12-31-2010, 04:05 PM
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10mm MW
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Join Date: Sep 2008
Location: Michigan
Posts: 767
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Quote:
Originally Posted by 47dodge
The rack limiter, how does this play/work with torque control? You recommended putting it back in before any torque control adjustments.
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A properly set rack limiter prevents the rack from going beyond the point where the pulse width of the injection exceeds the time available for the fuel to burn as completely as possible. There really isn't any reason that the rack should ever go beyond that point. From a "quality tune and drivability" aspect, it is a very good feature.
By turning the rack limiter in all the way, or removing it completely, you remove one of the players in the governor, and the result is that the rack position limit is determined by the balance point between the Throttle Spring, Torque Control, and Max Speed Limiter spring tensions. IMO this is not a good way to increase fueling because there is no positive control of the rack at full power, which is where the engine can melt down if EGTs are not monitored and the throttle adjusted accordingly.
For a competent driver this not a problem, but for the typical, "idiot light" driver, it is only a matter of time before the EGTs go to critical mass. Remember that the 240D is underpowered and the typical driver will have it floored 95% of the time. Just my 2 cents.
If you send me your e-mail address, I will send what I came up with to answer your other question in a more detailed manner, however, since you are knowledgeable about IPs, I do not explain everything in regards to theory as a novice would need.
On a side thought for philosophical discussion;
I was talking to a friend the other day about the difference in explaining how something specialized works, and how to do something that is very specialized.
We both agreed that the difference is value. Providing an explanation of how something works, (information that is available in text books etc), is an educational exercise and is in the value of a favor, however, special knowledge that is acquired via sources, methods, and experiences outside of the traditional educational domain are much more valuable. This is why IP shops don't post the "secrets" as to what and why they do what they do, people will pay to have them do that voo doo that they do.
Like many others in this country, I am not as finically secure as I would like, and I am always trying to figure out how to take what I know and can do and make money with it. After all it cost me time and money to acquire the knowledge in the first place. I imagine that some will say that I am being selfish. My first response to that would to say, “I’m not stopping them from providing the information to the world”.
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