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 Porting Pictures Written by Bevan Sutton 13B 6Port The size of standard intake ports varied somewhat depending on markets and time. The port seen here is quite a large standard port. 130-160hp 13B Extend Port Also known as Street Port, Mild Port. This porting design enlarges the port marginally giving more top end power with slightly less bottom end (much like a mild cam in a conventional motor). Original carb and exhaust can be retained (with only a slight loss in power), and the vehicle will be very drivable in every day traffic. 160-180hp 13B Bridge Port Bridgeporting is possibly the most popular form of porting. Substantial power gains can be made at relatively low cost, whilst maintaining engine lasting ability. In order to obtain the maximum potential of the engine the standard carb must be replaced with a high performance carb, and the exhaust with a high flow item. This porting style increase the inlet and exhaust port overlap greatly , causing the distinctive brapping idle. More mid-range to top-end power will be developed by a bridgeport, depending on primary and secondary port sizes. Note : the dotted green line in the picture denotes the approximate position of the water o-ring on the plate, and the red dotted line denotes the edge of the rotor housing when positioned on the plate. 200-250hp 13B JPort J-Porting is a little ambiguous in it's definition, so I'll try to give the most logical definition, that I've heard. A J-Port is a Bridgeport that has had the secondary port widened beyond the edge of the rotor housing (see red dots on picture) . This requires the edge of the rotor housing to be cut just short of the water o-ring groove to assist gas flow. Note : Another interpretation of the J-port is to cut the secondary port beyond the o-ring groove, just short of the water-jacket. 240-280hp 13B Monster Port A Monster Port is the most radical of the porting designs. It is similar to the Bridge and J Ports, but due to the size of the secondary port, a large amount of the rotor housing must be cut into the water jacket, and filled to prevent water leakage. A gap must be cut in the water o-ring and sealed off. The purpose of the motor was to dodge rules preventing peripheral ports in competition racing. Engine life is greatly reduced to about 6 months (usually water leaking into the motor). 280+hp 13B Peripheral Port A Peripheral Port involves blocking the side intake ports with devcon (or similar) and cutting a large port (similar to the existing exhaust port) in the rotor housing. Although this engine will last better that the Monster Port, torque at low engine RPM in virtually non-existent and idle speed is 2000+RPM. 300+hp Note: Information on this page is adapted from David Morris' ( www.dmrh.com.au ) article in Fast Fours and Rotaries magazine. Standard Port The standard port is common to Australian RX-2s, 3s and 4s. In 12A form, it is good for around 130hp. With intake and exhaust mods they can produce up to 180hp with excellent driveability and fuel efficiency with outright air-flow being the limiting factor. These standard housings form the basis for mild, extend and bridge porting. PRO'S: Standard drivability and fuel efficiency CON'S: Limited scope for power Mild Port A mild port is the first step to rotary porting. This version has been "shaped" slightly with a metal porting tool towards the upper area of the port, increasing air-flow and top-end power without creating any significant drawbacks. The port design is suitable for the standard induction with around 200hp being achievable. A mild port is a popular choice for those wanting slightly improved performance without changing the standard engine�s characteristics. PRO'S: Smooth driving, good for daily street use CON'S: Slight fuel consumption increase Extend Port The extend port is a larger version of the mild port and works best with improved intake and exhaust systems. Typically with these modifications, the engine will start to exhibit the rotary�s signature rough idle, although the extend port�s is very slight. There is also a slight but noticeable loss of low-down torque below 4,000rpm. Importantly the increase in air-flow ability translates to the potential for around 220hp providing the best compromise for regularly-used street cars. This is the popular choice for those who don�t want the numerous drawbacks of a bridge-port. PRO'S: Good power increase while retaining drivability. CON'S: Increase of fuel consumption and noise and the need for modified intake and exhaust systems to maximise power. Bridge Port The Bridge port uses an additional "eyebrow" opening alongside the original "modified" port and introduces the characteristic lumpy idling. The bridge that now exists between the 2 