whitefox

Ok so someone tell me what is stopping me from doing this, it seems really easy to just tap the elbow and install there....

AO

money

animal8526

hmmmmm... exactly how safe is it to put small shot, say under 100hp into an 81 auto, porting the nozzle right at the MAF elbow, below the wire, as mentioned? btw, money isnt that bad... dry shot kits can be had for $500 or so... cheap compared to other power add ons. oh, and not to hijack, but...

has anyone ever tried any of those E-chargers? cheap, for sure, and not meant to be permanant, but does anyone have and advice for me if I planned to use two of them as a temp hold over for more horse till I pony up for a blower?

AO

TIm-

E-chargers are a waste of time. They "might" give you a tenth of a second off of stock... "maybe."

On a 81 Auto, 1st off do not have a MAF. They have "Barn-Door" AFM. Rather than explain where I put the NOS set up on my ol' 82, I suggest you read this thread. Nitrous Install

You definitely want to go with a wet system. I was running a 75 shot. Very fun. I think you could go to a 100 shot without issue - maybe even 125. The system is very straight forward. I bought the system for $500 (used) off a fellow rennlister.

FYI... My 82 stock (non-s) 0-60 time was 8.2 seconds. With the NOS setup I dropped it down to 6.3 seconds.

mark kibort

logically, let me correct it back.

it is the bomb! no bombs. pretty hard to get yourself into trouble, unless you really due something stupid with NOS . Most failures are related to too much hp for the engine to handle. not the myth of the engine blowing up due to "leaness) remember, superlean is not = to superhot. aircraft engine have been running lean of stoich for years for fuel economy and lower head/egt temps. you only run the risk of burning an engine if you run at near stoich. (ie 14.7:1 or there abouts) for example, if you are running a 100shot of NOS and the fuel nossel fails, you just run the risk of the engine running real lean and not running smoothly. temps would be REAL low.
a partial clog would be most likely, but for some reason, burning valves at near 14.7:1 fuel to air, is not that common, even though i personally dont think its good. probably due to the fact that the 928 engine is designed for much more hp than the 300rwhp range most of us see. thermally and structurally.

NOS away, its a great power adder, only a hassel as far as the bottle goes.

MK

Jon B.

NOS is the name of the company, Nitrous Oxide Systems. N2O = Nitrous. You guys sound like you've watched fast and the furious too many times. It's NAWWSSS yo!

I don't see any reason why something bigger than a 100 shot (so long as your fuel system/engine was up to it) wouldn't work. LS1 cars use bigger shots routinely and they have just as much compression as these cars do. Not sure why the 100 shot limit is all.

Spray it!

Jon

AO

Jon-
I think it (100 shot limit) has to do with making sure the fuel atomizes properly. The way it works, for those watching at home, the nozzle that goes into the plenum has two "IN" ports (1-N2O, 1-Fuel) and one out port. The metering occurs on the "IN" port where you use fittings with different sized holes to achieve your desired mixture of N2O and Fuel. The N2O is under very high pressure (900~1100psi!) and it is this pressure that is used to atomize and mix the fuel. The result is a highly flammable gas and "air" mixture that is sucked into the combustion chamber through the intake port, thus increasing your effective HP.

If you start adding too much fuel there is a limit to which the N2O can effectively atomize it. When that happen you may end up dumping raw fuel into your plenum and also run the risk of going lean. That's BAD. If I had my car back, I would definitely try a 125 shot for the helluvit. I'll tell you that bottle sure was fun!

whitefox

How many of you think I can buy and install a Nitrous setup before SITM and still sleep at the hotel?

AO

All depends on how much time and money you have on your hands. The install itself only takes a few hours - but there are some parts that will need to be fabbed. You'll need to tap the MAF or the plenum, and you'll need a Fuel Rail nut adapter. Other than that you could go down to you rlocal speed shop and get a kit and have it running the same day. Seriously. Not that difficult to do. My Nitrous install thread shows most of what needs to be done.

animal8526

oooooohhhh. aaaaaahhhhh. I have new hope.

Jim bailey - 928 International

Mark the comparison to airplane engines is somewhat flawed because you basically never accelerate with an airplane pulling under load. They spend the vast majority of their time at a constant engine speed. The damage from going lean is from detonation "pinging" like if you try to pull a hill in too high a gear too low an engine speed too much open throttle the little clickity click marbles sound becomes knockity knock bang ity bang as rings break cylinders get scored and pistons break. But other than that lean is FINE. Introducing an oxidizer like N2O dry no fuel immediately makes the mixture go more lean than it would normally be since the injection brain really does not know you added N2O. The use of N2O on aircraft was for use ONLY at high altitude where the atmosphere was lacking oxygen. Because in dogfighting he who has the altitude usually wins

Big Dave

Oh Mark...I was kidding! I even went for a ride in Andrew's car with the giggle juice installed.

Brett928S2

Hi All

Well I have read all the advice here and WILL be fitting a Nos SYSTEM..no matter what anyone here in the UK says about blowing engines...
I will start at a 50 shot and work my way up to 200....and see what happens

All the best Brett

928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH.K&N.
PCGB UK 928 FORUM MODERATOR

zoltan944

OKBrett
let us know how it goes

mark kibort

not really flawed. in an airplane, you can be climbing at some % of max power. say its 80% thats no different than if our engines could be making 400rwhp and you are climbing a hill floored at 350rwhp. lean of stoich in both situations will cause no damage to your no likely to knock at 17:1, if it can run smoothly. at the point of lean of where it starts running poorly, you can richen it up slightly. it still can be very lean, and lean of stoich, but you will have a huge drop in power, but in airplanes this is the most fuel efficient mixture setting that is safe for the engine.

Now, pinging at part throttle , as you mention (marbles knocking around) as we have all heard in most american V8, V6s 4s, etc, is due to a hot spot in the combustion chamber that causes ignition (or pre-ignition)

adding NOS without fuel if a moderate amount, not to push the mixture to 14.7 or there about, is not going to cause pinging, actually, its better than the airplane example due to the fact that it is very cold.

NOS was used in airplanes for the same reasons as it is used today. more air mass flow added with more fuel mass flow to equal more power.

there is NO reason in the world to run at lean of stoich, unless you want a more fuel efficient burn, at the expense of massive power loss . (as compared to the correct, best power settings of the mixture , i.e. 12.5:1 or so)

For those airplanes to get the best power at altitude, where there was little air, supercharging is used , like it is with cars to get more air to be mixed with more fuel , to at least get close to performance at sea level or lower altitudes.

as a side note. if you only cooled the runners, (real cold ) the warm air mass going through the MAF would increase. the volume of the intake charge being always the same, would contain a higher density of air. now, if you only injected NOS into an engine with no fuel, the volume again would be the same entering the combusion chamber, but the mass would decrease from what the MAF sees, but the density of air (or NOS) would increase due to volume being made up of part air and part very cold and dense NOS.
Finally, that same last situation would be not much different when you now think of the intake charge now, also containing the fuel to match not only the mass flow of air metered by the MAF, but the pre matched NOS and fuel (ie wet system) that would be injected after the MAF and un metered.
MK