What is the minimum RPM I need before activating my nitrous system?

[mrr23]

answers from the manufacturers:

Right off the starting line, (traction permitting) will give you the best ET due to the amount of torque produced. You should be at or above 2500 RPM and at wide-open throttle to eliminate the chances of a backfire.

The RPM level is not as important as is the motors ability to rev freely when the nitrous is engaged, I.E. If the vehicle is in low gear, nitrous can be engaged at any time, but if the vehicle is in a higher gear moving at a slow speed when the nitrous is engaged the engine will detonate and damage will occur.


At wide open throttle only (unless a progressive controller is used). Due to the tremendous amount of increased torque, you will generally find best results, traction permitting, at early activation. Nitrous can be safely applied above 2,500 RPM under full throttle conditions.

We recommend at least 2500rpm as a minimum for nitrous system activation. This ensures that you will not have excessive cylinder pressures that could cause engine damage.

[spike_africa]

I have sprayed as low as 2,600rpms with no problems at all backfire wise. Traction however was hard to come by as the low rpm you spray nitrous the more tourqe the motor will produce. I would say when at the track if you have sticky tires and good suspenion then it shouldnt be a problem otherwise its just going to blow the tires off liek mine does. Even with fat 275 nitto drags radials its pointless to go that low for me.

[mrr23]

yeah , this is an ongoing debate. most keep saying you'll have a backfire and blow up the motor if you go below 3000 rpms. i've sprayed 150hp at 1800 rpms before. my thoughts are, so long as the motor can handle it, then hit it. of course, expect to pay when you play. my only problem has been traction as well.

[spike_africa]

I wonder what kinda tourqe numbers you make at 150shot at those rpms it has to be 2 or 3 times what the shot would normaly produce over 3krpms.

[speedtweekerz]

alot of that has to do with the volumetric efficiency, vacuum levels and the style of delivery system, such as direct port or throttle body nozzle. but usually if everything is doing what it should be doing slightly off idle is fine

[n20_kid]

well they say you dont want to spray below 2500 - 3000 rpm, but if your tune up is right you can spray at low rpm's (if the motor will take it). i personally grab the button as soon as i deck it out of the hole on tires, and i have never had a problem with it except the rear end gear really dont like it to much (7.5 10 bolt)....

[kaya]

if your engine makes 300bhp at wot(say 6000rpm) and you have a single shot of 150 bhp nitrous adding it at 1500 rpm your engine is only making 75bhp(6000rpm/4), so pop goes the piston, but at 1500rpm you could add 37.5bhp at wot as your engine is already making 75bhp, progressive controllers are the way to go, unless that one legged english guy finishes perfecting the tap first!!

[mrr23]

guess i better stop hitting it at 1500 then.

[speedtweekerz]

personally i try to leave the line at higher than 1500 anyways, usually about 3000-4000 rpm depending on track conditions. because lets think about that for a second if you are making that much more power with nitrous that you have to leave off the line at 1500 rpm to keep from smoking the tires why even have the nitrous activate at that low of an rpm. even in an automatic car you should still be bringing the rpm's up on the converter. just my 2 cents!:D

[SadisticMystic]

I've sprayed my car at 2500 before, however I try and keep the revs above 3k before I hit the juice.

When I get a window switch I plan on setting the low limit to around 3200 and the high limit at about 6800. My car has Intake Manifold Runner Controls (keeps secondary intake valves closed down low for improved low end torque)so it kind of scares me to spray below 3250 rpm (when they open) for fear of puddling on the backside of the plates and then :eek:

[Ground Rat]

I sprayed a 4 banger rental car right off idle quite a few times with a compucar dry kit (street heat) and didn't have any problems. I went through about 20# beating on the car like that. That was with the second biggest jet in the kit too, I think it's about an 88hp shot.

[nxcoupe]

I don't want to give away too many secrets here, but I have data logged as low as 1800 on a launch with traction pulling the engine down. My car makes over 700 ft/lbs of torque at 3000 rpm's on the spray, so wouldn't you want to take advantage of that? The curve goes upwards from that rpm backwards, so just do the math.

