nitrous jetting

[-EpicEVO-]

K so i have be running a .42 n20 jet and a .25 fuel jet.

I am thinking about changing these to a .52 n20 jet and a .35 fuel jet..

The question is will the afr change by just allowing more fuel and more n20 in??

By bumping the jets up evenly will it work right?? Is this how your suppose to change jets??

MARK

[DlandryTSI]

How much boost are you planning on running with it?

--Dave

[-EpicEVO-]

20 psi.. 110octane

[-EpicEVO-]

2-3 psi less than before...


How much boost are you planning on running with it?

--Dave

[SpdJunkie]

no, nitrous jets dont work like that. Running a 52 nitrous jet will see you running real rich. Here is a pretty good list of what you can expect from jets...http://ls1tech.com/forums/showthread.php?t=441077 Hope its okay to to refer to other forums around here... ;) I was running a 62 nitrous jet with a 33 fuel jet and still hit below 9.5:1 AFR on my TA.

[v413nc3]

Actually it does work the way he's thinking, and the thread you directed to is a lot of information about DRY jetting with DUAL jets :)

If you scale them close to each other like you are thinking you should get a close equal scaling, but you should ALWAYS check on the wideband and log knock of course.

[SpdJunkie]

'Dry' jetting? Not familiar with that term.

[Hal]

Dry system inject only n2o and rely on the oem fuel system to supply the required fuel.

dry = n2o only via the foggers
wet = n2o & fuel via the foggers

[sbiggi]

Dry = no nitrous back fires

[Hal]

Wrong.

Dry still puts n2o into the manifold and the injectors still put fuel into the head on the runner side of the valve.

So, you still have an explosive mixture.

Putting n2o alone into the manifold, combined with the fuel delivered from the injectors while starting the car is more than enough to cause a nitrous backfire.

Dry systems do not protect you from a nitrous backfire.

[SpdJunkie]

Okay, so i know the difference between a wet kit and a dry kit just never heard of it referred to as 'dry' jetting. anyways, v413nc3, if you refer to that forum that i linked to; it has both dry and wet kit jet sizes. That is just a conglomeration of most of the major kit makers' jet recommendations for certain horsepower increases. It has both dry and wet sizes.

[Hal]

Jetting for fuel needs to account for fuel pressure.

60 psi of fuel in a normally aspirated car is a LOT more fuel than 60 psi in a turbo dsm.

[SpdJunkie]

Doesnt that totally depend on the size of injectors that you are running? e.g. higher fuel pressure, smaller injectors and lower fuel pressure, larger injectors. Up to a certain point at which the pindle(?) in the fuel injector cannot open anymore due to excessive fuel pressure.

[Hal]

Sure, injector flow rate matters, so does pulse width.

The point is that different jets are used to make the same hp level depending on the base fuel pressure of the system.

[sbiggi]

Dry kits are about as likely to back fire as with out any nitrous at all. The fuel mixture would have been there anyways.