machinehead

Since I have sold my single turbo and went back to running the twins I bought the ZEX nitrous kit to try to regain some of the power I lost. I have run it a few times but with the 50 shot its kinds hard to tell if its even working. I don't know if the weather is still to cold to really feel the effect or what. Anybody have any experience with it? I can feel something its just not what I expected. As it is my intake temps in the low 30C range so maybe that is the problem?

cewrx7r1

iTrader: (2)

My friend Rick Sheveland also has the DRY nitrous system as well and runs a 50HP shot. He normally only uses it with hot weather. He said it is more noticeable when hot as compared to cold. He also said it needs a bottle heater for cold weather to operated properly.


This implies that the power increase in cold weather is less than 50HP.

machinehead

Thanks you don't happen to know if it is the Zex kit do you? If so, could you ask him which tps wire he used for a trigger? Since our cars have 2 tps signal outputs. one reaches 4.5v at like 1/2 throttle and the other never does quite reach 4.5 at all.

cewrx7r1

iTrader: (2)

Contact Rick at sheve@swbell.net

KZ1

I am doing my last round of mods(yeah right) an dit is going down for awhile. I am goign to finishoff the bolt-ons with 1200ccs and teh dataloggit. I was reading about this ZEX kit, sound sinteresting. I thought of it today my intake temps dropeed to 19C with the weather, generally at 40C. Man what a difference, thought NOS would be great way to get that feeling back even during warmer weather.

Anyone else have experience with this kit?

SPOautos

Do you really not get the full 50hp in the cold weather or is it that you get more than 50hp in hot weather???

I've heard that turbo cars tend to benefit from nitrous more than NA cars. In other words if its a 50hp kit a turbo car in the certain conditions might make 70hp with it.

As an example, I remember seeing a rx7 running a 50shot that increased about 70rwhp while spraying on the dyno. I THINK it was Pluto but could be wrong. Maybe it was Chrispeed....or neither. Who knows maybe it was something else affecting it as well.

Does anyone know how cold the intake temps get while under nitrous???? I would imagine its extremely cold, at least enough that you would still get 50hp when your intake temp are around 30C.

Maybe I'm wrong though, I've never dealt with nitrous so this is all 2nd hand except for the dyno sheet I saw.

I have a friend with nitrous(not hooked up though) and I'd like to test this with his car by making a dyno run without nitrous and then a run with to see the difference.

Later,
STEPHEN

Jodeny

iTrader: (3)

Horsepower supplied by nitrous all depends on the pressure in the bottle and how many cubic inches the engine is which is in direct relation to how hot the bottle is and how full the bottle is. A fifty horse dry shot can make anywhere between 35 to 65 horse depending on conditions but usuallly it is the neighborhood of 45-55. Nitrous also suppresses detonation because it is very cold.
John

rotary4

One question why did you sell your single turbo?

machinehead

It was a bit too loud for my tastes.

KZ1

it suppreses more pre-ignition than detonation. If not properly tuned will cause detonation. Just like intercooler.

Jodeny

iTrader: (3)

Pre ignition is Detonation. Hence the prefix- Pre. Durnig detonation- pre ignition occurs and then regular ignition occurs- the two flame fronts collide in the chamber and that is the poping sound you hear.

Obviously anything not properly tuned will cause heartache however nitrous only has to be 'set up'. The most important factor in runig nitrous is fuel volume. Once you run out of fuel the mixture is unbelievably lean and it just toasts the motor. As long as you have enough fuel available in an otherwise healthy engine everything will be ok......................usually.

John
PS- Notrous was fun in the early eighties wehn they did not have fuel/no2 ratios worked out yet. Can you say Booooom.

