hey-

i just wanted to see what guys had to say about nitrous. i was wondering what kind of power increases you can actually expect if the advertised increase is 250hp. I was wondering because i thought i saw in one of the articles when they tested some nos, they were gaining around the advertised power in horsepower but were actually getting some significantly larger gains in torque. i was lookin at putting a two stage nos on a 406 small block. i just had some concerns about the engine holdin up. it has all 4340 forged internals and forged pistons. im pretty sure the engine could easily hold up to a two staged 250 shot but i had concerns about the fuel. the setup i have has a c.r. of around 9.6 with iron heads and a cam with 224/230 duration and .532/.540 lift. I was wonderin if put on a good nitrous controller and eased the nitrous in and also turned the timing back a bit if i could get away from runnin racing fuel or if i could just boost the octane a bit before i planned on using it.

-mark

I know nothing about nitro but i saw a car show the other day where they built two firebirds with nitro and the key they said when running nitro was the gap on plugs because the big shoot of mix can blow out the plugs then miss fire and then mess up the motor iam thinking of adding nitro on my corvette soon also after alot of other troubles are fixed.      good luck  

first of all to the second poster, nitro is usually referred to as nitromethane, Nos, or laughing gas, or funny gas, or juice, or NO2 is Nitrous Oxide

Of course nitrous shows huge torque gains yet motors cant take advantage of them, using nitrous off of the line is risky business and usually left to the guys that rebuild their engines ever few passes, it spikes cylinder pressure too fast for many engines to hold up especially with a shot as big as a 250, if you really want to use nitrous off of the line some money will have to be put into the system i belive, one thing it cant really be used at the buttom of gears, another a solenoid controller is usually required to help the engine keep traction and not blow it sky-high

I guess a small shot on the throttle and then the larger shot coming by a button at the top end can probably be done but you must have buku traction and face the fact that the engine will be treated more as a race car than a street car, and will probably last a quarter as long between overhauls plugs have to be chaged, timing has to be severly retarded (this is another place where money must be spent if its a dual purpose car to retard timing under juice only) race gas must be used, ring gaps need to be spread, a single plane intake is needed for a effective plate system, and the fuel system must be doubled, and the list keeps going on and on

"...i was wondering what kind of power increases you can actually expect if the advertised increase is 250hp."  It depends.  The more efficient a normally aspirated engine is, the less increase it will experience from nitrous.  Meaning a 300hp small-block with 250 pills (jets) may actually increase by ~250hp.  A highly tuned and efficient 700hp small-block will likely generate something less than an incremental 250hp with the same pills.  

"...i was lookin at putting a two stage nos on a 406 small block. i just had some concerns about the engine holdin up. it has all 4340 forged internals and forged pistons. im pretty sure the engine could easily hold up to a two staged 250 shot but i had concerns about the fuel. the setup i have has a c.r. of around 9.6 with iron heads and a cam with 224/230 duration and .532/.540 lift. I was wonderin if put on a good nitrous controller and eased the nitrous in and also turned the timing back a bit if i could get away from runnin racing fuel or if i could just boost the octane a bit before i planned on using it."  No matter how you slice or dice it, a 250 shot is a lot of juice.  You'll need the forged pistons, a rock-solid bottom end (inc. stout main caps), significantly reduced ignition timing, and plenty of fuel and pressure.  Also, with that much juice you'll probably want a cam with more duration - particularly on the exhaust side. 

* Nitrous is a wonderful power adder... but, be smart or you'll quickly regret ever hitting the button.  Good luck.

Nitrous can be a very nice power adder especially where you have to keep an emissions legal engine as it just doesn't figure in anything till you use it.

Modern systems can be programmed to come on gradually so you don't go from zero to 250 more horsepower/ft. pounds of torque in an instant. Instead you can blend it in in say 50 horsepower increments over several seconds.

Your engine sounds like it's pretty well built and should be capable of the occassional dose of laughing gas.

