427SC Shelby Cobra Roadster


We have completed the construction of our second Pro Street Hot Rod. This car is a replica of a 1967 Shelby 427SC Cobra Roadster. This car was built from a Kit from ERA Replicas in New Britain, CT. ERA makes a very accurate replica of the 427SC Cobra and their website provides a wealth of good information on the design of their 427SC Roadster.  We are in the process of building our own 427SC Cobra Roadster. A few pictures of our completed Cobra are shown below or click here to go to the video of the completed car.

Our 427SC Cobra

The 427SC Cobra was, until recently, the highest performance production vehicle available. The 427SC version of these cars are capable of going from 0 to 60 mph in less than 4 seconds and from 0 to 100 mph and back to 0 in about 12 seconds. They were originally built by Carroll Shelby for sports car racing in the 1960's. The first cobras were build by combining a defunct British Sports Car called the AC Bristol with a Ford 260 ci light weight V-8 engine. These cars were an instant success in sports car racing. Carroll Shelby motors also made a version of the Cobra Roadster for the street. Later, when Ford created the Hi-Performance 289 ci light weight V-8, Shelby switched over to this more powerful engine in both the competition and street versions of the Cobra Roadster. This engine combined with the racing grade suspension and brakes that Shelby added to the AC Bristol made a great all around Sports car. In 1966, the story goes that there was a Ford Big Block 427 FE motor sitting in the back of Shelby's shop that somehow found its way in the the Cobra Roadster and the 427 Cobra was born. The 427SC was and remains one of the fastest production vehicles ever made. Only a handful of original Shelby 427 Cobras still exist. Fortunately, a number of replica manufacturers are making reproductions of the original 427SC Cobra. The following link gives a more detailed history of Carroll Shelby and his Cobra cars.

The 427SC was originally made with the Ford Big Block 427 FE Side-Oiler motor and an independent rear suspension (IRS).

Ford 427 FE Motor in an ERA 427SC

ERA IRS with Competition Outboard Brakes

Our car is based upon a hand-built chassis which is much stronger than the original car. The chassis is hand welded in a jig and then powder coated.

ERA #753 (Our Car) Being Built in the Chassis Jig

ERA #753 Completed Chassis

Our car is constructed using a high quality fiberglass body which is a very accurate duplicate of the original 427SC Cobra's aluminum body. The body is then permanently bonded to the chassis to ensure that it maintains its shape and does not crack over the life of the car.

Actual Body for ERA #753 (Our Car)

Body after installation and bonding to Chassis

As a result, the car is painted at a relatively early stage in its assembly. We again chose Ron Randall at Metal-Morphous, Inc.  in Wallingford, CT to do the paint and body work on our Cobra. Ron has a tremendous amount of experience in body and paint work on Cobras and is the proud owner of ERA #148. Ron's attention to the body work side of a Cobra paint project is unbelievable.

Show Quality Body and Paint Work by Ron Randall at Metal-Morphous

As an example of this, Ron felt that he could create a more accurate looking set of rear fender flairs on the ERA body so he completely rebuilt the flares to ensure  the proper "look".

Completed Paint Job on our Cobra - Note the reworked rear fender flares

Ron did a show-quality paint job on our Cobra and then applied his proprietary metallization process under the hood and trunk lid. Ron's process makes the car appear to have an aluminum body as the original Cobras did. He also carried the racing stripes on the car through to the aluminum finish under the hood and the trunk lid.

Ron's Metallization Process on the underside of Hood and Trunk

We turned to Keith Craft Performance Engines of Arkadelphia, AR  to build the motor for our Cobra. Keith started with an aluminum Shelby performance FE Side-Oiler block. He bored and stroked the motor to displace 482 ci.

