TurboRX7.com > Tuning with Wideband O2 and Datalogit

Original Information Production Information Understand your VIN Car Specifications Original Brochures Vacuum Diagrams Turbo Specifications Efini RX-7 (96-now) Stock Fuel System Catalytic Converter Concept Art and Design Technical Documents Products/Reviews Recommended Upgrades Fuel System Upgrades Power FC Instructions Single Turbo Upgrades Twin Turbo Upgrades Porting Info and links Nitrous usage Blitz FMIC Installation 20B Rotary Engine Info Warnings Apexi RX-6 vs. Stock Greddy Pulley Kit Basics Apex Seals Turbocharger Basics Basics of Rotary Engines Rotary Engine History Gasoline/Ignition Info Detonation Wideband O2/Datalogit ECU Pictures/Info Rotary Engine Vehicles FAQs Media Home Page RX-7 Lingo Rotary Engine Pics Blow Off Valve Media Rotary History Pics Rotor and Housing Pics Polishing Links Mechanic Locations My RX-7 Mods My RX-7 Photo Gallery Links 2nd Gen RX-7 FC 1986 RX-7 Brochure Rotary Engine PickUp My '74 REPU project Mazda's REPU Page Pictures and Diagrams Other RX Models RX-3 Brochure RX-2 Brochure RX-8 Renesis Info/Specs Wideband O2/Datalogit Tuning Stoichiometric : Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted ( taftan ) Approximately 14.7 parts Air to 1 part Fuel (14.7:1) for the perfect complete combustion. Pressure Conversions: Remember: when the term 1 bar is used to describe pressure what most forget to state is that it is assumed they mean "above atmospheric pressure." Naturally the atmosphere has pressure (1 BAR approx 14.7 PSI) but this is assumed constant. Stating a turbo "kicks out" 14 PSI that is actually 14 PSI more than the atmospheric hence 14.7 PSI is technically 2 BAR 101.325 kPa = 1 ATM 100 kPa = 1 bar 200 kPa = 2 bar = 14.7 PSI (referred to 1 bar assuming it is understood to be 1 bar above atmospheric pressure) Goals of a tuner: Fuel related: For any given moment have the A/F ratio, Load, and RPM to make calculations and then output the corrected amount of fuel for the desired A/F ratio in those same conditions . Typical A/F ratios : high 14's up to "0 PSI" AKA atmospheric pressure (1 BAR) mid 12's up to 6 PSI (1.4 - 1.5 BAR) mid 11's up to 14.5 PSI (2 BAR) and above. Fuel related links: http://www.rceng.com/technical.htm http://www.maxcooper.com./rx7/how-to/fuel_system/index.html Detailed information on both Gasoline/Ignition Ignition related: In terms of ignition, proper timing is needed to ignite the compressed air/fuel mixture at the most opportune time avoiding preigniting (detonation) or retarded ignition What is DETONATION ? Typical timing advances: 30 to 35 deg advance to 90kpa (0.9 BAR) 20 odd up to 120kpa (1.2 BAR, 3 PSI) as low as 10 to 17 total advance up to 200kpa (2 BAR, 14.7 PSI) If you stick to a total engine advance of no more than 15 deg, assuming your static timing (pick up) is set correctly, then you are much less likely to suffer engine failures due to timing EGTs: Exhaust gas temperatures is one way to measure timing. If the timing is too retarded (combustion happens too late) then the fuel is still burning in the manifold causing higher EGTs Effects of porting on timing: *1 BAR boost assuming constant ambient temp of 15 C and charge temp of 30 C* STOCK PORT 20-23 deg advance ...lowest effective "dynamic" compression at max power. STREET PORT 15-17 deg advance...midrange effective "dynamic" compression at max power. PERIPHERAL PORT 10-12 deg advance...highest effective "dynamic" compression at max power. Before you tune you must ask yourself: 1) What ECU are you using? 2) What amount of performance/reliability do you want from your car?. 3) How modified is your car? 4) How much boost do you plan on running? 5) What octane gas do you use? (better be more than 92 octane) 6) How easy is it to access a dyno, wideband O2 sensor and data logging kits for all vital engine information? 7) Where is your EGT sender located? Wide Band O2 Sensors Why do I need a wide band 5-wire sensor on my air fuel ratio meter? 