EFI University

[Gadgeroonie]

has anyone tried this ?

can you inject it just like fuel, or is it best to spray it in like you would with methanol/water inj ?
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Dyno Developments
2WD and 4WD Chassis Dynamometers



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[sam@tdi]

You can add it pretty much any way you want but be warned this stuff doesn't burn it explodes. And on top of that it's can be a nightmare to set fire to, if your using higher Nitro ratio's then you'll need the ignition system from hell, possibly twin plugs, oh and well built pistons, heat transfer paths become a serious subject.

In Top Fuel drag racing 2x 50amp magneto's are the norm!
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Sam Borgman
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[Gadgeroonie]

i am looking to inject it to see what happens - using it like water/meth

concerned it will ignite before the spark event
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2WD and 4WD Chassis Dynamometers



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[sam@tdi]

Seriously I wouldn't worry about that at all this stuff is pretty much inert until it's under very high pressure just remember that the lambda is ridiculously low in terms of afr.
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Sam Borgman
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[Martiens]

If you are adding it to normal fuel you will have serious detonation problems.
You need to run it with methanol or something with a higher octane rating.

[Gadgeroonie]

you have confirmed my suspicions, the normal petrol combustion will set it off and create an unusual burn

i wonder of retrding the ign to suit may be able to get the thing to produce mbt reliably
_________________
Dyno Developments
2WD and 4WD Chassis Dynamometers



www.DynoDevelopments.co.uk

[sam@tdi]

I vote for buying a cheap briggs & stratton from ebay and "run a testing program"
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Sam Borgman
www.facebook.com/torquedevelopments
www.tdi-plc.com
www.rototest.com

[Gadgeroonie]

ha ha ! now that could be good fun
_________________
Dyno Developments
2WD and 4WD Chassis Dynamometers



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[TurboNova]

[alexchevelle1]

I once read an article in Car Craft or Superchevy. They increased the Nitro percentage in fuel and gained ut to 50hp in a 300hp engine if i remember.
It was very hard on engine componants and spark plugs.
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1100 Din HP @ 6660 RPM 1250 Nm @ 3670 RPM
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[Will@RDT]

maybe you'd end up with 'block lift' if adding it to petrol.... like that tractor pulling video blowing the block off the pistons

[Power-Tripp]

While considering myself far from a nitro expert, I have run nitro/methanol mixes in varying concentrations up to 60% in injected two-stroke and four-stroke engines without issue. But the learning curve can be steep if you don't take your time and work up to a given mixture and the tuning required.

10% tunes much like leaded gasoline. But as you increase nitro percentages, each engine (and combustion chamber design and diameter) will have results that vary. You will likely find that a 5% increase in mixture (by density, not volume) may only show a slight increase in output, yet the next 5% increase may show a larger than expected increase in output.

With each increase in mixture %, you need to start rich, and with reduced ignition advance, and "sneak up" (work slowly) on your best tune-up, or nitro can, and will, hurt your feelings.

Keep a log of weather conditions (especially temp and humidity) that you can refer back to. This will help answer questions that will pop up on your tuning. Logging engine data will help as well. Engine and exhaust temps play a big part in the results.

And as mentioned above, having an ignition system that is overkill (high output CDI or Magneto) can be a big advantage, and make life easier.

Mixture delivery is important. The injector pressure, pattern, and angle/location all influence the burn - even moreso than many other fuels.

My best advice is to start slowly, and work slowly.

Not much, but I hope it helps.
_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss

[baldur]

To illustrate how violent the nitro burns, here's an engine that warms up on methanol and then switches to nitro.

http://www.youtube.com/watch?v=_f3kaC4_4IY

[rotorhead]

Have run 100% nitro through a stock A15 Nissan engine for short period with good results (as an experiment ) Car went from making 38 rwkW on pulp to 74 rwkW running 100% nitromethane. Had to run the carb with no jets in it and adding more via a plastic bottle sqirting into the carby got good enough mixtures to do a power run with the above result.
Engine suffered no damage and std ignition system was used (electronic). You would find this article in an old zoom (aus) magazine.
Was good for a laugh .. we had various people too scared to be in the dyno room at the time
I say do it...but you would want to do it with the aid of an ecu that can switch maps when its activated.

