As some may or not know, I blew my Nitrous fed engine here read this

http://forums.maxima.org/showthread....t=Blown+engine

As some suggested it may be due to my running too lean, which I have come to realize may be the case. So here is my solution.

Since I need to realize a stoichiometric balance I figured, for one, I need an air/fuel guage, a fuel pressure regulator, a walboro fuel pump, fuel pressur guage, nos guage, and maybe an exhaust temprature guage just for overkill. Now I will tune the air/fuel balance using the pressure regulator in accordance with the air/fuel guage to insure that i will not be running lean again. Know my dilemna is whether I should go ahead and get a FMU like the Apexi s-afc or a jet vforce power control module.
Any imput would be greatly apreciated. Thank You

 

What you really need to decide is what shot you want to run now, and determine if you ever want to bump up the shot in the future. If you don't plan on increasing the shot you would be fine with the walbro, fuel pressure gauge, colder plugs and SAFC. I have the same setup dyno tuned for a 70 shot which I tuned slightly on the rich side of 12.5:1 for safety. I don't plan on increasing my shot, so everything will stay constant for as long as I continue to run nitrous.

If you ever decide to change shots your dyno tuning becomes worthless and you'll have to spend more money to retune to your new shot.
-hype

 

Learn how to read your plugs, that will be the best way to tell if you are running lean or rich. Also get a real A/F gauge like a apexi or greddy, one with its own O2 sensor, not the garbage piggyback autometer one.

 

why is it garbage, it uses the stock o2 sensor which doesn't seem that bad to me.

 

Even if you hook up the Autometer O2 gauge, you're only monitoring 3 of 6 cylinders.

 

The factory O2 sensors aren't accurate enough to tune a car by, but they're fine for the closed loop tuning of the ECU. They'll give you ballpark tuning, but you don't want to entrust them with the safety of your engine.
-hype

 

what about the rear 02 sensor at the catalyctic converter which is the one I used. I cant conclude the results since I have blown cylinder and anytime I turn on the engine it billows out smoke. its usually on the rich side initially but after the idle settles, it starts to go lean and it stays there consistently.

 

The O2 sensors in our cars are narrow band, that means that they are only accurate over a very narrow band ie 13-15 +or-. That is no good for nitrous which should be turned to 11.5-12 or in that ballpark. You need a wideband sensor that will be accurate in the area.

Here is what I am now using and I consider it more accurate tuned on the track or street than on the dyno because the dyno does not load the car the same way it is when its on the road or track. Either way you need to tune with an accurate instrument.

The stock one would be ok for tuning N/A because the A/F is in its accuracy range.

BTW The wideband O2 sensor is installed in the Y to get all cylinders and they last longer operating at reduced temps. Just need to get a bung welded on to insert it.

http://wbo2.com/default.htm

 

Jime: I thought your Max got burned.

 

Just the 97 I still have my 95. Fortunately they only stole one of them.

 

Oh. I thought the really fast one got hurt.

 

The 95 is back to stock now too, going to work on another one for next year. Probably another 95.

 

maybe a 5speed this time.

 

never, auto's rule, if I thought I could get one to go as fast as the auto I would but you ain't never gonna convince me.

 

Now that you will be getting a new maxima, are you going to do anything a different way?

 

well never did get the 2 stage working because of some faulty equipment. Probably lighten some more but other than that I will probably stick with the same stuff. I didn't get to tune with the wideband or the S-AFC so that will help a lot. Probably going to run two smaller shots, not going to exceed 100-125 total, just going to get into the high 12's and this year I ran 13.1 with a 35 shot so hopefully it won't be too hard. Just want to be able to race in the mid to high 12 range without taxing the engine TOOOO much.

 

What are you recommending for me to get, the vw wideband from 1stvwparts.com sensor or the stuff being sold on the website.

 

That is only the sensor from 1stvwparts you still need the wideband unit. I am using the VW sensor I don't believe there is any difference in accuracy with the other one.

This is for people who are serious, they aren't cheap, take time to tune etc, but if you want to have maximum performance and know you are running in a safe A/F range they are a must. You must also have a S-AFC so that you can adjust the A/F once you know what it is at the various RPM ranges.

 

I need for you to explain the whole idea for me in more detail cause I'm pretty serious about getting all the performance tunning down I can't let lightining strike twice. What I dont get is how do you apply the device, do you connect it the stoichimetric guage or to the S-afc or are their other applications.

Btw autometer has an 02 sensor that can be used I with the guage.dont know how effective that one is band wise and if it is any good with nitrous.

 

The device is stand alone. It uses its own O2 sensor etc. It will readout on its own display in realtime and also datalog to a Palm or PC. It has inputs for RPM, EGT etc but RPM is the main one you are interested in.
Once you have a datalog through the RPM range in each gear you adjust and S-AFC to increase or reduce the A/F ratio to coincide with the reading you have taken.
Then you do it again to confirm that you have brought the A/F into the ratio you want. If its still out a bit,(and it will be) you keep doing it until you get it exactly where you want.

Now there are differences of opinion of what consititutes a perfect A/F ratio under nitrous ie 11xx-12.xx so you have to decide what you want and go for it. I am still experimenting or I would give you hard numbers.

What I am after is accuracy of the A/F ratio measurement. This device does that because it is a wideband unit. The ones that connect to your existing O2 sensors are not because they are narrowband and will not give accurate readings in that range.

 

that made a lot more sense, thanks. So which version do you have the 1.6 or 2.0

 

I have the 2.0 just got it a month or so ago and so far have only tried it out on a DSM.

Thank you for being understanding and not like that jerk on the 5th Gen board from that stupid mag.

http://forums.maxima.org/showthread.php?t=253836&page=2

You know I like trying to help people and go out of my way to do just that but when some jerk that thinks he knows everything finds his way on the Org I am ready to call it quits.

 

its funny how it took him that long to realize that different nissans have different transmissions and that if you know one that does not mean you know them all. Like the old saying goes, ignorance is bliss. Thanks for the info.

BTW I was wondering since you are running 150 shot nitrous, dont you have some seriuos traction issues, how do you deal with it.

 

I bought the 2 stage because of that. I am ok with a 100 shot, no problems. So going to start with a smaller shot and hit the 2nd stage after the shift to 2nd.