The Premier's Limo: 2004 Toyota Prius "winter beater" ecomodding thread

[freebeard]

Originally Posted by Cd

From what I understand from everything I have read, the limit will be around 58 mpg at 65 mph.
And this is set in stone.
.....
I planned to do some aero work on the car, but if the return is this low, I'm not going to waste my time with it.

If it's speed limited, wouldn't lowering the load be beneficial? Julian Edgar's posts are still available. A-pillar testing on Gen 1 Insight and Side pressures and attached flow.

--air curtains. There'll be a post about that [side-plated Gurney flap], but these are all unrefined prototypes. For the A-pillar, lay up some carbon fiber on the A-pillar and put it on stand-offs. At least as good if not better.

The Kammback might be a curved hoop:

Maybe a little shorter?

[Cd]

@ Freebeard,
Thanks for the reply. I was beginning to wonder if I was being 'ghosted' on the forum for some reason.
From what little I understand about the G2 Prius, the limitation is based on the RPM of the ICE combined with the M otor G enerator 1 & 2.
Once the MG1 reaches a certain RPM, the ICE has to run to keep the MG1 from over revving and being damaged since the two are connected.
So it's not a speed limitation as In miles per hour, but an RPM speed that limits any further fuel economy gains.

[freebeard]

Even if it's speed RPM limited, wouldn't lowering the load be beneficial?

[Gasoline Fumes]

Originally Posted by Cd

I was beginning to wonder if I was being 'ghosted' on the forum for some reason.

We've all been ghosted here!

[Cd]

Originally Posted by freebeard

Even if it's speed RPM limited, wouldn't lowering the load be beneficial?

The way it has been explained to me is that no matter if you reduced the load to zero, you would have limited benefits in mpg.
You would max out at around an 8 - 10 mpg improvement.
Instead of getting Aerocivic like numbers at 65 mph, you would max out at 58 mpg.
( With an unmodified baseline of 48 mpg @ 65 mph )

It IS an improvement, but not worth the effort.

I recently took a trip from Houston to Austin, and drove behind a UHaul truck for 90 % of the trip.
This guy was going painfully slow, but I decided to drive behind him and see what numbers I got.
His speed ranged from 48 mph to 52 mph the entire way there ( 75 mph posted speed limit, with some areas going to 85 mph - the highest in the USA ! )
I drove at around a two second gap and could not see his mirrors.
I managed to get just over 66 mpg.
But this was a combination of the extremely slow speed as well as the drafting.

What this tells me is that this car is just not going to give any good MPG numbers if I aeromod it.

I saw the post earlier in this Darin getting over 70 mpg at 50 ish mph .

That's encouraging, but I'd really like to read those results of the 65 mph tests with the aeromods.

[Cd]

Did anyone here ever see the drone video or see the data on the 65 mph run ?

I'm guessing the results were so bad at 65 mph that the entire project was canceled and this is one of the reasons Darin was so eager to get rid of the car.

[Piotrsko]

My thoughts: aero wasnt the issue, the powertrain was so crappy that improving the aero was pointless. However there's the point it was sitting is really turbulent flow.....

[pgfpro]

Originally Posted by Cd

Did anyone here ever see the drone video or see the data on the 65 mph run ?

I'm guessing the results were so bad at 65 mph that the entire project was canceled and this is one of the reasons Darin was so eager to get rid of the car.

I remember the tufts video, but I think it was at a slower speed.

[Cd]

I'd still like to add a full length retractable boat tail to the 2008 Prius I'm driving.
I have all the materials, but would just like to know if it is going to be a waste of time.
Looking over Darin's design really makes me appreciate it even more.
I had forgotten just how easy it was to remove with his design.
And the thing was so lightweight too !

[pgfpro]

Originally Posted by Cd

I'd still like to add a full length retractable boat tail to the 2008 Prius I'm driving.
I have all the materials, but would just like to know if it is going to be a waste of time.
Looking over Darin's design really makes me appreciate it even more.
I had forgotten just how easy it was to remove with his design.
And the thing was so lightweight too !

I'm pretty sure it wouldn't be a waste of time. Plus, it would be great to have the data either way for you and the Forum.

You are on the right track with keeping the weight and the design to remove/install easy. I also on every aspect of building the Camaro have two major rules.

#1) The Aero added idea has to be light weight.

#2) My Aero Package has to be easy to remove/replace and to work around without interfering with other parts of the car.

I also make every idea I've installed have at least two jobs.

Example:
My air to water intercooler has three different jobs. The first is to cool the air intake air charge when making high HP. The seconds is also cool the engine oil while on full high HP mode. The third is to increase the IAT temps when in FE mode by starting the FE run with how water vs ice water when in HP mode.

Anyway, Looking forward to your project.