1) The output of a sensor with less than 5-wires is binary. That means it'll only tell you if you are rich or lean. It cannot tell you how rich or lean you are. Once the mixture goes a little bit fat, the meter will pin to the rich side. Likewise if the meter goes lean, the meter will pin to the lean side. Very often, a meter maker using these cheap sensors will write on their faceplates that the meter goes from 10.0 to 20.0 AFR. This is just paint on the panel. It is simple dishonesty. It is more likely 13.5 to 15.0 in reality. They might as well use three LED's to tell you the AFR - LOW, MED and HIGH! 2) There are only two wide band sensors widely available today. One is made by Bosch and the other by NTK/NGK. They have five wires. These sensors require sophisticated closed loop controllers to determine the air fuel ratio rather than a simple switch type OEM sensor that requires only a voltmeter. All sensors can only determine the air fuel ratio at the switch point where the mixture goes lean to rich. This is any sensor's zone of accuracy. The difference between the OEM sensors and the 5-wire widebands is that this zone can be moved around to different air fuel ratios in the widebands. In other words, 5-wire sensors have an electronically controllable air fuel ratio in their reaction cavities. What this means is that you can make the sensor operate in it's zone of sensitivity at air fuel ratios ranging from 8 to 24 or higher air fuel ratio. The problem is that this requires some clever circuitry to keep the sensor in this delicate balance. ( lamdaboy ) Many RX-7 tuners actually wire their wideband directly into the O2 sensor location for the aftermarket ECU. As long as the Wideband O2 sensor has a 1-4V output it can replace the stock O2 Sensor. Many do this so that, like in the PowerFC, one unit logs O2 and all other engine parameters. The standard scale is: 4V is amount of oxygen in open air 2.5V is combusted fuel at a 14.7 A/F ratio This is the Tech Edge Wideband O2 sensor kit which is used in proper tuning of a RX-7 This is the FJO Wideband O2 sensor kit which is used as well. Lambda-Boy Standard Air Fuel Ratio Meter Innovate Motorsports LM-1: Digital Air/Fuel Ratio Meter Data Logging ability with excellent software All of these kits have a data logging feature which is crucial for tuning because it retains past information so tuning does not have to be "on the spot" Data is logged into either a laptop or a PDA and reviewed as the fuel map is corrected to get as close as possible to the desired Air to Fuel Ratio. Stoichiometric combustion is always dreamed about, but is unattainable due to the detonation in turbocharged rotary engines. Detonation is more likely with the air is hot and pressurized. It is a debate as to what the "correct" AF ratio is for a FD. I have personally seen as low as 11.5 to as high as 13 used in setups. (this information is used as education resources only) This website chronicles an installation of a wide band o2 sensor on a 3rd Gen RX-7. http://www.negative-camber.org/crispyrx7/wideband.htm Knock Sensors Use primarily in tuning the ignition maps for the RX-7, the J&S Knock Sensor is not only a monitor, but a safety net as well. The unit is capable of detecting preignition and displaying that to the driver. The unit adjusts timing as needed to avoid early timing. If the timing is too soon preignition/detonation will occur. If the timing is too late, the timing is considered retarded and ignites what is already expanding because the rotor is in motion causing a change in pressure and volume. Perfect timing is the goal. This document has several articles related to knock sensors and detonation. www.iluvmyrx7.com/3rdgen/manuals/Misc/Ignition.doc Datalogit for PowerFC Data logging unit that "splices" the signal for the commander and sends it to a laptop via serial port. The laptop must have correct software installed to read signals and log data from ECU. Most useful features include logging Load vs. RPM graphs and correction maps. www.fc-datalogit.co.nz The manual (PDF) www.jimagu.com/tinou/pfc/FC-Edit-Pro-Manual.pdf This site is meant to give information related to the 1993 (o)Mazda RX-7 Twin Turbo. Anything from rotary engines to wiring diagrams and turbo upgrades to tuning info, this site has it all! efini 93 rx7 13b anfini Turbo RX-7 Turbo RX7 turbo rx7 rx7tt rx-7tt As well as the Rotary Engine Pickup Truck aka REPU repu