[DefEddie]

I spray my 6000k lb all internally stock,200k mile truck with a 100hp wet shot from the hole everytime.I launch at about 1600rpm which is my brakestall on my convertor(flashstall 2500)
The only problem I've had is blowing the 20's off the line..

[gprunescaper2]

excellent thread!!!

[jmill98Z]

I don't even run a window switch. I stall it up on the footbrake to around 2500 and it's spraying as soon as I hit WOT. I haven't had a problem yet (knocks on wood) Companies say 3000 because it's safe. It covers their ass.

[Mike@HSW]

I don't even run a window switch. I stall it up on the footbrake to around 2500 and it's spraying as soon as I hit WOT. I haven't had a problem yet (knocks on wood) Companies say 3000 because it's safe. It covers their ass.


That is a good point. Lord knows if i told someone its ok to spray at 2500 and they break, ill be hearing about it along with a lot of posts made. Truth be told there is no lowest rpm range to give someone, its
entirely dependent on your motor and suspension setup. Even given that information i couldnt say for sure. your car maybe be running excessively rich down low, i tell you to spray at 2000 not knowing that and BANG your out a 1000 intake if not more

by the way, how the heck are you cutting 1.30's on a 2500 stall??? i need time slips.

[jmill98Z]

I didn't say it was a 2500 stall. That's just the point it starts to push past the breaks a little. It actually flashes up to about 4500 on the spray. Look in the alaska thread for a mid 1.3

[hammered54]

what do you think he should be runnig?

[Mike@HSW]

what do you think he should be runnig?

what do i think he should be running in relation to what? his 60's?

[hammered54]

what do i think he should be running in relation to what? his 60's?

you sounded like you did'nt think 1:30's where poss at that low of a leave.

[jmill98Z]

My setup is horrible right now. It goes pig rich up top (I'm slowly leaning it out), and I'm manually activating the second stage. Best run to date is 10.07

[Mike@HSW]

you sounded like you did'nt think 1:30's where poss at that low of a leave.

depends on your setup. there are **** loads of LSX cars out there making as much power as jeremy's if not more and could never touch his 60 ft times.

[jmill98Z]

I don't know why it works, but it does. I was racing a 67 Camaro with a 540....lots of **** talking back and forth...he cuts a 1.42 every time. We both left with real close R/T's, and I put a car on him immediatly. He swore I got the holeshot on him till I showed him the slip. He was so pissed he called Pheonix and asked why a car on radials out 60'd him by a tenth :D

Yeah, I lost that race due to an empty 2nd bottle, but gained alot of respect from him.

[RedMetal]

jmill, your car is sick (as if you haven't been told that before) but on to the topic at hand.

My car is a M6 with the factory 10bolt so obviously I can not leave the line hard. So to combat that problem I purchased a progressive controller to comand my dry system. It activates at 2400rpm and by 3400rpm is 100%

[Robert56]

Here's the real issue that everyone has forgot to mention. The lower we activate the bigger chance we have to hurt something. Why? Two things conspire against us, very, very high cylinder pressures and the fact that these cylinder pressures, or commonly known as the torque spike, stay there longer per revolution, the lower in the RPM band we are. That's why why dual stages and progressives can allow a larger total shot per set-up, they introduce some of the torque/spray at higher RPM where the chance of damage is less severe. The biggest reason that the manufacturer's rec a 3000/3500rpm as the activation is a blanket save their azz thing. Not all cars will get away with continually launching on the spray at off idle, just doesn't work that way. Now if we have a built dedicated race car, then getting the torque to the ground as soon as possible is the goal, no doubt. But if we are a street/stripper and need the car to get to work, then launching at a safer 3500rpm might be advisable. Like most things, knowledge is power, so if we have a plan, we can likely survive at what ever RPM we have chose to launch at. 680rwtq at 1800rpm with a stock short block, or 3500rpm, which would be wiser, or would it be even wiser to break that TQ spike up into a dual stage at 3500rpm and at 4500rpm? Only the end user can decide how far he is willing to push his combo. Myself, I do 5500rpm clutch dumps from hell and never see lower than about 4200/4500rpm through the run and thus can get away with a much larger hit.
Robert