I am by no means very knowledgeable when it comes to nitrous. So here's a few questions:
From my understanding it is foremost the shock of sudden increase in cylinder pressure when nitrous is engaged that takes a toll on the engine. Is that correct?
And could I decrease that shock by wiring in a nitrous controller for gradual engagement?
Would that make sense, or would it be a waste of money?
Currently I run a 100 shot wet with WOT switch, window switch and FPSS. I am a bit nervous about going any higher, but I would like to run a 150 shot if I can pull it off without major destruction down the road.

 

You pretty much have it; the other big advantage for a street car is traction. Drag radials + 150 shot + progressive controller = you can now spray sooner since you'll have traction. As long as you have enough fuel (and timing is stock), a 150 shot should not be a problem, progressive controller or not. With the progressive controller there will be less of a shock to the engine & rear.

Matt

 

^ is definatly right traction problems relly start to occur with a 150 shot my car has a 150tnt kit and my 275 nitto drag radials just cant handle it im getting mickey t's friday but as far as a progressive controler is concerned i would do it anyways it will help with the launch and cut down some 60' times. oh and go ahead and go with the 150 u wont be disappointed.

 

> could I decrease that shock by wiring in a nitrous controller for gradual engagement?

Gradual engagement is definitely a good thing.

In order to answer your question I have to go a bit into the fundimentals.

One problem with nitrous is it's a constant horsepower device. If you jet it for 100hp, it will make 100hp regardless of what RPM you use it at. Cylinder pressure is what causes detonation, and is also what causes load on the rings and bearings. Cylinder pressure is roughly proportional to torque. In theory it is proportional to torque, there's engine drag, timing, and fueling play a role which is why I'm saying "roughly".

Since torque = RPM * HP / 5252, a device that makes constant horsepower regardless of RPM inherantly makes torque as an inverse relationship to RPM. So 100HP is 175 ft/lbs @ 3000, 131 ft/lbs @ 4000, 105 ft/lbs @ 5000, and only 87 ft/lbs @ 6000. The bottom line here is a 100hp shot of nitrous is more torque / cylinder pressure (and therefore more "bad" for the motor) the lower the RPM you go. This is why the rule of thumb not to spray below 3000.


With that groundwork laid I can answer your question.

Different nitrous controllers operate with different goals. Most nitrous controllers adjust nitrous flow over time. The goal of these controllers is to limit nitrous flow at low vehicle speed, to help with traction. For example, a car with an automatic transmission, with a controller tuned to help keep traction would be a formidable opponent on the street. Some nitrous controllers however (the NX maximizer and maximizer II) control nitrous flow based on engine RPM rather than time. This is useful if your biggest concern is protecting the engine, rather than traction.

> Would that make sense, or would it be a waste of money?

The 2nd type of nitrous controller I mentioned is a very good use of money, if your goal is to protect your engine. Those controllers also have the ability to cut off the nitrous flow if your o2 sensor shows you going lean, which is also good protection. They will also cut off nitrous before your rev limiter, though you dont need a nitrous controller for that, a simple window switch will do.

> Currently I run a 100 shot wet with WOT switch, window switch and FPSS. I am a bit nervous about going any higher, but I would like to run a 150 shot if I can pull it off without major destruction down the road.

There are never any guarantees when you modify your engine to make more power than the factory designed it for. That said, if you are safely running 100 shot now you can probably do 150 safely with an rpm based controller.

Steve

 

from what I understand being a noob tho n2o the progressive controller would take the place of a window switch correct?

 

>from what I understand being a noob tho n2o the progressive controller would take the place of a window switch correct?

Yes, if your nitrous controller has RPM limits. The two I mentioned do.

 

Thanks Slart, that seems to make sense.
Now, a progressive controller controls the solenoids by pulsing them. Will the high frequency of on and off changes harm the solenoids?

 

Over time there will be more wear and tear on them. That's what Lifetime warranties are for.

Matt

 

how long will they last untill you need ot send them off and have gone threw?

 

It can vary with diffrent solenoids, Teflon plungers will last longer than a normal one. I used an NOS progressive with NOS cheater solenoids on my car for about 5 months and never had to rebuild them. I would just keep an eye on them to see how they are holding up.

 

does anyone make a 'failsafe' solenoid that will always stick closed if broke?

 

I'm not sure about other controllers but the NOS 15835B had 2 polls to hook your solenoids to, NOS 1 and NOS 2 NOS 2 did not pulse and was there to hook a saftey solenoid to in case the first solenoid leaked. The Part number for the saftey kit was 0050NOS but any nitrous solenoid will work as a saftey. Although you will probably have a slight loss in power due to the increased pressure drop from running another solenoid.

 

It will vary based on the brand of solenoid and how often it's used. Checking them out is real easy, and should be part of your regular maintenance schedule, progressive controller or not, it only takes 5 minutes to check them out. You could wire in a second solenoid as a safety if you wanted to on any brand controller, although depending on what brand solenoids you are using and if you are doing regular maintenance it's overkill, and like srsnow said, you'll get hit with a power loss with the nitrous traveling though a second solenoid.

Matt

 

my noids are NX how will they hold up to the controler you have matt? and can you pm me on how to check them out? rember if i sound dumb im still pretty new to nitrous and still learning.

 

They would be fine when being used with a progressive controller. For checking the solenoids pick up a solenoid wrench (they are $5, here's a LINK to one) as it will be a bit easer to disassemble the solenoid, but you don't need one. Take the nut off the top of the solenoid and pull the coil off of the tower. At the base of the solenoid tower will be two holes for the solenoid wrench. Using the wrench twist the tower off from the base of the solenoid. When you get the tower off the solenoid base you will have an O Ring that is on the solenoid base and a piston & spring inside the tower. Be careful so you don't loose anything and take a look at the seal that is on the end of the piston. You might see a slight indentation on the seal where it contacts the orifice on the base of the solenoid, but there shouldn't be any tears/rips, cracks, or junk on the seal. On the fuel solenoid when you check the seal on the piston make sure it is not swollen, basically that the seal is flush with the piston and not protruding from the piston. For reassembly just follow the steps backwards. Take your time doing it the first time and you shouldn't have any problems.

Matt

 

meatfoam
I have a progressive setup in my car and it rocks the house. much more controllable for traction and reduces stress on the shortblock. highly recomended. A simple 2 stage can also help.

 

I puchased the FJO Nitrous Controller for a good price and Ive been really happy with it. It has a window switch,WOT switch and a RPM based or Time based progressive mode inside it. It's kind of nice to have all these functions for the price on one controller, It makes for a neater install with less **** to wire up. and yes I think it does make sence if you have a stock bottom end like me.

 

the times based contorler will be a little easer on the bottom end to wont it?