Original Information

Production Information Understand your VIN Car Specifications Original Brochures Vacuum Diagrams Turbo Specifications Efini RX-7 (96-now) Stock Fuel System Catalytic Converter Concept Art and Design Technical Documents

Production Information

Understand your VIN

Car Specifications

Original Brochures

Vacuum Diagrams

Turbo Specifications

Efini RX-7 (96-now)

Stock Fuel System

Catalytic Converter

Concept Art and Design

Technical Documents

Products/Reviews

Recommended Upgrades Fuel System Upgrades Power FC Instructions Single Turbo Upgrades Twin Turbo Upgrades Porting Info and links Nitrous usage Blitz FMIC Installation 20B Rotary Engine Info Warnings Apexi RX-6 vs. Stock Greddy Pulley Kit

Recommended Upgrades

Fuel System Upgrades

Power FC Instructions

Single Turbo Upgrades

Twin Turbo Upgrades

Porting Info and links

Nitrous usage

Blitz FMIC Installation

20B Rotary Engine Info

Warnings

Apexi RX-6 vs. Stock

Greddy Pulley Kit

Basics

Apex Seals Turbocharger Basics Basics of Rotary Engines Rotary Engine History Gasoline/Ignition Info Detonation Wideband O2/Datalogit ECU Pictures/Info Rotary Engine Vehicles FAQs

Apex Seals

Turbocharger Basics

Basics of Rotary Engines

Rotary Engine History

Gasoline/Ignition Info

Detonation

Wideband O2/Datalogit

ECU Pictures/Info

Rotary Engine Vehicles

FAQs

Media

Home Page RX-7 Lingo Rotary Engine Pics Blow Off Valve Media Rotary History Pics Rotor and Housing Pics Polishing Links Mechanic Locations My RX-7 Mods My RX-7 Photo Gallery Links

