Gen 2 Prius Newbie Questions

[graham2493]

Had the above for a week now and just wondered if I could get some thoughts on whether I'm on the right track with what I'm doing?

(It's a 54 plate T4 with 75k on the clock & FTSH).

1. The Cruise control seems to be a little too eager for my liking when it encounters even slight inclines. I think I'm doing the right thing by cancelling it & using my foot before this happens to save that little bit of fuel/noise. Does this make sense?

2. My Battery pack always seems to hover around the 6-bar mark. It's been as low as 3 very briefly, as high as 7 on occasion and only once has it managed to get up to full albeit for roughly 10 seconds. Is this normal?

3. I do realise this is a "how long's a piece of string" question but how quickly does the ICE take to warm up and how much does, specifically, heating affect MPG in everyone's experiences?

4. What MPG benefits are there in the LRR tyres? I've looked into the different makes etc but my tyre fitter just recommended the usual £65-70 jobs and over-inflating them. (Which immediately made me think "Hang on then. what about over-inflating LRR tyres??").

5. I've a droning noise from about 45mph up over. Could that be wheel bearings or is that just a standard noise with maybe the CVT/whatever on the Prius in general?

6. I'm hooked on MPG. Can LPG conversions be done on the Prius or is it more bother than it's worth?

Any thoughts on the above gratefully received!

I've had the car a week now and have gone through roughly 9 gallons for an MPG of 56.7 (the on-board computer showed 58.6) That's with roughly 50/50 motorway and multi-stop town driving. *edit* filled up an hour or 2 ago & did a 14 mile run up the A1 for an MPG of 67.8. Checked the official figures and that's pretty much on the mark. Surprisingly good for such an old car!!! Put simply I'm over the moon with that (I've come from a manual Mercedes A-140 1.4 that was getting 34MPG) let alone the ride/comfort/automatic box/size/cruise! Don't know why I didn't go for a Prius years ago!

[timberwolf]

Had the above for a week now and just wondered if I could get some thoughts on whether I'm on the right track with what I'm doing?

(It's a 54 plate T4 with 75k on the clock & FTSH).

1. The Cruise control seems to be a little too eager for my liking when it encounters even slight inclines. I think I'm doing the right thing by cancelling it & using my foot before this happens to save that little bit of fuel/noise. Does this make sense?

I also think the cruise control is too aggressive on my later revision (2006-2009) of that model. Yes, it makes sense to cancel.

2. My battery pack always seems to hover around the 6-bar mark. It's been as low as 3 very briefly, as high as 7 on occasion and only once has it managed to get up to full albeit for roughly 10 seconds. Is this normal?

It's Normal. As a strategy, it makes sense for the car to try to keep the Battery approximately half charged, because the car doesn't know whether the driver/environment will need to use the charge in the Battery (e.g. for accelerating) or putting the charge into the Battery (e.g. regenerative braking).

3. I do realise this is a "how long's a piece of string" question but how quickly does the ICE take to warm up and how much does, specifically, heating affect MPG in everyone's experiences?

I normally only do 7 mile trips, between winter and summer I see a 15 mpg difference. Using an OBDII scan tool, I monitor the engine coolant temperature, and in summer it can warm up to the full operating temperature (85-87C if my memory is correct) within a mile or so, and when it is below freezing it can take nearly 7 miles. I don't recall how the Hybrid modes change with engine temperature (search for 5-stages document).

I'm lazy when it comes to grille blocking, so I can't recall if it made that much difference when I did it last year. Please be careful to follow the correct information on whether to block the upper or lower grille, it differs between the models!

4. What MPG benefits are there in the LRR tyres? I've looked into the different makes etc but my tyre fitter just recommended the usual £65-70 jobs and over-inflating them. (Which immediately made me think "Hang on then. what about over-inflating LRR tyres??").

I would always go for LRR tyres. I don't know the difference. Over-inflating is certainly an option, but you should be aware that it does affect harshness of ride, traction and handling. In the case of my Prius, it is most noticeable that traction is affected when lightly braking over for example a manhole cover.

