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Old 12-15-2009, 05:19 PM   #18 (permalink)
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Originally Posted by The Atomic Ass View Post
I have never heard lugging as being ascribed to carburetors, I've been told that lugging is the detonation you get under high load at low RPM, which for a 4-cyl can be as high as 1,500, and in the case of my Ninja, 2,500.
The carburetor in your Nnja (correct me if I am wrong) is very similar to the original SU types used in Britain dating back to the mid century.

They are a variable venturi type without accelerator pumps. A single tapered needle and seat with a ported vacuum operated diaphragm (either rubber or metal) raises the needle and changes the volume of fuel in relation to throttle opening and engine speed.

Without any accelerator pump you do not have the issue of a specific volume of fuel being introduced into the engine regardless of the engine's speed.

In the classic term, the way I learned it in the 1960S, lugging an engine meant you were engaging the accelerator pump at too low RPM. The amount of fuel entering the engine was far too much for the volume of air. This made the mixture so rich, most of the fuel was not mixed properly for combustion.

Lugging a Ninja would certainly occur at higher RPM, when you consider the redline of the 250 CC engine, which (again if memory serves me right) is in the 12-14k RPM range. Some Bike engines are even higher.

Now I would not consider that a typical passenger car engine, especially if we are discussing a diesel, many of which would never operate at RPM ranges much higher than 2500. At 12k, I am not aware of any diesel that would not have disintegrated long before that RPM level was reached.

My VX shift indicator lights up to recommend an up shift at 1000 Rpm in 5th gear. That's a very low RPM level for 5th gear operation, but in the VX the engine is designed for that low speed torque.

To the original poster;

When I recommend drafting in heavy traffic, it is always in the right lane. The Interstates here have very heavy traffic volumes. One section here has 49,000 cars pass over the same spot, in the same lane, every day.

When you divide 84,600 seconds per day by 49,000 vehicles, you have less than 2 seconds of average separation per vehicle 24-7. Understand that during the 10PM to 6 AM hours the traffic volume is much lower on average, the separation time during heavies flow is less than 2 seconds per car, probably less than 1.5 seconds. At 55 MPH PSL, that amounts to an average separation distance of about 110 feet minus the vehicle length average of 15 feet. 95 feet separation distance average for 18 hours a day, including tractor trailers and other large vehicles.

My drafting distance is the same as my stopping distance in those conditions. Even then, you will have people cut in front of you and pass on the right, the vehicle in the left lane. Some separation distances and so ridiculously low, I can read the month and year on the license plate stickers in my rear view mirror, and my eyes are not that good any more.

If you leave more distance between you and the vehicle in front of you and the vehicle behind you is inches from your rear end (as you previously stated), is the danger not greater than if the distances were more close to the same?

The last 5 plus times I have been involved in any collision, I was hit in the rear, so that is where the danger is greatest, at least for me in my particular circumstances.

Driving for 44 years.

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