AO

As Jon points out make sure you have a provision for the blowdown tube. You could even use braided brake lines for the cool look.

As for teh purge valve - I don't think this is needed for street use or track (road course) use. These are mostly use at the drag strip to make sure you have nice cold nitrous as far up the line as possible. It will be cold enough within a tenth of a second or so which is a big deal at the drag strip, nut not as big a deal on the race track

Jon B.

Exactly, and guess what brings that pressuse down to a safe level? Purge valve baby. Not to mention it'll give you a clean spray with no condensation in the lines.

Jon

Brett928S2

Hi

So its a yes to bottle warmers....so wiring them in....do they need a relay to offset high amperage usage ?
Over pressure ??? So if i left my luggage cover off are you saying the bottle could blow the valve if bottle gets TOO HOT ???

All the best Brett

928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH.K&N.
PCGB UK 928 FORUM MODERATOR

AO

There is a pressure switch on the warmer that monitors the pressure. When pressure gets up to 1100psi it turns it off automatically. The big issue with NOS is if you have the bottle closed and the heater on. Watch out! I was a bit paranoid on this point - and rightfully so. Perhaps there is a newer version that only comes on if the pressure is above 200-300 psi to avoid this issue?

mark kibort

It depends. as was said, generally, you want the bottle pressure to be near 1000psi. usually, in a 70f car, its near 800psi when full and lower below that. to get the best results, you need to have the bottle heater and its a pretty easy install. for one shot down a dragstrip, its probably not needed, but if you want the exact flow and mixture all the time, the bottle heater keeps things at 1000psi . as you use NOS, the bottle cools FAST, and it gets real cold. (so then the pressure goes down too!) so, the only thing you have to worry about,is that you NEVER turn off the main valve while the heater is on. if you forget to disarm the heater > (done this before) there is nothing to tell the heater to turn off, then you have KABOOM! and from some internet pictures, its not pretty. guys loose their cars, and their garages from the explosion. tie your heater to the ignition side of the power, make sure you have an arm and disarm for the heater alone and one for the main NOS switch. this way, you can have the NOS on all the time, but no bottle heater until you are in serious mode. also, if you then forget that you were in serious mode, leave your car, turn off the main valve on the NOS bottle, you dont have a serious problem. (in otherwords, making it fault proof) the bottle heater system is the only risky thing of the NOS modification. (as long as you dont exceed the power abilities of your engine as well, and 50 to 75hp is no problem for our engines. dont expect any life shortening by using NOS on our engines at that level.)

MK

mark kibort

no, you wont blow with just heat from the car's interior.
the blow off valve is only for when it does blow due to over heat from the heater, that it blows down the tube. OFTEN, this doesnt happen, as the bottle blows at 3000psi to 4000psi. there is no way to protect yourself from forgeting to turn off the heater, thats why you need to wire it into the ignition,
(only if the bottle valve is closed do you really have a problem as the heat sensor should trip a relay as the pressure goes near 1200psi. (thats how they work) current tripping wouldnt work due to the resistance of the heater going up not down with temp. current flow doesnt change that much, but you have a chance here by using a very small battery!! (ha ha) I think the current draw was near 10amps, so in an hour with a 10amp hour battery, you might escape disaster!

the main fix to this is never close the bottle with out turning off the bottle heater, or tie the heater to the ignition just in case.

Jon B.

Negative. The valve SHOULD have a burst panel in place that will give WAY before your bottle goes BOOM. Which is why you need to make sure your blowdown tube is there. Bottle explosions are NOT very common, and if you do everything safely, like moniter your temps and like Mark said make sure to turn the heater off if the bottle is closed. Most of the newer bottle heaters shut themselves off at a certain temp point. But it better safe than sorry. I wouldn't be worried about bottles blowing apart in your car.

Jon

Jon B.

Here are some good bottle heater links...

http://www.nitrousoutlet.com/catalog...del=76&dept=11

http://www.dynotunenitrous.com/store...?idcategory=15

Or you could do something really slick and wire it into your rear derost/defog wiring. Then it'll just stay on as long as the switch at the front of the car is on.

Jon

928SS

I thought the nos charge was regulated down to 100psi or so at the nozzle? but if it's too cold, it could screw up the AF and cause extra lean? iirc, FP was supposed to be regulated down to about 10/20psi also, no/yes? there are lots of controllers on the market that seem to handle a lot of safety stuff too, like a drop in fuel pressure, etc.... one switch controls all, etc

mark kibort

No, the nossil pressure is 1000psi and fuel pressure is near 50-55psi.

no, you cant screw up the AF, due to the fact of two things. one, the NOS is injected after the MAF or AFM. two, the AF is controlled by the fuel pressure nossil size and the NOS nossil size , both under their nominal pressures.

yes, there are controllers that react to lower fuel pressure or lower NOS pressure. (basically, assuring proper mixtures as things change)
But, with a 50-100hp shot, there is really no need for these kind of fancy controllers, or the progressive controllers . those are for the 250HP shot systems.

mk

mark kibort

Yes, the should, but often they dont blow first, as luck would have it (or bad luck) the blow down tube is the path for the NOS to vent to should the pressures get too great. But, often times, as all the internet pics , show, the bottle blows first. (not really often, but it does happen.)


MK

Jon B.

I'm not gonna make this an argument because I respect Mark and his opinion. But do a search for Nitrous bottle explosions and see what you come up with. It wont be that much. He has used Nitrous in an actual race application, I have not. Take what you read for what it's worth. Do your OWN research and use it to your benefit.

Jon

928SS

scuba tanks do the same thing at 3500psi.. I've had the burst disk go on a few - sometimes its gradual, sometimes it really pops

whitefox

http://www.nearlygood.com/video/nitrousexplosion.html

Jon B.

I was talking about BOTTLE explosions. Not Nitrous backfires. That one looked like it went way rich and the fuel puddled in the intake and well...THAR SHE BLOWS!

Jon