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Discussion Starter · #1 ·
I was just thinking this weekend, why do I need a power commander when I change exhaust and intakes but I don't when I change these items on my Silverado? Are the computers in vehicles just more complicated and can adjust to the changes? Also why does a chip void the warranty on my truck but not my bike?
 

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I was just thinking this weekend, why do I need a power commander when I change exhaust and intakes but I don't when I change these items on my Silverado? Are the computers in vehicles just more complicated and can adjust to the changes? Also why does a chip void the warranty on my truck but not my bike?
To get the most out of your Silvy, you need to tune it. I use HP tuners on my TBSS. It wouldn't run at all on the stock ECU program.
The bikes smaller engines are more suceptible to fuel requirement changes.
 

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To maintain a safe and consistent AFR (air fuel ratio). After changing both exhaust and intakes the bike could be very rich or very lean depending on the set up. Could potentially harm the engine, better safe than sorry.
 

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I was just thinking this weekend, why do I need a power commander when I change exhaust and intakes but I don't when I change these items on my Silverado? Are the computers in vehicles just more complicated and can adjust to the changes? Also why does a chip void the warranty on my truck but not my bike?
Stock zooks are programed for the restrictive way they were built. One opens the engine up to breathe better the computer is not a smart computer, One that adjust to conditions, We need to tell the computer to give more fuel and when.
 

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Vehicles run an open loop/closed loop system and bikes do not. Vehicles pcm has the ability to gather data from a MAF sensor, MAP sensor along with O2 sensors and others, then adjust the fuel mixture. Our motorcycles have the ability to make small adjustments using information from the AIT sensor and TPS sensor. Large changes need to be made with a different control, such as a power comander.
 

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I see 2 answers to your question:

1. If you change enough in your car or truck, you will need a fuel management system.

2. You can change far more in a fuel injected car or truck before you need fuel management, because you already have one in the stock computer. You already have an O2 sensor and a computer that adjusts fuel based on what it reads. Bikes do not usually have the sensor and are therefore not built with a computer that makes such adjustments.
 

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Discussion Starter · #7 ·
See, I knew I would get good answers. Just like the field of dreams around here, if you ask, they will answer. :bigthumbsup:
 

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If you put on an after market exhaust without putting on a power commander (adjusts air and fuel) you could damage your engine if it is running too lean.

You have to know some terms. One is the air-fuel ratio (AFR), which is the mass ratio of air to fuel mixture during combustion. If the air and fuel are perfectly matched, all the fuel will be burned. In the lab it will be 14.7. In any engine, this is never the case and there is much debate on what a motorcycle engine's AFR should be. Engines vary even within the M109s, which is why owners get theirs tuned on a certified Dynojet with a certified technician.

Simply put, if you run an engine too rich you will foul the plugs, which are cheap. If you run the engine too lean you will damage pistons, valves and maybe other things. These are costly.

May I suggest doing a search on the net by putting in stoichiometric mixture for motorcycle engines or Air Fuel Ratio's for motorcycle performance, etc.

There are many other folks here who know a great deal more than I on this subject.

Hope this helps.

Doc
 

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Discussion Starter · #9 ·
If you put on an after market exhaust without putting on a power commander (adjusts air and fuel) you could damage your engine if it is running too lean.

You have to know some terms. One is the air-fuel ratio (AFR), which is the mass ratio of air to fuel mixture during combustion. If the air and fuel are perfectly matched, all the fuel will be burned. In the lab it will be 14.7. In any engine, this is never the case and there is much debate on what a motorcycle engine's AFR should be. Engines vary even within the M109s, which is why owners get theirs tuned on a certified Dynojet with a certified technician.

Simply put, if you run an engine too rich you will foul the plugs, which are cheap. If you run the engine too lean you will damage pistons, valves and maybe other things. These are costly.

May I suggest doing a search on the net by putting in stoichiometric mixture for motorcycle engines or Air Fuel Ratio's for motorcycle performance, etc.

There are may other folks here who know a great deal more than I on this subject.

Hope this helps.

Doc
I'll tell you what, if there are other people on here that know a great deal more than you on this I'm not interested. I hardly understood everything you eluded to. :-\
 
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I was just thinking this weekend, why do I need a power commander when I change exhaust and intakes but I don't when I change these items on my Silverado? Are the computers in vehicles just more complicated and can adjust to the changes? Also why does a chip void the warranty on my truck but not my bike?
Because on cars they don't typically give the changes needed to produce their inflated horsepower gains. Bikes on the other hand are very sensitive to these things.
 
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