Bogie

i was thinking along those lines, i was planning on hooking it up with a controller to ease in the nitrous with very little being used off the line at all and steadily increasing the power down the strip, the system would be occasionally used, maybe once or twice a year, which is why i could tolerate buying a little race gas, turnin back the ignition and changing the plugs once or twice a year

-mark

can the once or twice a year justify the inital costs requied to make it happen?

if it would only be used once or twice a year, i can see it is heavily street based (or it just sits in a garge) and not unless you are really concerned with ET's i dont see the risks of losing a engine to it, but just my opinion!

i have a 350 bored .40 and 6.0 rods, 1.94/1.5 iron heads and a .484/.484 cam @224 duration with cast flat tops. and a performer plate single stage @ 250. to make things easier for me i installed a mallory HYfire VI digital ignition system. it has a rev limiter start retard tach tester, boost retard-nitrous retard that is adjustable, 2 rpm windows ( ie nitrous on at say 2500 rpm and nitrous off at 6500 rpm). it also fires the plugs 6 times in 20 degrees of crank rotation to burn all gases. its a nice piece, easy to install and easy to work with, and great for nitrous apps.  other wise your build up is almost bullet proof. good luck and have fun  

hey-

thanks for the input, you say your running a 250 shot with cast pistons? how often do you use your system and how well is your mill holding up? im pretty sure my assembly could hold up to the shot with everything being forged , i didnt replace the main caps but i did put in studs. i was also planning on using that same ignition system or one in the like. do you have to do anythin in the way of fuel when you spray the motor?

-mark

i use mine on weekends but i destroyed my rear end so for now i have to wait.  if the bottom end is built right a 250 shot is about the max shot, just get the coldest non projected plugs you can find, no platinum or exotic just regular one, set them about .020 (but you will have to tune and tune to get the right setting). as for the fuel make sure you have at least 6-7 psi fuel pressure at wot (wide open throttle) , if you dont , get a high flow pump, maybe even a regulator. too much fuel is better than not enough. also get a hobbs switch and hook it to the fuewl solenoids. this will shut off the no2 and fuel if there is not enough fuel. but most important retard the timing 2 degree's every 50 shot + a safety of 2 degrees. 250 shot = 10 degree's for the no2 and 2 degree's for safety, you can test and tune from there but adding advance for performance based on et or mph but as soon as you get detonation stop!! turn back. and constantly check your plugs.  

 too much fuel is better than not enough.

I seem to recall a quote, from Mike Thermos i believe, on the fact that with large shots and overly rich conditions that fuel wash can get so horrible that it will break rings!

Anytime you blow some Yuppy and his BEEMER, Acura or other piece of over priced, job stealing, foreign crap in the weeds you get a big dirt eat'n smile and that's priceless. While junor goes back to the salesman that told him how fast that thing was, sure it is right there in "Car and Driver". Sorry but "If you can't build it, you shouldn't be allowed to drive it."

Yeah, I just grin ear to ear.

Speak softly, drive nice and carry a big Chevy.

Bogie 

huh, that was a little off topic, was it directed to me, ???

Here is a combo I am helping a friend with, motor was not set up to run nitrous,(rings are gapped bigger for nitrous, but we have pushed our luck on 250 hp units before)-

Mild 460 BBC

Edlebrook 200HP Nitrous unit

Roller Crane Cam R-274 @.50- .737/.726, 274/284, 110 lc

12:1 comp.

Iron 990 heads

1050 Dominator

Powerglide with trans brake

5500 stall converter

4.11 rearend 17/33/15 slicks

@1800lbs w driver dragster

Runs in the 1/4-

8.76 with 42 total degrees total timing equals @ 529 rwhp

9.30 with 32 total degrees total timing equals @ 422 rwhp (we only need a 9.12 ET for corrected 8.90 index Super Comp class)

36 degrees is the recommended for a 200 hp nitrous unit. We played it safe and ran it at 32 total degrees, and since we knew what it ran on the motor with this timing, we could see the improvement. Ran 2 steps colder plugs. We rigged the unit to come on as soon as the trans brake is released, and the additional torque helped the car hook, and shifts are at 6800. 

8.27 with 32 total degrees total timing equals @ 629 rwhp

629 rwhp 8.27 run

422 rwhp 9.30 run

______

207 hp improvement

Based on our runs, it looks like it is as advertised. We run C14 race fuel without nitrous, C16 fuel with nitrous. We had some C14 in it when we tested it on a short first pass, and we shot small flames out the exhaust. We realized our mistake, drained and switched fuels.

Our goal is 8.12 index to move up to next class, the Super 'E' Class. All times are at 2700ft, and a corrected 8.12 is 7.90 ET's at a sea level track.

sounds like a awesome combo, but i may ask some explanation on this?

and we shot small flames out the exhaust. We realized our mistake, drained and switched fuels.