Brand New 2014 Dyna Wide Glide Exhaust
#21
10-22-2014, 05:29 AM
Outstanding HDF Member
Keep the old one in case something bad happens.
The Delphi System on our Harleys is a 'dumb' computer. It can make small, minor adjustments for altitude, fuel quality, etc.
But you start in with messing with the Air Intake and that's going to be more than it can handle.
Our delphi system is NOT a Mass Air Flow system like you find on many cars..... Like Mustangs, Corvettes, etc. It is NOT a 'smart' computer. It's dumb as a box of rocks.
It reads throttle position, manifold pressure and -- That's about it.... Oh yeah, the O2 sensor. Another 'dumb' sensor.
The Delphi System on our Harleys is a 'dumb' computer. It can make small, minor adjustments for altitude, fuel quality, etc.
But you start in with messing with the Air Intake and that's going to be more than it can handle.
Our delphi system is NOT a Mass Air Flow system like you find on many cars..... Like Mustangs, Corvettes, etc. It is NOT a 'smart' computer. It's dumb as a box of rocks.
It reads throttle position, manifold pressure and -- That's about it.... Oh yeah, the O2 sensor. Another 'dumb' sensor.
Nothing wrong with that system. In fact, some of the Corvette high-performance guys switch from the Mass Air Flow system to the Speed/Density system. It doesn't automatically handle cam changes well, but nobody here is suggesting changing cams without a tune anyway.
#22
10-22-2014, 10:25 AM
It really doesn't matter that the system isn't a "mass air flow" system, nor does that make it a "dumb" system. It's more of a "speed/density" system, which derives air flow information from throttle position and manifold vacuum, and which also applies information taken from from the oxygen sensors when the engine is at cruise, using it to tweak the rest of the map (the "open loop" map).
Nothing wrong with that system. In fact, some of the Corvette high-performance guys switch from the Mass Air Flow system to the Speed/Density system. It doesn't automatically handle cam changes well, but nobody here is suggesting changing cams without a tune anyway.
Nothing wrong with that system. In fact, some of the Corvette high-performance guys switch from the Mass Air Flow system to the Speed/Density system. It doesn't automatically handle cam changes well, but nobody here is suggesting changing cams without a tune anyway.
Corvettes?
okay 
But you can take an EEC IV and change cams, put on long tube or shorty headers...... Hell, I even put a Super Charger on mine -- And the Mass Air took it all in stride perfectly. Went from 240 HP to over 400 HP without messing with the computer at all. Had to add a fuel management unit and chip to retard the timing for the Supercharger however. So I guess you could say the FMU was an adjustment on the computer. Or not. More like 'not'
WhateverTry that on a Speed Density and show us the vid of your vehicle blowing black smoke out the exhaust as it fades in the distance.
Our Harley system is a Speed Density system. It has a 'dumb' computer in that it can't 'learn' as you add/change parts.
You can make (VERY) minor changes to it and it will adapt to an extent.
You can change the exhaust out with absolutely NO changes in the computer. Our engine, our cam specifically, has no overlap in it. No way an exhaust change can change the A/F ratio, or the flow of it, into the combustion chamber. Not without any overlap. Can't do it.
Now, it might scavenge the spent fuel (exhaust) better but -- So what? That doesn't change the A/F mixture in any way. That happens on the other end, at the intake, nowhere near the exhaust....... Unless there's a substantial overlap in the cam.
Which we don't have. At least I don't.
Our Delphi System is pretty good. But it needs tweaked when you start into anything to do with the A/F, A/C, cam, heads, valves, pistons, bore/stroke, etc.
Exhaust don't matter. Neither do pegs or saddlebags
#23
10-22-2014, 10:37 AM
FYI:
Speed Density
Speed Density systems accept input from sensors that measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a much larger (in comparison to an N Alpha system) preprogrammed lookup table, a map of thousands of values that equates to the engine’s volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used.
Production-based Speed Density computers also utilize an oxygen (O2) sensor mounted in the exhaust tract. The computer looks at the air/fuel ratio from the O2 sensor and corrects the fuel delivery for any errors. This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can retard timing as needed.
GM’s Tuned Port Injection (TPI) set-ups used Speed Density metering from ’90-’92, as did ’91-’93 LT1 engines. All ’86-’87 and ’88 non-California Ford 5.0L-HO engines used Speed Density metering. Most Mopar fuel- injection systems have used Speed Density too.
Because a Speed Density system still has no sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed, so any significant change to the engine that alters its VE requires reprogramming the computer.