ports primary purpose is to ensure the rotors corner seals � which pass indirectly over the bridge � don�t fall out. The improved air-flow increases top-end power dramatically with a noticeable power-band peaking around 8,000rpm while drivability, smoothness and fuel efficiency is reduced. Maximum power of around 260-280hp is largely dependent on the choice of intake and exhaust systems. Unfortunately for street cars, faster normally means louder. PRO'S: Very good potential for power, increased rev-range CON'S: Poor drivability, fuel consumption and excessive noise J or Monster Port The J ported engine (also known as monster port) is as big as conventional side-plate porting can go. It is the same as the bridge port in design, but the bridged port is now fatter and extends past the face of the rotor and into the housing�s water seal / O-ring requiring the need for the seal to be cut back and filled with a metal type sealant such as "Devcon", plus, depending on the side plate used, the water gallery requires blocking off and filling on the side plate and the rotor matching. Cutting into the rotor housing is also needed for port matching. The main problem with this design of port is a short life-span as water does and will seep through the seals. The main field where a J-port is likely to be seen is on the track where restrictions don't allow peripheral porting, or a slightly wider power band is desired. Typically around 300hp can be expected. PRO'S: Slightly better power than a bridge port (5 to 10%) without the expense of a PP CON'S: Short life-span, 6-12 months / 5,000-10,000km, narrow power band, need for free-flowing/loud exhaust system, poor drivability Peripheral Port The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular - peripheral - intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 300hp but as it is developed for racing, results in very poor drivability, fuel consumption and needs an exhaust system designed to produce excessive noise. Like the bridge port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components. And instead of idling at around 1,000 � 1,500rpm for the previous porting methods, the PP engine will not idle much below 2,000rpm and is impractical and virtually unusable on the street. PRO'S: The ultimate form of rotary porting for maximum power CON'S: Excessive noise, extensive intake mods, very poor drivability and fuel consumption, relatively short engine life, very expensive, narrow power band 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 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
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
Porting Pictures Written by Bevan Sutton 13B 6Port The size of standard intake ports varied somewhat depending on markets and time. The port seen here is quite a large standard port. 130-160hp 13B Extend Port Also known as Street Port, Mild Port. This porting design enlarges the port marginally giving more top end power with slightly less bottom end (much like a mild cam in a conventional motor). Original carb and exhaust can be retained (with only a slight loss in power), and the vehicle will be very drivable in every day traffic. 160-180hp 13B Bridge Port Bridgeporting is possibly the most popular form of porting. Substantial power gains can be made at relatively low cost, whilst maintaining engine lasting ability. In order to obtain the maximum potential of the engine the standard carb must be replaced with a high performance carb, and the exhaust with a high flow item. This porting style increase the inlet and exhaust port overlap greatly , causing the distinctive brapping idle. More mid-range to top-end power will be developed by a bridgeport, depending on primary and secondary port sizes. Note : the dotted green line in the picture denotes the approximate position of the water o-ring on the plate, and the red dotted line denotes the edge of the rotor housing when positioned on the plate. 200-250hp 13B JPort J-Porting is a little ambiguous in it's definition, so I'll try to give the most logical definition, that I've heard. A J-Port is a Bridgeport that has had the secondary port widened beyond the edge of the rotor housing (see red dots on picture) . This requires the edge of the rotor housing to be cut just short of the water o-ring groove to assist gas flow. Note : Another interpretation of the J-port is to cut the secondary port beyond the o-ring groove, just short of the water-jacket. 240-280hp 13B Monster Port A Monster Port is the most radical of the porting designs. It is similar to the Bridge and J Ports, but due to the size of the secondary port, a large amount of the rotor housing must be cut into the water jacket, and filled to prevent water leakage. A gap must be cut in the water o-ring and sealed off. The purpose of the motor was to dodge rules preventing peripheral ports in competition racing. Engine life is greatly reduced to about 6 months (usually water leaking into the motor). 