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guys i want to get your advise, i have a car that i am gonna tune for dune climbing comptition. Engine is TB48 4.8L 6 cylinder engine, NA -10 low pressure pistons full strocker, car will be runing on pure methanol, what i am planning is to run about 500 to 700 hp shot of nos, i will tune the car on motec m800 ecu, what i am guessing is that the car might make 300whp without nos with nos it should reach about 800+whp. I plan to run the nitrous into 2 stages, 1st stage a single big wet foggor into the intake which is about 100 to 200 whp shot and the other stage is 6 foggers 1 in each cylinder about 75 hp in each fogger.
tell me what do you think about this setup and if there is anything i should take into account when tuning the car!
That all sounds reasonable. The only thing I'd be wary of is the split between your two nitrous stages. If you're planning on introducing a 450 hp shot then it's very possible you'll end up with the car breaking traction as that's a huge hit to add instantly. It may well work out just fine but I'd just be a little wary. You'll need to trim your ignition timing as you add nitrous. As a general rule you'll want to start by removing about 2 degrees per 50 hp nitrous shot. For my first test pull I'll then retard the timing an extra 2 degrees overall for safety. With methanol you should be relatively immune from knock. I'd also recommend you target similar lambda values when the nitrous is spraying to what you'd use on a turbo engine - 0.65-0.70 is a pretty good place to start.
Much of what I said in your nitro-methane post applies here as well - methanol is nasty stuff and you need to make sure ALL of your fuel system is compable with it or problems are guarenteed! This means everything - from the tank, pump, lines and fittings, regulator, injectors, anything else - EVERYTHING!
You also need to ensure your fuel setup can deal with the large volumes, at pressure, that you will need - roughly three times that of petrol/gasoline to be on the safe side. On volumes, you will need much larger diameter exhaust headers/manifolds for the gas volumes.
What is different is the way NO2 works - this is irrespective of rpm and is one of the leading reasons why it destroys engines. With normal engines power is a function of torque x rpm but with NOs torque is a function of power/rpm...
For simplicity, if you use, say, xxx power from NO2 at 8k rpm it will increase torque by yyy and cylinder pressures to produce that torque by zzz. if you use the same xxx of NO2 at 6k you will increase torque by a third to 4/3 yyy and cylinder pressure to 4/3 zzz. At 4k it will increase by 2zzz. You get the pattern?
This means that for your application the amount of NO2 will have to be carefully tailored to the minimum mechanical strength of your engine and at a rough estimate, you could be looking at peak cylinder pressures approaching 4 times what you have - you MUST make sure the engine can actually handle that sort of loading, and that the clutch/torque converter and transmission can also withstand that level or torque. Exhaust valves will take a hammering, so don't overlook them, either.
I have watched these sand climbs for some years and, from viewing them, I would expect the most dangerous condition, for you, would be if the vehicle starts to bog down - lose rpm - while still under NO2. this is a mixed blessing due to the NOs properties - as the rpm drops, the torque boost will increase proportially to counter this but it will also increase the load on the engine and transmission and so must also have some form of cut-off, probably at higher rpm than they switched on because the engine will be more highly stressed by that point.