Aluminum 482 ci Ford FE Side-Oiler Motor

The engine also features the following:

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Shelby Aluminum Side-oil block, CNC ported aluminum, 4.250" Bore

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Forged Scat Crankshaft, 4.250" Stroke, Internally Balanced

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Forged Scat H-Beam Rods

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Forged Custom Diamond Pistons, 10.5:1 Final Compression Ratio

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CNC Stage II Ported Edelbrock aluminum heads with 2.19"/1.75" stainless steel valves

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TWM Induction Stack Fuel Injection Intake Manifold and 58 mm Throttle Bodies;  modified for IAC motor with plumbing under intake

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Bosch 42 lb/hr Fuel Injectors running at 50 PSI and 47.5 lb/hr maximum output

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Competition Cams Custom Grind Hydraulic Roller Camshaft and Crane Hydraulic Roller Lifters (see below for CAM Specs)

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T&D Machine Products Shaft Mounted Roller Rockers, 1.76 Ratio

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Melling High Volume Oil Pump

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Aviad Cobra Oil Pan

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Ford Remote Oil Filter Setup

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BHJ Damper

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FAST XFI Computer with Electronic Traction Control

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FAST Dual Sync FE Billet Distributor

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MSD Digital-6 Ignition Box with Blaster HVC Coil

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Shelby Polished Valve Covers, Timing Cover and Water Pump

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ARP Fasteners Throughout, Polished SS Fasteners where visible

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Powermaster Polished 100A 1-Wire Alternator

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March Polished Accessory Drive with high water flow ratio water pump pulley

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McLeod Street Twin Dual Disc Clutch with Aluminum Flywheel

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Powermaster Hi-Torque starter

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Lakewood Safety Bell Housing, Modified for Cobra Ground Clearance

The specifications for the camshaft are shown below:

  Intake Exhaust
Gross Valve Lift 0.645 in 0.635 in
Advertised Duration 304o 315o
Duration @ 0.050 in Lift 242o 248o
Lobe Separation 112o

The package is tuned to run on 93 Octane pump gas. Click here to view the complete engine specifications. The motor was tuned and dyno'ed by Keith's team and made 654 HP and 633 ft-lbs of torque.

Dyno Test of 482 ci Ford FE Motor

This is the second street motor that we've built with Electronic Fuel Injection (EFI). The computer control associated with EFI systems allows what would otherwise be radical engine and injection setups on the street with good drivability and streetable performance. The EFI system we are using on our Cobra is a FAST XFI System with Electronic Traction Control (ETC). Cobra Roadsters are notorious for having traction problems due to their high torque and light weight (typically about 2300 lbs). The latest FAST XFI computer systems with ETC use a driveshaft speed sensor to detect when the rear wheels of the car are slipping via a sudden jump in driveshaft RPM. In these situations, the EFI computer automatically retards the ignition timing to reduce the motor's torque and stop the rear wheel spin before it gets out of hand.

FAST EFI Computer with Electronic Traction Control

The Cobra drive train is not a standard one so we had to fabricate a custom driveshaft sensor for the car. Bob Moran at JRM Machine in Hollis, NH started with a standard flying magnet driveshaft sensor and collar and fabricated a new collar for the magnets to fit ERA's driveshaft and differential yoke. You can see the custom flying magnet collar that he made along with the pickup sensor installed on the front yoke of the differential below. This arrangement requires a slightly shortened version of ERA's standard driveshaft.
 

Custom Driveshaft Speed Sensor

The TWM intake on our engine has been modified by adding a hard line from the port associated with each stack to a common plenum at the back of the intake where an Idle Air Control (IAC) motor is mounted. All of this extra plumbing is mounted under the intake manifold where it is not visible. This allows the EFI computer to control the amount of air the motor gets at idle and therefore manage the idle speed much more accurately.

IAC Motor Installed on Back of TWM Intake, IAC Air Block Under Intake, and Associated Connections to Intake Ports

The TWM intake also has a common plenum on the top side to allow connection of a MAP sensor so that the computer can measure Manifold Absolute Pressure (MAP). This allows the EFI computer to use a Speed-Density strategy for controlling the engine which creates a good combination of performance and street drivability.

Red lines connect to a common plenum for the MAP Sensor; Throttle Linkage is controlled via a center pull cable

We installed a flow-matched set of 55 lb/hr injectors from Marren Fuel Injection. Marren takes a new set of injectors and carefully calibrates them to provide matched flow rates to within 2%. They also provide detailed performance information on each set of matched injectors including an accurate Deadtime number as shown below. We used this data along with the individual cylinder correction capabilities of our FAST XFI system to further match the injectors to within 1% of each other.

