer technology is still in its infancy, so I can see it getting better with time and demand. Even first-year Insights are going for $10,000 with over 120K miles - because of the gas situation looking grim.
Does the Prius have an Engine Block Heater (I know it has a thickly insulated coolant storage tank), and
Do you have a Hot Air Intake system available for it (I assume it uses IAT for it's operating characteristics or is there a separate thermometer)?
No EBH, just the insulated storage tank. I used to have WAI but I removed it to make the WAI for the del sol. The remainder of the tubing went to SVOboy. I wasn't able to detect any FE increase with the WAI anyway.
The drive home was 72.4MPG at 68F, dry roads. The best drive home with the Del Sol was 65.8 MPG at 66F, dry roads. So you can see the Prius widens the gap in the warmer temps. My best ever trip home with the Prius was 78 MPG at 90F, dry roads. Best drive to work was 83 MPG at 70F, dry roads.