NITROUS OXIDE ( nos / n2o ) advice forum

Just thought I mention that we now have a new software program in the Max Extreme to achieve closed loop mixture control, to ensure the AF stays constant (delivering safe, constant optimum performance) and allows you to use THE FULL bottle contents including most of the gas.

What wideband lambda sensor setup does the max extreme use to do that trev? Or can it work with lots of different makes?

The original spec is to suit the sensor supplied with this system http://www.dynojet.co.uk/wideband/index.htm for 2 reasons;

1) The original design was for Dave Bailey and he uses that system
2) We're now agents for these products and will be adding them to our range/site ASAP

However, other sensors will probably work (and at worst only need some trim adjustments in the Max) and we'll aim to make it as flexible as possible for ease of direct fit to most vehicle with an existing wideband sensor.

Very cool feature then

cool Trev dyno jet see now it all makes sence to me like where the revo is going in terms of set up kit and control max with wideband software and control

Ill be on the list for a retail set but as always i have my own peramiters and when day comes i can fit revos with max and a wide band i will

ya is smart feker anit ya

woah, trev I'm impressed and also confused

closed loop...i'm probably wrong here, but wouldn't that mean the engine doesn't have to be running at WOT for the nitrous to start feeding into the engine? So in essence it would be a bit like a supercharger at half throttle, albeit limited by the bottle contents?

Nope, ALL our nitrous systems will always require the activation of a full throttle switch in conjunction with any other activation device.

In that case now I'm definately baffled

I thought open loop was full throttle and closed loop was anything up to about 70% throttle opening, according to the tps. If that's the case, how does the nitrous system work without going full throttle

I'm not talking about the OEM ECU managment arranegments, I'm talking about the Max taking control of the OVERALL mixture by closed loop lambda control over the Revo fuel & nitrous flow.

Closed loop is a term meaning that it reacts in real time to data from a sensor, the sensor then notices the change, feeds that information back in and further adjustments are made.
The term could refer to a car engine with fuelling and an oxygen sensor or it could refer to pumps and a level sensor on a reservoir, it merely refers to the type of operation, nothing more.

Most cars will only do this on light load for fuelling, as they only have a narrow band sensor.

Trev's controller does it at full throttle when on the gas using a wide band sensor.

If you tried to have the nitrous kit hunting down an 11:1 AFR at the same time as the car ecu was in closed loop looking for a 14.7:1 it would be absolute mayhem as the nitrous kit would be pouring more and more fuel in and the ecu would keep going leaner and leaner.

So you do NOT want both active at once!

Hi Chip

I see your point about both, so as an example on my car that doesn't have a modern ecu , the Maxx would control everything from the Wide band input...yes ?? And all work fine...

On a more modern car, wouldn't the fuel ecu (or map) have to be disabled in some way to allow the Maxx to take over ?


All the best Brett

The ECU will be in open loop mode, so it will NOT be responding to exhaust gas conditions, it will only be fuelling as per its open loop fuel map.

The MAXX will be operating in closed loop, so it will look at the overall resultant fuel condition which occurs as a result of the cars ecu fuelling combined with the MAXX's fuel efforts, it will then look at the overall mixture in the exhaust, and will compare it to the target set as its closed loop value.
The car's ecu will continue to function as normal and the max will raise or lower its fuelling to make the overall effect of both sets of fuelling be the target AFR that the user has set.

Well not control "everything" merely control the closed loop fuel trimming, the ECU will continue to function as normal, the MAXX wont touch the normal fuel injectors, the ECU will still control them, the MAXX will control only its own fuel delivery, and will use this to try and keep the overall mixture at your 11:1 target (or whatever you set) so if the car normally runs 10:1 at WOT, the MAXX will fuel the nitrous kit lean to bring the overall mixture to 11, if the car normally runs 12:1 at WOT then the MAXX will fuel the nitrous kit rich to bring the overall mixture to 11.