Fuel Injector Performance Information from Marren

Finally, the XFI system uses a Wide-Band O2 (WBO2) sensor to accurately measure the Air-Fuel Ratio (AFR) while the engine is in operation. This allows the system to run in a "closed-loop" mode where the computer can adjust the fuel going into the engine to account for operational conditions and tuning errors. An EFI setup with a WBO2 sensor is also much easier to tune since the sensor provides real-time information about the status of the engine (rich or lean) while it is operating.

Most aftermarket EFI systems support several different strategies for operating a Fuel Injected Motor. The most common ones available on many aftermarket systems are Speed-Density and Alpha-N strategies. Alpha-N is usually used for very radical race motors where the fuel delivery is metered based upon engine speed and throttle blade angle. This is essentially a more precisely tunable version of the system used on mechanical fuel injection systems for years. The other strategy is called Speed-Density. This approach uses manifold vacuum (or boost) as an estimate of engine load along with engine RPMs to meter the fuel delivery and ignition timing. This system is much more common in street and many race applications and it is the one that we are using on our Cobra. In a Speed-Density system, three basic tables are used to provide the normal operating "tune" for the motor: a Volumetric Efficiency (VE ) Table, a Target Air/Fuel Ratio (AFR) Table, and a Spark Advance Table. VE is a measure of how efficient an air pump a motor is under different operating conditions (for example, if our 482 ci motor could intake a full 482 ci of air at a certain operating point, then VE would be 100 and the motor would be 100% efficient). The target AFR is the mixture of Air and Fuel that the engine operates at. An AFR of 14.7:1 is generally optimum in terms of fully burning all of the fuel that is associated with the charge in an engine's cylinder. This ratio is good for fuel economy and emissions performance in light load or cruising conditions. A richer mixture of 12.7:1-13.2:1 generally produces the best power output in a normally aspirated motor (no blower, turbo, or Nitrous Oxide) under full load conditions at the expense of fuel economy and emissions performance.

Base EFI Tables from our Cobra

As you can see from the picture, these tables are a function of engine load (as measured by a Manifold Absolution Pressure or MAP Sensor) and engine RPM. They control the fuel delivery and spark advance for the engine in steady state situation (engine warned up and constant throttle position). There are several other tables in a typical EFI system that control transient conditions like engine starting, warm up, rapid changes in throttle position (equivalent to accelerator pump and dashpot functions on a carburetor), etc. As you can see from the pictures above, an EFI system provides a much more precise level of tune-ability than a carburetor can. For example, if you change jets in a carburetor, you would effect a broad area of the fuel delivery curve of the motor. Using EFI, you can choose a specific engine load and narrow RPM range and change the fuel delivery for the motor under EFI control without effecting any other part of the fuel delivery curve. The same is true with ignition timing. This precise tune-ability is why EFI systems can make relatively radical engine and induction combinations perform well in street applications. All of these adjustments to the engine tune are made via a laptop computer and can be done while the engine is operating. Most modern EFI system (including the FAST XFI) can also record all of the sensors and resulting operating conditions in the engine in real time. Many systems can record such information as frequently as 20 times a second or more and display it via a laptop mapped on the tuning tables or in other forms that allow it to be used to correct problems in or improve the tune. For example, it is quite common to discover "flat spots" or "backfires" in a motor's initial tune once its operated in the vehicle in real driving situations. The tuner can simply set their EFI system up to record what is happening with the engine when the problem occurs and use this information to determine precisely where in the tuning tables the problem is occurring and what needs to be changed to correct it. Again, such adjustments are made only in the specific areas of engine operation where the problem is occurring and will not have a negative impact on other parts of the tune.

If you are interested in building and/or tuning a EFI motor, I would highly recommend Engine Management: Advanced Tuning by Greg Banish. This is an excellent text covering both fuel system theory and practical EFI tuning.