Home Page

RX-7 Lingo

Rotary Engine Pics

Blow Off Valve Media

Rotary History Pics

Rotor and Housing Pics

Polishing Links

Mechanic Locations

My RX-7 Mods

My RX-7 Photo Gallery

Links

2nd Gen RX-7 FC

1986 RX-7 Brochure

Rotary Engine PickUp

My '74 REPU project Mazda's REPU Page Pictures and Diagrams

My '74 REPU project

Mazda's REPU Page

Pictures and Diagrams

Other RX Models

RX-3 Brochure RX-2 Brochure RX-8 Renesis Info/Specs

RX-3 Brochure

RX-2 Brochure

RX-8 Renesis Info/Specs

Wideband O2/Datalogit Tuning Stoichiometric : Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted ( taftan ) Approximately 14.7 parts Air to 1 part Fuel (14.7:1) for the perfect complete combustion. Pressure Conversions: Remember: when the term 1 bar is used to describe pressure what most forget to state is that it is assumed they mean "above atmospheric pressure." Naturally the atmosphere has pressure (1 BAR approx 14.7 PSI) but this is assumed constant. Stating a turbo "kicks out" 14 PSI that is actually 14 PSI more than the atmospheric hence 14.7 PSI is technically 2 BAR 101.325 kPa = 1 ATM 100 kPa = 1 bar 200 kPa = 2 bar = 14.7 PSI (referred to 1 bar assuming it is understood to be 1 bar above atmospheric pressure) Goals of a tuner: Fuel related: For any given moment have the A/F ratio, Load, and RPM to make calculations and then output the corrected amount of fuel for the desired A/F ratio in those same conditions . Typical A/F ratios : high 14's up to "0 PSI" AKA atmospheric pressure (1 BAR) mid 12's up to 6 PSI (1.4 - 1.5 BAR) mid 11's up to 14.5 PSI (2 BAR) and above. Fuel related links: http://www.rceng.com/technical.htm http://www.maxcooper.com./rx7/how-to/fuel_system/index.html Detailed information on both Gasoline/Ignition Ignition related: In terms of ignition, proper timing is needed to ignite the compressed air/fuel mixture at the most opportune time avoiding preigniting (detonation) or retarded ignition What is DETONATION ? Typical timing advances: 30 to 35 deg advance to 90kpa (0.9 BAR) 20 odd up to 120kpa (1.2 BAR, 3 PSI) as low as 10 to 17 total advance up to 200kpa (2 BAR, 14.7 PSI) If you stick to a total engine advance of no more than 15 deg, assuming your static timing (pick up) is set correctly, then you are much less likely to suffer engine failures due to timing EGTs: Exhaust gas temperatures is one way to measure timing. If the timing is too retarded (combustion happens too late) then the fuel is still burning in the manifold causing higher EGTs Effects of porting on timing: *1 BAR boost assuming constant ambient temp of 15 C and charge temp of 30 C* STOCK PORT 20-23 deg advance ...lowest effective "dynamic" compression at max power. STREET PORT 15-17 deg advance...midrange effective "dynamic" compression at max power. PERIPHERAL PORT 10-12 deg advance...highest effective "dynamic" compression at max power. Before you tune you must ask yourself: 1) What ECU are you using? 2) What amount of performance/reliability do you want from your car?. 3) How modified is your car? 4) How much boost do you plan on running? 5) What octane gas do you use? (better be more than 92 octane) 6) How easy is it to access a dyno, wideband O2 sensor and data logging kits for all vital engine information? 7) Where is your EGT sender located? Wide Band O2 Sensors Why do I need a wide band 5-wire sensor on my air fuel ratio meter? 