here in a few weeks i'll be purchasing the 305 tbi nitrous kit from NOS, i have installed 2 nitous kits before on friends rides and i finally decided to get one for myself s a cheap power adder until i get a new motor built up. around here all we have is a 1000ft track (320 ft less than a 1/4) so i never get out of second gear while racing, the question i was asking is what is a safe rpm to spray nitorus at..can i do it in 1st gear as well as 2nd gear? i have 700r4 trans with (what i'm guessing) 3.08 geared one wheel wonder rear end, being a BONE stock motor i have ran 13.20@ 82 mp in the 1000ft which i am told is roughly arounf 15.5 seconfd range in the 1/4 mile so i'd be shooting for at least 15.0 to 14.7 in the 1/4 rang do you this could be done with a 75 shot? a 100 shot? just give me some feed back!

 

hey i think i can offer advice. i just bought a used zex dry kit, and i need to convert to a wet kit before i can use it. but with that out of the way, i have the same engine as well, (305 tbi)

with research i have read that some have shaved 2 secons off their time with a 100shot!

i can tell you right now with a 75 shot you will shave close to a second off if not a bit more.

a safe rpm to use it at? really anything above 3k is fine, and make sure you are WOT before u push the button.

i wouldnt recomend using it right off the line, u wouldnt move very fast, but once you hit second you can let it rip open!


the reason i went with zex is for the nitrous on WOT setup, no buttons to hold down after arming it.

 

yeah i don't want a WOT switch because its to the floor off the line and have absolutely no wheel spin and it would pray in that case, i figured it was about 3k rpms to spray but i figured i'd better check first before i went and hurt my engine or something, the engine has 140k miles on it but is very well taken care of (women driven before me, and her aunt was the original owner) so its a perfectly runnig engine i hope to see 1-1.5 seconds with about 100 shot i'm gonna go ahead and upgrade the ignition and stuff

 

well you still ahve the arming switch, and u can leave it off when u launch, and when you hit second gear, then flip the switch and the it will work off your WOT.

 

first off id say you can safely spray at 1500 RPMS, maybe even idle, not too sure, but i know 1500 if fine, just make sure its a wet kit, and secondly any kit can have a full throttle activation switch... is zex the one that uses TPS voltage? i know my edlebrock kit just has a switch that mounts on the side of the throttle body and that little moon shaped thing that the cables wrap around will actually push the button when at full throttle.... and it can actually be adjusted when it hit, but only a tiny bit of adjustment... anyways id say use the full throttle switch and have it adjusted so that it only sprays when the pedal is completely to the floor, then just when you leave the line push the pedal almost to the floor... again dont worry so much about RPM, just hit it as soon as you have very little or no wheel spin, and if you decide not to use a full throttle switch (bad idea) make sure you have it a WOT when ever that nitrous is spraying... i let my friend borrow my kit (carb, not that it makes a diff) and he didn't use a full throttle switch, and he launched, hit the nitrous, well then his car didn't want to shift into second... hes convinced it was the throttle cable... might be torq conv though... but anyways first instinct when something screws up is to let off the throttle.... well if you not using a full throttle switch the nitrous still sprays of course, and that will blow a motor up very fast! luckily nothing happened to his, but still i wouldnt run nitrous w/o a full throttle switch, and i dont recomend running NOS w/o a fuel pressure safety switch either.. but i've done that a lot

 

yes zex runs off the TPS voltage

 

NO FREAKING WAY.

N2O is pretty much like forcing that added extra amount of O2 into the engine wherever you turn it on. Do your own math:

Torque = (HP * 5252) / rpm

Now tell me what happens when you hit and engine with 150hp worth of spray at 1500 vs 3000rpm.

As far as when to spray it… the sooner you spray it, the faster you'll run, slightly at least. Personally, I've always set mine up to turn on any time the arming switch is on, the car is over a certain rpm (usually between 3 and 4K, you really don't loose much WRT to time by going higher since you shouldn't be below that for more then a split second coming off the line) and the throttle is at WOT. I don’t screw around with "buttons" or anything like that. This setup pretty much lets you drive the car, and the spray happens when it's right…

FWIW, progressive controllers are pretty nice… they'll let you adjust the way the spray comes in, in some cases you could set it up to come in so gently that you can't tell that the car is sprayed, it just runs much faster then it should.

 

No way, not 1500 rpm, double that is even a little low for my liking.

 

nos recomends no less then 3k

 

but also you have to think, the l03 redlines at only 5k rpms, and i never get out of 2nd gear in the 1000ft, so anything more than a 3k rpm spray would only be a split second spray and wouldn't be worth the money to mne, but then again i can always just put a 4bbl adapter when i switch to my new engine and still run the same system because i plan on using nitrous anyways

 

Yea, and??? You can't spray it in first? It doesn't spend most, if not all of it's time in second above 3K?

 

exactly what i was saying, i drive an l03 and when i shift at 5k, it dropps me to about 4k

it will be fine

 

I personally wouldn't run nitrous without a RPM activated window switch.

I am going to run a MSD window switch that kicks on at 3k and off at 5300rpm...then shift at 5500rpm. That way I do not have to worry about pushing any buttons...its safer and more consistant.

I am cutting it off before the shift that way the poor old 700r4 will not take as much abuse...from what I understand stock 700r4s do not like nitrous.

I also wouldn't run nitrous without:

- Upgraded fuel pump
- Fuel pressure safety switch
- WOT, and window switch
- and with some sort of spark drop rev limiter...not a stock fuel cutoff.

 

just be sure it cuts off the nitrous before cutting off spark.

 

A rpm window switch should do the trick nicely.

 

whoops. i missed where he said window switch right above it... lol

 

I think I have all the basis covered. I hope so anyways. Also gotta make sure I have a gauge so I do not spray when the pressure is to high.