ERA has been great about working with us to provide some nice custom touches for our Cobra. We obtained all of the visible aluminum pieces for the engine bay, trunk, and nose of the car and polished them. This was a large amount of work and required over 100 hours to complete. The polishing process is accomplished via a combination of several steps of machine sanding with progressively finer papers followed by buffing on a wheel buffer, and finally completed with a hand polishing step. We also had a set of stainless steel brake and hard lines made  by Inline Tube from ERA's originals. These were then polished by hand to create a nice finish. Stainless lines are very resistant to rust and corrosion and will last indefinitely.

Polished Aluminum Panels and Stainless Steel Brake and Misc Hard Lines

The next stage in the construction of our car was to add the aluminum panels and lines to the the chassis and body. The following are some pictures of that work in progress. Note the addition of some of the electrical components such as the Fuel Pump controller, Battery, etc. in the trunk. Also Ron Randall did a exquisite job of painting and clear coating the foot boxes. This not only improves their appearance but also makes them more resistant to any fluids from the engine that they might come in contact with. The details on the car are very accurate when compared to the original Cobra. For example, note the independent fluid reservoirs along with the custom made stainless steel lines. These provide fluid for the front and rear brake circuits as well as the hydraulic clutch system.

Polished Aluminum Panels and Electrical Components in Trunk, Foot Boxes and Polished Firewall in Engine Bay

Our Cobra has a race bred suspension and braking system. It features 12" competition front brakes, pin drive wheels, and a quick ratio rack and pinion steering unit. The rear suspension (lower right below) is based on Jaguar components. This particular unit uses ERA's outboard brake design and features extra strong stub axles to help the car handle the torque produced by the Big Block power plant without breakage. You can also get a good view of the the polished fuel tank in the lower right picture.

Front/Rear Suspension, Steering, and Brake Components

The interior features a competition style dash layout with the original Smith's style gauges. We're replaced the ammeter used on the original cars with a Smith's style voltmeter to allow for the use of the high output alternator and provide a better means of monitoring the performance of the charging system. Note the reverse style 180 mph speedometer as was used on the original competition cars.

Competition Style Dash Layout with Smith's gauges

The original electrical system on the Cobra was pretty simple and ERA does a good job of duplicating it. Most of the components were mounted on the firewall in the original cars as they are in our ERA. ERA made a few minor modifications to the original harness to accommodate the additional electronics on our car. As you can see, these changes are all but invisible when compared to an original Cobra.

Cobra Electrical Harness and Components

We have worked very closely with ERA to conceal all of the electronics and special components related to the EFI system on the car. They have done an excellent job with this. As an example, the following pictures show the FAST XFI Computer, MSD Digital-6 Ignition Box and an auxiliary fuse panel hidden under the dash and the Fuel Pump and associated pre- and post-filters hidden under the left rear fender well . The red switch allows the FAST XFI computer to accept software upgrades.

FAST Computer, Ignition Box, and Fuel System Components

The other area where we added a significant number of additional electrical components was in the trunk of the car. Again, ERA helped us to conceal these items. Show below are the Fuel Pump Controller, Battery, Remote Battery Cutoff Relay, and a Filter Capacitor (above the fuel pump controller). ERA fabricated a custom cover for these components which provides easy access to them when required and completely hides them when the car is in service.

Electrical Components in Trunk Hidden behind a Removable Panel

ERA also modified the throttle linkage on the car to connect to a stainless braided throttle cable for the TWM intake. This cable will then connect to the linkage in the center of the TWM intake manifold.

Throttle Linkage and Cable Connection on TWM Intake

ERA is in the final stages of finishing the construction of our car. Shown below is the completed front section of the car. All of the polished aluminum pieces have been installed inside the nose as has the Oil Cooler, Radiator, Front and Rear Cooling fans. The front nudge bars and hoop are also on the car. Note another authentic feature from ERA - the original Lucas Style Tripode headlights.

Completed Front Section including Oil Cooler, Fans, and Nudge Bar

The rear section of the car is also complete at this point. The rear nudge bars and hoop, gas cap, and tail lights are all installed which pretty much finishes up the back of the car.

 

Completed Rear Section

And finally, the following shows the completed interior all done in black leather. Note the fire extinguisher mounted between the seats. We will cut the hole and install the shifter once the engine and transmission are in the car.

