2005 Prius on my chassis Dyno!!

[BT Tech]

About a year ago I had the idea to use the facilities at my work where I usually tune high horsepower cars to see how much power the Prius would put out. I posted the results but when the PC server crashed a while back all of that data was lost.

Well I just found it and I know that there were a lot of people that were interested in looking at the data.

I have attached the actual dyno sheet that will show the HP, Torque and Air Fuel ratio. I remember that I had one hell of a time to be able to dyno this car!! I had to physically disconnect the VSS connectors on the rear wheels so that I would be able to let the front wheels turn the dyno rollers.

Remember this is the power that the car is making to the ground. Generally speaking an automatic transmission will show a 20 percent reduction in power however I have no idea what efficiency what a CVT would be. We normally would multiply the amount of power/torque by 20 percent for auto and 15 percent for manual transmissions for crank hp/torque figures.

At any rate here is the graph!!

[Pinto Girl]

Wow, that's pretty cool, Brian. Thanks for posting the dyno sheet!

[BT Tech]

No problem Pinto... Imagine if we could get into the PCM and richen up the A/F ratio!! Take a look and see how lean the car runs accross its entire RPM range.

I just finished tuning a 07 Z-06 tonight and the A/F ratio was 10.5-11.0:1 STOCK!!!





<div class='quotetop'>QUOTE(Pinto Girl @ Oct 20 2006, 08:38 PM) [snapback]335932[/snapback]</div>

Wow, that's pretty cool, Brian. Thanks for posting the dyno sheet!
[/b]

[NuShrike]

Thanks for reposting this. The only other online copy of it exists at image shack posted by Tideland Prius on http://www.toyotanation.com/forum/t106804.html.

[auricchio]

What's with the hiccup at 4375rpm? There's a very minor bump in the air-fuel ratio, but a fairly big one in HP and torque.

[HTMLSpinnr]

<div class='quotetop'>QUOTE(BT Tech @ Oct 20 2006, 05:48 PM) [snapback]335938[/snapback]</div>

No problem Pinto... Imagine if we could get into the PCM and richen up the A/F ratio!! Take a look and see how lean the car runs accross its entire RPM range.[/b]

Toyota does that for emissions reasons. Richen it up, you'd get more power, but you'd lose that lovely SULEV rating (not to mention the 60mpg EPA city rating).

[hobbit]

I've got the two old pix from your original posting saved, one of
which is the same as Tideland's imageshack one. If you've misplaced
them and want 'em back or want me to throw 'em up on techno-fandom
or something, yell.
.
The tests don't seem to show anything under 3000 RPM. I, in fact,
rarely get anywhere near 3000 RPM and I would have been really
interested in some lower-speed testing. The torque curve is
reassuringly flat and I think some of that comes from how the ECM
does its throttle management. The A/F is also interestingly flat;
I thought there was a little bit of enrichment scenario when you
really punch it and RPM gets up near 4K. Then if you back down very
slowly from there, the ECM stays in an oddly different mode right
down into lower-RPM regions -- not sure if it's actual enrichment
but the injector time wanders all over the place and a lot more
fuel is burnt in general.
.
_H*

[BT Tech]

Hello Hobbit... When I had the Prius on the dyno it was very interesting in that the car would INSTANTLY rev to 3k and this is the reason why there was no data on anything below this RPM.

The A/F ratio was meaaured on a calibrated Bosch wideband 02 and was VERY consitent 15:1 with a small spike around 4700 RPM. What was also interesting is that even though the HV battery level would drop the amout in affected the HP/Torque was not a huge amount. I did not however run the car with the very last 2 bars remaining so it would have been interesting to see what she would do on motor alone.

At any rate it was pretty fun to put the Prius up there!! Especially when I had 4 other C5's to work on and they were all in a row waiting for the Prius to get off their dyno!!




<div class='quotetop'>QUOTE(hobbit @ Oct 21 2006, 11:02 AM) [snapback]336078[/snapback]</div>

I've got the two old pix from your original posting saved, one of
which is the same as Tideland's imageshack one. If you've misplaced
them and want 'em back or want me to throw 'em up on techno-fandom
or something, yell.
.
The tests don't seem to show anything under 3000 RPM. I, in fact,
rarely get anywhere near 3000 RPM and I would have been really
interested in some lower-speed testing. The torque curve is
reassuringly flat and I think some of that comes from how the ECM
does its throttle management. The A/F is also interestingly flat;
I thought there was a little bit of enrichment scenario when you
really punch it and RPM gets up near 4K. Then if you back down very
slowly from there, the ECM stays in an oddly different mode right
down into lower-RPM regions -- not sure if it's actual enrichment
but the injector time wanders all over the place and a lot more
fuel is burnt in general.
.
_H*
[/b]

[Tideland Prius]

Interesting. Your new copy shows 102hp which is more than the old copy that I saved (100.07). However, the torque is slightly down the maximum recorded on your old copy which was 115.01

[BT Tech]

I did about 10 different runs and all of them varied by a small percentage. This was probably due to the state of charge of the HV battery, temperature of the engine, varying inlet air temperature and minor variations in the dyno itself.




<div class='quotetop'>QUOTE(Tideland Prius @ Oct 21 2006, 03:57 PM) [snapback]336154[/snapback]</div>

Interesting. Your new copy shows 102hp which is more than the old copy that I saved (100.07). However, the torque is slightly down the maximum recorded on your old copy which was 115.01
[/b]