280+hp 13B Peripheral Port A Peripheral Port involves blocking the side intake ports with devcon (or similar) and cutting a large port (similar to the existing exhaust port) in the rotor housing. Although this engine will last better that the Monster Port, torque at low engine RPM in virtually non-existent and idle speed is 2000+RPM. 300+hp Note: Information on this page is adapted from David Morris' ( www.dmrh.com.au ) article in Fast Fours and Rotaries magazine. Standard Port The standard port is common to Australian RX-2s, 3s and 4s. In 12A form, it is good for around 130hp. With intake and exhaust mods they can produce up to 180hp with excellent driveability and fuel efficiency with outright air-flow being the limiting factor. These standard housings form the basis for mild, extend and bridge porting. PRO'S: Standard drivability and fuel efficiency CON'S: Limited scope for power Mild Port A mild port is the first step to rotary porting. This version has been "shaped" slightly with a metal porting tool towards the upper area of the port, increasing air-flow and top-end power without creating any significant drawbacks. The port design is suitable for the standard induction with around 200hp being achievable. A mild port is a popular choice for those wanting slightly improved performance without changing the standard engine�s characteristics. PRO'S: Smooth driving, good for daily street use CON'S: Slight fuel consumption increase Extend Port The extend port is a larger version of the mild port and works best with improved intake and exhaust systems. Typically with these modifications, the engine will start to exhibit the rotary�s signature rough idle, although the extend port�s is very slight. There is also a slight but noticeable loss of low-down torque below 4,000rpm. Importantly the increase in air-flow ability translates to the potential for around 220hp providing the best compromise for regularly-used street cars. This is the popular choice for those who don�t want the numerous drawbacks of a bridge-port. PRO'S: Good power increase while retaining drivability. CON'S: Increase of fuel consumption and noise and the need for modified intake and exhaust systems to maximise power. Bridge Port The Bridge port uses an additional "eyebrow" opening alongside the original "modified" port and introduces the characteristic lumpy idling. The bridge that now exists between the 2 ports primary purpose is to ensure the rotors corner seals � which pass indirectly over the bridge � don�t fall out. The improved air-flow increases top-end power dramatically with a noticeable power-band peaking around 8,000rpm while drivability, smoothness and fuel efficiency is reduced. Maximum power of around 260-280hp is largely dependent on the choice of intake and exhaust systems. Unfortunately for street cars, faster normally means louder. PRO'S: Very good potential for power, increased rev-range CON'S: Poor drivability, fuel consumption and excessive noise J or Monster Port The J ported engine (also known as monster port) is as big as conventional side-plate porting can go. It is the same as the bridge port in design, but the bridged port is now fatter and extends past the face of the rotor and into the housing�s water seal / O-ring requiring the need for the seal to be cut back and filled with a metal type sealant such as "Devcon", plus, depending on the side plate used, the water gallery requires blocking off and filling on the side plate and the rotor matching. Cutting into the rotor housing is also needed for port matching. The main problem with this design of port is a short life-span as water does and will seep through the seals. The main field where a J-port is likely to be seen is on the track where restrictions don't allow peripheral porting, or a slightly wider power band is desired. Typically around 300hp can be expected. PRO'S: Slightly better power than a bridge port (5 to 10%) without the expense of a PP CON'S: Short life-span, 6-12 months / 5,000-10,000km, narrow power band, need for free-flowing/loud exhaust system, poor drivability Peripheral Port The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular - peripheral - intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 300hp but as it is developed for racing, results in very poor drivability, fuel consumption and needs an exhaust system designed to produce excessive noise. Like the bridge port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components. And instead of idling at around 1,000 � 1,500rpm for the previous porting methods, the PP engine will not idle much below 2,000rpm and is impractical and virtually unusable on the street. PRO'S: The ultimate form of rotary porting for maximum power CON'S: Excessive noise, extensive intake mods, very poor drivability and fuel consumption, relatively short engine life, very expensive, narrow power band 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
