Another exhaust question
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Cruiser
Joined: Oct 2005
Posts: 134
Likes: 0
From: Monkton, Maryland
Another exhaust question
I have a 2001 Road King Classic and just did the 98" big bore. With the big bore I installed a PCIII, had the heads done, and the throttle body bored and had it dynoed. I was surprised at the dyno results, 89.7 HP, 103.1 torq., 14.7 AFR., thought the HP and torque were a little low and the AFR high. The shop that did the dyno told me the only way to get more was to go with a better exhaust. I kept the stock headers and have V&H classic slip-on mufflers. They suggest a 2 into 1 exhaust but I like the two pipe look. Is there any other options?
Banned
Joined: Nov 2005
Posts: 3,499
Likes: 2
From: CANADA
RE: Another exhaust question
For sure lose the stock headers and go with a dual, or 2 into 1 system. For duals, Hard Krome (below), no clamps or slip-ons, fantastic performance, sound and looks. Favorite 2 into 1 would be, Bassani Road Rage. Your AFR looks lean compared to most!
Thread Starter
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Cruiser
Joined: Oct 2005
Posts: 134
Likes: 0
From: Monkton, Maryland
RE: Another exhaust question
Thanks for the feed back. The dyno shop said to stay away from true duals cause it hurts torque. The shop I bought the kit from said the AFR should be about 13.25. How's that sound to you?
Extreme HDF Member
Joined: Nov 2005
Posts: 16,125
Likes: 24
From: Linden New Jersey
RE: Another exhaust question
14.7 is waaaaay lean
Any dyno number can be subjective. Run you rear tire pressure up to 50 and see what happens to your dyno numbers
Even the operator can be late on the throttle and give funny numbers. Was the bike in 4th gear during the pulls
Any dyno number can be subjective. Run you rear tire pressure up to 50 and see what happens to your dyno numbers
Even the operator can be late on the throttle and give funny numbers. Was the bike in 4th gear during the pulls
Road Master
Joined: Mar 2006
Posts: 791
Likes: 0
From: Arizona
RE: Another exhaust question
I thought the higher the number, the richer it is? No? Correct me if I'm wrong!
Thanks!
Thanks!
ORIGINAL: Bruce00
14.7 is waaaaay lean
Any dyno number can be subjective. Run you rear tire pressure up to 50 and see what happens to your dyno numbers
Even the operator can be late on the throttle and give funny numbers. Was the bike in 4th gear during the pulls
14.7 is waaaaay lean
Any dyno number can be subjective. Run you rear tire pressure up to 50 and see what happens to your dyno numbers
Even the operator can be late on the throttle and give funny numbers. Was the bike in 4th gear during the pulls
Thread Starter
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Cruiser
Joined: Oct 2005
Posts: 134
Likes: 0
From: Monkton, Maryland
RE: Another exhaust question
That's what I thought too. I thought 14.7 meant I was running too rich. Man this stuff can be confusing.
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Extreme HDF Member
Joined: Nov 2005
Posts: 16,125
Likes: 24
From: Linden New Jersey
RE: Another exhaust question
Stable combustion conditions require the right amounts of fuel and oxygen. The combustion products are heat energy, carbon dioxide, water vapor, nitrogen, and other gases (excluding oxygen). In theory there is a specific amount of oxygen needed to completely burn a given amount of fuel. In practice, burning conditions are never ideal.
When air and gasoline are mixed together and ignited, the chemical reaction requires a certain amount of air to completely burn all of the fuel. The exact amount is 14.7 lbs of air for every pound of fuel. This is called the "Stoichiometric" Air/Fuel ratio. It's also referred to the Greek letter "lambda."
When lambda equals one, you have a 14.7:1 Stoichiometric Air/Fuel ratio and ideal combustion. When the Air/Fuel ratio is greater than 14.7:1, lambda also will be greater than one and the engine will have a lean mixture.
Lean mixtures improve fuel economy but also cause a sharp rise in oxides of nitrogen (NOX). If the mixture goes too lean, it may not ignite at all causing "lean misfire" and a huge increase in unburned hydrocarbon (HC) emissions. This can cause rough idle, hard starting and stalling, and may even damage the catalytic converter. Lean mixtures also increase the risk of spark knock (detonation) when the engine is under load.
When the Air/Fuel ratio is less than 14.7:1, lambda also is less than one and the engine has a rich fuel mixture. A rich fuel mixture is necessary when a cold engine is first started, and additional fuel is needed when the engine is under load. But rich mixtures cause a sharp increase in carbon monoxide (CO) emissions. When the relative proportions of air and fuel are "just right," the mixture burns clearly and produces the fewest emissions. The trick is balancing the mixture as driving conditions, temperatures and loads are constantly changing.
When air and gasoline are mixed together and ignited, the chemical reaction requires a certain amount of air to completely burn all of the fuel. The exact amount is 14.7 lbs of air for every pound of fuel. This is called the "Stoichiometric" Air/Fuel ratio. It's also referred to the Greek letter "lambda."
When lambda equals one, you have a 14.7:1 Stoichiometric Air/Fuel ratio and ideal combustion. When the Air/Fuel ratio is greater than 14.7:1, lambda also will be greater than one and the engine will have a lean mixture.
Lean mixtures improve fuel economy but also cause a sharp rise in oxides of nitrogen (NOX). If the mixture goes too lean, it may not ignite at all causing "lean misfire" and a huge increase in unburned hydrocarbon (HC) emissions. This can cause rough idle, hard starting and stalling, and may even damage the catalytic converter. Lean mixtures also increase the risk of spark knock (detonation) when the engine is under load.
When the Air/Fuel ratio is less than 14.7:1, lambda also is less than one and the engine has a rich fuel mixture. A rich fuel mixture is necessary when a cold engine is first started, and additional fuel is needed when the engine is under load. But rich mixtures cause a sharp increase in carbon monoxide (CO) emissions. When the relative proportions of air and fuel are "just right," the mixture burns clearly and produces the fewest emissions. The trick is balancing the mixture as driving conditions, temperatures and loads are constantly changing.
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Road Master
Joined: Jul 2005
Posts: 840
Likes: 0
From: elkton, va
RE: Another exhaust question
ORIGINAL: RKC2001
That's what I thought too. I thought 14.7 meant I was running too rich. Man this stuff can be confusing.
That's what I thought too. I thought 14.7 meant I was running too rich. Man this stuff can be confusing.
Hope this clears it up a little for you.