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I put my 2018 Volt Premier on a dyno the other day. I believe this may be a first. I found one YouTube video of a Gen 1 with no results posted.


700 miles on the odometer.

Mustang AWD 150 Dyno. Front wheels in cradle rollers, dyno in 2wd mode.
50*F ambient temperature. Clear Day. 5200 feet above sea level.

The Volt did not want to fully disengage traction control. Eventually the system faulted and allowed me to do full throttle driving with the back wheels not spinning. It did throw a check engine light that could not be cleared with several different scan tools. Required a trip to the dealer to clear the code.


The horsepower readings are fairly accurate as the dyno measure horsepower directly. It then calculates torque using engine speed as part of the equation. Since there is no tachometer for any of the 3 motors, I had to come up with something.
I used wheel speed to sync the vehicle to the dyno. This is a very common thing to do with many different vehicles with geared transmissions. Once in gear, engine speed and wheel speed will always be linear. The dyno knows how fast the rollers are spinning. You then tell the dyno what the engine speed is and it correlates that to the wheel speed. The dyno essentially calculates what the final drive ratio is. So I Googled "Volt Final Drive Ratio" and found a number somewhere. I think it was 2.88. This is the number I told the dyno to use. The results seem plausible, but I cannot say they are accurate.


I started with a fully charged battery. I did 3 pulls from dead stop to 70mph. The graph shows the best results from all of my tests in the various modes. I did not test in Mountain Mode as the battery level never dropped below 50% so the gas motor never came on.
Normal and Sport modes were almost identical. Hold mode was a little laggy with a much lower torque output, but had much better HP especially at higher wheel speeds.
Normal - 149 HP 291 Tq
Sport - 147 HP 285 Tq
Hold - 171 HP 248 Tq



The dyno does apply a full SAE correction for weather and altitude. The correction factor on this day was about 23%. I do not believe the correction should be applied to the Volt as the altitude has no effect on the electric motors. The gas motor loses available power output, and this may be the reason for the lower torque in hold mode... but it made more horsepower...


I also did a 0-60 timed run and a standing 1/4 mile test.

0-60 8.64sec

1/4 Mile in 16.259sec @ 78MPH
 

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Great info. I was curious if anyone ever did this. I did see this article on this site which talks about the gear ratios so maybe this info can help.

https://gm-volt.com/2015/05/21/deri...lanetary-gear-set-ratios-and-speed-equations/

I've driven short highway trips in straight electric and in hold mode. My 2017 seems to always have better 60-80 passing power in hold mode than electric only. Even though electric only has that huge low speed torque advantage it does seem hold mode has the HP and torque advantage at higher speed and somewhat confirms my seat of the pants feel.

Can they lock the front and back rollers together? I know it is added drag but I would be even more curious how it would affect the mode differences without the traction control system freaking out. Always makes you wonder if the dyno test changes the way the trans behaves or limits motor torque.
 

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Great information and thanks for posting. What was the code that had to be reset? Something with a WSS I assume??
 

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Yeah, thanks for doing this! When I did my 0-60 video testing normal, sport, and hold, I noticed that in hold mode, it took a lot longer for it to reach the peak 120kW. I think they are delaying power delivery in hold mode where you eventually reach peak 120kW but it takes significantly longer. Looks like the Volt could be a lot faster if they added a "track" mode where it would keep the normal mode characteristics of the electric motors and just add the power of the ICE.

The 0-60 seems a bit suspect. Not sure if that's due to wheel speed that's slightly off? I've never seen the gen2 slower than about 7.6 in any 0-60 test including all the car mags and my own testing.

Question: you said the dyno applied 23%. Does that mean the numbers in your graphs were adjusted by 23%? Or did they back that out?

Mike
 

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Discussion Starter #5
The dyno rollers can be locked in to spin the rear wheels. It usually reads about 20hp lower due to the extra drag.

We were getting some wheel spin on the rollers from a dead stop, so that could be eating up some of the 0-60 time, same for the 1/4 mile.

Yes, the numbers have an extra 23% in them.
 

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pull the relay for the ABS system so the car has no idea how fast the tires are moving or not moving.
 

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Well, the results seem to answer the question as to whether Sport Mode uses the second electric motor for added horsepower torque, doesn't it?

Don
 

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I don't think the altitude correction applies to electric motors. I'm guessing the temperature correction wouldn't be right either.
 

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I don't think the altitude correction applies to electric motors. I'm guessing the temperature correction wouldn't be right either.
And that might not be all. Interesting exercise though.
 

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It would have been interesting if you had put it in L and setup for a regen rate of approx 28KW to fully charge the battery in 30 mins
 

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Well, the results seem to answer the question as to whether Sport Mode uses the second electric motor for added horsepower torque, doesn't it?

Don
Exactly what I was thinking. It also answers the question on why 0-30 was worse in hold mode in my testing but 0-60 was the same. It does seem to pull harder in hold mode above 65 MPH; the graph shows more torque above about 45 MPH but you can really feel it above 65 MPH.

Mike
 

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Discussion Starter #14
It would have been interesting if you had put it in L and setup for a regen rate of approx 28KW to fully charge the battery in 30 mins
99% of motorsports dynos can not spin the wheels to recharge. The dyno is basically a big brake.

I don't know about other brands, but an AC motor can be added to Mustang Dynos to spin the wheels of the vehicle. It's not a cheap add-on and has some pretty serious electrical requirements. This may become more common as electric vehicle modification becomes more mainstream. There's probably only a handful of dyno's in the United States that are capable of doing this currently.
 

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Hey great thread,

Here is the 2018 spec:

Horsepower: 149 hp
Torque: 294 lb-ft

Pretty close all around.
 

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Did you have the ICE fully warmed up before the Hold mode pull? I've noticed it'll definitely hold back a bit more for higher throttle inputs when it's below ~150-160 F, but it seems to eventually ramp up regardless (safety concern?).

I haven't really matted it much with the ICE cold, but my general impression is it holds back a bit before up to temp. Could be imagination, but might explain some of the softness. I agree there is some lag in Hold, but maybe not quite as much as is shown.
 

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Trouble codes, Yes if you attempt to tow dolly your Gen2 it with through a huge amount of codes, Multiples of Traction control, steering, braking etc. Then the car operates strangely for a couple of drive cycles. In contrast my Gen 1 had no issues. Someone suggested putting the Volt in "Transport mode" . I will try this next time I tow it
 
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