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E85+Nitrous? Some basic questions

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Maxthepersonz

Supporting VIP
350
62
Feb 3, 2014
Madison, Wisconsin
So guys after at least a good year of slacking my engine is getting torn out. Going to build something to make big power (600+ at the wheels minimum).. Running a 6466 Gen 2 precision with all supporting mods obviously.

I have E85 available pretty easily where I live and definitely plan on using nitrous specifically to spool some boost for launching my auto. That's the only time it'll be used on the street,strip,etc. I'm curious if people would recommend mixing these two? I've searched and seen it's been done but never has to many details.. If I were to do so would I want to run some E85 compression ratio pistions like 10.5.1? Would this still play well with the nitrous? Or should I just run some regular 9.5.1 and call it a day?

I'll be using HD pistions, I beam rods, with a Kiggly girdle at bare minimum.

I am not at all opposed to running 93 for fuel as well but I know E85 makes power easier and people also say it helps with spooling the converter.

Thanks!
 
I am not a big fan of high compression pistons. My car has regular 8.5:1 CR Wisecos, on E85 and made 700whp some four years ago relatively easily with a setup that was not exactly optimized (Web cams and stock intake.) If spraying, the low compression would help you even more. Good luck.
 
So guys after at least a good year of slacking my engine is getting torn out. Going to build something to make big power (600+ at the wheels minimum).. Running a 6466 Gen 2 precision with all supporting mods obviously.

I have E85 available pretty easily where I live and definitely plan on using nitrous specifically to spool some boost for launching my auto. That's the only time it'll be used on the street,strip,etc. I'm curious if people would recommend mixing these two? I've searched and seen it's been done but never has to many details.. If I were to do so would I want to run some E85 compression ratio pistions like 10.5.1? Would this still play well with the nitrous? Or should I just run some regular 9.5.1 and call it a day?

I'll be using HD pistions, I beam rods, with a Kiggly girdle at bare minimum.

I am not at all opposed to running 93 for fuel as well but I know E85 makes power easier and people also say it helps with spooling the converter.

Thanks!


I am auto. I run e85. And I use a 35-50 dry shot to stall on the line. Until recently, I also had 10.5:1 pistons.

My take:

I never noticed any kind of issue running a small dry shot with e85.

Someone smarter than me can chime in with actual data, but I don't think e85 in and of itself helps spool over 93. If it does, I didn't notice.

The 10.5 pistons are nice in regards to feeling more responsive on the streets, but my goodness, at least on my setup, even with e85, they were a PITA to tune. Would still get knock. Way more than with my 8.3's. I had to run mid 9's afr on a gas scale and run 5* or less at peak torque to keep it happy. I eventually got it "figured out" but it took a long way to get there.
 
I will say, from my experience with nitrous, that I used a 150 wet shot on a 11:1 Small Block Chevy and it was definitely more responsive than on a flat top, 10:1 motor. That motor had CAST Corvette pistons and a lot of cylinder wall clearance but ran like a bat out of hell in my little Chevy Vega GT.
Just my 02 on the nitrous and high compression, not sure how it will work with BOOST, since I never did forced induction until I got into my DSM's but I currently run 10:1 in my Red Talon. I agree it didn't like a lot of timing until I went to E85, just like @Kapok6 said, but if you are going to run E85, that went away for me and I was running 20-21* with it up top with good results.
 
ive got a 50 wet shot on my auto. weve only used it a couple of times on my car but haven't had any kind off issues. id say go for it. I would recommend a wet shot over a dry shot though
 
I would love to see that car run!!!! :applause:
 
I should make it clear, I am only using the dry shot on the line to stall up and get over the hump. Once it's on the limiter, I'm off the nitrous, and launch boost only.
 
So when you shoot a "dry" shot, are you enriching the mixture at all thru your engine management? I wanted to ask about that because of the wording or are you really just introducing NO2 and thats it? Thanks, sorry to interrupt he thread.
 
The 10.5 pistons are nice in regards to feeling more responsive on the streets, but my goodness, at least on my setup, even with e85, they were a PITA to tune. Would still get knock. Way more than with my 8.3's. I had to run mid 9's afr on a gas scale and run 5* or less at peak torque to keep it happy. I eventually got it "figured out" but it took a long way to get there.

What happened to your 10.5:1 motor?

I'm not auto, i'm not nitrous. but i've played a lot. I've never had a high compression motor either. But I am a doctor. My engine simulation codes suggest that high compression on a boosted motor has a huge increase in peak cylinder pressure for a very very small gain in thermal efficiency.

What I'm saying is that even on a 8.5:1 motor without detonation and at mbt we can generate enough cylinder pressure to be hard on parts such as head gaskets. On a 10.5:1 motor it's even worse, and there is a possibility that even pulling the timing back you can be harder on parts while making less power with less compression.

Finally, no one ever looks at the VE side of this either. If you manage to have a turbo setup with less exhaust pressure than intake pressure (easily done with a decent big turbo in a loose housing at medium boost) you will have less cylinder filling with higher compression.
 
What happened to your 10.5:1 motor?

I'm not auto, i'm not nitrous. but i've played a lot. I've never had a high compression motor either. But I am a doctor. My engine simulation codes suggest that high compression on a boosted motor has a huge increase in peak cylinder pressure for a very very small gain in thermal efficiency.

What I'm saying is that even on a 8.5:1 motor without detonation and at mbt we can generate enough cylinder pressure to be hard on parts such as head gaskets. On a 10.5:1 motor it's even worse, and there is a possibility that even pulling the timing back you can be harder on parts while making less power with less compression.

Finally, no one ever looks at the VE side of this either. If you manage to have a turbo setup with less exhaust pressure than intake pressure (easily done with a decent big turbo in a loose housing at medium boost) you will have less cylinder filling with higher compression.

Doing a test launch, vac line to MAP sensor blew off at 30psi, car went lean, detonation on all cylinders. Yeah, fun time. So Curt redid it but I had him use 8.5's this time.
 
So when you shoot a "dry" shot, are you enriching the mixture at all thru your engine management? I wanted to ask about that because of the wording or are you really just introducing NO2 and thats it? Thanks, sorry to interrupt he thread.

you should be enriching the fuel through the tune. imo its more of a pita than its worth when a wet kit is just as easy to run.
 
Dry shot is so misleading, it could be dangerous. I have a wet shot for mine, but just had to ask and new they had to be enrichening it or it goes BOOM!!! Thanks for the answer.
 
Dry shot is so misleading, it could be dangerous. I have a wet shot for mine, but just had to ask and new they had to be enrichening it or it goes BOOM!!! Thanks for the answer.

dry just means its only adding nitrous to the system and you have to compensate for fuel in the tune while the wet adds fuel and nitrous and all you have to do is retard timing depending on how big of a shot youre running.
 
Thank you. I have only ran wet shots. Back in 1980, when I ran my first setup, there was no elecronic fuel injection yet so I was just curious. I got that set up for $100 because the fellows had blown up their SBC in a '57 Chevy. 5 years later, I'm cleaning up the plate to put it on my V8 Vega, and noticed why the guys had problems...solenoids were on the wrong spray bars....BOOM. I swapped them and it worked fabulous.
That was way back in the day. No pills yet.
 
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