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I'm working on a mpg issue. What is your RPM's at 60 mph? Mine is 2500 at a smooth steady 60 mph.
 

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@60mph: around 2000
@70mph: 3000

a related question if that is ok...is it safe to drive the is300 engine between 3 & 4000 rpm? does this have any adverse effects on the engine? i test drove the car and compared it with the gs300. the gs300 hit around 80 mph and the rpm was at 3000. does the 5hp difference cause this? i know that most cars say to stay between 2 - 3000 rpms to prevent unnecessary engine wear. thanks for any help given.
 

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Originally posted by rnrstar:
@60mph: around 2000
@70mph: 3000

a related question if that is ok...is it safe to drive the is300 engine between 3 & 4000 rpm? does this have any adverse effects on the engine? i test drove the car and compared it with the gs300. the gs300 hit around 80 mph and the rpm was at 3000. does the 5hp difference cause this? i know that most cars say to stay between 2 - 3000 rpms to prevent unnecessary engine wear. thanks for any help given.
The gearing of the GS tranny is probably different, hence the lower engine speed. I run my car up to 8000rpm every day, no adverse effects here! =) I highly doubt 3-4k is going to hurt your engine. Now if you run at 5500 all day long, yeah, that'll probably do something bad.
 

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you wrote: I highly doubt 3-4k is going to hurt your engine. Now if you run at 5500 all day long, yeah, that'll probably do something bad.

thanks a lot for the info! i've got 2 questions on your comments:
i do a lot of highway driving, maybe about 70 miles a day.

1. do you think its ok to drive around 3.5k rpm? i just can't see driving 70 in the car all day.

2. do you know if this will seriously affect fuel economy?
 

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you wrote: I highly doubt 3-4k is going to hurt your engine. Now if you run at 5500 all day long, yeah, that'll probably do something bad.

thanks a lot for the info! i've got 2 questions on your comments:
i do a lot of highway driving, maybe about 70 miles a day.

1. do you think its ok to drive around 3.5k rpm? i just can't see driving 70 in the car all day.

2. do you know if this will seriously affect fuel economy?
 

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Originally posted by rnrstar:
i do a lot of highway driving, maybe about 70 miles a day.

1. do you think its ok to drive around 3.5k rpm? i just can't see driving 70 in the car all day.

Of course, if the car is geared that way then I'm sure the engineers took that into consideration when building the engine. For example, I run at about 4500rpms when I'm doing 80mph. That's just the way it is.


2. do you know if this will seriously affect fuel economy?
Actually, since you're not varying your rpms much (if at all) and since you're not accelerating, it will do nothing but give you better fuel economy. This is the main reason why city driving (stop/go/stop/go) reflects a low MPG rating and why highway driving reflects a better MPG rating.

Now will cruising at 3500rpm yield better fuel economy than cruising at 2500rpm? No, simply because you're using more fuel to run 3500 than at 2500. You should see a marginal difference between the two on your MPG gauge, give it a shot.
 
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