Porting Pictures Written by Bevan Sutton
Porting Pictures
Written by Bevan Sutton
13B 6Port The size of standard intake ports varied somewhat depending on markets and time. The port seen here is quite a large standard port. 130-160hp 13B Extend Port Also known as Street Port, Mild Port. This porting design enlarges the port marginally giving more top end power with slightly less bottom end (much like a mild cam in a conventional motor). Original carb and exhaust can be retained (with only a slight loss in power), and the vehicle will be very drivable in every day traffic. 160-180hp 13B Bridge Port Bridgeporting is possibly the most popular form of porting. Substantial power gains can be made at relatively low cost, whilst maintaining engine lasting ability. In order to obtain the maximum potential of the engine the standard carb must be replaced with a high performance carb, and the exhaust with a high flow item. This porting style increase the inlet and exhaust port overlap greatly , causing the distinctive brapping idle. More mid-range to top-end power will be developed by a bridgeport, depending on primary and secondary port sizes. Note : the dotted green line in the picture denotes the approximate position of the water o-ring on the plate, and the red dotted line denotes the edge of the rotor housing when positioned on the plate. 200-250hp 13B JPort J-Porting is a little ambiguous in it's definition, so I'll try to give the most logical definition, that I've heard. A J-Port is a Bridgeport that has had the secondary port widened beyond the edge of the rotor housing (see red dots on picture) . This requires the edge of the rotor housing to be cut just short of the water o-ring groove to assist gas flow. Note : Another interpretation of the J-port is to cut the secondary port beyond the o-ring groove, just short of the water-jacket. 240-280hp 13B Monster Port A Monster Port is the most radical of the porting designs. It is similar to the Bridge and J Ports, but due to the size of the secondary port, a large amount of the rotor housing must be cut into the water jacket, and filled to prevent water leakage. A gap must be cut in the water o-ring and sealed off. The purpose of the motor was to dodge rules preventing peripheral ports in competition racing. Engine life is greatly reduced to about 6 months (usually water leaking into the motor). 280+hp 13B Peripheral Port A Peripheral Port involves blocking the side intake ports with devcon (or similar) and cutting a large port (similar to the existing exhaust port) in the rotor housing. Although this engine will last better that the Monster Port, torque at low engine RPM in virtually non-existent and idle speed is 2000+RPM. 300+hp Note: Information on this page is adapted from David Morris' ( www.dmrh.com.au ) article in Fast Fours and Rotaries magazine. Standard Port The standard port is common to Australian RX-2s, 3s and 4s. In 12A form, it is good for around 130hp. With intake and exhaust mods they can produce up to 180hp with excellent driveability and fuel efficiency with outright air-flow being the limiting factor. These standard housings form the basis for mild, extend and bridge porting. PRO'S: Standard drivability and fuel efficiency CON'S: Limited scope for power Mild Port A mild port is the first step to rotary porting. This version has been "shaped" slightly with a metal porting tool towards the upper area of the port, increasing air-flow and top-end power without creating any significant drawbacks. The port design is suitable for the standard induction with around 200hp being achievable. A mild port is a popular choice for those wanting slightly improved performance without changing the standard engine�s characteristics. PRO'S: Smooth driving, good for daily street use CON'S: Slight fuel consumption increase Extend Port The extend port is a larger version of the mild port and works best with improved intake and exhaust systems. Typically with these modifications, the engine will start to exhibit the rotary�s signature rough idle, although the extend port�s is very slight. There is also a slight but noticeable loss of low-down torque below 4,000rpm. Importantly the increase in air-flow ability translates to the potential for around 220hp providing the best compromise for regularly-used street cars. This is the popular choice for those who don�t want the numerous drawbacks of a bridge-port. PRO'S: Good power increase while retaining drivability. CON'S: Increase of