Nitrous

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xThunderbirdSCx

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I just read the SC nitrous FAQ, and decided my next project over the winter is to install a nitrous kit in my car. Heres my deal. Soon i will have a head gasket rebuild, and a better, free flowing cat back exhaust on my car. Everything else is stock. Will i need to upgrade my stock 89 injectors or fuel pump to run a 100HP shot? If the answer is yes, what about a 75Hp shot? What do you guys recommend? Also, where would you recommend i rather drill and install the fogger nozzle: in the upper IC tube (with the lettering), or the lower IC tube?
 
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Generally, the nozzle is installed after the IC, in the lower tube or the return plenum; some put it after the ACT sensor, and some before it.

If installed before the ACT, the computer will read in the cooler temp and advance timing accordingly.

If after the sensor, the cooling effect will be ignored by the computer, so timing will be left the same.

Keep in mind you'll generally want to retard 2 degrees of timing per 50 HP N2O... Some have talked about removing the octane plug, which retards the timing 4 degrees.


Now as for 100HP shot... :confused: :confused: :confused:
I know Dave Neibert gets almost exactly 100 HP form his wet kit, and he hasn't been jumping up and down to raise the bar; and he had a built bottom end with hbeams and custom forged pistons, etc etc. So i would say stick with 75 max on the stock bottom end. Some may disagree, and I know XR7Dave hit about 450 HP on a stock bottom end with an AR screw compressor and alky injection, but keep in mind, he is the tuning master ;) And I think N2O is more of a shock to the engine than the "cooler boost" of the AR and alky...


I started with the dry 5.0 mustang kit, and after I realized one of the solenoids was stuck opened, I called NOS systems and on two occasions they told me that the dry kit was not a good idea. The dry system taps into a vaccum line for the fuel pressure regulator, where the extra pressure provides more fuel.

Well in our cars, this is how the blower richens the mixture to compensate for more boost, so since the blower, especialy if overdriven, and with a lower pressure fuel pump, we are already near maxing out the injectors.. Which is why NOS systems doesn't recommend it.

That being said, the ZEX dry setup is being used by some folks here, more notably, fastsc92 has the zex kits, and with all his mods, he is running 12.7 ets with the dry 75HP zex kit. However, he has larger injectors, fuel pump, and knows how to tune his car with eec or sct tuner, and also monitors with a wideband 02 meter.

You must also be aware that supercharged applications tend to amplify the effects of N2O, and of course each car will be differnt, but the NOS Systems guy told me something like a 75 shot may actually provide 100HP or more. So they recommend smaller shots. Probably a liberal estimate but he probably wanted me to err on the side of not blowing the motor up...

They also gave me some jet sizes for the wet kit, which I have written down, but I would suggest you call them, and see what they say, then we'll compare notes. I say this because the 2 different guys I spoke with gave me two different size suggestions...

The biggest concern is that the correct N20 and fuel jets are used with each other. A certain size N2O jet will work with a certain size fuel jet, to keep a safe A/F ratio. So, so long as the car is well in tune w/o the nitrous, if the correct jet sizes are used, the A/F ratio will be good to go. But its a gamble if not using a wideband meter...

Not sure if that article you read covered this, but lots of folks think its just the cold that gives the HP, but the N2O actually releases "extra" oxygen during the combustion process, which must be accompanied by more fuel. So I would certainly suggest an 02 meter; and if possible, a wideband 02 meter to keep from going lean!

Off the top of my head, I know that fastsc92 (12.7ish), and Dave Neibert (11.6ish) both use the juice with great results! fastsc92 the dry zex, and Dave the NOS Systems wet kit.

I'd do some searching, an pay particular attention to their input.

You'll also want to look into safety devices, such as fuel pressure safety switch, and RPM window switch, and even using dual N20 solenoids for safety. If a N2O solenoid sticks open, then the motor will most likely be blown... If the fuel solenoid sticks open, there could be a BAD backfire. If the bottle get empty, you could get a backfire, and you can image other combinations of solenoids sticking open or closed can be bad!

I am now thinking of using dual solenoids for both fuel and N2O, a little more expensive, but I'd HATE to lose and engine due to a bad solenoid...

If you mess up with the N20, it can be dangerous! Which is why not many use it, and alot of those that do blow stuff up. But if done correctly, it is of couse the cheapest HP money can buy...

All that said, do your own research to make sure you are comfortable with your decisions, and don't pay too much attention to me, cuz I aint had a chance to hit the juice yet :eek: My car is all over the garage and driveway right now getting a built-up engine, upgraded brakes, etc, etc...

Oh, one more thought, I'd really stay away from a used kit, the one I bought used had a bad stianless line, and a bad solenoid... I'd pay for a new kit if I had to do it again... You don't want a crusty ole solenoid sticking on ya!

Good luck!
 
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i didn't read all that, nor do I have any experience with n20, but I wouldn't run more than a 50shot on 30# injectors. Nor would I run more than that without it being dyno tuned.
 
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