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Hello world, I bought the 1.6 gasoline (petrol) a few days ago and I am curious to the RPMs your obtaining at highway speeds. Im doing around 3,000 RPMs at 65mph. I thought it might be high and I am wondering if it IS high then how to I change the gearing? Im new to stick shifts so I wanted to hear from other 1.6 errrrs.
 

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I have a 2.0 auto and my RPM's are high as well. Around 3500 rpm going 75mph.

They really need to add a 5th gear to the automatic. Would improve gas mileage by a lot.

My 1992 silhouette went around 1800 RPM's at 75mph.
 

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I have a 2.0 auto and my RPM's are high as well. Around 3500 rpm going 75mph.
My god that is screaming! Glad I went for a manual.
 

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I usually keep my cruise control at 82mph on the turnpike. My rpm's stay around 3500. I was wondering if this was high or not. It's been a few years since I've driven a manual transmission (5-speed gasoline).
 

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Hello world, I bought the 1.6 gasoline (petrol) a few days ago and I am curious to the RPMs your obtaining at highway speeds. Im doing around 3,000 RPMs at 65mph. I thought it might be high and I am wondering if it IS high then how to I change the gearing? Im new to stick shifts so I wanted to hear from other 1.6 errrrs.
Hi Atrm84:
Your engine RPM's aren't "high" and don't fool with the gearing. The Engineers at the Factory know what they are doing. The only time you'd need to change gearing - would be if you made a significant change to the tire diameter - that would in effect change the over-all gear ratio's of your car. Or if you wanted to use your car for some more narrowly defined use - like drag racing, or pulling stumps out of the ground.

I don't know about the 1.6 Liter - but the 2.0 Liter Twin Over Head Cam is Red Lined at 6500 RPM - That engine should have no problem running 7/24 between 3000 and 4000 RPM once it is broken in properly.

I believe that when I looked - my 2.0L A/T was right at 3000 RPM at 70 mph and still under 3500 RPM at 80 mph.

In general you want your engine running within the mid point of its Power Band, with a no load situation at cruise, at highway speeds. At that point the timing can be advanced and the Air/Fuel ratio ran very lean - ie the best mpg's for the speed. If you were to lower the numeric ratio of the overall gearing..{changing from say 4.10:1 to 3.3:1}... to the point that the engine dropped out of its Power Band at cruise - the engine would be running under a load condition {lugging along} - timing would be retarded and Air/Fuel ratio's enriched.... and mpg's would drop.

Push the speed of the car on up much past 80 mph with its stock gearing - and aerodynamic drag would increase greatly - and again the engine would be working in a "load condition" and mpg's would drop significantly. Because now the engine is not only in a Load condition - it is in a Load condition and turning at high RPM.

BTW - depending on the over-all diameter of the tires - 15", 16" or 18" - your RPM at Speed may vary a couple hundred RPM from others reporting. While the manufacturer tries to keep over-all diameter of the tires close to the same, with out regard to the wheel size - buy using lower profile tires with larger wheel diameters - they aren't all exactly the same. Tire diameter will effect the relationship between RPM and Speed.

FWIW,
Carl B.
 

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I have a manual base model with the 1.6, and yeah its in thet 3k range, may seem high to you, especially if your used to a American cars they rely on torque, seems most foreign cars run higher rpm, its normal..
 

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I have a 2.0 auto and my RPM's are high as well. Around 3500 rpm going 75mph.

They really need to add a 5th gear to the automatic. Would improve gas mileage by a lot.
Hi Bodycount:
I'm not sure that adding a 5th gear to the A/T would significantly improve highway mileage. 3500 RPM at 75mph wouldn't be considered "high RPM's with the 2.0L engine - thats about mid range.

Normally adding a 5th gear to an A/T allows the first 4 gears to be of a lower ratio and closer together. This can help city driving mpg's, but it usually doesn't result in much improvement in highway mpg's.

Adding an Over-drive 5th gear to a standard transmission does pretty much the same - and in both cases manufacturers normally lower the rear-end ratio of cars equipped with overdrive 5th gears. It all depends on the Torque and HP bands of the specific engine used.

The real goal is to keep the engine within its Power Band at cruise. Most likely wouldn't hurt much to knock off a few hundred RPM between 3500 and 3000 RPM - but drop it much more than that and the load on the engine may go up and mileage down at slightly lower speeds {55mph to 65 mph}

The bottom line is - the Engineers at the Factory know the power band of the engine, the weight of the car, the aerodynamic drag involved at any speed - - and they select the gearing to keep the engine running at its most efficient levels at the various speeds used daily. It's usually pretty hard to beat them for over-all use. Of course if you have a very specific use - and your willing to trade off over-all efficiency.. yes they can be beat when you change the rules of the game.

My 1992 silhouette went around 1800 RPM's at 75mph.
Yes - but that is a quite different vehicle with a quite different engine design. What both vehicles have in common - is that the people that designed them were aiming at the same efficiency goals, matching the engines power band with the demands placed on it with vehicle weight, aerodynamic drag etc. at highway speeds and for in town driving.

FWIW,
Carl B.
 

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Discussion Starter #9
Thanks @Carl Beck! That explanation helped a lot. I have not been over 75mph in it just yet, waiting for the break-in period to elapse. I guess this is what I get for being raised in automatics!
 
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