'05 vs 08 FEH - MMH
Created February 4, 2008, at 5:39 pm by GaryG
Met with John Dixson a new proud owner of a '08 Fwd Mmh who lives 20 miles north of me. I wanted to compare FE and other things to my '05 Fwd FEH when new and report my findings here.
John is running 35psi in his Eco-Plus tires, so coasting was not as good as my FEH with 50psi. He has just 1,100 miles on his Mmh , so it's not broke-in yet either. I took Johns Mmh on a ~20 mile RT to a nice little restaurant where we had lunch. I averaged 53mpg, which was about 12mpg better in my '05 back in the days with 1,100 miles on my '05 FEH . It's a winner folks! The ride, the looks, Nav sys and the comfort is so much better now.
Good luck John, you have a great vehicle and Ford is job 1!
GaryG
Related Forum Topics
Most Popular Pages
4 years ago
Did you have the scangauge II hooked up to the 08 Mariner? If so, could you report on whether the 08 models allow 35 to 65% hybrid battery SOC as reported by Mark Smith on the "other" site?
4 years ago
Hi Billy
John has a new Xgauge with SoC programmed but I was only monitoring Current MPG. I do monitor two SGII's in my '05 and would have loved to monitor SoC in John's '08MMH had he had a second gauge. John and I talked the entire time and it was hard enough watching one Xgauge, the other standard gauges, nav sys and the road at the same time without causing an accident. I've heard that Mark is incorrect about the 35% to 65% charge/discharge limits, so that was not a concern to me. My techniques focus on driving with the lowest SoC possible anyway. Regen is much milder in the '08 and it takes longer to go EV using "L". You get about the same amount of charge in the battery with the FS in "L" because it takes a longer time to go EV in "L". I'm sure I could adjust my techniques to get better FE overall than my '05 given a few days of driving.
It is my opinion that a 35% to 65% charge/discharge limit would not increase FE on its own. I use a small percentage (39% to 43.5) on average SoC to exceed 60mpg now, so I don't think going higher or lower would do much good for me. The plug-in in the new Ford FEH that Ford has introduced to a CA Electrical Company is another story.
GaryG
4 years ago
You only use 39-43.5% SOC to achieve 60mpg? WOW. That seems completely different than what many of us do--that is get a high SOC and then drain it via EV mode and then repeat. Hmm, I better get a look of your video on the internet and study it.
4 years ago
There is a number of reasons why keeping SoC low allows better gas mileage.
1. The HV battery takes a faster charge from the generator and regen to stay in EV longer.
2. The worst mode to be in is negative split mode with a full HV battery.
3. When you must exceed 40mph and no EV, the battery has room for a charge for EV down the road.
4. Cold engine and HV battery warm-up is faster because of low RPM engine load by the generator and a heavy charge heats up the battery.
5. The warm-up strategy allows the SoC to drop down to ~32% while you gain speed for "L" FS's to build SoC faster.
The key is to keep the engine off longer with faster charges when the engine is running. A long slow fuller charge decreases MPG and carrying around HV battery stored energy is a waste. With a plug-in FEH/MMH, you can use that energy first and fast charges later.
4 years ago
Gary, I have been paying attention to the SOC guage and to date have not been able to get below about 40% for the ICE start threshold. As you know, I do always run the nav and radio, plus the circulation fan at its lowest setting.
I really do appreciate the instructional ride.
Still no response from Linear Logic as to why the CTQ guage is disfunctional.
Thanks,
John Dixson
4 years ago
Good to hear from you John and it was my pleasure driving a new '08 FWD MMH for the first time. Thanks! Anytime you want to get together again and exchange differences in the two models, let me know.
Thanks for confirming billy's question on the '08 SoC range with your Xgauge. Sounds like Desertdog (Carl) is working with Ron Delong at Linear Logic on some of the issues with processors and coding, and he will report their findings ASAP. You have to remember the FEH/MMH has much more gauges available than the other Hybrid Makers thanks to Carl and Ron.
Also, welcome to Hybridcars.com with the new site format. It has changed two times since I joined in Dec. '04 when I placed my order for my '05 FEH. Brad Berman does a great job with the site and we've spoke on the phone about the site a few times.