1) The output of a sensor with less than 5-wires is binary. That means it'll only tell you if you are rich or lean. It cannot tell you how rich or lean you are. Once the mixture goes a little bit fat, the meter will pin to the rich side. Likewise if the meter goes lean, the meter will pin to the lean side. Very often, a meter maker using these cheap sensors will write on their faceplates that the meter goes from 10.0 to 20.0 AFR. This is just paint on the panel. It is simple dishonesty. It is more likely 13.5 to 15.0 in reality. They might as well use three LED's to tell you the AFR - LOW, MED and HIGH! 2) There are only two wide band sensors widely available today. One is made by Bosch and the other by NTK/NGK. They have five wires. These sensors require sophisticated closed loop controllers to determine the air fuel ratio rather than a simple switch type OEM sensor that requires only a voltmeter. All sensors can only determine the air fuel ratio at the switch point where the mixture goes lean to rich. This is any sensor's zone of accuracy. The difference between the OEM sensors and the 5-wire widebands is that this zone can be moved around to different air fuel ratios in the widebands. In other words, 5-wire sensors have an electronically controllable air fuel ratio in their reaction cavities. What this means is that you can make the sensor operate in it's zone of sensitivity at air fuel ratios ranging from 8 to 24 or higher air fuel ratio. The problem is that this requires some clever circuitry to keep the sensor in this delicate balance. ( lamdaboy ) Many RX-7 tuners actually wire their wideband directly into the O2 sensor location for the aftermarket ECU. As long as the Wideband O2 sensor has a 1-4V output it can replace the stock O2 Sensor. Many do this so that, like in the PowerFC, one unit logs O2 and all other engine parameters. The standard scale is: 4V is amount of oxygen in open air 2.5V is combusted fuel at a 14.7 A/F ratio This is the Tech Edge Wideband O2 sensor kit which is used in proper tuning of a RX-7 This is the FJO Wideband O2 sensor kit which is used as well. Lambda-Boy Standard Air Fuel Ratio Meter Innovate Motorsports LM-1: Digital Air/Fuel Ratio Meter Data Logging ability with excellent software All of these kits have a data logging feature which is crucial for tuning because it retains past information so tuning does not have to be "on the spot" Data is logged into either a laptop or a PDA and reviewed as the fuel map is corrected to get as close as possible to the desired Air to Fuel Ratio. Stoichiometric combustion is always dreamed about, but is unattainable due to the detonation in turbocharged rotary engines. Detonation is more likely with the air is hot and pressurized. It is a debate as to what the "correct" AF ratio is for a FD. I have personally seen as low as 11.5 to as high as 13 used in setups. (this information is used as education resources only) This website chronicles an installation of a wide band o2 sensor on a 3rd Gen RX-7. http://www.negative-camber.org/crispyrx7/wideband.htm Knock Sensors Use primarily in tuning the ignition maps for the RX-7, the J&S Knock Sensor is not only a monitor, but a safety net as well. The unit is capable of detecting preignition and displaying that to the driver. The unit adjusts timing as needed to avoid early timing. If the timing is too soon preignition/detonation will occur. If the timing is too late, the timing is considered retarded and ignites what is already expanding because the rotor is in motion causing a change in pressure and volume. Perfect timing is the goal. This document has several articles related to knock sensors and detonation. www.iluvmyrx7.com/3rdgen/manuals/Misc/Ignition.doc Datalogit for PowerFC Data logging unit that "splices" the signal for the commander and sends it to a laptop via serial port. The laptop must have correct software installed to read signals and log data from ECU. Most useful features include logging Load vs. RPM graphs and correction maps. www.fc-datalogit.co.nz The manual (PDF) www.jimagu.com/tinou/pfc/FC-Edit-Pro-Manual.pdf This site is meant to give information related to the 1993 (o)Mazda RX-7 Twin Turbo. Anything from rotary engines to wiring diagrams and turbo upgrades to tuning info, this site has it all! efini 93 rx7 13b anfini Turbo RX-7 Turbo RX7 turbo rx7 rx7tt rx-7tt As well as the Rotary Engine Pickup Truck aka REPU repu

