Hello all,

I recently bought (but haven't completely committed to) a used 2003 Prius and had my first opportunity to commute with the car this morning. My normal commute time is about 45 minutes, which I'm quite comfortable with. Unfortunately that commute time is predicated upon the assumption that I drive 70-80mph most of the way there.

The Prius seemed a little... strained every time I passed the 70mph mark. It was as though it needed to shift into a higher gear but didn't have such a gear to shift into.I will be the first to admit to not being much of a "car person", but I've never driven a car that started straining at 70. Is this normal? Is it just the side affect of driving such a little car or could there be something wrong? This is a used car, after all.

If I just have to accept that I can't drive as fast as before then I can deal, I just want to know if this behavior is indicative of something more serious. Any tips for improving performance?

Thanks!

 

The first gen Prius needs quite a bit of power to travel at high speed, mostly because it has quite a bit of drag. The Prius engine will adjust it's RMP in response to the amount of power required, so going up hills, accelerating and travelling at high speed will cause it to rev quite high. The reason it needs to rev quite high to deliver the needed power is because it's running in an Atkinson/Miller cycle that significantly reduces the torque but improves efficiency. The main thing you need to know is that the car won't really let you hurt anything, it's completely computer controlled so that no part will be 'overspun' and damaged. The engine is limited to 4500 RPM so it's never going to use it in any sort of unsafe manner.

The only thing you may want to watch is the energy monitor because if you are using battery power + engine power for extended times at high speed then there's a risk that the Turtle light may come on, meaning the battery is too low to continue providing boost and must charge back to 50%. It's pretty difficult to do that unless you are climbing a long hill at speed.

 

Slow down, put on some good music, and enjoy the ride

 

I drive 150 mile round trip (buffalo to rochester, ny) 2 or 3 times a week doing 74-80 the whole way. Haven't had any trouble, 2002 Prius.

 

The 2001-2003 Prius have no sound-deadening material installed under the hood. All Prius' gas engines rev up at such speeds. Your high-speed rides will be more serene if you install there, and inside the front door panels. I used the cheapest stuff, but there are many other options. These steps do much to limit the "ICE roar" sounds.

Slowing down is always an option, but quietly climbing hills is an improvement.

DAS

 

The engine is small and as other said it runs at higher RPM than a normal car so you hear noise that you associate with straining. The car can do those speeds with no problem what so ever. The only thing you need to be aware of is that once you get much over 65 mph your mpg will start to drop -- but that is the case in any car.

I do the speeds you are talking about in my '02 with no concern.

 

Engine RPM and ground speed are not directly related in a THS or HSD system. Sometimes ICE RPM noise and driving conditions are unrelated, sometimes ICE RPM seems ridiculously loud compared to what we perceive as normal operating conditions.

Prius I wasn't really optimized for high speed driving. It can do it, but you are pretty much at the top end of its performance spectrum. You should be able to do 75 pretty easily, beyond that you are going to need a pretty good amount of battery assist. Keep an eye on your energy monitor and make sure that when you are cruising or going with the flow of traffic that you do not have a sustained draw on the battery without at least occasional driving in dead band or with surplus energy charge going back to the battery. If so, you might get the turtle. You don't want to get the turtle.

 

The Japan version (97-99) could do over 80 (up to 86) on the flat with no battery assist, so US Prius I should be able to do a little better with more horses. As long as you aren't pulling extended hills the Prius will be ok and you won't get a turtle.

Check out the Japan version Prius Simulator if you want to see a turtle: http://www.wind.sannet.ne.jp/m_matsu...=en?Country=US

 

In my 2001 Prius, extended level highway cruising at 85 mph gives no turtle, in fact I have not seen it yet in >78k miles. Going uphill requires more power of course. A detailed mathematical model of 2001-2003 Prius by Graham Davies is posted in the Yahoo prius_technical_stuff files. It indicates that ICE power alone will achieve 100 mph. I have never done this. In fact I will deny in court that I ever went 98.

DAS

 

I managed to cruise around 80-85 mph through the Dakotas earlier this year, and other than some noise coming from the engine compartment, the car was nice and smooth, even with the a/c on. I didn't get a turtle either, whatever that is. I have been to St. Louis and Chicago a few times now, cruising ~75 mph most of the time, and still get high 30's to low 40's for mpg.