The only precondition is that the car ecu must be running in open loop mode at the time, but almost all cars are when at WOT anyway, in fact Ive personally never owned one that isnt, so the normal map doesnt need disabling, in fact quite the opposite that must be allowed to function as normal, the MAXX doesnt wish to effect its operation, merely to add or subtract a relevent amount of fuel as it adds the nitrous to ensure it makes its target condition.

I know nothing at all about the MAXX doing closed loop, ive never discussed it with Trev, in fact until it was mentioned in this thread, I didnt even know that was a feature being introduced.
Every post Ive made in this thread, has simply been based on the way that as an experienced engine tuner and experienced control systems software engineer I know is how it SHOULD be done, so I made the very safe assumption, that is exactly how you were doing it

I get more and more confused the more I read about it. I read chip's latest posts and I was thinking "yeah that's how I'd have thought it would work also", BUT I still don't understand how he got there when you said "closed loop mixtures control"

I totally understand it all now but still bemused as to how he understood what you meant. For what it's worth, I would have gotten it first time around if you had said open-loop mixture control, but I'm really not sure about how closed-loop ties in here

On a more positive note, that's a very cool feature. I'm guessing the benefits would be cleaner combustion, maximum power output because of a bang on mixture, better fuel usage under nitrous

That's awesome news

I have a Innovate LM-1 which can work with my ECU as it has a autotune feature, can a wideband signal be shared

BillB

Trev can the Max be also used as a display for a wide band or at least data log a sample from a wide band sensor , so that in basic form ya could just add a wideband sensor to zorst to check A/F as and when needed

Because the Maxx works in closed loop, it looks at the lambda sensor and adjusts in real time, that is what closed loop is mate!



Its closed loop because it works on a closed loop with the lambda sensor, if he called it open loop it would be wrong, because it isnt, a normal nitrous controller is open loop, this one can be, but in this instance isnt.




Safer / more efficient use of nitrous and fuel / more power

BEST feature though I would imagine is no need for a push system to keep mixtures correct, as a bottle pressure drop can be accounted for in real time, likewise no real need for a bottle heater to stabilise mixture (still has other uses though) and no worries about hot or cold weather in terms of mixture

We're currently at the first stage of this project, so for now I'm happy that it works in isolation of anything else. With any luck the signal can be shared, but if not its only a matter of adding another sensor to the exhaust.

Many wideband kits have more than one output anyway, my innovate does for exmaple.

If its a high impedence input on both items though, i cant see it being a problem sharing, obivously need to test to find out for certain though, at a later stage in teh development.

[quote="Noswizard"
Its about being on the same wave length and unfortunately there's not as much of that about as we could do with. The fact that Chip (and others) picked up on my statement but you didn't, is a perfect example of how poor human communications are and why there will always be wars. Any person can make a statement with a specific meaning, yet out of 100 people who read or listen to that statement, there will be a good number of different interpretations of that statement, sadly! [/quote]

Bizarrely you managed to strike a chord there despite chips best (and very well explained) efforts!

Now I get it. I was confused because I thought the MAXX would take a reading (albeit via it's own sensor) of the engines mixture when IT's in closed loop, then the MAXX would perform some witchcraft to calculate what the correct conditions should be for nitrous injection when the engine is at full throttle. Its this that had me so confused and I kept thinking "yeah but how the hell would it know what to do as they're both different conditions!!"

But now I understand (I think ) it as the engine will still do it's own thing independantly of course, but the MAXX will take a closed loop (there's that term again, lol) reading for itself via it's own sensor and then adjust the mixture while the engine is in open loop ...if I got that wrong, I give you permission to use this smiley and not feel at all guilty >>> <<<

You are 100% correct.

Hi Trev, I recall in previous posts you have expressed a concern that wideband sensors may not be capable of reporting accurate readings when "on gas". I was wondering why that might be and harboured a few theories myself.

Would it be reasonable to assume you don't have those concerns anymore?