Cheers
_________________
13BT RX3 sedan pure circuit (race)
13BT Courier Ute (work)
MY97 WRX Hatch (wife)
HSV TWR Group A Commodore 304 (show)
And now a Mazdaspeed 6 MPS

[Power-Tripp]

I can't blame people for being scared of nitro on the dyno. I have seen fuel vapor in the exhaust ignite and blow the dyno room door off its hinges, and destroy the exhaust extraction system.


_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss

[horsewidower]

Did this go anywhere?

We are trying to decide whether or not to use EFI instead of MFI for a land speed car. 140ci inline 4 NA.

To say that tuning Nitro seems shrouded in myth and legend instead of science would be an understatement.

I'm having some difficulty sizing the fuel system. We probably won't use more than 60% nitro, the rest will be methanol. I suppose I could work with the MFI vendors to try and figure out basic fuel system volume, but I hate to use a vendor and then not buy from them.

So far, using advice from a friend that runs a Jr. Fueler, and then comparing that to a couple of internet sites (you know how much you can rely on that... ) the spread is 500 Lbs per hour to 800 lbs per hour. A little too wide for my taste. What I'm generally told is to run it rich enough to drown the plugs at the top end, and then start leaning it out. I'd like to get closer than that.

Anyone here have any recommendations that are backed up with some science?

Bob Holmes

[C. Ludwig]

[Power-Tripp]

EFI works very well. The better control of injection and ignition events you have, the better you will be.

Shrouded in myth is an apt description... for good reason. Nitro has the potential to produce very large output compared to gasoline fuels - 265% more. Two engines built identically can have very different requirements due to many differences. Even a small change in atmospheric conditions can require different fueling and ignition alterations.

Different percentages do not produce a linear output change. Nitro tends to see increases in small steps of percentage increases, with little increase in between.

Make sure your injectors and fuel system are generously sized. Compared to gasoline fuels (non-oxygenated), I generally increase injector flow 225% up to 50% mixes. I've used up to 73psi injection pressure with good results.

I do not recommend diving in at 60% mixes. Start at 10% (tunes like gasoline), and work up from here. Expect a STEEP learning curve if you do not start slowly. Start RICH - it won't kill output as much as you expect. A little lean and things go wrong QUICKLY. Do not cut corners. This is where many find out how expensive running Nitro can be.

You will need a good ignition system... very good. CDI seems to work well since it will fire when WET.

Realize that nitro burns SLOWLY and without much heat. If it burned just a couple of degrees cooler in open air, it would not even require a FLAMMABLE label for shipping. This makes it hard to ignite evenly. The result is lots of cylinder pressure - instant torque. Gear for this, but watch ignition advance at lower rpm.

The volume of nitro/methanol in the cylinder tends to produce liquid compression. keep this in mind when building the engine - static compression and squish/quench clearances. The same volume of fuel will displace a lot of air - ensure your ports are up to it.

Nitro caries a lot of O2. It can run away (rev on its own from a throttle blip at idle) with a closed throttle. Wire in an ignition kill.

Use a small amount of top cylinder lube in the mix. I prefer Redline Synthetic two-stroke oil for Alcohols - very clean burning. You may find something that works better.

I hope this helps.
_________________
"To achieve anything in this game you must be prepared to dabble in the boundary of disaster." -Sterling Moss

[horsewidower]

Thanks for the response.

Right now I'm looking at using two Moran 235 injectors per cylinder. We can add some pressure and duty cycle during the dyno phase of the testing. I'll need to add an injector per cylinder when we get to higher percentages of Nitro. I'll either have to go to a couple of weldon pumps to supply the fuel or go to a mechanically driven pump. Although I'll have to get familiar with mechanical pumps, their pressure generally varies with rpm.

Sneaking up to the nitro percentages is probably a good idea. I've heard conflicting opinions, but I think we need to get it running competently on Methanol first, than "tip the can."

We had planned on warming the engine on Methanol and then switch it to the blend. Its amazing how the demeanor of the engine changes so radically when the switch is made. I observed some folks starting their engine on propane, which provide a docile idle, as soon as it warmed and they switched over, it was a beast.

Bob

[TurboNova]

You better have a mechanical fuel shut off handy. Shutting off the ignition did not kill our engine. If you look most of the nitro guys are shutting a fuel valve to stop the engine.
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Brian Macy
EFI University Instructor
Horsepower Connection
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