Mass Flow
By contrast, Mass Air Flow (MAF) systems use a sensor mounted in front of the throttle body that directly measures the amount of air inducted into the engine. The most common type of mass-flow sensor is the hot wire design: Air flows past a heated wire that’s part of a circuit that measures electrical current. Current flowing through the wire heats it to a temperature that is always held above the inlet air temperature by a fixed amount. Air flowing across the wire draws away some of the heat, so an increase in current flow is required to maintain its fixed temperature. The amount of current needed to heat the wire is proportional to the mass of air flowing across the wire. The mass-air meter also includes a temperature sensor that provides a correction for intake air temperature so the output signal is not affected by it.
The MAF sensor’s circuitry converts the current reading into a voltage signal for the computer, which in turn equates the voltage value to mass flow. Typical MAF systems also use additional sensors similar to those found in Speed Density systems. Once the electronic control module (ECM) knows the amount of air entering the engine, it looks at these other sensors to determine the engine’s current state of operation (idle, acceleration, cruise, deceleration, operating temperature, and so on), then refers to an electronic map to find the appropriate air/fuel ratio and select the fuel-injector pulse width required to match the input signals.
GM used MAF sensors on the turbo Buick V-6 Grand National, ’85-’89 TPI, ’94-’98 LT1, ’96 LT4, and all LS1 engines. Ford has used MAF metering on ’88 California 5.0L engines and all ’89-and-later V-8 engines.
MAF systems are much more flexible in their ability to compensate for engine changes since they actually measure airflow instead of computing it based on preprogrammed assumptions. They are self-compensating for most reasonable upgrades, as well as extremely accurate under low-speed, part-throttle operation. On the other hand, the MAF meter, mounted as it is ahead of the throttle-body, can become an airflow restriction on high-horsepower engines. On nonstock engine retrofits or EFI conversions on engines never produced with fuel injection, it may be hard to package an MAF meter within the confines of the engine bay and available intake manifolding.
Which Is Best?
In a perfect world, virtually all street-performance engines would use Mass Air, due to its superior accuracy and greater tolerance for engine changes.
Read more: http://www.carcraft.com/techarticles...#ixzz3Gt97Y4fo
Speed Density
Speed Density systems accept input from sensors that measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a much larger (in comparison to an N Alpha system) preprogrammed lookup table, a map of thousands of values that equates to the engine’s volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used.
Production-based Speed Density computers also utilize an oxygen (O2) sensor mounted in the exhaust tract. The computer looks at the air/fuel ratio from the O2 sensor and corrects the fuel delivery for any errors. This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can retard timing as needed.
GM’s Tuned Port Injection (TPI) set-ups used Speed Density metering from ’90-’92, as did ’91-’93 LT1 engines. All ’86-’87 and ’88 non-California Ford 5.0L-HO engines used Speed Density metering. Most Mopar fuel- injection systems have used Speed Density too.
Because a Speed Density system still has no sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed, so any significant change to the engine that alters its VE requires reprogramming the computer.
Mass Flow
By contrast, Mass Air Flow (MAF) systems use a sensor mounted in front of the throttle body that directly measures the amount of air inducted into the engine. The most common type of mass-flow sensor is the hot wire design: Air flows past a heated wire that’s part of a circuit that measures electrical current. Current flowing through the wire heats it to a temperature that is always held above the inlet air temperature by a fixed amount. Air flowing across the wire draws away some of the heat, so an increase in current flow is required to maintain its fixed temperature. The amount of current needed to heat the wire is proportional to the mass of air flowing across the wire. The mass-air meter also includes a temperature sensor that provides a correction for intake air temperature so the output signal is not affected by it.
The MAF sensor’s circuitry converts the current reading into a voltage signal for the computer, which in turn equates the voltage value to mass flow. Typical MAF systems also use additional sensors similar to those found in Speed Density systems. Once the electronic control module (ECM) knows the amount of air entering the engine, it looks at these other sensors to determine the engine’s current state of operation (idle, acceleration, cruise, deceleration, operating temperature, and so on), then refers to an electronic map to find the appropriate air/fuel ratio and select the fuel-injector pulse width required to match the input signals.
GM used MAF sensors on the turbo Buick V-6 Grand National, ’85-’89 TPI, ’94-’98 LT1, ’96 LT4, and all LS1 engines. Ford has used MAF metering on ’88 California 5.0L engines and all ’89-and-later V-8 engines.
MAF systems are much more flexible in their ability to compensate for engine changes since they actually measure airflow instead of computing it based on preprogrammed assumptions. They are self-compensating for most reasonable upgrades, as well as extremely accurate under low-speed, part-throttle operation. On the other hand, the MAF meter, mounted as it is ahead of the throttle-body, can become an airflow restriction on high-horsepower engines. On nonstock engine retrofits or EFI conversions on engines never produced with fuel injection, it may be hard to package an MAF meter within the confines of the engine bay and available intake manifolding.
Which Is Best?
In a perfect world, virtually all street-performance engines would use Mass Air, due to its superior accuracy and greater tolerance for engine changes.
Read more: http://www.carcraft.com/techarticles...#ixzz3Gt97Y4fo
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