E85 and aluminum fuel tanks??


New Member
May 10, 2010
Hey guys my name is Jimmy and although Ive read a lot of threads here I haven't signed up until know. First off, out of all the forums Ive been in, this one has by far the most factual information about E85.

I'm sorry I don't have a Buick But I know you guys will have the best factual information I need to complete the 4 projects Im currently considering the switch to E85. I have a list full of questions I hope you guys can help me with.

1. Project number one is a 77 Southwind jet boat.
bbc 468 nitrous motor
low end is a 4 bolt main gen 4 block, forged steel crank ( nothing special)
eagle h beam rods, probe 11-1 compression forged alum pistons.
total seal rings I think.
Top end, rhs 360 cc aluminum heads race ported with all the best top dollar component's, valves, springs, keepers, retainers etc. Howard's solid roller hi performance lifters ( 10 x better than most) beefy push rods unsure on brand, I'm in in my office. 720 lift custom grind solid roller cam (big) Don't have the specs with me. Jessle shaft mount roller rockers. Aeromotive vacuum pump. The intake is a piece of art. It started as a weiand hi ram tunnel ram with the top machined off and a 871 plate welded on to adapt the 2' up and 3' forward blower riser and machined for the nitrous injectors. On top of that is a bds bug catcher-throttle body. The intake was also machined at the lower runners for my threaded 72 lb bosch injectors controlled by a fast xfi ecu. Rite now its has a 300 shot from nx express and it runs on 110 octane at all times. This motor is new and last sat I finally got a good tune on it. Long story It was dynoed last year but I lost the tune because of a wiring issue. It put out 740 hp at 6700 and 1050 on the nitrous at a similar rpm range. I'm running a fast duel sync distributor witch I recently got to finally work after sending it back 3 times. My fuel system consist of all an hoses and ends -8 from 2 tanks to a y block to a fuel water separator to a 100 micron aeromotive filter then to the areomotive a-1000 fuel pump good up to 1300 hp with my app. I'm also running a big oil cooler and a bypass over sized oil filter. Keep in mind that my nitrous system is a bit advanced meaning The nitrous lit only injects nitrous, the ecu adds the 30% fuel from the injectors not the nitrous nozzles.

So now that you have a history on my motor here are my questions
1. can you run E85 with aluminum fuel tanks, I head they corrode easy.
2. with my 72 lb injectors they are never at full duty cycle even with the n20 but with the switch I know it will be too close for comfort. Will 120 lb injectors be enough. Max hp of 1300 Also because of the added performance of E85 I may easily go from a 300 shot to a 400 shot of nitrous. a 500 shot will be the max rating of my fuel pump but may upgrade that if needed but don't want to buy injectors twice.
3. How does nitrous react with E85?
4. will I need to go bigger than - 8 fuel lines. I was thinking of converting the fuel line to -10 from where the 2 tanks merge to the y block to the fuel pump. Do you think that is necessary?
5. Can I add 2 stroke premix oil (Small amount) to the e85 to lube the motor and help with the corrosion of the aluminum
6. How long is the E85 shelf life?
7. Is there ant additives for E85 to keep it stable for storage and keep it from separating.
8. I also heard that it can also eat through aluminum fuel rails over time is that true? Some hard anodize them.

This is a long first post! Thanks for your help. I still have 3 other projects I still need help with but didn't want to overwhelm you guys rite off the bat.:D
I will post some pictures if some one will tell me how!
I will take on a few of your questions- the topics I know the best;

#1) While there are likely many aluminum alloy types-- all the ones I have seen so far are unaffected by E85 that is kept dry. Fuel transport trailers are aluminum, the fuel filter bases I have have been in use over 5 years and are still clean and bright as the day they went into service. Many guys that are racing kept their aluminum fuel cells for E85.
#5) I do not feel this is necessary and could be detrimental- In fact if you do choose to do this then you should be sure to put some E85 in a sealed clear glass jar with the ratio of 2 stroke oil you intend to use and make sure after shaking it does not come to the bottom after a few days or weeks. Not all 2 stroke oil is acceptable in very high ethanol blends.
#6) The shelf life is determined by one thing--how well did you seal it! Since you are on the water this will be especially important. However since you are EFI (no carb to seal) then your only challenge will be to seal the tank vent when not in use for few days.
#7) No additives are needed and some additives out there (usually not storage types) can be very detrimental. E85 will not phase separate in your use (unless you leave the filler cap of with 2-3 gal of product in the tank over the winter. You are thinking of E10 gas. Look at it this way- E0 gas will only carry approx 1/10th teaspoon of water/gal before it falls to the bottom, E10 can carry 4 teaspoons of water/gal before it falls to the bottom in phase separation. E85-it takes a huge amount and this would take a long long time even under completely ventilated condition. WHAT YOU NEED TO GUARD AGAINST IS: allowing air to contact E85 such as with open vents- while E85 is very unlikely to phase separate it will acquire water from such free air exchanges that happen when the tank cools down and draws in cool moist night air and just keeps doing this for weeks especially when the tank is near empty. This moisture, if allowed to enter the tank, will eventually overwhelm the corrosion inhibitor that is spec'ed in all fuel grade ethanol- this happens because with too much water and time you will start to form acetic acid. Do not be afraid of this happening IF you go to a good tank vent that is both pressure relief and vacumm protected. You could model your system after a modern car or I have seen some excellent ideas from guys who leave their stuff sit. Lots of boat guys running E85 now- I bet they have some good ideas.
8) A lot of guys do upgrade their fuel lines since often they are too small anyway. The concern is likely not the fuel line as much as it is having dissimilar metals and some plastics in the ends of a few street car fuel system. I and others have run high ethanol blends in aluminum for well over 5 years without incident or line replacement- yet sitting in a high value, high HP boat on the water, with fuel spraying out on the exhaust manifold would not exactly be my idea of fun.

Again- virtually all corrosion issues with E85 can be controlled by keeping the fuel sealed and dry. Also be aware that your first tank is going to remove every bit of water and gums left behind by gas- have a plan for dealing with this issue and then you will have a clean fuel system thereafter.
2. I would go larger than 72's with a big block, nitrous and E85. 120's would be cool.

4. I would go with -10 feed and -8 or -10 return and be sure you are using an electronic fuel pump controller to save wear and tear on your external fuel pump when idling. IMHO, you cannot go too big with fuel lines and remember that the return line is under little pressure so it needs all the help it can get!