How To Convert A Fourth-Gen F-body To E85 With FIC

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When it comes to making horsepower, 91 octane can only take you so far—93 if you’re lucky enough to hail from the east coast. So what do you do when you start pushing your car past what “high octane” can support?

Well, you have two choices: 1. make the leap to race gas. And to be fair, it’s a valid option. There are lots of options out there for that and you can even find it at the pump if you’re lucky enough. Or, Option 2 — the route we decided on — is to make the switch to E85. With that in mind, we turned to Fuel Injector Clinic and EFILive to help us make the jump to the biofuel with our 2002 Camaro SS.

Jimmy Crack Corn, But Why Care?

But before we get down to the nitty gritty of how you would make the jump, lets talk about the why for a minute. Our fourth-gen Camaro project car has been around for about a year now. So far we’ve only done a few minor things to it. In past articles, we put a set of drag wheels from JMS Chips and a set of sticky tires from Mickey Thompson on it. The car came to us with a full assortment of bolt-ons and a mild cam. But with the fourth-gen’s near limitless potential on hand, we knew it was only a matter of time before we started getting more drastic with the vehicle.

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We were cognizant that eventually the car would get a power adder of some sort and perhaps even a built engine. So we thought, “why not make the switch to E85 now, instead of down the road?” That way we can give you a true comparison of just how much power the corn-based fuel is bringing to the table without changing a thing in the engine. And, to be completely honest with you, we’d never done an ethanol build—and much like you, it makes us want to tinker with it.

Balancing Pros And Cons

There are a lot of good reasons to make the change to E85, but there are probably just as many barriers. To us, the pros just ended up outweighing the cons. But that might not be the case with your particular build. Hopefully this will give you some insight into whether you want to tackle a project like this yourself, and if you do, let this serve as a guide to getting it done.

One of the first things to consider when making the switch to E85 is the availability of the fuel in your area. The corn-derived fuel is pretty abundant in our neck of the woods (southern California). That made it an easy decision, since we knew we wouldn’t have to order the fuel or drive great distance just to get a tank of the stuff. There are several gas stations around that offer E85, so that’s no problem for us.

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But, if you live somewhere that doesn’t have E85 on tap, it might not be the right option for you. While you can buy and store E85 yourself, it is expensive and the fuel is also hygroscopic—meaning it absorbs water. This means you have to be very careful about how you store it and, even if you are, it might not keep for a long time due to its propensity to absorb water.

The next thing to consider is whether or not it really makes sense for you considering all of the changes the switch can necessitate. If you are fortunate enough to have a fifth- or sixth-gen Camaro or a C6 or newer Corvette, many were already designed to work with E85. In fact, converting these vehicles to flex fuel—a system that can blend back and forth from pump gas to E85 seamlessly—is a relative breeze and requires minimal investment.

In our fourth-gen, however, the swap is not so simple. Ethanol contains about 50 percent less energy than gasoline does. That means 30-50 percent more fuel has to be run through the engine for a relatively equivalent amount of power. With that in mind, several components in the system will have to be upgraded to ensure that our LS1 will still get the amount of fuel it requires.

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Photo courtesy of Propel Fuels.

In our case, that meant swapping out the fuel pumps to high flowing units that were compatible with E85 and going larger with the fuel injectors. Not all fuel pumps are E85 compatible and you can quickly damage a fuel pump that wasn’t designed to work with ethanol by running the fuel through it. The reason being that ethanol has substantially less lubricants in it. Because of this, a standard fuel pump will wear out quickly in an ethanol environment. Many newer vehicles were designed with ethanol in mind and their pumps can handle both, the fourth-gen Camaro however, is not one of them.

Luckily, most OBD-II equipped vehicles were designed with a moderate amount of ethanol in mind—since most gasoline is already about 10 percent ethanol. Thus, the rest of the system has been designed to resist the corrosive effects of ethanol. A common misconception is that making the switch to ethanol will cause the car’s fuel system to leak, but if it is ’96 or newer you should be just fine—as long as you replace the fuel pump to an E85 specific unit.

We made the decision to go with E85 due to the fuel’s intrinsic resistance to knock. While it’s hard to say that ethanol even has an octane rating, since it is uncommon for it to pre-detonate, most agree that it lands somewhere in the 105-110 octane rating area. And, at $2.30 a gallon (local), that’s a pretty good deal for race gas to us. But remember, you’re burning through the fuel at a quicker rate so the costs are somewhat offset. However, just like we assume many of you will feel, we don’t particularly care about fuel economy in our project cars.

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There are alternatives out there that can be somewhat easier to implement as well. Water/meth injection systems can have the same sort of effect and can bring 91 octane’s effective rating up to as high as 116 octane, according to companies like Snow Performance.

