i was wondering how much of a spray i can do on a 305 with a zex dry shot while i use old school water injection with methane mix? the catch is without changing timing. i have 75 shot 100 and 125

 

Thats a good question... running it with methy helps keep octane up to prevent detonation and also helps cool intake temps which is what nitrous is doing as well, and probably alot better job to boot.

Stock timing is something in the range of 32-34 deg at WOT. I'd feel safer about pulling 2-3 deg for a 100 shot at least and only if you can tune it to provide enough fuel to keep air fuel ratios happy with the spray. Timing seems to be most critical component with spray. You can run alittle lean and have high chamber temps but if timing is down, it still will run fine.

I think it will take a 75 shot with some meth injection and run abit richer. 100 shot may also work with alot of meth injection. You could just set base timing to 2 deg and be safer if you dont want to add an external timing management device.

And i'd spray MOSTLY meth in the mix, if not all meth. water does well, but meth gives octane which is crucial when not changing timing

 

would putting more pressure on the fuel regulator help with the fuel? also i thought it was the water that increased octane rating cause of the water cant detinate like high octane?

 

Water is just water...its there to cool and buffer the charge abit, but its not an octane adder. Alcohols have higher octane rating than gas so thats where the extra octane comes from, the methanol.

 

alright i just thought it was the water cause it didnt detinate which i thought was what octane did

 

I must have been out of the game for too long - but I didn't know you could get 1.7 ratio rockers on an SBC engine? Not a big block, not an LS series engine, but a plain jane SBC from the '80s? Feel like giving me a part number or a link Hellbird? I would think these would cause serious valve train angle issues and reliability problems?

 

Water absorbs some of the heat which controls detonation so it does help. Alcohol just does it better while adding octane which fights detonation.. Its 2 times the detonation fighter than water. cooling and adding octane, 2 seperate ways.

 

plus they say with water it helps clean out the heads ....

 

well i kinda took a chance with these ones i had a set of 1.7s from another project i had done a year ago and with the cam not being very big lift on the tpi i just kinda said lets try it and i am not having any issues with it i know that they are from rpw (racing parts warehouse) when i put them on i just made sure to have them line up correctly and got taller valve covers. my uncle also has a third gen and he was debating on a pair of 1.6 or 1.7 and desided 1.6 cause the guy he bought them from said he wouldnt have a difference in power but he is regretting it now.

 

Well, yes, no, sorta...

N2O disassociates at combustion temperatures into N and O2 with a larger percentage O2 then in he atmosphere. You have to add a fuel to it to prevent it from going lean and using the pistons and other parts as a fuel.

Alcohol (methanol...) is a fuel that has a relatively high octane, but lesser energy content than gasoline, so you have to add proportionately more to burn with the same amount of O2. Also, like most liquids will evaporate when exposed to heat and absorbs some of that (latent heat of vaporization) cooling it (gasoline will do the same also if injected high enough up, for this reason, carburated and TBI engines have less detonation sensitivity at the same mixture).

Water also will evaporate and has a much higher latent heat then methanol so it actually will cool more for the same amount. It also has some interesting affects in the chamber- Flashing to steam actually results in some downward force and will make some power, the droplets spread evenly through the chamber result in nodes which control burn rates and decrease detonation sensitivity much more than just the cooling affect on the intake air charge.

Potentially this could be a great combination for making power, but real world, I don't know of anyone that has actually documented how everything would interact...

 

thank you 83 crossfire ta i am thinking of doing a 50/50 water methanol so the fluid isnt flameable but it wont freeze either from the nitrous. ill have too post what happens when i get it all set up and probably first try a quick 100 shot just to see if i should go down to a 75

 

I'd go with a 75 and decide to go up based on those results. You may only get one shot at it

 

alright also on the tpi's are u able to retard the timing by just the distributor or does that through the computer off?

 

You can retard overall timing by the dizzy, just setting base a few degrees less than stock. that works fine. BUT when you do that, on motor performance will suffer alittle. On Nitrous however, it will be safe and sound.

Thats why an aftermarket timing box is recommended that can pull timing when nitrous system is activated, and leave timing in when you are just running all motor.

 

Well, a few things:
- N2O will chill things down to -17x*, any water mixture in the path of the N2O spray will freeze.
- Detonation isn't the problem with N2O, it's a problem. In other words, the engine is not more prone towards detonation, real world, typically less so (cools the charge, also changes burn rate making it slightly less prone to happen). The problem comes in if something isn't right, and it's lightly detonating already or something causes a hot spot. With the additional forces detonation happening while you're spraying makes it more destructive. Secondly, the more N2O you spray the less effect timing advance has on power production. This is the reason why _some_ manufacturers recommend x* of retard per 50hp or whatever, it's a question of playing it safe + it won't effect power anyway.

 

so would i even have to do really anything with water/methanol cause it would remove most or all hot spots and make sure that my motor isnt already having any detonation problems?

 

Again, I think that you're getting into an area that is not well documented. Both water and methanol have interesting affects (in addition to what I already listed, methanol almost acts like it's carrying some of it's own O2, so you can make slightly more power than what you'd expect from the amount of air you mix with it), but the temp of the N2O as it changes phase when it is injected could be an issue. Even straight meth freezes at -143*, so I suspect that if you used a normal N2O nozzle you'd have an issue with it freezing (a standard nozzle shoots the N2O spray across the fuel to vaporize it and mix it, I suspect you'd create methanol snow with one). If you have the time to experiment it might be worth while, but if you just want something proven to work then skip it...

 

ok thank you i will try and do some testing. I also will look online for more answers

 

well i did some more research and according to this website (http://www.alcoholinjectionsystems.c...icle_info.html) they say

Allows The Use Of Little Or No Timing Retard - As a result of water injection effectiveness as an octane enhancer and it's ability to slow down and stabilize the combustion process. By adding a water methanol injection system, nitrous users are able to run little or no ignition timing retard even with large 250 shots

so i think im safe with a 75-125 shot of nitrous