Wideband O2/Datalogit Tuning

Stoichiometric : Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted ( taftan ) Approximately 14.7 parts Air to 1 part Fuel (14.7:1) for the perfect complete combustion. Pressure Conversions: Remember: when the term 1 bar is used to describe pressure what most forget to state is that it is assumed they mean "above atmospheric pressure." Naturally the atmosphere has pressure (1 BAR approx 14.7 PSI) but this is assumed constant. Stating a turbo "kicks out" 14 PSI that is actually 14 PSI more than the atmospheric hence 14.7 PSI is technically 2 BAR 101.325 kPa = 1 ATM 100 kPa = 1 bar 200 kPa = 2 bar = 14.7 PSI (referred to 1 bar assuming it is understood to be 1 bar above atmospheric pressure) Goals of a tuner: Fuel related: For any given moment have the A/F ratio, Load, and RPM to make calculations and then output the corrected amount of fuel for the desired A/F ratio in those same conditions . Typical A/F ratios : high 14's up to "0 PSI" AKA atmospheric pressure (1 BAR) mid 12's up to 6 PSI (1.4 - 1.5 BAR) mid 11's up to 14.5 PSI (2 BAR) and above. Fuel related links: http://www.rceng.com/technical.htm http://www.maxcooper.com./rx7/how-to/fuel_system/index.html Detailed information on both Gasoline/Ignition Ignition related: In terms of ignition, proper timing is needed to ignite the compressed air/fuel mixture at the most opportune time avoiding preigniting (detonation) or retarded ignition What is DETONATION ? Typical timing advances: 30 to 35 deg advance to 90kpa (0.9 BAR) 20 odd up to 120kpa (1.2 BAR, 3 PSI) as low as 10 to 17 total advance up to 200kpa (2 BAR, 14.7 PSI) If you stick to a total engine advance of no more than 15 deg, assuming your static timing (pick up) is set correctly, then you are much less likely to suffer engine failures due to timing EGTs: Exhaust gas temperatures is one way to measure timing. If the timing is too retarded (combustion happens too late) then the fuel is still burning in the manifold causing higher EGTs Effects of porting on timing: *1 BAR boost assuming constant ambient temp of 15 C and charge temp of 30 C* STOCK PORT 20-23 deg advance ...lowest effective "dynamic" compression at max power. STREET PORT 15-17 deg advance...midrange effective "dynamic" compression at max power. PERIPHERAL PORT 10-12 deg advance...highest effective "dynamic" compression at max power. Before you tune you must ask yourself: 1) What ECU are you using? 2) What amount of performance/reliability do you want from your car?. 3) How modified is your car? 4) How much boost do you plan on running? 5) What octane gas do you use? (better be more than 92 octane) 6) How easy is it to access a dyno, wideband O2 sensor and data logging kits for all vital engine information? 7) Where is your EGT sender located? Wide Band O2 Sensors Why do I need a wide band 5-wire sensor on my air fuel ratio meter? 1) The output of a sensor with less than 5-wires is binary. That means it'll only tell you if you are rich or lean. It cannot tell you how rich or lean you are. Once the mixture goes a little bit fat, the meter will pin to the rich side. Likewise if the meter goes lean, the meter will pin to the lean side. Very often, a meter maker using these cheap sensors will write on their faceplates that the meter goes from 10.0 to 20.0 AFR. This is just paint on the panel. It is simple dishonesty. It is more likely 13.5 to 15.0 in reality. They might as well use three LED's to tell you the AFR - LOW, MED and HIGH! 2) There are only two wide band sensors widely available today. One is made by Bosch and the other by NTK/NGK. They have five wires. These sensors require sophisticated closed loop controllers to determine the air fuel ratio rather than a simple switch type OEM sensor that requires only a voltmeter. All sensors can only determine the air fuel ratio at the switch point where the mixture goes lean to rich. This is any sensor's zone of accuracy. The difference between the OEM sensors and the 5-wire widebands is that this zone can be moved around to different air fuel ratios in the widebands. In other words, 5-wire sensors have an electronically controllable air fuel ratio in their reaction cavities. What this means is that you can make the sensor operate in it's zone of sensitivity at air fuel ratios ranging from 8 to 24 or higher air fuel ratio. The problem is that this requires some clever circuitry to keep the sensor in this delicate balance. ( lamdaboy ) Many RX-7 tuners actually wire their wideband directly into the O2 sensor location for the aftermarket ECU. As long as the Wideband O2 sensor has a 1-4V output it can replace the stock O2 Sensor. Many do this so that, like in the PowerFC, one unit logs O2 and all other engine parameters. The standard scale is: 4V is amount of oxygen in open air 2.5V is combusted fuel at a 14.7 A/F ratio This is the Tech Edge Wideband O2 sensor kit which is used in proper tuning of a RX-7 This is the FJO Wideband O2 sensor kit which is used as well. Lambda-Boy Standard Air Fuel Ratio Meter Innovate Motorsports LM-1: Digital Air/Fuel Ratio Meter Data Logging ability with excellent software All of these kits have a data logging feature which is crucial for tuning because it retains past information so tuning does not have to be "on the spot" Data is logged into either a laptop or a PDA and reviewed as the fuel map is corrected to get as close as possible to the desired Air to Fuel Ratio. Stoichiometric combustion is always dreamed about, but is unattainable due to the detonation in turbocharged rotary engines. Detonation is more likely with the air is hot and pressurized. It is a debate as to what the "correct" AF ratio is for a FD. I have personally seen as low as 11.5 to as high as 13 used in setups. (this information is used as education resources only) This website chronicles an installation of a wide band o2 sensor on a 3rd Gen RX-7. http://www.negative-camber.org/crispyrx7/wideband.htm Knock Sensors Use primarily in tuning the ignition maps for the RX-7, the J&S Knock Sensor is not only a monitor, but a safety net as well. The unit is capable of detecting preignition and displaying that to the driver. The unit adjusts timing as needed to avoid early timing. If the timing is too soon preignition/detonation will occur. If the timing is too late, the timing is considered retarded and ignites what is already expanding because the rotor is in motion causing a change in pressure and volume. Perfect timing is the goal. This document has several articles related to knock sensors and detonation. www.iluvmyrx7.com/3rdgen/manuals/Misc/Ignition.doc Datalogit for PowerFC Data logging unit that "splices" the signal for the commander and sends it to a laptop via serial port. The laptop must have correct software installed to read signals and log data from ECU. Most useful features include logging Load vs. RPM graphs and correction maps. www.fc-datalogit.co.nz The manual (PDF) www.jimagu.com/tinou/pfc/FC-Edit-Pro-Manual.pdf This site is meant to give information related to the 1993 (o)Mazda RX-7 Twin Turbo. Anything from rotary engines to wiring diagrams and turbo upgrades to tuning info, this site has it all! efini 93 rx7 13b anfini Turbo RX-7 Turbo RX7 turbo rx7 rx7tt rx-7tt As well as the Rotary Engine Pickup Truck aka REPU repu

Stoichiometric :

Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted ( taftan ) Approximately 14.7 parts Air to 1 part Fuel (14.7:1) for the perfect complete combustion.