5. I've a droning noise from about 45mph up over. Could that be wheel bearings or is that just a standard noise with maybe the CVT/whatever on the Prius in general?

It doesn't sound like a standard noise, but noises are very difficult to diagnose from descriptions. It could be a wheel bearing.

6. I'm hooked on MPG. Can LPG conversions be done on the Prius or is it more bother than it's worth?

Any thoughts on the above gratefully received!

As the Prius uses a modified Atkinson engine cycle, I wouldn't think it would be suitable. As you've mentioned it we will probably now get some cowboy business recommending it when the search engines get updated:-(

I've had the car a week now and have gone through roughly 9 gallons for an MPG of 56.7 (the on-board computer showed 58.6) That's with roughly 50/50 motorway and multi-stop town driving. *edit* filled up an hour or 2 ago & did a 14 mile run up the A1 for an MPG of 67.8. Checked the official figures and that's pretty much on the mark. Surprisingly good for such an old car!!! Put simply I'm over the moon with that (I've come from a manual Mercedes A-140 1.4 that was getting 34MPG) let alone the ride/comfort/automatic box/size/cruise! Don't know why I didn't go for a Prius years ago!

A second-hand model would have been more expensive years ago, petrol wasn't as expensive, less Hybrids to choose from?

Sorry, the high mpg is an illusion it will soon settle down.

[korat102]

It's worth noting that the Battery charge indicator doesn't show from 0% to 100% charge. The car doesn't allow the Battery to reach those extremes so it doesn't bother to show them. Not sure what the parameters are but I think the lowest bar is around 30% and the highest about 70% or so. Don't obsess over the indicator, just drive the car normally and let it do its thing :)

[kithmo]

There are LPG conversions available for the Gen 3, I've not seen any for the Gen 2.

[Joseph D]

4. What MPG benefits are there in the LRR tyres? I've looked into the different makes etc but my tyre fitter just recommended the usual £65-70 jobs and over-inflating them. (Which immediately made me think "Hang on then. what about over-inflating LRR tyres??").

I would always go for LRR tyres. I don't know the difference. Over-inflating is certainly an option, but you should be aware that it does affect harshness of ride, traction and handling. In the case of my Prius, it is most noticeable that traction is affected when lightly braking over for example a manhole cover.

I would just like to point out that I have found that running my tyres at the handbook recommendation (35F/33R) that I was getting uneven wear over the width of my tyres in that the tyres were wearing more on the inside and outside edges when compared to the middle. This indicates under-inflation, so I now run my tyre pressures at 4 PSI above (39F/37R) and have a much more uniform wear pattern on all tyres. I mention all this as I do not consider my tyres over-inflated, but correctly inflated.

In addition to having my tyres wearing more uniformly, I get better mpg's due to the tyres not being under-inflated. (Under-inflation increases rolling resistance.)

I would recommend using tyres with the lowest rolling resistance you can afford, they are not all expensive and certainly not the most expensive option. Not all LRR tyres are marketed as such, but the lower the rolling resistance the better your mpg's will be in relation to tyres.

Remember though, tyres are just one arrow in your quiver. There is no one magic bullet in the quest of high mpg's.

[timberwolf]

Personally, I found 39f/37r too high for the Bridgestone tyres on my car, it was just a bit too prone to the slip indicator activating over uneven surfaces when braking, and I didn't really get used to the harsh ride.

[Joseph D]

Personally, I found 39f/37r too high for the bridgestone tyres on my car, it was just a bit too prone to the slip indicator activating over uneven surfaces when braking, and I didn't really get used to the harsh ride.

Personally, I don't notice any difference in respect to harshness of ride. I find the quality of the roads to be much more of a factor. In respect to the anti-skid activating, I did notice that to be so when braking while passing over a steel man-hole cover or the like, but only when my tires were new. Not so much now they have worn in a bit.

Each to their own.

[graham2493]

Excellent advice everyone. Many thanks!