KZ1

not entirely true. detonation is not pre-ignition. I will start with pre-ignition as it is easier to understand. pre-ignition is an accidental ignition of comnustoin gases, generally caused by the combustion tempereatures being to hot for your plugs. see, as the temp of combustion increase your plugs willr etain more heat, and pre-ignition happens when that heat held in spark plug( or maybe stuick piece of carbon, etc) ignites the gases prior to the spark plug firing. kind of like a diesal.

detonation happens when plug is fired at wrong time for the volatility of your combusiton gases.(sorry lack of corret terminology). PIcture yoru combustion chamber under compression, from the point when spark plug fires there is minute delay until is consumes all the gases or generates enough force to move anything. Thus the advent of advance timing, firing the plug before the optimal point in anticipation of the complete burn. So, detonation occurs effectively when the apex of power, or enough of it, causes the rotor to turn the other way. thus powering the rotor against itself. this is achived by the follwoing which are both intertwined. either the plug being fired too early, or the mixture being mroe volatile for the timming the fire, and causing the combustion to happen too quickly.

Everythign is realted, but basically you can advance too much for a given volatility of m ixture and have detonation, while at same time not lowering the heat range of plugs to reduce pre-ignition. The best way to cool the combustion chamber is add more fuel. adn yes pre-ignition coudl cause detonation, but not realiably.

Also, I take back my earlier statement about NOS helping pre-ignition, it doesn't do that either. although on the surface lower intake temps woudl lend to lower combustion temps, this generally does not happen, the added heat generate form more power will increase those temps thus the requirement to buy colder plugs when using NOS.

BTW, volatility is most increase by more oxygen, so boost and lower intake temps will increase it.

Jodeny

iTrader: (3)

--wrong again


Go back and reseach this topic more and I hope you don't set up nitrous systems for a living..

John

By the way is French your first language??

KZ1

SO are you saying you don't need colder plugs and retarded timing for nitrous? I guess it woudl be possibel to keep combustion temps the same if you added enough fuel, but what is the point of that?

Also, if you think I am so wrong, enlighten us all as to why. My info I gathered is not sacred, offer someting up we can debate.

Jodeny

iTrader: (3)

I have been using nitrous for a long time- since the mid eighties. There are a lot of myth's and beliefs about it that theoretically- make sense but when it comes to real world use, they are not necessary correct or they just dont work at all. There are a lot of variables when using nitrous.
When it comes to using juice on a rotary, the results are different than a piston engine. What may be good for one may not be good for another. Dry systems, wet systems, port injected, plate injected, nozzles, we can go on and on. When you are talking about an itty bitty 50 horse dry system, not much has to be changed- just add more fuel. On STOCK piston engines, anything up to 150 horse will work well. If you want to run more juice then you have to build the engine for it in order for it to work efficiently. When you build a high horse engine , you already have the colder plugs and decreased total timing. Yes, when running big kits you have to decrease the total timing even more(depending on cam duration and overlap/cylinder pressure....all variables) but that is when you are running over 175 horse and up. Rotaries on the other hand need a lot of fuel just with a turbo, I can imagine what would happen if you run too lean with squeeze- kaboom, you wont even have a chance to lift.

Combustion temps are cooled significantly with nitrous because it is so cold.

John
I am out of time but if you are looking to run juice- find someone that has it on a similar setup that runs well and speak to them about what works.

silvr94r2

iTrader: (3)

The one thing I haven't seen on here is about bottle pressure. To get the shot desired you must have the right pressure or it will be more or less. If you are jetted for a 50 shot dry (dry kits are my favorites...i have them on everything that i own) then you would want about 900-950psi of bottle pressure to get the true 50 shot....any less and you are running fat which equates to less of a hit. If you wanted to up a 50 shot you could up bottle pressure a little to do the "poor mans" jetting. Bottle pressure is everything along with bottle placement. You need to get the best supply of nitrous that you can....and a purge can't hurt things.... it makes things alot stronger and consistent.

silvr94r2

iTrader: (3)

Oops....just went back and read this.....I guess someone already did touch on bottle pressure.

