Nitrous with Turbochargers:
Using Nitrous Oxide with a turbocharged engine. Why & how it works.
Nitrous Oxide and Turbochargers
would you want to, or need to?
There are lots of very good reasons for adding
Nitrous Oxide Injection to a turbo car or to a turbo
Apart from more power, how would you like
BOOST at any RPM? Maximum power from the second you push the
pedal? No waiting just go.
Just to get more power you can, even with a small
road car sized turbo, usually turn up the boost to a degree to get a little more
but the problem is that there will still be that bit at low revs where there is
no boost and you wait. Its called lag and its horrible.
If you want really big power you need to fit a
bigger turbo, as a small one that boosts at sensible revs is very restrictive
and inefficient at high power outputs. It kind of gets in its own way!
Now you have an even bigger hole at the bottom end
and even more horrible lag. Nitrous can completely eliminate this. I mean gone!
Completely! Full boost from the moment you floor it.
You fit it because:
Because it totally removes all turbo lag -
completely! Full power/boost from idle RPM's upwards! Stand
on the gas and GO! The nitrous initially provides the go,
but this makes a lot of exhaust gas that spins the turbo up
fast! Sudden boost too! from almost no revs.
Because if used as a "turbo lag remover" the nitrous is
automatically turned off as soon as boost is achieved via a manifold
pressure switch, so the bottle lasts AGES!
Because PEAK power can be drastically improved - if used
normally (on all the time @ full throttle) rather than just to eliminate
the turbo lag.
Because the charge cooling effect gives a measure of safety
and prevents detonation, meaning higher turbo boost
pressures can be used.
Because it means a much bigger turbo can be used! The
turbo is the limiting factor for higher power outputs since
if its small enough to come on boost at say 3000 rpm, it is
already restrictive in size at full power... See number 1
MORE power than expected is usually obtained on turbocharged
vehicles, because it also improves charge density, and boost
levels at the same time.
Because its easy to fit! Your fuel injected car already has
the required 3 port regulator for the fuel, and its a simple
matter of tapping into this fuel line and fitting a
nitrous/fuel injector AFTER the intercooler and preferably
as soon after the throttle body as possible. This way the
correct psi above intake pressure is already taken care of by the existing fuel
For option 1 to work as a boost
lag elimination device you need to also fit a simple
pressure switch, (a cheap one would be an old oil pressure type
switch), that switches the Nitrous off as soon as it sees say
2/3 of your normal boost level. Say 8 to 10 PSI.
In short - Turbo cars and bikes
are crying out for Nitrous Oxide! It improves them in all
the areas that they are weak. Gives the same effect as
simply having a larger engine!
Injected & Intercooled or Road going Fuel Injected Turbo Cars
Most of the above will be running 3 bar (3 bar above
manifold pressure or whatever the manufacturer chose) fuel pressure to the injectors. Because
the fuel pressure on these types of systems is regulated to
be 3 bar or 45 PSI above the manifold pressure you can just
fit the system as if it was not a turbo car or bike. You
will automatically get an increase in fuel pressure as the
Turbos boost level increases. So at 1 bar boost you will
actually have 4 bar of pressure in the fuel system.
This is because of the use of a compensated 3 port
as standard. So unless its been modified by increasing fuel
pressure to suit other tuning work, jet as for a stock 3 bar or whatever your
car is set to
fuel system. Start with small power levels!
Blow through carb
systems - some bikes, early turbo cars, aftermarket
conversions, metro turbos...
These are a little
strange and usually a bit overly complex as even the
manufacturers ones were a bit on the "bodged" together side!
But basically they all used a carb with as float, that
needed feeding with fuel at around 3 to 5 PSI pressure ABOVE
manifold pressure. Because for the carb to work properly its
float bowl must be at the same pressure as the inlet
manifold. The float chambers breather pipe is connected to
the inlet manifold. Now for the fuel to feed into the carb
at the correct 3 to 5 PSI above this boost pressure they too
must use a high pressure pump, and a 3 port
This COULD be used to feed your nitrous systems fuel supply
too since it maintains a few PSI above Boost level at all
times. But only for small amounts of Nitrous. For larger
doses its unlikely that the pump fitted will have enough
So in this case you will need a
pump capable of enough flow @ max boost pressure, plus the
pressure you choose to run your nitrous enrichment fuel at.
For e.g., You need 1 BAR boost, (15PSI) plus say 10PSI working
pressure plus 10 percent at least. And a 3 port regulator,
set to 10PSI and connected to the inlet tract after the
Draw Through and
obviously Non Intercooled Applications - Mr Turbo systems on
bikes, all out race vehicles, home designed systems etc.
Treat these as a simple
carb low pressure system if the point of injection is after
the carb, before the turbo! Easiest, and it works fine. Use
simple pump /
regulator, or gravity feed fuel.
If its to be injected after the
turbo, then you will need to arrange your setup as for a
blow through system with compensated
the term NOS is incorrect as this refers to an specific
company (called Nitrous Oxide Systems, in the US)