fuel consumption and noise and the need for modified intake and exhaust systems to maximise power. Bridge Port The Bridge port uses an additional "eyebrow" opening alongside the original "modified" port and introduces the characteristic lumpy idling. The bridge that now exists between the 2 ports primary purpose is to ensure the rotors corner seals � which pass indirectly over the bridge � don�t fall out. The improved air-flow increases top-end power dramatically with a noticeable power-band peaking around 8,000rpm while drivability, smoothness and fuel efficiency is reduced. Maximum power of around 260-280hp is largely dependent on the choice of intake and exhaust systems. Unfortunately for street cars, faster normally means louder. PRO'S: Very good potential for power, increased rev-range CON'S: Poor drivability, fuel consumption and excessive noise J or Monster Port The J ported engine (also known as monster port) is as big as conventional side-plate porting can go. It is the same as the bridge port in design, but the bridged port is now fatter and extends past the face of the rotor and into the housing�s water seal / O-ring requiring the need for the seal to be cut back and filled with a metal type sealant such as "Devcon", plus, depending on the side plate used, the water gallery requires blocking off and filling on the side plate and the rotor matching. Cutting into the rotor housing is also needed for port matching. The main problem with this design of port is a short life-span as water does and will seep through the seals. The main field where a J-port is likely to be seen is on the track where restrictions don't allow peripheral porting, or a slightly wider power band is desired. Typically around 300hp can be expected. PRO'S: Slightly better power than a bridge port (5 to 10%) without the expense of a PP CON'S: Short life-span, 6-12 months / 5,000-10,000km, narrow power band, need for free-flowing/loud exhaust system, poor drivability Peripheral Port The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular - peripheral - intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 300hp but as it is developed for racing, results in very poor drivability, fuel consumption and needs an exhaust system designed to produce excessive noise. Like the bridge port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components. And instead of idling at around 1,000 � 1,500rpm for the previous porting methods, the PP engine will not idle much below 2,000rpm and is impractical and virtually unusable on the street. PRO'S: The ultimate form of rotary porting for maximum power CON'S: Excessive noise, extensive intake mods, very poor drivability and fuel consumption, relatively short engine life, very expensive, narrow power band 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
13B 6Port
The size of standard intake ports varied somewhat depending on markets and time. The port seen here is quite a large standard port.
130-160hp
13B Extend Port
Also known as Street Port, Mild Port. This porting design enlarges the port marginally giving more top end power with slightly less bottom end (much like a mild cam in a conventional motor). Original carb and exhaust can be retained (with only a slight loss in power), and the vehicle will be very drivable in every day traffic.
160-180hp
13B Bridge Port
Bridgeporting is possibly the most popular form of porting. Substantial power gains can be made at relatively low cost, whilst maintaining engine lasting ability. In order to obtain the maximum potential of the engine the standard carb must be replaced with a high performance carb, and the exhaust with a high flow item. This porting style increase the inlet and exhaust port overlap greatly , causing the distinctive brapping idle. More mid-range to top-end power will be developed by a bridgeport, depending on primary and secondary port sizes. Note : the dotted green line in the picture denotes the approximate position of the water o-ring on the plate, and the red dotted line denotes the edge of the rotor housing when positioned on the plate.
Note : the dotted green line in the picture denotes the approximate position of the water o-ring on the plate, and the red dotted line denotes the edge of the rotor housing when positioned on the plate.
200-250hp
13B JPort
J-Porting is a little ambiguous in it's definition, so I'll try to give the most logical definition, that I've heard. A J-Port is a Bridgeport that has had the secondary port widened beyond the edge of the rotor housing (see red dots on picture) . This requires the edge of the rotor housing to be cut just short of the water o-ring groove to assist gas flow. Note : Another interpretation of the J-port is to cut the secondary port beyond the o-ring groove, just short of the water-jacket.
