Engine Questions

Rough idle when you first start it, or rough all the time? What grade gas are you using? My car idles so smooth I can't even hear it running with radio off.

Yeah. I found that weird also. All cars I have had; idle at about 1000rpms. I almost forgot to turn it off it was so quiet.

It's not that the needle bounces around. The idle at 500 rpm's when stopped seems low to me. The engine is very smooth but in park it seems noisy and I thought lexus exhausts were supposed to be quiet. Mine has a rumble in it at 60-70 mph. I know the exhaust was tuned by lexus so that you could here it but does everyone else notice this rumble.

no they are not, actually, an inline motor can idle smoother and rev up higher, because by their design in nature, they are a smoother, better balanced motor, just in design.

Originally posted by sloop:
I have a few questions about the Inline-6. Are Inline-6's rougher idling that V-6's Mine seems rough for some reason. Also, concerning idling what does everyones car idle at in Drive mode) (500 rpm's seems low to me. Is this correct?)

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No, the I6 is one of four "perfect" engine configurations (F6, fully-counterbalanced V8, V12 are the others) that are balanced for 1st and 2nd order forces and moments. That's why Aston Martin, BMW, Jaguar, and Mercedes have been using this relatively difficult-to-implement configuration for years. (It's narrow and long for its displacement.)

If it's idling at 500rpm, that may be the entire reason for the roughness. Mine idles at around the more usual 700rpm. (I think; it's too late for me to find out tonight.)

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051/LP/SR/LD/HH

[This message has been edited by DtEW (edited February 16, 2001).]

I don't remember what my IS idles at, but my previous Toyota Camry idled at around 600 rpm--having one for 5 years kind of burns it into your memory. Toyota engines in general idle lower for some reason.

--k

It will idle higher in park than when you are in Drive with your foot on the brake. The exhaust does make some noise at highway speed, but that's the nature of the car. I saw somewhere that the IS300 is rated at 74 dB at full throttle and 73 dB at highway speed. I've been to lazy to take my dB meter out to the car and take any measurements, maybe I'll have to do that.

Originally posted by sloop:
It's not that the needle bounces around. The idle at 500 rpm's when stopped seems low to me. The engine is very smooth but in park it seems noisy and I thought lexus exhausts were supposed to be quiet. Mine has a rumble in it at 60-70 mph. I know the exhaust was tuned by lexus so that you could here it but does everyone else notice this rumble.

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[This message has been edited by rubley (edited February 16, 2001).]

[This message has been edited by rubley (edited February 16, 2001).]

The engine is so smooth, I once forgot to turn it off while fueling. It is idling at 700-800 RPM.

Originally posted by DtEW:
No, the I6 is one of four "perfect" engine configurations (F6, fully-counterbalanced V8, V12 are the others) that are balanced for 1st and 2nd order forces and moments. That's why Aston Martin, BMW, Jaguar, and Mercedes have been using this relatively difficult-to-implement configuration for years. (It's narrow and long for its displacement.)

If it's idling at 500rpm, that may be the entire reason for the roughness. Mine idles at around the more usual 700rpm. (I think; it's too late for me to find out tonight.)

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That is very interesting. Know where we can learn more about why these engines are so good (I have heard the same things, but do not know the technical reasons behind it).

My IS300 engine is very smooth. As stated I6 engines tend to be among the most smooth available.

I think 500 rpms is a bit low for idle speed.
(I haven't checked but I think mine is like 750)

It it seems rough have your dealer look at it.

Here you go!
http://www.fortunecity.com/silverstone/lancia/58/technical_school/engine/smooth1.htm

Originally posted by hurricane:
That is very interesting. Know where we can learn more about why these engines are so good (I have heard the same things, but do not know the technical reasons behind it).

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