McPikie

Someone on aother site:

"Mcpikie, i could quite happily run a cossie at 500bhp on gas with a set of yellow injectors, as the nitrous kit provides the fuel it needs anyway.
The pump would need to be up to flowing enough though obviously.

FRP wouldnt need changing it would remain the same."

Erm, i'm kinda of the opinion this is bullshit, your advice lads??

Cossiep

Correct.......... Nos kits pump in gas AND fuel, so in theory it works

Stu @ M Developments

iTrader: (12)

Technically that is correct, providing he is just talking about the capabilities of the fuel system and not the head and turbo etc etc...

McPikie

But i thought yellows give up at 280-ish stu?? surely then there wouldnt be enough fuel to run it?

Phil

iTrader: (1)

Nothing up with what he said at all.

Phil

iTrader: (1)

Nitrous runs its own fuel injectors.

McPikie

so you dont need petrol when running nos?

U could, in theory, fuel it with nos alone??

Stu @ M Developments

iTrader: (12)

With Nos kits you run 2 jets.

1 for fuel
1 for nos

You balance the 2 jets so they can add their own correct mixture on top of your engine basic standalone settings. So on 280bhp cossie he would technically require a 220bhp shot of nos.

Ian2wdsaffcos

How about an RS500 running 8 yellows

Phil

iTrader: (1)

No, nitrous is just compressed oxygen basically (with some nitrogen in it!) And it burns a lot more efficiently than normal air. But as it is only oxygen it still needs a propellant to make it burn! The point is that it has its own fuel injector that comes on with the nitrous, therefore no extra fuelling is required from the normal injectors.

Or if you are Sean Bicknell, you can go one step futher and map the nitrous fuelling into the normal injectors!

Jim Galbally

as per stu... the extra fuel required is supplied by the nitrous kit, it pumps in nitrous AND fuel

very simple. you just T off of the std fuel feed hose and this runs to the nitrous pulsoid, which when activated will open and allow the extra fuel required to flow thru into the crossfire injector (via a jet which is just a "thing" with a hole in it, depending on what size hole you use depends on how much fuel can flow)

but getting a std cossie up to 500bhp with JUST nitrous... erm... very doubtfull

RWD_cossie_wil

iTrader: (9)

how does direct port nitrous work then?? does it have a single jet for nos and fuel on each cylinder?

Stu @ M Developments

iTrader: (12)

Correct.

RWD_cossie_wil

iTrader: (9)

I take it you would need to run a separate fuel pump for direct port?

alistair

nope, just a separate injector.

Jim Galbally

the feed will come from the same place that it would on a single/normal system it just runs into a distribution block which seperates it to each injector

so you have 1 pulsoid, 1 jet and then a single line going into a distribution block with 5 holes on it (4 o/p one 1 i/p) and each output receives 1/4 of the total extra fuel.

direct port isnt really THAT much extra complication, you just have to drill a lot more holes and get some distribution blocks (glorified T peices)

nitrous is SO simple its unreal!

RWD_cossie_wil

iTrader: (9)

how big are the jets for fuel and nos then?? would the two of them fit inside a standard size injector hole on a cossie manifold?

Jim Galbally

theyre not big on the direct port things, i'd say about 3mm holes? (going from memory)

steve/rapid1 tried direct port a while back (switched back to normal in the end) and it all fitted fine on his std plenum... (4inj)

RWD_cossie_wil

iTrader: (9)

cos I got a WRC 8 injector manifold that I am only gonna use 4 injectors in, just wondering if I could machine some blocks up with 2 jets in to sit in the spare injector holes to keep it all tidy

Jim Galbally

or sell the 8inj plenum for a tidy sum and buy a standard one + some more bling bits

RWD_cossie_wil

iTrader: (9)

but surley that would be a better option than chopping a 2wd manifold about to fit it? only thing I having next is an R&B inlet plenum cover

Jim Galbally

not really... id have thought it'd be easier just to drill 8 little holes in a std plenum to be honest! lol

altho IIRC steves were in the inlet manifold itself (now i think about it) as its closer to the head therefore better. i think they were in the runners (that what they called? the individual tubes)

Anonymous

I use Direct port 4 cross fire injectors which combine the Fuel/Nitrous drilled into the bottom of my inlet manifold (M10 thread) Works well & much better than a one shot system. The Nitrous Fuel ratio is controlled by changing the jets in the Fuel & Nitrous Pulsoids. Ratio best set on rolling road or Lambda check on road. The Factory settings are set very rich for safety reasons & lots more Power can be found if set-up correctly.
Rod

RWD_cossie_wil

iTrader: (9)

do they spray stright into the bellmouths inside the plenum rod? And how much are you looking at for a kit/set-up like that?

