Top speed and IMA

[OuttaSight]

Earlier this year I had an "opportunity" to drive my I2 in Germany. I call it an opportunity because it wasn't planned. We were supposed to be flying on holiday but the volcano ash cloud over the UK the day before we were to fly put paid to those plans.

So we decided to drive to Berlin and the Czech border (as you do in situations like this).

The I2 is plenty comfortable for a long cruise. The seats are more comfortable than my old Accord and the engine is very quiet at cruising speeds below 70mph. Most of the time we travelled at a steady 53mph (83km/h) to save fuel as much as possible but it would have been rude not to test the I2 to it's limits on the autobahns.

The I2 is pretty good off the line with lots of IMA assist and 50-70mph is not too bad, although the CVT can take a little while to spool up. It can even hussle along quite well at 100mph (160km/h) on all but quite steep autobahn inclines. On one particularly long straight though I had it up to 121mph (195km/h) but that was the absolute maximum it could do and then I got a nasty shock... The IMA assist ran out and instead went into regen mode still with the throttle planted. I thought it was never supposed to do this - stop assisting, yes, but regen mode???

The result was a sudden slowing of the car from 195km/h to about 180km/h and an unnerving shimmy as it happened. Like lifting off too quickly (don't even think of touching the brake at those speeds - aero braking is plenty enough deceleration).

I didn't dare try it again and after that kept it at a max of 160-170km/h.

I think the IMA still needs some work on it's algorithms. If it is going to fade the assist, it should do it more gradually (currently it just sort of snaps off when the battery monitor has decided you've had enough). It should definitely not suddenly regen while climbing hills (I noticed this within days of taking delivery but Honda claim it's "normal behaviour"). It should never regen when running full throttle at over 180km/h - that's just dangerous! OK... You probably won't get the chance to find out but I wouldn't buy an I2 if I lived in Germany... I didn't see another I2 the whole time we were there. I did see a couple in France and Belgium though.

On that stretch of road I missed my old Accord... It could cruise at 130mph (210km/h) continuously and max out "off the dial" although the GPS said 143mph (230km/h)... Back when petrol was less than £1.00 a litre in Germany

[Cobb]

Yeah, the assist slacks off over 70. Many cases I see it dip into regen slightly and if I am coasting slightly it will peak out then return to the middle mark. I see the most assist below 35mpg.

I briefly drove 90mph and I think the needle dipped into the regen area the whole time and was pushing 4 grand.

The car has a mind of its own. Its thinking is that if you are driving inefficiently, it can divert some of that wasted power to recharge the battery. I guess I can see this above 35mph or 55 cut off where it wont regen vs regen regardless of petal input, but not from a dead stop.

Most of the US i2 owners have a problem where it will regen from a dead stop, a slight hill or merging into traffic.

[OuttaSight]

Yeah, I get the problem with it going into 50% regen when pulling away at a junction at the top of another hill. It always uses up all the battery getting to the junction at the top of the hill and then when you go to pull away up the even steeper hill it goes into regen and the engine bogs down. It then spends the whole of the next hill regenning. Very annoying.

I have to shift it into Sport mode before pulling away at that junction just to get the CVT to hold a low ratio and rev more to get going on that junction and keep going up the steep hill with the thing charging the battery at the same time! It's a pain as it's on the normal route we take to my folks house.

They should upgrade the firmware on it... definitely ill behaviour sometimes. A larger battery wouldn't go amiss either...

[Cobb]

From what I can tell in econ and drive it loads or lugs the engine depending on how you want to look at it to at least 80%. In sport mode it reduces it to 60%.

Of course in econ it retards the closing of the intake valves to reduce pumping losses and to make an artifical atakins cycle motor. True its more efficient, but it leads to that vacuum leak feeling.

Pressing the gas petal to the floor should "fix" this as the computer deems necessary, but I too use both as needed sport mode after turning off econ and turning off just econ.

Some say a bigger pack would be best, others say it could hinder fuel economy as it would neeed to be recharged. As is braking doesny fully charge the pack. I think a bigger 12 volt battery would be well worth the investment.

[cheesie]

the fastest ive gone is 101mph but i dont remmember if the needle was on regen or assnt
yeah honda should make an system update
or maybe try cobb's theory... a more powerfull battery?

[Don19]

Last week when I was driving through the mountains in Scotland I had the regen problem. It gave assist for amost of the way while I was climbing the steep hill but suddenly it went into regen and I lost some power. I made a quick check and the battery was no where near empty. I could not understand why it decided uphill where I needed a bit of extra pull it decided to waste power on charging. That said I was impressed with the cars ability to keep the speed up climbing up some very steep roads better than my old Jazz. One other thing to mention is I did a single run of 380 miles and I can say I had no problem at all with with the I2 it was far more comfortable and easier to drive than my old car. The mileage was good considering I drove it for speed rather than economy and it was fully loaded, it finished at 58mpg ( UK mpg ) not bad.

[Cobb]

The soc meter is delayed for some reason where as the needle is almost real time plus or minus a few seconds. In my cases you see the battery screen show more than half full, then after it starts to regen the battery suddenly becomes empty. This seems to happen after some steering and use of the AC. I am assuming the car has no way to count or measure the draw the 12 volt side has and when it sees something like a sudden drop in voltage it does the recal.

I can understand the car using extra capacity to top off the battery if you insisting on driving inefficiently, but the situations where it regens regardless of your input, then the system stops for a minute, then returns to normal is what I hate.

Now that I do not use the ac or power steering it will just stop assisting and return to nutral and when I lift it starts to regen, but I can interrupt it with asking for more acceleration.

Driving in excess of 75 it doesnt offer me that much assist at all, I just see it dip a bar or few into regen for a minute, then returns to nutral. The cvt is wonderful, Ive driven econboxes and hate not having the right gear and other lug it in one gear or redline it in another.

[srh5454]

Photo at 109 at GrapeVine (North of Los Angeles). I eased off the gas at 120 to grab my phone. This was a few months back though...
I took another photo about 10 seconds later at 93MPH and 199.9MPG after i reset the trip.....

[joecvt]

Originally Posted by srh5454

Photo at 109 at GrapeVine (North of Los Angeles). I eased off the gas at 120 to grab my phone......

Please people Do not take pictures of your speedometer at this speed especially when you are trying to grab your cell phone at 120 MPH....

You put your life in danger as well as other peoples lives. It is obvious in the photo that there were other vechiles on the road right next to you.

I hope the previous post does not inspire others to take photos at high speed.

JoeCVT = Just your average CVT owners

[GoMetricToday]

Originally Posted by joecvt

Please people Do not take pictures of your speedometer at this speed especially when you are trying to grab your cell phone at 120 MPH....

You put your life in danger as well as other peoples lives. It is obvious in the photo that there were other vechiles on the road right next to you.

I hope the previous post does not inspire others to take photos at high speed.

JoeCVT = Just your average CVT owners

AMEN!!! Joe. What a foolish thing to do. If one is going to take pictures of excess speeds, then they need to find a way to mount the camera or phone and take video. Or have someone else take the picture. Granted no one should be driving that fast on the Interstates. It may be acceptable in other parts of the world, but not here. I don't want my life endangered because someone wants to see what their car will do.