GaryG
4 years ago
Thanks for checking with Ron and Carl about the Scanguage II and SOC issues. It always is interesting to learn more about our vehicles. I hope your hypermiling status can work for you (and all of us) in the future in reviewing and reporting on the newest version of the FEH. I wonder if you could put your skills to work in promoting this vehicle for dealerships and/or Ford Motor Company itself? I wondering if you should hire(?) an agent in an attempt to do this. I'm sorry to highjacking this thread but you have some special driving skills that could pay off in many different ways.
4 years ago
Thanks Billy
The problem with dealerships in Florida is not selling, but getting enough units. Hypermiling is a hobby and a challenge with myself to overcome everyday conditions.
John Dixson allowed me to prove a brand new FWD MMH that has low tire pressure and miles, can exceed far over 40mpg if the driver is willing to learn and use the techniques myself and others have discovered. Many driver are satisfied with driving a SUV with 28mpg and that's find also.
GaryG
3 years ago
Gary will be ecstatic to know that his "encouragement" made me increase the tire pressure to 37.5 psi, and on the flat roads around Stuart, Fl, I could not discern any difference. ( Having been an engineering test pilot for a helicopter company for 39 years, I do have an accelerometer implant in my fanny, or so the engineering VP used to say ). Comment on how much higher one might go without messing up the ride?
Thanks,
John
3 years ago
John
Try increasing your tire pressure like you just did by 2.5psi at a time till the ride is no longer acceptable to you. High tire pressure will only enhance other techniques such as gliding in "N" or "D", slow acceleration, faster and longer EV speeds and uses less HV battery energy.
If you looked at the remaining tread on my original Eco-plus tires, they were in great shape with almost 45,000 miles. High tire pressure slowed tread wear a great deal on my FEH. As I said, my tire pressure from the factory was 40psi and I seen tire ware fast till I went to 44psi. It got even better when I went to 50psi and my FEH also handles much better now.
If I had to choose from high tire pressure and ride, I would choose high psi and get cushions for my seats. Most of the ride problems seem to me are from noise from the suspension hitting road issues.
GaryG
3 years ago
Thanks. I did notice that the tire wear rating for the OEM tires was a healthy 520.
John
3 years ago
Some questions for GaryG from the postings here.
The worst mode to be in is negative split mode with a full HV battery. What is that and why is it worst?
When you must exceed 40mph and no EV, the battery has room for a charge for EV down the road.
Again, speaking as the 'ignorant', again, why do you need this 'room for charge?'
I have the feeling I'm not grasping some concepts here!
3 years ago
Hi Ranger
Let me start out with, the negative split mode is when the small generator/motor/starter uses energy to control the engine RPM. This energy is not totally wasted because it is reducing or controlling the RPM of the engine. In other words, the generator is taking stored energy from the battery and not providing energy to the traction motor or HV battery. Out of the other modes of operation, this is the one least FE. Positive split mode is when the generator is charging the battery and provides energy to the traction motor for torque boost.
As far as the HV battery being full, there are 2 limits. The first limit is full at around 52% when the small generator/motor/starter stops charging the HV battery. The exception is when the computer conditions the battery with over charging for protection of the battery life. The second limit is 60% and this is the room the designers made for regen charging. In other words, charging above 52% is reserved for regen from the traction motor. Understand that regen charging occurs while driving in "D" or "L", even without applying the brake pedal. This is why coasting in "N" is ~36% better than "D", "N" eliminates regen completely and you have no traction motor drag.
When the small generator charges to its limit of 52%, the generator starts to control engine idle at highway speeds. This is when negative split occurs. To avoid negative split during this condition, I've concluded shifting in and out of "N" at highway speeds (P&G) with a full HV battery stops the negative split mode. During "N" coasting, the engine idle is controlled by the engines PCM, and not the generator (battery powered). This idle is called the secondary idle and is most often a higher RPM. Instant MPG can drop on the SGII from just coasting in "D", but remember your coasting 36% better and longer. Using this technique combined with drafting at a safe distance, can yield better than 45mpg at 65-70mph.
3 years ago
Thanks there GaryG. I'm sure it will all become more clear the more I drive and study the various gauge readouts.
Post a new comment