Saul "The Surgeon" Gutierrez...
Saul "The Surgeon" Gutierrez of Extreme Automotive prepares Aeromotive's 4.6-liter fuel rails (PN 14103) for installation on Sean Roberts' '99 Mustang GT. If you weren't able to tell Saul is working with a fuel rail, that's because it's covered with a heat-deflecting wrap that we're experimenting with for this month's TI. The fuel-rail-wrapping heatshield is in its prototype stage, but we were
given an opportunity to see what-if any-temperature differences exist when fuel rails are protected from engine and ambient heat.
This month's Tech Inspection highlights our brief study on thermodynamics, or the study of energy conversion between heat and mechanical work, and subsequently its macroscopic variable-temperature. Your tech editor and Saul "The Surgeon" Gutierrez of Extreme Automotive had an opportunity to check out an interesting and potential new fuel-rail insulation product from Aeromotive and Heatshield Products of Valley Center, California.
My past (and bad) experience with the effect of excessive heat imposed on a 'Stang's fuel system prompted us to accept the exclusive opportunity to test the yet-unnamed rail wraps. Basically, the easy-to-install covers are designed to act as heat deflectors that keep rails and fuel protected from high temperature in the engine compartment.
If you're saying to yourself, this stuff is similar to the shiny deflective covering that I've seen on turbochargers, you're absolutely correct. However, the idea of insulating fuel rails in similar fashion is intriguing, as we know that keeping fuel as cool as possible is important for high-horsepower Mustangs that are used in high-temperature environs.
The fuel-rail wrap is a simple...
The fuel-rail wrap is a simple design-a swath of form-fitting, high-temperature, aluminized-fiberglass insulation material that secures to Aeromotive fuel rails with Velcro and four small Phillips-head screws on the bottom of the rails. The material, formally known as S Glass, is capable of reflecting over 90 percent of radiant heat in ideal conditions (i.e., 1 inch plus of airspace and good airflow).
After 1997, the government mandated that fuel-injected vehicles be equipped with non-return fuel systems. With the non-return design, fuel does not circulate back to the tank and thus has a high potential to become superheated by underhood and ambient heat. As a result, the gasoline may boil, as it basically remains in the rails while the engine is running and the fuel system is pressurized.
To simulate actual underhood...
To simulate actual underhood operating conditions during both tests, the wickedly flamed hood of Sean Roberts' '99 'Stang remained closed for 10 minutes...
...and we only recorded fuel-rail...
...and we only recorded fuel-rail temps after confirming coolant temperature was 200 degrees. We used Raytek's MiniTemp infra-red temperature gun to measure temperatures.
In our baseline reading (without...
In our baseline reading (without fuel-rail wraps), rail temperature fluctuated between 109 and 112 degrees. The passenger-side fuel rail was used as the temp source for data consistency with each test, as that fuel rail isn't influenced by additional heat that emanates from the thermostat housing.
Our study involves taking baseline temperature readings of Aeromotive's 4.6 fuel rails (PN 14103) without the wraps, and then installing the prototype, covered fuel rails, to determine what type of difference-if any-the fuel-rail insulators make. We selected 10 minutes of runtime with the hood shut as the control timeframe for establishing consistent underhood temperature for both tests. The time window allowed the 'Stang's cooling fan to cycle at least once and give us repeated engine temperature (200 degrees) for both evaluations.
The following photos and captions show you what we learned. Procedurally, setting the wrapped fuel rails up on a 4.6-liter Two-Valve engine is not difficult. For our tests, Saul actually switched rails without removing the Pony's strut-tower brace or discharge tubing for the supercharger.
The wraps fit cleanly and...
The wraps fit cleanly and definitely look at home on Sean's engine. According to the rail-wraps' designer, Steve Heye of Heatshield Products, the covers can reflect 500 degrees Fahrenheit of direct-contact temperature (1,100 degrees of radiant heat). Because Aeromotive's '98-'04 4.6 rails are designed for return-style fuel systems, the fuel-pressure sensor must be relocated. Aeromotive offers a kit (PN 17114) that makes moving the sensor a simple effort.
Our final temp check was taken...
Our final temp check was taken with the wraps in place. After pulling back the wrap slightly (it's held in place using Velcro and must be tight on the fuel rail to ensure the covers will stop the most heat possible) to expose the rail, the readout showed a 106- to 107-degree (Fahrenheit) temperature range for the covered fuel rail-a decrease of approximately 5 to 6 degrees. It's important to understand that this data certainly is prone to being different per higher or lower underhood and ambient temperatures (ambient temp was in the middle 70s in our test environment). For the sake of our independent and unofficial review, the fuel-rail wraps did protect the rails from the influence of the two heat variables.
While it's not certain that...
While it's not certain that these fuel-rail wraps will ever be produced for the masses, they did perform well in our experiment. The results have extended our curiosity about how insulating the entire fuel-line system-especially on a non-return system-will affect the fuel-system, as well as a Mustang engine's overall performance/operation under high-heat conditions. Stay tuned, as we may venture down that path of investigation at some point in the future.
Remember, this Tech Inspection features a product that, for now, is purely in its prototype stage. We're glad we were given a chance to do some independent testing of the wrapped fuel rails, and we think the idea is cool enough to share.