Jim Galbally

if you use 4 crossfire injectors thats not quite the same as the "conventional" setup, which uses 8 normal/little ones.

i woulda thought 4 Xfires would work better tho

Jim Galbally

as for the AFR check, you'd need non-std equipment to do that as the nitrous content in the exhaust gas confuses your normal lambda readings... makes it read rich when it aint. i beleive you can buy special (and VERY expensive) equipment which means you can get round this tho...

a few rolling roads have blown up nosed engines that way.... thinking its rich when its not so leaning it off till it goes pop

just a little unrelated bit of info for you there... lol

Anonymous

Yes!!
Its a standard wizard of Nos Streetblaster system with a Direct port Nitrous upgrade, which included bigger pipes etc. Despite what is claimed a sustained 100bhp is absolutely max with a Single shot system.
Complete with a progressive controller i expect cost is in the 900/1000 region. Allows upto a 200bhp shot capability . Only tried 130 shot so far , but will use much more when we return to Brunters in the new year.

Sean Bicknell

I don't totally agree with the answers that have been given to this question. Yes you can just 'T' off the standard fuel system, but that isn't a great idea in my opinion because:

Direct port NOS is usually chosen when you are injecting a large amount of Nitrous, say 150BHP upwards.

So you throw in your 150BHP NOS jets, but there is no way to get the fuel jets correct as the standard cossie fuel system has a rising fuel pressure.

For example at 0 bar boost we are running say 3 bar fuel pressure. But at 2 bar boost we are running 5 bar fuel pressure. We can't change the delivery pressure of the NOS as the fuel pressure rises, so we end up with a rich mixture at full boost or a lean mixture at anything less than full boost (this is why standard kits are normally rich on boost as they are compensating for off boost mixture).

It isn't to much of a problem on say a 50BHP single fogger setup, but the problem gets explanentially worse as you raise the BHP of NOS that you want to inject.

Brom and I have gone for a seperate fuel pump and seperate regulator for the NOS. The other beauty of this system is you can very acuratly adjust the NOS / Fuel ratio by tweaking the fuel pressure of the NOS fuel system.

Sean..

Jim Galbally

i disagree with you there sean (but if im wrong sum1 please correct me as i'm curious to know)

the reason the fuel pressure changes is becasue the pressure being forced upon the std injector is high, so we increase the pressure of the fuel to equal out the difference. that way the pressure differential at the ijector tip always stays constant nomatter what boost/vacuum we're running.

the same thing would be occuring to the nitrous fuel jet, it is having boost thrown against it, so we would also want the fuel pressure increased to compensate. if we did not then we would be running less extra fuel at high boost than not on high boost, hence making the system LEANER as the boost increases.

also if youre using a seperate regulator for yours, then the fuelpressure is also increasing in this seperate fuel system (that is ofcourse if it is a rising rate reg) so youve got the same thing you get on the std system

Anonymous

Jim
My car is checked by Mark Shead who has all the correct equipment on the RR its no different & my RR man does loads of Nitrous cars with no probs.
It sounds as if you have listened to Trev who is altra cautious on such matters to protect his system from the 'Nova' boys & runs his systems very rich. Believe me 200mph finds out the correctly set-up Nitrous systems .

RWD_cossie_wil

iTrader: (9)

top answer shaun

RWD_cossie_wil

iTrader: (9)

I am assuming that nitrous in these instances is only used at full throttle, so boost levels should be fairly constant? hence negating the need for rising rate fuel pressure?

Jim Galbally

nitrous IS only used on full throttle...

but boost stil varies at full throttle depending on lag and mapping etc.

rod, i dont doubt your install, im not picking holes, but i stand by what i said. on "normal" afr gear it WILL read rich, the laws of chemistry/physics/whatever dictate that! the sensor/reader needs to be able to adjust for this

also saying 200mph finds out if its set up correctly is a bit of a dodgy statement to make... why does a car doing 200mph show if a nitrous setup is correct or not? it could still be running rich/lean and pull 200mph...

foreigneRS

top answer jim - the mass flow through a restriction is proportional to the pressure difference across it.

Sean Bicknell

On a large turbo car, between gears for example, when you floor the throttle in the next gear the engine isn't instantly on full boost.

Say you are throwing in 150BHP of NOS and you have set the mixture to be correct at full bosst, say 2.2bar. As soon as you hit full throttle after the gear change and the turbo is rising from a vacuum and climbing through boost for a few seconds before reaching full boost you are only throwing in enough fuel for say 50bhp of NOS but all the time throwing in the full 150BHP of NOS.

As i said this problem gets explanentially worse as you increase the amount of NOS you want to run. On a 50 - 75BHP single fogger type system, it would not really be an issue.

Sean..

Anonymous

Lets just say that my system works Sean & ive not adopted your method.

Sean Bicknell

I agree with what you say Jim, but the boost pressure is also pushing back on the NOS jet by the same degree, but we are not increasing the NOS delivery pressure to compensate.

And no the regulator on the NOS fuel line is not a rising rate regulator it is static, but still adjustable to make fine tweeks.

Sean..

Jim Galbally

sean, good answer, explains it perfectly for me

do you in that case sean run a non-rising rate reg for the nitrous fuel system?

Sean Bicknell

I'm not knocking your car at all Rod, its a complete weapon. Just giving my opinion on a different method.

Sean..

Sean Bicknell

Yeah Jim, the reg on the NOS line runs at a static pressure, but is adjustable to make fine AFR tweeks to the NOS system without changing the jets.

Sean..