08 vs 07 test results
#1
12-10-2007, 09:07 AM
Join Date: May 2007
Location: College Station Texas
Posts: 744
08 vs 07 test results
I got to drive a 08 MMH at the Houston hybrid meeting. I was able to use my scan gauge and noticed some significant differences in the software. This MMH was NOT broken in so some of the differences may be due to the battery has not cycled enough.
1) The upper SOC is allowed to go about 2% higher. I was unable to test the lower limit SOC. On highway cruise the battery was no longer recharged by the MG1 after 54%. I did not and was unable to test the max recharge as the software is very aggressive in the use of the traction motor. Refresh rate seemed to be about the same.
2) The use of the traction motor is MUCH more aggressive when in Hybrid drive. Even with light acceleration in hybrid mode the SOC would drop 2-3%. It was very easy to run the battery down to 41% SOC with normal acceleration when in Hybrid drive. Clearly the are using more assist. I think this is where the mileage increase has come from. EV mode seemed about the same as the older models. LGA and double tap worked the same.
3) ICE start up was indeed much softer. Much softer than mine even after my PCM was replaced.
4) Hot restart ICE on time seemed much shorter. I noticed on 2 hot restarts after key off for 5 min the ICE only ran for maybe 15 seconds. Though I didn't put a stop watch on it.
I think on the 08's attention must be paid to SOC and keeping it high not low. It will be imperative to use regen braking otherwise you will be charging the battery allot of the time. After driving this 08 I KNOW I dont have the 08 software.
1) The upper SOC is allowed to go about 2% higher. I was unable to test the lower limit SOC. On highway cruise the battery was no longer recharged by the MG1 after 54%. I did not and was unable to test the max recharge as the software is very aggressive in the use of the traction motor. Refresh rate seemed to be about the same.
2) The use of the traction motor is MUCH more aggressive when in Hybrid drive. Even with light acceleration in hybrid mode the SOC would drop 2-3%. It was very easy to run the battery down to 41% SOC with normal acceleration when in Hybrid drive. Clearly the are using more assist. I think this is where the mileage increase has come from. EV mode seemed about the same as the older models. LGA and double tap worked the same.
3) ICE start up was indeed much softer. Much softer than mine even after my PCM was replaced.
4) Hot restart ICE on time seemed much shorter. I noticed on 2 hot restarts after key off for 5 min the ICE only ran for maybe 15 seconds. Though I didn't put a stop watch on it.
I think on the 08's attention must be paid to SOC and keeping it high not low. It will be imperative to use regen braking otherwise you will be charging the battery allot of the time. After driving this 08 I KNOW I dont have the 08 software.
#2
12-10-2007, 09:48 AM
Re: 08 vs 07 test results
I got to drive a 08 MMH at the Houston hybrid meeting. I was able to use my scan gauge and noticed some significant differences in the software. This MMH was NOT broken in so some of the differences may be due to the battery has not cycled enough.
1) The upper SOC is allowed to go about 2% higher. I was unable to test the lower limit SOC. On highway cruise the battery was no longer recharged by the MG1 after 54%. I did not and was unable to test the max recharge as the software is very aggressive in the use of the traction motor. Refresh rate seemed to be about the same.
2) The use of the traction motor is MUCH more aggressive when in Hybrid drive. Even with light acceleration in hybrid mode the SOC would drop 2-3%. It was very easy to run the battery down to 41% SOC with normal acceleration when in Hybrid drive. Clearly the are using more assist. I think this is where the mileage increase has come from. EV mode seemed about the same as the older models. LGA and double tap worked the same.
3) ICE start up was indeed much softer. Much softer than mine even after my PCM was replaced.
4) Hot restart ICE on time seemed much shorter. I noticed on 2 hot restarts after key off for 5 min the ICE only ran for maybe 15 seconds. Though I didn't put a stop watch on it.
I think on the 08's attention must be paid to SOC and keeping it high not low. It will be imperative to use regen braking otherwise you will be charging the battery allot of the time. After driving this 08 I KNOW I dont have the 08 software.
1) The upper SOC is allowed to go about 2% higher. I was unable to test the lower limit SOC. On highway cruise the battery was no longer recharged by the MG1 after 54%. I did not and was unable to test the max recharge as the software is very aggressive in the use of the traction motor. Refresh rate seemed to be about the same.
