How to Modify / Tune your car - 2 - Nitrous Well GTO had put up a post on Modding and Tuning your car where he talked about modding the car in stages and what could be done and what not. I thought that I could add to that bit in this post where I would primarily focus on detailing the forced induction aspect of things before anything else. This thread will focus on nitrous, there is another thread for superchargers here.
There are enough and more options out there for going fast but what exactly is right for you and when is the biggest question. the next question is usually how far can you go and what does it take, I shall take these up in a few posts gradually in this thread and share as much information as I can. Shall be starting with Nitrous as the first option Nitrous:
One of the quickest approach to a fast car and a quicker approach to a blown(no reference to turbo's or superchargers here) car if not done right.
Nitrous is just packaged air to send more oxygen into your combustion chambers in a chemically stable form so that it does not explode outside your cylinders. More fuel and more air can help get more horsepower also lead to detonation (which is capable of destroying your engine)
So what does it take to run the right choice of a nitrous system on your vehicle?
Check the key parameters: Compression Ratio: 8:1 - 10:1 (Have not brought cc into consideration yet and prices are only indicative without import) - Lower the compression ratio more the effects of nitrous are obvious on a stock car
- Lower the compression ratio higher the nitrous shot (Shot: A measure of nitrous that is injected into an engine)
- Lower compression engines tend to handle dry shots(without additional fuel being injected) much better
- Higher the compression the lower the limit of nitrous used theoretically
Fine if that is the base minimum then what kind of nitrous system should I use: Types of nitrous systems- Single Nozzle - Dry Shot
- Can be suitable to any type of car
- Easier to fix and run
- Just about enough bang for the buck
- Prices typically start at $ 350
- Can handle 35 - 150 shot (rough translation into HP figures too)
- Typically comes with multiple jets
- Single Nozzle - Wet Shot
- Can be suitable to any type of car
- Needs additional plumbing for the fuel line
- Fuel Pressure Regulator reccomended
- Prices typically start at $ 450
- Can handle 50 - 150 shot (rough translation into HP figures too)
- Typically comes with multiple jets
- Once in a while race
- Do not try above 50hp on your own on a 1.5 ltr on and definitely not such a high shot on a lower capacity engine
- Plate Type - Dry and Wet
- Suitable to carburetted cars
- Needs additional plumbing for the fuel line
- Prices typically start at $ 350
- Can handle 50 - 300 shot (rough translation into HP figures too)
- Typically comes with multiple jets
- Race scenario only recommended
- Needs the hand of a good tuner
- Direct Port -Wet Shot
- Suitable to Fuel Injected cars
- Needs additional plumbing for the fuel line
- Fuel Pressure Regulator reccomended
- Prices typically start at $ 400
- Can handle 50 - 300 shot (rough translation into HP figures too)
- Typically comes with multiple jets
- Direct Port - Progressive Controllers
- If you race quite often
- Needs a good tuner
- Might need multiple sets of jets based on the controller used
- Costs start to skyrocket
Let me now start with the key points that can help destroy your engine before going further - Factory plugs - trust me they will blow out before you release that nitrous button
- RPM Trigger / WOT Trigger: Fire nitrous on a low revving engine on partial throttle and you are sure to blow it to heaven come
- Lean fuel mixtures: Nitrous use requires a lot more additional fuel else the knock of death is for sure
- Restrictive exhausts: Overheat your valves
- Ignition Timing: Needs to be retarted for nitrous use and not advanced
- NOS Bottles: would not blow your engine apart but your car instead if you do not use the forged aluminum bottles CO2 bottles are not direct replacements. It makes me jittery when people try to run NOS systems with cast iron bottles and then try to regulate heat by pouring water on it have seen a guy blow to smithereens while filling in helium in a co2 bottle, stay away
What are the mods that will benefit my car for nitrous use - Better intakes and exhaust
- Plugs with short ground straps
- Race Cams
- Porting and Polishing
- Fuel pump upgrade
- Additional Fuel Pump
- Forged parts - Pistons, Con Rods, Crank
- Aftermarket ignition controller especially for distributorless cars
- or a Good ECU - piggy back or stand alone
- A good clutch and drive train to transfer the power
- good tyres to grip and not spin out (look who's talking
) - A good tuner who knows what he/she is doing
Ok now you know the types of Nitrous systems and the risks out there, BUT how do I jet them???
Please be careful from this point on and I would never reccomend that you do this on your own - Jetting a nitrous system and fuelling is best left to the pro's as it depends on too many factors to list out here
- Jetting can never be copied from one car to another as it varies as per the mods / fuel / fuel pressure / ignition system / strength of the engine etc
- So go to your tuner and have him do it

I know this post may not have answered all your questions and I may not be able to do so in one go so I am taking the liberty to point you to some good material here
Have fun and be careful. Do not use nitrous on the street and be responsible drivers.
Last edited by Rehaan : 20th March 2009 at 12:52.
Reason: Superchargers link cross referenced.
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