900-950psi. is optimum for the novice
1000-1050 is still good but only for the more experienced nitrous users
1050-and up are for very experienced nitrous users or the brave or stupid depending on who you talk to

SPOautos

John, could you please give a brief explanation about what was wrong with KZ1's statements? I didnt see much that was wrong but I'm still learning. Would you please say what was wrong instead of just saying "wrong again" If his statements are not right then I need to know why(so I can learn) cause they seemed ok to me.

Thanks,
STEPHEN

Jodeny

iTrader: (3)

Let's start from here. What are you looking to run? %0 horse, 75, 100??
John

SPOautos

Well, I'm not planning on running nitrous right now, if I ever decide I probably wouldnt run over a 75 or so shot. I was mainly interested in what was wrong with KZ1's post. There were a lot of places where you inserted that his description was wrong and I was just curious what it was that was wrong. I was hoping you'd just give a brief reason as to why all those statements were wrong instead of just saying they were and leaving it at that. It all sounded about right to me and just wanted to know if its wrong whats wrong with it. I might need to change my way of thought on the combustion process as I'm definatly no expert. I'm just looking for whats correct.

Thanks,
STEPHEN

KZ1

alright, I did do some more research, and while I was not entirely accurate nothign I suprise at how accurate I was.

detonation is not only cause by too advanced of timing, but also, if the temps are too hot, or something stuck in chamber, the plug fires and the compression and raising temperatures will cause another explosion to occur, the collsion of these two expolions is detonation. however, in this process if the second expliosion is more powerful than the one generated by the spark plug, it will overwhlem it and apply forces in the wong direction. pre-ignition is still not detantion, although much debate surrounds the issue of terminology. pre-ignition, is simply the pre-ignition of gases before spark plug fires. So detonation often happens after plug fires, and force wave created it hurdling through the gaes. so if you lean out mixture and generate more heat from combustion dentonation is more likely to occur.

This is conjunction with my previous post is pretty accurate from what I have read

Furthermore, I would like to clarify something. the differnce that intake temps make on the heat from combustion is immaterial, the temperature is mostly controled by the a/f ratio. so adding a bunch of cold nos has little effect on combnustion temps, as long as proper a/f ratio is maintained. if you take this in light of previous statements, the lean mixture will more likely cause detonation. However, regardless of power you are producing or cold air intake combustion heat will stay the same. nonetheless, the more porting, boost,oxygen(nos, cold air, etc)will make complete combustion happen faster, thus the need to retard ignition.

temperature and heat generated are too differnt things, many things can contribute the effective disapation of heat. so while heat may not increase, temperatures may from other factors, but generally prove to be insignificant( from what I read)

Jodeny

iTrader: (3)

Close, let me add- There are three points. First, nitrous oxide is comprised of 2 parts nitrogen and one part oxygen (36% oxygen by weight). When the nitrous oxide is heated to approximately 572° F (on compression stroke), it breaks down and release extra oxygen, However, it is not this oxygen alone which creates additional power, but the ability of this oxygen to burn more fuel. By burning more fuel, higher cylinder pressures are created and this is where most of the additional power is realized. Secondly, as pressurized nitrous oxide is injected into the intake manifold, it changes from a liquid to a gas (boils). This boiling affect reduces the temperature of the nitrous to a minus .127° F. This "cooling affect" in turn significantly reduces intake charge temperatures by approximately 60° - 75° F. This also helps create additional power. A general rule of thumb: For every 10° F reduction in intake charge temperature, a 1% increase in power will be realized. Example: A 350 HP engine with an intake temperature drop of 70° F, would gain approximately 25 HP on the cooling affect alone. The third point, the nitrogen that was also released during the compression stroke performs an important role. Nitrogen acts to "buff or dampen" the increased cylinder pressures leading to a controlled combustion process.

John

KZ1

okay

intresting info on the nitrous.

Lost Time

Damn. Gold star for John. Thanks for all the info.

Jodeny

iTrader: (3)

We just hooked up a 275 horse kit tonight (not an FD).....should be fun.
John