Pressure Conversions:

Remember: when the term 1 bar is used to describe pressure what most forget to state is that it is assumed they mean "above atmospheric pressure." Naturally the atmosphere has pressure (1 BAR approx 14.7 PSI) but this is assumed constant. Stating a turbo "kicks out" 14 PSI that is actually 14 PSI more than the atmospheric hence 14.7 PSI is technically 2 BAR

101.325 kPa = 1 ATM

100 kPa = 1 bar

200 kPa = 2 bar = 14.7 PSI (referred to 1 bar assuming it is understood to be 1 bar above atmospheric pressure)

Goals of a tuner:

Fuel related:

For any given moment have the A/F ratio, Load, and RPM to make calculations and then output the corrected amount of fuel for the desired A/F ratio in those same conditions .

Typical A/F ratios :

high 14's up to "0 PSI" AKA atmospheric pressure (1 BAR)

mid 12's up to 6 PSI (1.4 - 1.5 BAR)

mid 11's up to 14.5 PSI (2 BAR) and above.

Fuel related links: http://www.rceng.com/technical.htm http://www.maxcooper.com./rx7/how-to/fuel_system/index.html

Fuel related links:

http://www.rceng.com/technical.htm

http://www.maxcooper.com./rx7/how-to/fuel_system/index.html

Detailed information on both Gasoline/Ignition

Ignition related: In terms of ignition, proper timing is needed to ignite the compressed air/fuel mixture at the most opportune time avoiding preigniting (detonation) or retarded ignition What is DETONATION ? Typical timing advances:

Ignition related:

In terms of ignition, proper timing is needed to ignite the compressed air/fuel mixture at the most opportune time avoiding preigniting (detonation) or retarded ignition

What is DETONATION ?

Typical timing advances:

30 to 35 deg advance to 90kpa (0.9 BAR)

20 odd up to 120kpa (1.2 BAR, 3 PSI)

as low as 10 to 17 total advance up to 200kpa (2 BAR, 14.7 PSI)

If you stick to a total engine advance of no more than 15 deg, assuming your static timing (pick up) is set correctly, then you are much less likely to suffer engine failures due to timing

EGTs:

Exhaust gas temperatures is one way to measure timing. If the timing is too retarded (combustion happens too late) then the fuel is still burning in the manifold causing higher EGTs

Effects of porting on timing:

*1 BAR boost assuming constant ambient temp of 15 C and charge temp of 30 C*

STOCK PORT 20-23 deg advance ...lowest effective "dynamic" compression at max power.

STREET PORT 15-17 deg advance...midrange effective "dynamic" compression at max power.

PERIPHERAL PORT 10-12 deg advance...highest effective "dynamic" compression at max power.

Before you tune you must ask yourself: 1) What ECU are you using? 2) What amount of performance/reliability do you want from your car?. 3) How modified is your car? 4) How much boost do you plan on running? 5) What octane gas do you use? (better be more than 92 octane) 6) How easy is it to access a dyno, wideband O2 sensor and data logging kits for all vital engine information? 7) Where is your EGT sender located?

