Non Transferable!!!

[JimIsbell]

After two months of ownership of an Insight it occurred to me that the techniques used to get fuel mileage on the Honda might be transferable to the Jaguar. So today I tried it.

I inflated the tires from their normal 28 PSI to the max sidewall pressure of 35 PSI, and generally tried to drive with a light foot on the pedal and off the pedal when I could.

Inflating the tires made such a small difference it was not noticeable. Since I normally drive with a light foot anyway, the driving techniques made no discernible difference. Turning off the AC made a 3 mpg difference. A three MPG difference is about 10% since I normally get 26 to 30 mpg on the highway at 55 mph anyway. This is virtually the same as the 6 to 10 mpg difference with the Honda when you are talking about a percentage of the total.

So, all in all I was not able to improve my mileage on the Jaguar.

I thought the harder tires would make a big difference, but they didnt. The rest was predictable.

[Patrickmilburn]

What year and model of Jag do you drive?

[red1dr]

A big difference is that the Jag does not have lean burn. The Insight thrives on light throttle because you can stay in lean burn that way.

For the Jag, a better strategy would be to accelerate **briskly** (not foot to the floorboard but firmly) to an upper limit, say 60mph, and then coast in neutral (engine on) down to a lower speed, say 50 or 45mph. If a long gentle downgrade appears, then you might consider coasting engine off (but test this at low speed on a deserted back road first!!*). This is Pulse and Glide. It works because the engine burns gas very inefficiently at very small throttle openings, so it is more efficient overall to accelerate with a more open throttle and then coast at idle (or off). Ideally you want a fairly short pulse and as long a glide as possible.

Tire pressures play into this because higher pressures will lengthen your glides.

Obviously you may have to narrow the range if you have traffic behind you, but it is surprising how few problems it causes. Equally important is keeping alert to situations when you have NO traffic behind you and so can WIDEN the range.

Awareness of traffic and road gradient and other strategies are very transferable between the Insight and non-hybrids.

* - if you have a manual you can do a bump restart (which can be very quick and so smooth it's barely noticeable) rather than use the key.

[JimIsbell]

Yes, awareness of the road conditions and pulse and glide do work, but I was doing that on the Jag before I ever bought the Insight. The most useful strategy on the jag is the roller coaster strategy for hills which we have a lot of here. Before I got the Insight I thought I was pretty smart gett5ing 28 to 30 mpg with the jag. Now I know I was a piker.

In answer to the question about what jag I drive, mostly its the 1988 XJ40 (gets the best mileage) but I also have a 1970 XKE and a 1982 XJ6 neither of which get better than 24 mpg.