And while water/meth is a great solution, especially if you don’t have access to E85, the need to constantly refill the tank and the possibility that the system could fail in the heat of battle lead us to go with E85. With E85, if the fuel pump stops pumping the car stops running, with water/meth it might stop spraying and you could melt down your engine fairly easily without knowing it—though a lot of newer system will warn you if that’s happening. Fueling with E85 can also often be more precise than water/meth, or at least less complex. 

Another consideration to take into account with E85—which is supposed to be 85 percent ethanol 15 percent gasoline—is that it may have a lower ethanol content than advertised. Depending on how long the ethanol has been sitting, it may contain lower concentrations of ethanol. This can be bad news if you don’t have a flex fuel system and are tuned for E85. Recently, our sister magazine EngineLabs published an article about how California only has to ensure that “E85” has at least 51 percent ethanol content; that means what you are pumping could be as low as E51. This is why a flex fuel system or at least an ethanol content gauge is a bare minimum to running the fuel.

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So, if you’ve looked through all the pros and cons and still think E85 is right for your fourth-gen, then follow along as we implement it on our 2002 Camaro SS

Going E85

For us, the decision to go E85 was an easy one. Like we previously mentioned, we knew boost would soon enter the equation and we knew that ethanol and boost play well together. It’s also the first time we’ve ever done it, so we turned to Fuel Injector Clinic to help us out with the physical conversion to E85.

As we perviously mentioned, we knew that the stock fuel pump was just not going to cut it when we made the switch to ethanol. The stock pump in the F-body is designed to work with at most E15 (15 percent ethanol content). After that, we would quickly burn it up. Another factor was that the stock pump wouldn’t be able to keep up with the power either.

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Since we would need to move a lot more fuel to keep our LS1 fed, we knew it was time to go larger with the pumps. Fuel Injector Clinic sent us over two ASUS 340 LPH E85-compatible pumps to use on our build. Each pump is precision manufactured and designed for long life even in ethanol environments. Flowing 340 liters per hour, just one of these pumps would be able to easily keep up with our naturally aspirated LS1, even on E85. However, like we mentioned, we knew boost was in the cards and wanted to future-proof our fuel system, so the decision to run two was made.

But before we took the pumps out of the tank, we address the electrical system first. In order to ensure that our pumps were always moving as much fuel as possible, we installed a hot wire kit.

This kit simply attaches to the alternator and routes 14 volts to a relay that we mounted behind the seating area. The rest is simple plug and play and uses the stock system to activate the new, hotter circuit to provide the main pump with juice.

The installation was a breeze, but we did have to loosen the fuel tank straps and fish the harness up to the top of the tank with a coat hanger. After zip tying the new wiring harness to the chassis, we were ready to move on to the pumps.

After removing the T-top tie down, you can pull the carpet back and access the sheet metal right above the fuel tank. We traced an outline where we wanted to cut. Starting at the edge at the rear of the car, and using the stamped steel indentations as a guide, we made three cuts on each and then bent the steel back.

If you’ve ever worked on a fourth-gen Camaro, you’ll know that getting the fuel tank out of the car can be a real pain. The panhard bar and most of the rear axle are in the way of dropping the tank. This has lead many to cut access panels in the rear hatch area of their F-body to more easily access the fuel sender. While it may seem hokey to some, we knew that we would likely soon be returning to the fuel sender to make even more upgrades as our build progressed—that’s why we decided to cut an access panel of our own.

The access panel was easy to cut and we simply used a Dremel with a cut-off wheel to get the job done—just be careful not to go too deep and cut the lines or wiring underneath. Once the cuts were made, we simply folded the sheet metal back. With the fuel sender exposed, we unplugged the sending unit both electrically and from the fuel lines. Finally, we used a punch to knock the sender lock ring loose—it can be a real pain so you may have to be persistent.

After bending the sheet metal back, the sender is easily accessible. To prevent debris from falling into the tank, we cleaned as best we could before disconnecting the wiring connections and fuel lines. We then used a pry bar to pound the lock ring.

Next we removed the sender from the fuel tank and used a flashlight to check the inside of the tank for build-up and varnish. Ours looked pretty good but if you have a lot of garbage inside the tank, you’ll need to drop it in order to clean it out. We then covered the hole to make sure nothing fell into the gas tank while we were working on the sending unit.

The bucket was then detached from the sender hat. The fuel pump simply unplugs with a simple clip. Then we had to remove the fuel level sender. This is held to the bucket with two clips which are black and beige respectively. Both simply push out and allow you to leave the fuel level sensor with the upper portion of the fuel sender.

Once the fuel sender was out, we began separating the fuel bucket from the upper portion. Two clips hold the fuel level sensor to the bucket and have to be removed so it can stay with the hat. We then disconnected the 1/4-inch velocity tube from the top of the pump and then cut the flex hose and unclipped the electrical connection on the pump.