2) The use of the traction motor is MUCH more aggressive when in Hybrid drive. Even with light acceleration in hybrid mode the SOC would drop 2-3%. It was very easy to run the battery down to 41% SOC with normal acceleration when in Hybrid drive. Clearly the are using more assist. I think this is where the mileage increase has come from. EV mode seemed about the same as the older models. LGA and double tap worked the same.
3) ICE start up was indeed much softer. Much softer than mine even after my PCM was replaced.
4) Hot restart ICE on time seemed much shorter. I noticed on 2 hot restarts after key off for 5 min the ICE only ran for maybe 15 seconds. Though I didn't put a stop watch on it.
I think on the 08's attention must be paid to SOC and keeping it high not low. It will be imperative to use regen braking otherwise you will be charging the battery allot of the time. After driving this 08 I KNOW I dont have the 08 software.
May I ask what SOC and PCM stand for?
(please forgive me, I'm a rookie in the hybrid world)
#3
12-10-2007, 10:06 AM
Join Date: May 2007
Location: College Station Texas
Posts: 744
Re: 08 vs 07 test results
SOC is the State Of Charge of the High Voltage battery
PCM is the Powertrain Control Module, also called the computer or processor. Used to be refered to as an ECM or Electronic Control Module. Usually an ECM only controlled the engine, now most cars use a PCM which also controls the transmission ans in the case of the hybrids ALLOT more.
PCM is the Powertrain Control Module, also called the computer or processor. Used to be refered to as an ECM or Electronic Control Module. Usually an ECM only controlled the engine, now most cars use a PCM which also controls the transmission ans in the case of the hybrids ALLOT more.
#4
12-10-2007, 10:19 AM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: 08 vs 07 test results
#5
12-10-2007, 10:23 AM
Re: 08 vs 07 test results
SOC = State of Charge and I think PCM is Powertrain Control Module but I can't recall. It handles decisions about when to charge and when to assist, when to shut the ICE off, etc. All that stuff.
This mirrors my own experience and is the reason I bought a 2008 instead of an earlier one, even though I could have gotten a 2007 with Nav for less than my 2008 non-Nav model.
Light acceleration needs seem to be handled primarily by the traction motor in the 2nd gen. At a steady 50, gently accelerating to 55 doesn't cause the ICE to rev a bit then settle back like it used to. As I drive around in urban areas, I'm often surprised to see the ICE is off. Several reviewers have commented on this, as well. The difference between the two is really noticeable.
Did you notice how quiet and settled it seemed too? I really like what they did with the ride and especially quieting everything down.
This mirrors my own experience and is the reason I bought a 2008 instead of an earlier one, even though I could have gotten a 2007 with Nav for less than my 2008 non-Nav model.
Light acceleration needs seem to be handled primarily by the traction motor in the 2nd gen. At a steady 50, gently accelerating to 55 doesn't cause the ICE to rev a bit then settle back like it used to. As I drive around in urban areas, I'm often surprised to see the ICE is off. Several reviewers have commented on this, as well. The difference between the two is really noticeable.
Did you notice how quiet and settled it seemed too? I really like what they did with the ride and especially quieting everything down.
#6
12-10-2007, 11:33 AM
Join Date: May 2007
Location: College Station Texas
Posts: 744
Re: 08 vs 07 test results
My impression was it felt more solid. As far as quiet, we had the moon roof open so cant say. The interior was a shock though, really different. I really liked the aggressive use of the traction motor. The way I drive would improve my mileage.
I am thinking it needs to be said before the 09's come out.
#8
12-10-2007, 12:20 PM
Re: 08 vs 07 test results
This has been reported several times, but I know for my '07, I can't even tell if the ICE has started unless I look at the tach. I just can't image it being any smoother/softer.
#9
12-10-2007, 01:33 PM
Re: 08 vs 07 test results
Pretty much, I need to get it over with because when the 09's or '10s come out with all the features I want(RSC, steering wheel audio control, redundant electric AC, tie-downs in back, easy-folding rear seat, decent roof rack) I'm going to be jealous as heck and not liking my '08 quite so much.
#10
12-10-2007, 01:44 PM
Re: 08 vs 07 test results