Completed Interior

Here are some shots of the car ready for delivery to me. We are going to run a set of Goodyear Racing tires ("Gumballs") on the car. They look great!

Our Cobra Ready for Delivery

We've been very busy preparing our motor for installation in the car. We've added all of the accessories, cooling system expansion tank, and all of the connection for oil, water, and fuel lines. Bob Moran of JRM Machine in Hollis, NH did some nice custom machine work on the accessory drive pulleys and alternator mounts to get the accessory setup on the motor to fit nicely inside of ERA's chassis. The fully assembled motor is shown below.

Assembled Engine with plumbing - ready to go into the car

Our car has finally been delivered to us here's a picture just prior to our starting final assembly.

Now we just need to get these two together!

Here are some pictures of the engine and transmission going into the car and right after installation. We removed all of the accessories from the front of the engine, the bell housing, and two sets of injector stacks to make clearance for installing the motor in the car. We also removed the seats, carpets, and the transmission tunnel from the car to facilitate the installation of the bell housing and transmission. Note the tilt angle of the motor as its going into the car. This is required to get everything to clear during the installation. There is quite a bit of clearance once the motor is in but it was a squeeze on the way in.

Engine Going in the Car

At this point, the entire drivetrain is completely assembled and all of plumping and mechanical work associated with the engine is done. We've tested the fuel, oil, and cooling systems for pressure and leaks. Also, the throttle cable is connected as is the clutch. The electrical system has also been tested including the starter.  Here are some pictures of the engine at our car's current stage of completion. This is the way the engine will look when the car is done.

Engine after Plumbing and Mechanical Assembly

Our car has a Tremec TK0-600 5-Speed Overdrive Transmission. Our overdrive ratio is 0.64 which allows us to run fairly low rear gears (the car has 3.54's) and still cruise at reasonable RPMs on the highway. A handy speed/RPM calculator which can be used to compare cruising RPMs with and without an overdrive can be found here (a more sophisticated calculator can be found here). We've also installed the driveshaft speed sensor for the Electronic Traction Control. The picture below shows these components.

Transmission and Driveshaft with Sensor for Electronic Traction Control Installed

After some delay, we got our rear wheels and had the Goodyear Billboard tires installed on the rims and balanced. After installing the wheels on the car, I set the ride height to ERA specs. The car's stance looks great.

Wheels with Goodyear Billboard Tires Installed

We have done quite a bit of custom electrical work on our Cobra. A FAST XFI Electronic Fuel Injection System and an MSD Digital-6 Ignition System are the heart of the electronics on the car. To these, we've added the following functions:

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We are using the red ignition indicator dash light on our ERA as a shift light controlled by the FAST XFI computer. This keeps the dash looking "stock". A hidden switch under the dash allows me to also use this light as a "Service Engine Soon (SES)" indicator from my FAST Computer. I can start the car with the light in the SES mode to check for any problems and then switch the light to be a shift light when I'm driving the car.

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We are using the 2-step REV limiter on my MSD Digital-6 and a shifter mounted button to implement a REV limiter for launching the car.

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We are using a driveshaft speed sensor with the XFI to implement electronic traction control as well as to implement recording of vehicle speed, tire slippage and gas mileage.

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We are using an accelerometer which is a sensor that allows the FAST XFI computer to measure and record the acceleration/braking, lateral, and vertical G-forces that the car is experiencing. I expect that this will be a useful tuning aid for the electronic traction control and other handling adjustments.

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We are using a digital controller for the fuel pump which runs the fuel pump at a lower speed below 2,400 RPM to keep the fuel cool and improve fuel pump life.

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We've connected a fuel pressure sensor to my FAST XFI computer so that it can monitor the fuel pressure on the car

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The FAST computer can store up to 4 separate programs for the fuel injection system. ERA made a custom control panel that is hidden under the dash which allows us to select which program to use. This lets us have different tunes in the car for street use, track use, and emissions and select the one we want with a flip of a switch.

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We are using the FAST XFI computer's internal data logging features to implement an on-board data logging system. This includes logging of all of the engine control functions as well as the driveshaft sensor, accelerometer, and fuel pressure. This should be me a good platform to fine tune the car and deal with any problems that might come up later.