The upper portion of the fuel sender separated from the bucket

Once you have the bucket off the sender, you can then cut the stock no-crimp hose and pull the stock fuel pump out of the sender. At this point, the bucket and lower portion of the fuel sender will have to be modified to allow the two new pumps to sit in the bucket. We started by breaking out the black canister out of the bottom of the bucket—this piece in stock form creates a vacuum that draws fuel into the bucket constantly. Since the tank doesn’t have any baffling, it’s the bucket that keeps fuel surrounding the pump. We used a Dremel to cut out the black canister and the original mount for the fuel strainer.

We used a Dremel to modify the fuel bucket to allow our aftermarket pumps to fit.

While this does modify the stock operation of the fuel system, the return line dumps back into the bucket as well and makes sure the pumps stay submerged in almost any condition. And, since the pumps fit the bucket so tightly, they do a good job of allowing fuel in but not allowing it to drain back out very quickly. This will ensure that we can run the tank nearly as empty as before without experiencing problems—though keeping the car at a quarter tank is never a bad idea to prevent the pumps from becoming uncovered and overheating.

We then used needle-nose pliers to break the diving walls and fins out of the bottom of the bucket to allow both pumps to fit. We also had to take a Dremel to the upper portion of the bucket that originally housed the stock pump. It is molded for the pump to slot into it and this all has to be removed to allow space for the new pumps.

Here you can see how snuggly the fuel pumps fit in the fuel bucket. You don't want the fuel socks to stick outside the bucket, since this would defeat the purpose of the bucket keeping the pumps fed under g-loading. We used 5/16-inch fuel injection hose and a 5/16-inch "T" to connect both pumps.

Once everything is out of the way, we used 5/16-inch fuel injection hose and a 5/16-inch brass “T” to tie both pumps together. With their fuel strainers on, both pumps fit snuggly into the bucket. Then, the final fuel hose that routes fuel to the exit of the hat was clamped into place.

The two new pumps also require wiring pigtails that are different than the stock sender. We got both pigtails along with the fuel strainers off of eBay for pretty cheap. The pigtails are virtually the same for any Walbro-style pump. For the main pump, we cut and spliced the new pigtail into the original pump’s wiring harness. For this, we used uninsulated butt connectors and then used two layers of overlapping heat shrink over them. The secondary pump, which we will wire to turn on via a Hobbs switch under boost, requires the pigtail to be routed through the hat.

For this, we use a 3/16-inch drill bit and carefully drilled a hole in the hat for the wires to pass through. Once the wires were routed through the hat, we then sealed them off with a little Seal All, which is basically a clear RTV that is resistant to oil and fuel. With our fuel sender modified, it was time to drop it back into the tank.

We used Seal All to seal the hole we drilled to run the second pump wires through the hat. This will ensure that we still have a seal on the tank for the evap system and it is fuel resistant.

The fuel sender went right back into the tank and we knocked the lock ring home. We then reconnected the wiring harness that now has a T-connection for the hot wire kit. Finally, we ran wires from the secondary pump to a relay that we mounted right next to the hot wire kit’s. From there, we ran a trigger wire forward to the engine bay. This will eventually be controlled by the Hobbs switch and only activate under boost. The setup ensures that we won’t have two pumps constantly pumping when they aren’t needed and helps to keep the pumps from unnecessarily aerating the fuel or heating it up.

The Injectors

Now that we were ready to pump massive amounts of E85, there was only one final concern—the injectors. The car had its original 28 lb/hr units, but they were getting close to their limit, even with the car only making roughly 360 rear-wheel horsepower. That meant we knew we needed to upgrade injectors regardless.

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Since we knew that boost was in our future, we asked Fuel Injector Clinic (FIC) to send us a set of their 1,000cc LS1 fuel injectors. This would ensure that our mill would be properly fed well into the future, with room to grow. And, since Fuel Injector Clinic’s injectors are so well flow matched, their operation at low pulse width isn’t a problem for our currently “under powered” setup. In this case there was no reason to not go with a large, capable injector. Tim Jilg of FIC explained why flow matching injectors of this size is important. 

“While flow matching and latency matching using our Data Match Technology clearly improves short-pulse-width repeatability, resulting in smoother idle, trailing throttle and cold start operation, it is not a silver bullet,” Jilg said. “On large injectors, we are still operating in non-linear territory of the injector, and that still has its challenges. To cure the next level of idle woes, we are currently working on an unheard of level of low pulse width matching, that testing has already proven to significantly improve idle quality on all of our large injectors. Look for more news on this in the near future.”