240-280hp
13B Monster Port
A Monster Port is the most radical of the porting designs. It is similar to the Bridge and J Ports, but due to the size of the secondary port, a large amount of the rotor housing must be cut into the water jacket, and filled to prevent water leakage. A gap must be cut in the water o-ring and sealed off. The purpose of the motor was to dodge rules preventing peripheral ports in competition racing. Engine life is greatly reduced to about 6 months (usually water leaking into the motor).
280+hp
13B Peripheral Port
A Peripheral Port involves blocking the side intake ports with devcon (or similar) and cutting a large port (similar to the existing exhaust port) in the rotor housing. Although this engine will last better that the Monster Port, torque at low engine RPM in virtually non-existent and idle speed is 2000+RPM.
300+hp
Note: Information on this page is adapted from David Morris' ( www.dmrh.com.au ) article in Fast Fours and Rotaries magazine.
Standard Port The standard port is common to Australian RX-2s, 3s and 4s. In 12A form, it is good for around 130hp. With intake and exhaust mods they can produce up to 180hp with excellent driveability and fuel efficiency with outright air-flow being the limiting factor. These standard housings form the basis for mild, extend and bridge porting. PRO'S: Standard drivability and fuel efficiency CON'S: Limited scope for power
Standard Port
The standard port is common to Australian RX-2s, 3s and 4s. In 12A form, it is good for around 130hp. With intake and exhaust mods they can produce up to 180hp with excellent driveability and fuel efficiency with outright air-flow being the limiting factor. These standard housings form the basis for mild, extend and bridge porting.
PRO'S: Standard drivability and fuel efficiency CON'S: Limited scope for power
Mild Port A mild port is the first step to rotary porting. This version has been "shaped" slightly with a metal porting tool towards the upper area of the port, increasing air-flow and top-end power without creating any significant drawbacks. The port design is suitable for the standard induction with around 200hp being achievable. A mild port is a popular choice for those wanting slightly improved performance without changing the standard engine�s characteristics. PRO'S: Smooth driving, good for daily street use CON'S: Slight fuel consumption increase
Mild Port
A mild port is the first step to rotary porting. This version has been "shaped" slightly with a metal porting tool towards the upper area of the port, increasing air-flow and top-end power without creating any significant drawbacks. The port design is suitable for the standard induction with around 200hp being achievable. A mild port is a popular choice for those wanting slightly improved performance without changing the standard engine�s characteristics.
PRO'S: Smooth driving, good for daily street use CON'S: Slight fuel consumption increase
Extend Port The extend port is a larger version of the mild port and works best with improved intake and exhaust systems. Typically with these modifications, the engine will start to exhibit the rotary�s signature rough idle, although the extend port�s is very slight. There is also a slight but noticeable loss of low-down torque below 4,000rpm. Importantly the increase in air-flow ability translates to the potential for around 220hp providing the best compromise for regularly-used street cars. This is the popular choice for those who don�t want the numerous drawbacks of a bridge-port. PRO'S: Good power increase while retaining drivability. CON'S: Increase of fuel consumption and noise and the need for modified intake and exhaust systems to maximise power.
Extend Port
The extend port is a larger version of the mild port and works best with improved intake and exhaust systems. Typically with these modifications, the engine will start to exhibit the rotary�s signature rough idle, although the extend port�s is very slight. There is also a slight but noticeable loss of low-down torque below 4,000rpm. Importantly the increase in air-flow ability translates to the potential for around 220hp providing the best compromise for regularly-used street cars. This is the popular choice for those who don�t want the numerous drawbacks of a bridge-port.
PRO'S: Good power increase while retaining drivability. CON'S: Increase of fuel consumption and noise and the need for modified intake and exhaust systems to maximise power.