The following is a picture of the custom bracket that ERA made for mounting the electronic controls our car. It mounts the FAST XFI computer (the black box), the MSD Digital 6 ignition box (the red box) and all of the fuses and relays associated with the FAST XFI computer (these are installed in the picture but not yet connected to the wiring harness). The computer is mounted face down so that the indicator lights on the FAST computer are easily viewed by looking under the dash. The entire assembly can be removed with 2 wing nuts to allow the settings on the MSD box to be easily changed.

MSD Digital-6 Ignition Box and FAST XFI Computer on Removal Bracket

Here's a picture of the Computer/Ignition Box installed under the dash:

FAST XFI Computer Installed Under the Dash of Our Cobra

Finally, ERA built a nice custom aluminum panel which mounts the FAST XFI program selector switch, an arming switch which allows the FAST XFI computer's software program to be updated, and an auxiliary fuse block and Fuel Pump relay. This panel is hidden under the dash next to the XFI computer - again, we were able to add all of the extra electrical components to the car in locations which are not visible.

FAST XFI Controls and Auxiliary Power

The attached is a picture of the FAST XFI computer and ignition box assembly with all of the wiring that could be done off the car (power circuits, grounds, relays, fuses, etc). As you can see, there were still quite a few wires left to connect.

FAST XFI Computer with Wiring Harness and Power Cabling

All of this wiring goes to two basic places: 1) to the sensors in the transmission tunnel for the driveshaft speed sensor for electronic traction control, accelerometer, and fuel pressure monitoring and 2) to the engine for all of the fuel injection associated sensors and controls. The following shows all of the connections for the driveshaft sensor, accelerometer, and fuel pressure monitoring.  The red button on the shifter in the left picture controls the 2-step rev. limiter for launching the car. The G-force measuring sensor (accelerometer) is a small device which is mounted directly to the frame near the center of the car (its the small red device in the lower part of the right picture).

Driveshaft Sensor, Fuel Pressure Monitor, and Accelerometer Connections in the Tunnel

At this point, what is left are all of the connections to the engine. To give those who might consider trying to build their own EFI harness a feel for what's involved in this, the engine connections include:

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CAM and Crank trigger connections to the distributor

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MAP Sensor connections (measures manifold vacuum)

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Air Temperature Sensor

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Coolant Temperature Sensor

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Throttle Position Sensor

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Idle Air Control Motor

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Wide Band O2 Sensor (in the passenger's side pipe)

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Fuel Injectors (there are 8, one in each intake port)

Obviously, most folks would opt to use an off the shelf harness which would not require all of this work. The advantage of building a custom harness is that everything fits perfectly with no excess wire to hide.

All of this may seem a bit complicated but the key to making a system like this work well and be reliable is to 1) use good electrical practices to build everything such as soldering connections, using heat shrink tubing and high quality sealed connectors everywhere, etc. 2) test all of the components and sensors as you go (for example, I've tested the entire ignition system, fuel pump controller, tachometer, etc. using an MSD ignition tester which lets me generate signals that trigger the MSD box and all of the RPM activated features; and 3) carefully document everything via diagrams and tables so that you can remember what you've built later if there's a problem.

The one challenge in installing a stack EFI setup like this in any car is to find a good location for the Air Temperature Sensor (ATS). This sensor must be in the outside air stream so that the ECU knows the inlet air temperature going into the motor. This allows the ECU to adjust the fuel mixture as appropriate for the inlet air temperature. To solve this problem, we decided to mount the Air Temperature Sensor in the passenger side air vent control of our ERA. The vent control gets fresh air from the ducts on the front of the car so this is an excellent location for the sensor. It will also sense temperature of  the heated air under the hood when the car is standing for awhile and allows the EFI system to adjust for this situation as well. The following are some pictures of the sensor installed in the air vent control on our ERA.

Air Temperature Sensor Mounted in ERA Vent Control

The vent was also modified by drilling a 9/16" hole in the gate directly above the Air Temperature Sensor to ensure that the sensor would read accurately when the vent is closed.