The set we chose are FIC’s High-Z fuel injectors. These are high impedance, ball and seat style injectors and will ensure that we have accurate fueling events, no matter the condition. High impedance injectors have become the industry standard for a lot of reasons. Since they only require 1-1.5 amps to open, they tend to heat fuel less and ensure greater reliability and don’t require a new or separate injector driver. But there’s more to it as Jilg explains:

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“Current high impedance injectors are capable of flowing the same amounts as their low impedance counter parts, while also providing much better low-pulse performance, providing a much more stable idle and part throttle,” Jilg explained. “Another advantage of the short-pulse-width stability of the more modern high-impedance injector is easier tuning for the shops or end user.”

This is a big reason why you see 1,000 horsepower monsters just idling around on the streets these days, when they would have been unbearable anywhere but the track just 10 years ago. It’s also a big reason why we chose Fuel Injector Clinic for our injectors. We know that the car will eventually see 700, 800 or even 1,000 horsepower, and the injectors we chose will take us there, but in the mean time they are just as at home in our 360-rwhp Camaro.

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Another huge benefit of going with Fuel Injector Clinic is the ECU data that they provide along with the injectors. Jilg explained just how important good injector data can be. 

“Accurate injector data is the key to your motor running smoothly from idle all the away to wide open throttle,” Jilg said. “This information becomes even more crucial as injector size increases, because as the injector gets larger, it is asked more and more to operate in a range at idle and part throttle where all port injectors of that size go non linear. A lot of the newer ECU’s have software that correct behavior in this nonlinear area. As an example, OE GM ECU’s have very detailed short pulse width adder tables, so we have spent a lot of time building data in this area that makes the cars run significantly better than without it.”

This makes getting the injectors in the car and scaling them to work with the ECU a breeze—more on that in an upcoming article. FIC gives you all the data you need for offset, short pulse adder, and flow vs. pressure tables, making implementing them in any system—and virtually any LS ECU—a breeze. Our particular set of injectors should be good for over 800 rwhp on E85 and boost.

A Bit Corny

The installation of the injectors was relatively simple. After disconnecting the battery and relieving the fuel pressure at the rail, we removed the bolts that held the rails to the intake manifold. Next, we removed the fuel injector pigtails from each of the injectors. The rear injectors can be a bit of a pain, since they are under the car’s cowl, but virtually everything on the rear of the motor on a fourth-gen typically is.

After relieving the fuel pressure with a screwdriver, we then moved on to removing the fuel rail bolts and disconnecting the injectors.

We then disconnected the fuel rails from the fuel line with a quick disconnect tool. After that, we simply pulled up on the fuel rails and they came free from the intake manifold. Then, we carefully worked the rails and injectors out of the engine bay.

Left: We disconnected the fuel rails from the supply line with a quick disconnect tool. Right: With everything disconnected and unbolted, we were ready to remove the fuel rails.

To remove the injectors from the rails, we next had to remove the metal retaining clips that held them in place. Once the clips were removed, we wiggled the injectors free—though almost all of them left their O-rings behind. We then used a pick to get the rings out of the rails.

From left to right: The fuel rails finally out of the car. The fuel rails complete with stock fuel injectors. Here you can see the retaining clips that have to come off before the stock injectors can be removed. The fuel rails and stock injectors separated.

Next, it was time to insert our new injectors in the rails. To lubricate the O-rings and prevent them from tearing, FIC recommends dish soap. It may seem odd, but they have no negative effect on the rings and once they are dry leave almost no residue behind. After being soaped up, they slid right in.

Before sliding the rails back in place, we first installed our fuel injector adapters. The outgoing injectors are an old style called EV1 and use a Jetronic connector. Our new injectors are an improved design called EV14 and use a Uscar connector. This facilitates the necessity of using the adapters so that our stock wiring harness can plug into the new injectors. We found it easiest to install these before the rails go back in.

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Here you can see the 1,000cc injector in its new home along with the Jetronic to USCAR harness adapter.

We were then ready to slide the fuel rails home. Since we had so much trouble with the rear connectors in the first place, we made sure to connect the two rear fuel injectors before the rails were fully in place. This made it much easier to do. After the rails were pushed down into the bosses in the intake, we reinstalled the four bolts that hold them down. After that, we reconnected the fuel line and reconnected the rest of the fuel injectors. We were now ready for E85—at least from a physical stand point.

Conclusion

While a conversion to E85 does require some updates to the fuel system, we felt that they were well worth the effort in terms of performance and future reliability when running boost. We know that there are many positives and negatives to the argument, but for us it made complete sense.

In our next article, we will discuss what it took to get our E85 LS1 up and running from a software standpoint as we tune the car with EFILive. Stay tuned for a how-to on E85 tuning and for the final power numbers on our E85 Camaro.

Article Sources

About the author

Chase Christensen

Chase Christensen hails from Salt Lake City, and grew up around high-performance GM vehicles. He took possession of his very first F-body— an ’86 Trans Am— at the age of 13 and has been wrenching ever since.
Read My Articles

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