Is anyone running nitrous and e85? I came across a nos sniper system cheap and couldn't pass it up however I'm a little concerned about my hyperuetectic pistons. The engine is supposed to be a 300 horse 355 with 9:1 flat tops, roller cam at .470/490 lift 115 lobe seperation 214/220 duration at .050 edelbrock performer intake and 600 edelbrock carb. I left the parts selection to my machinist and I just assembled the engine now kind of regretting that one. I was hoping to switch to e 85 as I now have a pump a mile from my house and take advantge of the higher octane. any input appreciated.

 

Running the motor and nitrous system on E85 fuel should increase reliability ( higher octane) and decrease the amount of extra ignition retard at higher power levels nessessary to avoid detonation. the nitrous/E85 mix ratio will be different.
Can't help ya there except the E85 fuel jet will be quite a bit larger for each power level. The solenoid/pump / filter etc has to be able to keep up with the higher fuel flow volume.

Your cast pistons will handle quite a bit of nitrous power as long as the fuel ratio mix is right and you avoid detonation.

You can open up the pistons top ring gap some to account for the extra heat load while on nitrous.
Most stock" replacement" cast pistons ring end gap recomendation (typical .012 to .018") is too small for performance WOT work, let alone nitrous heat.
Make your ring end gaps bigger. bigger is better. Your ring end gap will be normal while the motor is @ WOT as the extra heat load closes up the top ring end gap from expansion.

 

I'm kind of stuck on opening the ring gap as motor is assembled and runs great just not the power i had hoped for. I guess i could always tear it back down but hate to do it.

 

You'll be good to go as is up to about 175hp.
Much beyond that and its a good idea to open up the ring gaps to ensure the rings don't but under load.

You realize that just switching to E85 will not in itself increase engine power. You would have to either raise the compression ratio or supercharge the motor to take advantage of the increased octane of the E85.
Based on the parts you listed you should be making over 300 BHP. You make no mention of the cylinder heads on your motor thou. If they are stock low perf heads then the power will be very limited regardless of what else is bolted on..

Pull off one of the vave covers and read the head casting numbers. Bet you're in for a suprise.

 

Another thing you may need to watch for is the seal in the fuel solenoid being attacked by the E85. Has anyone here ran E85 through a fuel solenoid? If worse came to worse you could buy a methanol solenoid but those are large and expensive.

 

I do know the heads hurting me as they are the low perf version. The engine was a cheap budget rebuild as funds were tight at the time and the 305 gave up on me. I have a set of aluminum heads for the engine now but not quite sure how to put them on. They are gm aluminum heads but have no hole in the head for an intake pushrod to pass thru as the intake ports are considerably larger and in the way. if any one has any ideas on how to clear that hurdle speak up . If I remember I'll get the casting numbers tonight and post them up.

 

If the heads don't have slots for the pushrods, you'll need to run guide plates. I think that'll be the only hurtle. May want to go to a higher quality head gasket if you're going to be using nitrous. Just thinking out loud here, perhaps ARP head bolts as well.

Also you'll want to read off your current casting #, and the new heads casting number, I think you'll jump up your compression ratio a fair bit. Hopefully it'll still be in the ballpark, but if not, then again - the E85 comes into its own.

I would highly recommend opening up the ring gaps before using nitrous, that small ring gap really scares me. I'd go on up to like .025-.030" on the top.

On the same token, E85 runs SIGNIFICANTLY cooler, (ask Five7 kid on this one, he did some testing with his '57 car, not on nitrous, but I imagine the effect is still there)

Then you'd want to ask NOS what their thoughts on it is. You'd need to jump up your fueling jet ~30% vs gasoline, but again, NOS would be the first to ask. Err on the rich side of course.
Sniper is the big kit eh? Open up the ring gaps and SPRAY THE ***** OFF IT !

 

There _has_ to be a pushrod hole in them…, let me see a picture of them?

Anything big enough to relocate the pushrods significantly will use offset shaft rockers, but anything that big would be way too big for your (most if not all) real “street” setups.

I’m assuming that you mean broached pushrod holes rather then just open holes?

I don’t know why everyone is stuck on changing the engine internals… it’ll be just like spraying any other stockish engine, with a little extra leeway for the extra octane and cooling effect the alcohol has.

Yes, you’ll have to run larger fuel jets to maintain a/f ratio, but I would just call the manufacturer of your setup and start with their recommendations rather then guessing on your own. If you insist on guessing, I’d got with a fuel jet size for about 30% more hp then what you’re spraying, that should give you enough extra to cover the lower energy content of the ethanol.

WRT to seals… most N2O companies make fuel solenoids and rebuild kits/seals for their stuff to handle alcohol, but most are more concerned with methanol rather then ethanol.

 

How will you jet the nitrous on the fuel side? The jets are based on unleaded gas. I am looking at the same issue with my 91Z. BranZ

 

I haven't got around to figuring the jet sizes that I will need for this setup as of yet. I still have to redo the entire fuel system rewire the car install my 4.11s and put my true duals on before I slap on the nitrous kit so I may not have an answer for awhile