Hello, I'm new to the group. This seems like a really good newsgroup. I have
a P11 Primera GT '97 and am in the process of preparing it for a NOS
modification, clutch, brakes, manifold, exhaust etc. I'm just interested if
anyone here has direct experience of fitting a nitrous system on a road car
and if there are any bits of advice they might give prior to me having (or
doing, not decided yet) the modification.

TIA,
John

"Johnny" <repro007 (AT) hotmail (DOT) com> wrote


Just a little!!!
My site.
www.nitrous.info

--

www.optimabattery.co.uk
www.burgerman.info
www.fatnfast.com/robot

"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote

posting on here )))

I'm in South Yorkshire and I've been looking at getting the kit done by
these folks..
www.noswizard.com
They seem a little bit pricey but look to have some good kit. I spoke to one
of there guys on the phone and he said best/cheapest option is to buy the
kit, fit it and then have them test it.

"Johnny" <repro007 (AT) hotmail (DOT) com> wrote

Yep, trev knows what hes doing...
Talk to him often.

I would do it all myself but it depends on your abilities?

"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote

I admit my background knowledge is limited). My brother has master mechanic
qualifications and has much more in depth knowledge about engines and
systems, his day job is fixing cars. I'm still reading your site BTW,
chances are I'll end up having a go myself (with a little help). A mate of
mine is wanting to do the same to his Audi 80 coupe, that's got a 2.2L 5
cylinder Quattro engine and goes like stink already.

"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote

physically done in a controlled manner, is it just fired into the plenum
chamber with extra fuel feed once activated? Wouldn't they need to be
progressively linked to the engine RPM. How will this affect the ECU engine
and fuel management system which constantly monitors and adjusts, many times
a second, the standard fuel injection on this car. How can it ensure equal
distribution to all cylinders? The injectors fire the normal fuel supply
straight into the void above the cylinder inlet ports and not into the low
pressure plenum chamber reservoir. Will this affect the fuel/engine
management sensors once the nitrous mixture starts to be drawn into the mix?
The other thing that I can't quite figure is how the rising engine rpm and
subsequent increased air flow through this chamber which will affect the
n20/extra fuel/air ratio, can maintain the power increase with a fixed
n2o/extra fuel supply (Is it a progressive delivery?) and vastly more air,
wouldn't the n2o component be greatly reduced at higher rpm. Sorry if these
are daft questions.

Johnny wrote:
You can do progressive control, see the bottom of this reply. OTOH, you can
just cram in 50 horses (controlled by the size of the jet, you'd just open
the solenoid valve to let the flow through) of nitrous at say, 4000 revs and
get the power + torque lines instantly lifted up the graph.

How do you think SPI rather than MPI injection works? Assuming all your
pistons are managing to pull in similar amounts of air / fuel, they should
get similar amounts of laughing gas.

I'm pretty sure Burgerman covers progressive control through PWM (pulse
width modulation) of the fuel / gas solenoids. I read the old version of the
site, so I couldn't tell you where to look on the new one. PWM control would
look something like this for say, 66% of full power, pulses of on on off, on
on off, or off off on for 33%. With progressive control you'd be able to get
some boost from nitrous at lower revs without so much fear of turning your
engine's internals into shite from trying to transmit masses of torque.

"Doki" <doki (AT) spamtroNspidar (DOT) com> wrote

"Johnny" <repro007 (AT) hotmail (DOT) com> wrote

Yes. Constant nitrous, and constant fuel flow in a basic system.
You can do this progressively, via a pulsed controller based on time and/or
rpm.


No.

At WOT conditions it resorts to a fuel "map". No closed loop system is
used.
Even if it is you would simply jet it with the correct fuel for full power
whatever the engines own fuel system does.


How can it ensure equal

Because the nitrous is EXTREMELY effective in atomising the fuel as it
enters the motor into a fine fog of nitrous and fuel. It does this at the
trhottle body. From here each cylinder in turn draws in its own volume.

Actually since each one draws in a slightly different amount due to
manifold/cam/port/valve differences it is actually a more precise method
than ionjecting the "right" amount in the normal way per cylinder.



No.

It doesnt. Its a fixed x value regardless of rpm.


can maintain the power increase with a fixed
Of course.
Thats why it makes say 40 bhp at 2000 rpm and the same 40 extra at 6000 rpm




www.nitrous.info

"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote

the engines increasing RPM to match the increasing air flow being drawn
through the plenum chamber by the cylinders then the ratio of n2o/extra fuel
to air (in the chamber) must drop, it can't possibly be same can it? The
only constants are the internal dimensions of the chamber and the n2o/extra
fuel supply when on. The speed and therefore volume of the air stream it's
being injected and atomised into per unit time is constantly changing with
engine rpm. Much more air is being drawn through the chamber at higher RPM.
If the n2o/extrafuel supply doesn't increase to maintain the ratio then as
engine rpm increases the nitrous ratio per unit volume of air passing
through the plenum chamber will decrease. This is what i'm trying to
understand and trying to say in my usual cryptic way. Unless the nitrous
system is only ever on at a fixed engine rpm and thus fixed volume of air
per unit time.