Bridge Port The Bridge port uses an additional "eyebrow" opening alongside the original "modified" port and introduces the characteristic lumpy idling. The bridge that now exists between the 2 ports primary purpose is to ensure the rotors corner seals � which pass indirectly over the bridge � don�t fall out. The improved air-flow increases top-end power dramatically with a noticeable power-band peaking around 8,000rpm while drivability, smoothness and fuel efficiency is reduced. Maximum power of around 260-280hp is largely dependent on the choice of intake and exhaust systems. Unfortunately for street cars, faster normally means louder. PRO'S: Very good potential for power, increased rev-range CON'S: Poor drivability, fuel consumption and excessive noise
Bridge Port
The Bridge port uses an additional "eyebrow" opening alongside the original "modified" port and introduces the characteristic lumpy idling. The bridge that now exists between the 2 ports primary purpose is to ensure the rotors corner seals � which pass indirectly over the bridge � don�t fall out. The improved air-flow increases top-end power dramatically with a noticeable power-band peaking around 8,000rpm while drivability, smoothness and fuel efficiency is reduced. Maximum power of around 260-280hp is largely dependent on the choice of intake and exhaust systems. Unfortunately for street cars, faster normally means louder.
PRO'S: Very good potential for power, increased rev-range CON'S: Poor drivability, fuel consumption and excessive noise
J or Monster Port The J ported engine (also known as monster port) is as big as conventional side-plate porting can go. It is the same as the bridge port in design, but the bridged port is now fatter and extends past the face of the rotor and into the housing�s water seal / O-ring requiring the need for the seal to be cut back and filled with a metal type sealant such as "Devcon", plus, depending on the side plate used, the water gallery requires blocking off and filling on the side plate and the rotor matching. Cutting into the rotor housing is also needed for port matching. The main problem with this design of port is a short life-span as water does and will seep through the seals. The main field where a J-port is likely to be seen is on the track where restrictions don't allow peripheral porting, or a slightly wider power band is desired. Typically around 300hp can be expected. PRO'S: Slightly better power than a bridge port (5 to 10%) without the expense of a PP CON'S: Short life-span, 6-12 months / 5,000-10,000km, narrow power band, need for free-flowing/loud exhaust system, poor drivability
J or Monster Port
The J ported engine (also known as monster port) is as big as conventional side-plate porting can go. It is the same as the bridge port in design, but the bridged port is now fatter and extends past the face of the rotor and into the housing�s water seal / O-ring requiring the need for the seal to be cut back and filled with a metal type sealant such as "Devcon", plus, depending on the side plate used, the water gallery requires blocking off and filling on the side plate and the rotor matching.
Cutting into the rotor housing is also needed for port matching. The main problem with this design of port is a short life-span as water does and will seep through the seals. The main field where a J-port is likely to be seen is on the track where restrictions don't allow peripheral porting, or a slightly wider power band is desired. Typically around 300hp can be expected.
PRO'S: Slightly better power than a bridge port (5 to 10%) without the expense of a PP CON'S: Short life-span, 6-12 months / 5,000-10,000km, narrow power band, need for free-flowing/loud exhaust system, poor drivability
Peripheral Port The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular - peripheral - intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 300hp but as it is developed for racing, results in very poor drivability, fuel consumption and needs an exhaust system designed to produce excessive noise. Like the bridge port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components. And instead of idling at around 1,000 � 1,500rpm for the previous porting methods, the PP engine will not idle much below 2,000rpm and is impractical and virtually unusable on the street. PRO'S: The ultimate form of rotary porting for maximum power CON'S: Excessive noise, extensive intake mods, very poor drivability and fuel consumption, relatively short engine life, very expensive, narrow power band
Peripheral Port
The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular - peripheral - intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 300hp but as it is developed for racing, results in very poor drivability, fuel consumption and needs an exhaust system designed to produce excessive noise. Like the bridge port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components.
And instead of idling at around 1,000 � 1,500rpm for the previous porting methods, the PP engine will not idle much below 2,000rpm and is impractical and virtually unusable on the street. PRO'S: The ultimate form of rotary porting for maximum power CON'S: Excessive noise, extensive intake mods, very poor drivability and fuel consumption, relatively short engine life, very expensive, narrow power band
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