GST's 2.6-liter EJ25 turbocharged engine pumps out 560 whp on E85, thanks in part to the m
Reduced fuel costs and lower intake charge temps sounds like a winning combo, but what sort of modifications are required to make a car E85-ready? According to Mike, "There are some obvious issues that are expected with a fuel that requires roughly 30 percent more flow rate, so the first thing we do is work out the anticipated horsepower output of the car we're working with and match the fuel system accordingly. For example, with our time attack car we used to make around 500 whp on our Mustang dyno using Sunoco race fuel (C16 equivalent) and used RC Engineering 1,000cc injectors coupled to our main pump from our surge tank that was a Bosch Motorsports 044. With our first attempt with the E85, we upped the injectors to RC Engineering 1,600cc units and let the car fly on the dyno, where we saw fuel pressure dropping off at around 6000 rpm. After some testing, we found that we had maxed out the flow rate of the Bosch fuel pump, so we added another one running parallel with the existing unit. This allowed us to maintain the fuel pressure and tune the car to around 560 whp on our dyno."
When I asked Mike if they had any unexpected surprises come up while converting their Impreza to E85, here's what he reported: "The biggest surprise came from the cleaning properties of the E85 fuel itself. The strong ethanol mix loosens up a lot of dirt and carbon deposits in the engine, which clogs the fuel filter. So now we run a couple of gallons of E85 through the system when converting to it and then change all the fuel filters. We also learned that with fuel cells like those used in our time attack car, depending on how old the cell is, the sealants used in the bladder design will break down, so you need to have your bladder sent off to the cell manufacturer to be updated to support the running of ethanol. We have not seen any issues with cars running the stock tanks."
With many of the fastest teams from this year's Modified Tuner Shootout running E85, including defending champion GST Motorsports in its awesome GC Impreza L, it's clear that this corn-based fuel has some real performance advantages over traditional race gas. Whether or not it's worthwhile for you to convert your car for E85 will depend on a lot of factors, some already outlined by Mike from GST, but it certainly appears that from a cost and power output standpoint, if you've got a turbocharged track car, E85 may just be that winning edge you've been looking for. As you'll see later in this issue, it hasn't hurt GST's Impreza any, that's for sure!
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