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Discussion Starter · #1 ·
I have a question regarding purge a nitrous system on a 05 m6...i'm having a shop install the NOs plate kit with 100 shot and window switch. The guy doing the install said purge is not really needed, you can have the bottle on in the waterbox and purge it there by blipping the gas...Does this sound ok?...i've done some searching and it seems the purge is used to get the air out of the system and the car could bog down if it's not purged? Is this correct? also is there more risk of a nitroous backfire if there is air in the system?

Thanks for the help, I'm new to the bottle...
 

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thanks, how would you do it? Leave it in neutral and get the revs above 3k?
huh?

your kit should come with a purge, if not get one. all you have to do is push the button and it is purged. you dont want to spray your motor in neutral. if the shop is saying to purge like that and you dont need a purge i wouldnt mess with them.
 

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Discussion Starter · #5 ·
huh?

your kit should come with a purge, if not get one. all you have to do is push the button and it is purged. you dont want to spray your motor in neutral. if the shop is saying to purge like that and you dont need a purge i wouldnt mess with them.

The way he explained it was that it automatically sprays between 3k and 6k, so wouldn't you just leave it in Neutral and rev it so it sprays the air through so it wouldn't bog when you launch?

Sorry if this sounds stoopid , I didn't really understand what the the guy said about purging in the waterbox, I will try to get him to clarify it. The car is not finished yet, maybe I will just have him add the purge.
 

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I do not purge and this is why.

Instead of having to wait until 3,000 to get a full 100 shot hit why not skip the purge and bring it on earlier. It also gives a smoother transition instead of the WHAM all the sudden.

If you run a wet system there will be fuel before NOS but that is a good thing. I doubt it would be too rich to notice and the fuel would be there when the NOS comes through.

If you run dry like me there is a smooth transition that only takes half a second to be full on and it gives the MAF time to see it coming.

I go NOS on the instant the peddle hits the floor instead of having to wait.
 

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Buy a Hybrid. I Need Your Gas
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The way he explained it was that it automatically sprays between 3k and 6k, so wouldn't you just leave it in Neutral and rev it so it sprays the air through so it wouldn't bog when you launch?

Sorry if this sounds stoopid , I didn't really understand what the the guy said about purging in the waterbox, I will try to get him to clarify it. The car is not finished yet, maybe I will just have him add the purge.
If you're hitting it in the water box you're almost guaranteed a blown motor because you'll slam the rev limiter to all hell.

Do NOT spray in neutral - it only takes a couple of seconds to redline at WOT in neutral N/A, why would you want to spray at the same time and risk blowing your motor up.

Either get a purge kit and do it the right way, or just spray without purging it.
 

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Buy a Hybrid. I Need Your Gas
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I do not purge and this is why.

Instead of having to wait until 3,000 to get a full 100 shot hit why not skip the purge and bring it on earlier. It also gives a smoother transition instead of the WHAM all the sudden.
What happens if you make 2 runs in a row, the system is already purged - you're spraying under your "safe zone"
 

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Discussion Starter · #9 ·
Ok, so basically the only thing I have to worry about hitting the rev limiter (which I have done) when racing. But doesn't the rev limiter kick in at 6200? RPM and the window switch is supposed to shut the spray off at 6000 RPM. So theoretically if (and when) I hit the rev limiter the spray should be off...The one situation I don't want is the dreaded missed shift and accidently go from 3rd gear to 2nd gear. The last few times I've done the 1/4 mile I have finished it in 3rd gear, but it was really close to the rev limiter by the end.
 

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jetblast
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get the purge sys. installed, if you are not gonna purge you better know how rich it will be going, too much fuel can also hurt the motor. anything below 11 is too rich for me and most likely pinching the rings and or washing the cylinder walls and with the added blowby some will end up in your oil.
 

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street car
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i can say that if you don't purge you run the risk of having the motor fall flat (run to rich and drop in rpms) before the nirtous hits and the motor can drop below 3k rpm and if its below 3k and the nitrous comes in below that rpm you will have a nitrous back fire, happened to me in my LT1 Z28 and i ended up tearing up the MAF and blowing the MAP sensors. purge helps get any air pockets in the nitrous line (i know it sounds dumb but there was a guy that installed it on his fuel line and not the nitrous line) out so you can have a clean hit of nitrous. i to would have to agree with everyone else that says purging in the water box is to much of a risk. i would wait to get a purge or i wouldn't spray at all.
 

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cave dweller
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The way he explained it was that it automatically sprays between 3k and 6k, so wouldn't you just leave it in Neutral and rev it so it sprays the air through so it wouldn't bog when you launch?

Sorry if this sounds stoopid , I didn't really understand what the the guy said about purging in the waterbox, I will try to get him to clarify it. The car is not finished yet, maybe I will just have him add the purge.
The proper way to set up nitrous is to have a WOT switch. I don't know about you, but I've never done WOT burnouts in the water box.
 

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Bann3d
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I dont mean to jack this thread at all but I have a question for those of you in this thread that say "if you dont purge you will go rich"
1st question is: Do you know how rich your car runs stock from the factory ?
2nd just how long are you going to be rich and approx how rich will you be ??
I would almost bet that your car runs richer from the factory at WOT than it does
tuned and spraying raw fuel through a plate for less than .3 of a second.

Lastly what travels faster ?? 1000psi of nitrous or 55psi of fuel ??
 

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cave dweller
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Good points Slowgoat.

Plenty of guys run without purge, but I sure would not try to use nitrous in the water box.
 

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street car
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I dont mean to jack this thread at all but I have a question for those of you in this thread that say "if you dont purge you will go rich"
1st question is: Do you know how rich your car runs stock from the facory ?
2nd just how long are you going to be rich and approx how rich will you be ??
I would almost bet that your car runs richer from the factory at WOT than it does
tuned and spraying raw fuel through a plate for less than .3 of a second.

Lastly what travels faster ?? 1000psi of nitrous or 55psi of fuel ??
to answer your first question i have no idea each car is different so that can vary but i know what your saying. second question about how long your going to be rich depends on how big of a air pocket you have in your nitrous line, and how rich it will be can also vary but i went rich long enough to drop the rpms below 3k and the nitrous came in and it was trying to advance the timing still and it back fired through the intake. also if you've ever seen a car with a slightly leaky injector you will see that even a small leak on late model engines can cause them to go rich enough to stumble and bog so imagine what a fogger style nossle that is like having a extra injector stuck at WOT at only 3k or so will do to a motor that is not expecting it. as far as dry kits go i don't know i have no experience with them.
 
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