Modified Air Vent When Closed

We have some pretty cool weather here in New England and after driving the car some, we concluded that our engine oil temperatures were not getting to a level that they should be. With the oil cooler constantly in the oil system and our all aluminum motor, we rarely saw oil temperatures get even close to where they should be.  To solve this problem, we installed a Canton Oil Thermostat on our Cobra. The Oil Thermostat will mostly bypass our Cobra's oil cooler until the oil temperature gets to around 210o F. We choose the Canton unit because of its high oil flow capacity compared to other models. The following shows a diagram of how this until is connected into the car's oiling system:

Oil System with Remote Filter, Thermostat and Oil Cooler

The engine bay on an ERA Cobra is very clean and original looking. We did not want the rather large Canton Oil Thermostat to add clutter. To solve this problem, we created a custom bracket which allowed the Thermostat to be mounted down low in between the radiator and the front cross brace. The custom bracket allows the until to be bolded to the steering rack mounting tab on the frame. As you can see from the following photos, this hid the Thermostat well and made for a very clean installation.

Oil Thermostat Installation

It was a real challenge to get the oil even close to the correct temperature before the installation of the Oil Thermostat. The installation of the Oil Thermostat made quite a difference. The following table compares our oil temperatures before and after the installation.

Air Temperature Oil Temp without Thermostat

Oil Temp with Thermostat

90o F 165o F 205o F
60o F 140o F

175o F

45o F 110o F

160o F

Oil Temperature readings before and after Oil Thermostat Installation

The sensor for the Oil Temperature Gauge mounts in the front of the oil pan where it is exposed to the flow of cool air under the car. To avoid any false readings in cold weather, we decided to insulate the sensor with some 1/2" pipe insulation and some cable ties as shown below.

Insulated Oil Temperature Gauge Sensor

 

The completed car is very light and extremely responsive. We weighted our car when it was completed and got the following numbers ready to drive with a 1/2 tank of gas:

Total Weight

2503 lbs

Front Weight Distribution

48.8%

Rear Weight Distribution

51.2%

Actual Finished Weights for ERA #753


The car is very well balanced front to rear and, as you can see, the aluminum motor prevents the car from becoming nose heavy. The car runs and sound great! Here's a video of the car being revved up by a friend (click on the picture to play the video or you can download a copy by clicking here).

Here's a video of our cobra being revved by a friend.

Our Cobra has a really aggressive stance when viewed from a low angle. This is one of our favorite aspects of the car!

Some Pictures of our Completed Cobra

We've done some final detailing and other finishing touches on our Cobra. The first thing that we did was to repaint the letting on our Goodyear Billboard race tires. To do this, we first removed the old paint with a rag and lacquer thinner. Next, we used a Liquid Paint Marker (Tire Pen) and carefully outlined the letters on the tires. Finally, we used an 1/8" artists' brush and Ranger Tire Paint to paint in the letters. After progressively thinning four coats of Ranger Paint with Isopropyl Alcohol, we got a good result:

Repainted Goodyear Billboard Tire

 

Our Cobra with the Repainted Goodyear Billboard Tires Installed

We also had a custom mat made for our trunk. The mat with an embroidered logo was done by Custom Embroidery from Photos. This is a nice complement to the polished trunk panels and provides protection for them when we transport items in the trunk of our Cobra.

Custom Trunk Mat

 Finally, we installed a set of ERA's fender protectors. These leather splats protect the front of the rear fenders from stone damage when the care is driven and they are easily removed at shows, etc. The fasten to one of the touneau cover posts and to a snap mounted on the frame under the car. Here's a picture with them installed:

Rear Fender Protectors Installed on our ERA

The last step in the process of completing our ERA was to have Ron Randall buff the finish and then protect the car with a coat of Zymol Wax. Here are some pictures of the car after the final detailing step:

Our Cobra after Final Buffing and Detailing

We have kept a running a build log for our Cobra on our favorite Cobra Website, Club Cobra. You can check out our thread and see some more pictures and details of our car during the build in our ERA #753 Build Thread. We have created a one page spec sheet for our Cobra which includes some of the pictures from this page. You can download a copy by clicking here.


 

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