nitrous surging

[screamin 99]

i sprayed my car today for the first time in about a year. i have a zex dry kit with a 100 shot. when it started spraying the first run it fell on its face at 3000 rpms (when it kicks in) and then surged in and out untill i let off. the second time it did ok but still surged the whole time. Any body had this problem? It is a full bottle with NO heater btw.

[97rs4life]

Re: nitrous surging

what psi were you spraying?

Spark plugs being used?

any fuel upgrades?

Did you try a 50 or 75 shot first?

[screamin 99]

Re: nitrous surging

what psi were you spraying?

Spark plugs being used?

any fuel upgrades?

Did you try a 50 or 75 shot first?

PSI- what ever a full ambient air temp bottle psi is.
Tr6 plugs
ls1 28# injectors, stock pump though, i have an msd inline i bought from someone brand new for $20 i need to put in
the last time i sprayed it i ran a 75 shot and it ran like a beast.

[97rs4life]

Re: nitrous surging

is the car tuned for the injectors? Get that fuel pump in there so you are not running out of fuel.
get a bottle heater on it and get your psi higher, you need the psi up to run consistently.

Is the bottle full or almost gone?

[screamin 99]

Re: nitrous surging

yes the car is tuned for the injectors. I was thinking low psi or fuel pump not keeping up. The bottle was full at the time.

[Shodown]

Re: nitrous surging

You're asking for trouble if you arent using a bottle heater and spraying without knowing your bottle pressure...

[kristen]

Re: nitrous surging

/\ deff agree.


how much nitrous did it use?

[screamin 99]

Re: nitrous surging

You're asking for trouble if you arent using a bottle heater and spraying without knowing your bottle pressure...

could you please explain why this is

[kristen]

Re: nitrous surging

everything about nitrous is about the bottles pressure. if you spraying and you don't know the pressure that is just stupid. say you have your bottle heater on. ok you have one with a built in thermo.....who's to say that the thermostat is working at that present time. you could have had your heater on for 10 min and taken you pressure up to 1300psi. in which case might as well just give me your wallet. you alway need to know your psi to know if things are working right. what if your bottle isn't open and you hit wot...you just dumped fuel with no nitrous into your system etc....so many things can go wrong. spend 50 bucks and get the gauge that just mounts onto the bottle.

[RadRacer]

Re: nitrous surging

You guys are missing the part where he said it's a dry kit. Bottle pressure is still important, but it's not as big of a factor for a dry kit since the fuel is added via the MAF reading. If the pressure is low, the shot will be lower and the MAF will call for less fuel than a normal shot. If it ran good on the 75 shot, but not on the 100 shot, I'd say your injectors need to be upgraded. I'm running lS1 injectors too; on our fuel pressure they're really about 25.5-26. My car's mods should be about the same as a 75 shot; my injector duty cycle is 87%. That 100 shot put it over the top and the injectors can't handle it. Looks like it's time for some GTP 36#ers :)

[Shodown]

Re: nitrous surging

You guys are missing the part where he said it's a dry kit.

I knew full well that he is running a dry kit, but my statement still stands.

[screamin 99]

Re: nitrous surging

I knew full well that he is running a dry kit, but my statement still stands.

but still no explanation. from what i understood, low bottle pressure with a dry dry kit just meant the hit wouldn't be as hard. What did i risk by running low psi?

[RadRacer]

Re: nitrous surging

but still no explanation. from what i understood, low bottle pressure with a dry dry kit just meant the hit wouldn't be as hard.

Exactly. To be consistent, you will need a bottle heater, but if you don't mind the fact that you'll be spraying less each time, then go for it. Since the fuel is added via the MAF, you don't have to worry about running rich because of low pressure. With a wet kit, you spray both fuel and nitrous, so if your nitrous pressure drops, the fuel pressure will stay the same and you'll run rich. I'd go for a bigger set of injectors like I said before. Only thing that makes sense right now to me.

[97rs4life]

Re: nitrous surging

do you have hptuners to monitor what is happening at this point? We are just taking stabs in the dark if we don't know what the pcm is seeing.

[screamin 99]

Re: nitrous surging

no hp tuners. pcmforless tune. It is supposed to be tuned for nitrous so i am hoping they pulled some timing but that didnt seem to be the issue. I do have access to a scanner that i can check injector duty cycle. i am going to the track tonight for test and tune and im starting with a 75 shot to see how she does. i really think the problem was terribly low bottle pressure. The bottle was full but it was 67 degrees out that day according to nitroussupply.com that would be just shy of 760 psi.