E85 gas on Viper a good idea or not

[Shannon Whitehead]

#832

Not sure how good the rear pump is on gen 3 (I’m sure yours is upgraded already), but you have a fairly large injector already and at your power level I bet e50 or higher be worth 30rwhp…

Where I’m located e85 is available at most stations, roughly 2.30 a gallon right now. It’s winter Blend (68-70%) year round for us, which I happen to like since I know it’s predictable and I can set the stoich ratio in the tune accordingly and it saves me a little fuel on the fuel system side.

My plan for my car is to change injectors only, keep stock pump an run pump e85

[Shannon Whitehead]

#833

E85 Benefits

More Potential Power: we’ll start with the good stuff first—E85 has an octane rating of 100 to 105, which is 9 to 14 points higher than the 91 octane premium fuel found in many stations. E85 can support lots of boost for forced-induction engines, and crazy high compression ratios in N/A applications. Always a good thing.

Better Cooling: ethanol absorbs over twice as much heat during combustion as gasoline does, which makes it a much more efficient cooling agent than gas.

Cleaner Burning: engines burning ethanol leave fewer carbon deposits on valves and pistons. The exhaust actually smells better, too.

Smoother Power Delivery: one oft-heard comment from E85 consumers is, “Wow, the car just drives so smoothly.” It also can idle better too.

Reports of Your Fuel System’s Demise Are Greatly Exaggerated: GM’s official line is “Don’t use E85 in your Corvette.” However, many enthusiasts who’ve done long-term E85 testing have reported few to no fuel system issues on straight E85. Will every fuel system part last 200,000 miles on the ’shine? Probably not. But it won’t last that long on gas either.

E85 Drawbacks

Moisture Can Cause Problems: alcohol is hygroscopic, meaning it readily absorbs moisture—so E85 introduces more water into your fuel system. This isn’t a huge problem in modern fuel systems, but older Vettes with stock fuel systems will see accelerated corrosion unless it is upgraded.

Slight Fuel Economy Losses: E85 has roughly a third less energy than gasoline, which means that it takes more E85 to equal gas’ power. Now, GM’s factory Flex Fuel vehicles got a lot of bad press by getting way lower mileage compared to gasoline. However, a Corvette with aftermarket E85 ECM tuning can return mpg ratings within spitting distances of its factory gas ratings.

Fewer Places to Fill Up: Unless you live in the Midwest, finding E85 can be challenging, especially if you’re on a road trip in unfamiliar territory. Those of you who keep your Vettes close to home and have a few E85 pumps nearby should be fine. And C6-up owners can buy flex-fuel sensors that work with the ECM to let you switch between gas and E85.

Possible Lower Resale Value: misinformation is a powerful tool. The same people who think running ethanol will destroy your car, may very well be your future potential buyers. And as such, they may eye an E85-converted Corvette as a car this close to self-destructing, which could kill your sale outright or possibly lower its value.

Conversion Costs: late-model Corvettes won’t need much dough to convert—especially if your car still has the factory tune and you were planning on getting it modded and tuned anyway. But C4 and older Vettes will need a fuel system on top of the other mods, so keep that in mind. Speaking of converting…

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