XRT_si

iTrader: (2)

Right, bought my nitrous system second hand and looking to replace the jets for bigger ones to give 75bhp.

Here is the ratios Ive been given:


However are these correct of every nitrous kit (with the same fuel pressure and nitrous pressure)?

I ask as the jets that came out of the kit were .022 Nitrous jets and .018 fuel jets, which seem off ratio. I assume thats due to the particualr car they on beforehand but just want to check. It is a direct port fogger kit.

Cheers

105epwr

to be on the safer(ish) side i would put the slightly bigger fuel jet in
ie .003 nos jet and .024 fuel jet keep plenty of fuel there as the other way round you are looking at new pistons!
i had this prob on my old bmw e30 to the point of it pissing out black smoke as it had the biggest fuel jet in as the inlet track was long and i was getting det when i was using the kits data ratios.

vroooom ptssssh

Nitrous is a pain..

need to chill the bottle to fuck to get it full when filling, need to heat it with a bottle warmer to keep the pressure up when using, runs out often....blah blah

105epwr

it was alot of pissing about but it made a slow ol 320 bmw turn in to a monter with a flick of a button!

XRT_si

iTrader: (2)

Sounds like a good idea, does direct port make a difference to the size of jets over a standard one jet kit?

crazycage

i would think so mate as you will have 8 smaller jets instead of 2 bigger ones if that makes sense.

Rod-Tarry

Not so
I run direct port & 1 Nitrous & 1 Petrol jet at the Pulsoids. The injectors at the ports are all the same.
Ratio is about 3:1 to be safe, I use 4:1 cos thats where it makes most Power but unless your car is mapped with the gas its safer to run 3:1 or even 2:1 is recommended by the manufacturer, who dosnt want engine blow ups every week with people just fitting & squirting.

crazycage

ah yeah didnt think of that my bad.

TiB

iTrader: (1)

As Rod says... 3 nos / 1 fuel leanest 2 nos /1 fuel richest (it may start to miss slightly at this, if it does lean it off slightly)

Chip

iTrader: (3)

What fuel pressure are you running?

For some applications the nitrous jet actually needs to be smaller than the fuel jet.



When rod/tib refers to 2 or 3 times etc they are talking cross sectional area, not diameter, so you need to square the radius before applying that rule, as the jets they use are measured based on flow not diameter and flow is more or less directly related to the square of the diameter
(i say more or less, as velocity is included too and if the jet size get close to the pipe diameter you can see a velocity drop which results in slightly less flow, this wont be an issue at your level though)

Chip

iTrader: (3)

Depends on the kit, on a wizards kit like me and Rod use then no, on a crappy NOS or NX kit then yes.