Wide Band O2 Sensors

1) The output of a sensor with less than 5-wires is binary. That means it'll only tell you if you are rich or lean. It cannot tell you how rich or lean you are. Once the mixture goes a little bit fat, the meter will pin to the rich side. Likewise if the meter goes lean, the meter will pin to the lean side. Very often, a meter maker using these cheap sensors will write on their faceplates that the meter goes from 10.0 to 20.0 AFR. This is just paint on the panel. It is simple dishonesty. It is more likely 13.5 to 15.0 in reality. They might as well use three LED's to tell you the AFR - LOW, MED and HIGH! 2) There are only two wide band sensors widely available today. One is made by Bosch and the other by NTK/NGK. They have five wires. These sensors require sophisticated closed loop controllers to determine the air fuel ratio rather than a simple switch type OEM sensor that requires only a voltmeter. All sensors can only determine the air fuel ratio at the switch point where the mixture goes lean to rich. This is any sensor's zone of accuracy. The difference between the OEM sensors and the 5-wire widebands is that this zone can be moved around to different air fuel ratios in the widebands. In other words, 5-wire sensors have an electronically controllable air fuel ratio in their reaction cavities. What this means is that you can make the sensor operate in it's zone of sensitivity at air fuel ratios ranging from 8 to 24 or higher air fuel ratio. The problem is that this requires some clever circuitry to keep the sensor in this delicate balance. ( lamdaboy )

2) There are only two wide band sensors widely available today. One is made by Bosch and the other by NTK/NGK. They have five wires. These sensors require sophisticated closed loop controllers to determine the air fuel ratio rather than a simple switch type OEM sensor that requires only a voltmeter. All sensors can only determine the air fuel ratio at the switch point where the mixture goes lean to rich. This is any sensor's zone of accuracy. The difference between the OEM sensors and the 5-wire widebands is that this zone can be moved around to different air fuel ratios in the widebands. In other words, 5-wire sensors have an electronically controllable air fuel ratio in their reaction cavities.

What this means is that you can make the sensor operate in it's zone of sensitivity at air fuel ratios ranging from 8 to 24 or higher air fuel ratio. The problem is that this requires some clever circuitry to keep the sensor in this delicate balance. ( lamdaboy )

Many RX-7 tuners actually wire their wideband directly into the O2 sensor location for the aftermarket ECU. As long as the Wideband O2 sensor has a 1-4V output it can replace the stock O2 Sensor. Many do this so that, like in the PowerFC, one unit logs O2 and all other engine parameters.

The standard scale is: 4V is amount of oxygen in open air

2.5V is combusted fuel at a 14.7 A/F ratio

This is the Tech Edge Wideband O2 sensor kit which is used in proper tuning of a RX-7

This is the FJO Wideband O2 sensor kit which is used as well.

Lambda-Boy Standard Air Fuel Ratio Meter

Innovate Motorsports LM-1: Digital Air/Fuel Ratio Meter

Data Logging ability with excellent software

All of these kits have a data logging feature which is crucial for tuning because it retains past information so tuning does not have to be "on the spot" Data is logged into either a laptop or a PDA and reviewed as the fuel map is corrected to get as close as possible to the desired Air to Fuel Ratio. Stoichiometric combustion is always dreamed about, but is unattainable due to the detonation in turbocharged rotary engines. Detonation is more likely with the air is hot and pressurized. It is a debate as to what the "correct" AF ratio is for a FD. I have personally seen as low as 11.5 to as high as 13 used in setups. (this information is used as education resources only)

This website chronicles an installation of a wide band o2 sensor on a 3rd Gen RX-7.

http://www.negative-camber.org/crispyrx7/wideband.htm

Knock Sensors

Use primarily in tuning the ignition maps for the RX-7, the J&S Knock Sensor is not only a monitor, but a safety net as well. The unit is capable of detecting preignition and displaying that to the driver. The unit adjusts timing as needed to avoid early timing. If the timing is too soon preignition/detonation will occur. If the timing is too late, the timing is considered retarded and ignites what is already expanding because the rotor is in motion causing a change in pressure and volume. Perfect timing is the goal.

This document has several articles related to knock sensors and detonation.

www.iluvmyrx7.com/3rdgen/manuals/Misc/Ignition.doc

Datalogit for PowerFC

Data logging unit that "splices" the signal for the commander and sends it to a laptop via serial port. The laptop must have correct software installed to read signals and log data from ECU. Most useful features include logging Load vs. RPM graphs and correction maps.

www.fc-datalogit.co.nz

The manual (PDF)

www.jimagu.com/tinou/pfc/FC-Edit-Pro-Manual.pdf

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