NITROUS OXIDE ( nos / n2o ) advice forum

That USED to be the case, but the ones making real power now (like the Banks job), are running so lean you wouldn't believe me if I gave you the figure, because I couldn't believe it when Gale told me.
Unfortunately I've forgotten exactly what the figure was by it was INSANELY lean and certainly in excess of 20:1 and might have been as high as 70:1, just wish my memory was as good as it used to be.

I can wholly accept this statement though it would be great to know what the major differences are.
The more I learn about diesels and tuning (mostly from US sites) the more I'm forming the opinion that there may be a similar theory relating to US vs European/Japanese engines. I get the impression that any monkey could "invent" a tuning mod for US vehicles and get a seemingly impressive gain (with no disadvantages) due to the high state of de-tune and overly strong build of V8's with at least 4 litre capacity. i.e. Chuck a hand grenade in each pot and feel the difference Sounds stupidly funny I know, but not when you consider that some (if not all) Military tank engines are started from cold with explosives

As opposed to smaller, more efficient engines that are built much more delicately with finer tolerances meaning they're already closer to the limits and will not suffer over-abuse so readily?

I can well believe that now I've learnt more

It's perfectly possible to imagine such "lean" mixtures on a diesel Trev and (although I think it may be a rarety), did read that idling can be as lean as 300:1 while stupidly rich can be as low as 3:1 and the engine will still run under those conditions, unlike a petrol. Like a petrol, too rich and you get black smoke out the exhaust (but diesels can do it so much worse!)

All very interesting stuff Mike.

With regard to the difference between US and UK principles, it never ceases to AMAZE me that those with the US mentality (which includes numerous Brits and not all Americans), can't appreciate that its harder to get a 100% power increase from a small delicate engine than a 50% increase in a big strong engine. They judge that the achievement with the big engine is the best, purely on the basis that the big engine is making more total power - UTTER STUPIDITY!!!

Hi Mike,sorry, if a book's worth reading once,it's worth reading again,and again.No such thing as too much info.The wife found it for me on amazon,so shouldn't be too hard to get a copy.
Trev's recollection of 60:1 afr's is sort of correct,modern diesels idle at afr as low as 60:1.Turbo diesels make max power at 20 +:1

Apparently even old NA diesels run at 18:1 and leaner.But all diesels run on an "air surplus" and have no critical afr!,just have to stay on the lean side of stoich to avoid smoke.

I guess the "different" types of diesel would be direct and indirect injection,then there are different methods of direct injection.

I never realised how very different diesels are.I understood the basic principles of compression ignition but it is so much more than just squeezing diesel til it burns.
I'm not sure I'd want to pour water/methanol mix into my daily driver.

The richer you run a diesel the higher the EGT,even a heavy smoker will still be on the lean side of stoich(15:1) It's the surplus air that keeps temperatures down.
If you have a smoker thats when Nitrous can be of most benefit,making more power,cleaner exhaust and lower egt.
I would imagine anything running as rich as 3:1 would be very nasty to be around.

Forgive my ignoring all other comments now and focusing on this one but to me, the above quote is the piece of jigsaw that I was missing. I learnt about it yesterday (spent hours reading different articles) and it all makes sense to me now and re-inforces my belief that overfuelling is the reason for excessive EGT's. (The only thing I'm not sure of is what part(s) of the surplus air (oxygen/nitrogen) are responsible for keeping the temps down?). Excessive EGT's can and will melt turbos and pistons and crack housing and manifold.

So I can see no reason to believe that exceeding a 50% meth mix will cause any problems unless it creates an overfuelling situation (which is highly unlikely if I'm upping boost and spraying nitrous). As for being advised to keep the meth ratio even lower when using nitrous, that is still debatable (as I'm unsure which component(s) of air is responsible for cooling the combustion temperatures) but it's looking unlikely IMO.

Now I have the essential theory, I'm very much looking forward to putting it all into practice.

As far as the 50:50 mix goes,what part is the water supposed to play?
In a petrol engine WI can reduce inlet temp,lower egt,reduce the possibility of knock,increase the effective RON and so allow more ignition advance.These all help to make more power.
What does water do for a diesel? apart from maybe the cooling part? diesels only make more power by adding fuel-and more air if you do not have a surplus- seems to me you'd be better just adding methanol.Although propane does appear to the fuel adder of choice.

As far as fuel pressures go they talk of 24,000psi that's nearly enough for a water jet cutter. Mr hartman also states that 40% of the cost of a modern diesel car is in the electronic control system

All good stuff,I'm finding this diesel tech very interesting.Might have to find a small diesel to play with. Although I've got to find a cheap transit to carry the bikes before the season starts.I'll have to buy a smoker I've got a spare pair of pulsoids

Are peugot still the best for diesel?

My immediate reaction (based on my knowledge of petrol engines) was that excess air could NOT result in cooler EGTs but if lean burn is not a problem on diesels (as seems to be the case), then I suppose a surplus of anything would act as a coolant.

The element that will primarily be responsible will be the nitrogen I'd guess, because it makes up the majority of air and its responsible for damping combustion in a petrol engine.

You've suggested that nitrogen might be more important than people think,before.

Supposedly diesels do not maintain a constant flame front,instead they generate loads of small "burns" as individual molecules combust through the power stroke,guess thats why loads of torque.

You certainly have to think in a different way when dealing with diesels (in more respects than one might expect), which is not so easy after a lifetime of being a petrolhead.

That's what I dislike about Marketing BS, it muddies the truth by exaggerating or generalising the facts. I can only surmise water is for cooling the intake and damping the combustion process and possibly lowering EGT's too? When I begin my experimentation, I'll be better able to provide reliable data. One of the boasts from WI kit makers is that from all this cooling, the turbo is made more efficient by spraying a small amount pre-turbo.


That is the conclusion I'd drawn. Everywhere I went to ask, I was hit from all sides that it's "common sense" not to go below 50% water . Although I can see why people believe it - thinking equal amounts will not cause an imbalance but that's way too simplistic for my common sense to accept.


Unfortunately, I've only got an IDI engine to work on where pressures are not so mental (but still enough to pierce skin!).


I was wholly ignorant about diesels, until I bought my first, two years ago, and the more I learn the more I want to know. Petrol engines have probably evolved about as far as they can while diesel technology is about ten years behind and the way things are now (quieter, cleaner, faster, etc) I think they've got far more potential.


Historically, yes. PSA (Pug and Citroen) made the best IDI engines so I suspect that's translated nicely to the DI's though it seems the common rail, high pressure fuel systems have a lot bugs that needs ironing out.


Understandable. Inversely, I can imagine a diesel expert who's never really known petrol engines would have the same misgivings about excess fuel cooling the petrol engine.


I think (and hope) it's the oxygen as that is what determines the AFR's, not nitrogen?

As I say, I'm making a leap of faith here as it's something I've never considered before this thread started. Feel free to rip it apart if it's nonsense . I realise this is too simplistic and that other factors may have to considered, such as peak pressures etc.

As we know, AFR's are determined by measuring oxygen vs fuel. In a diesel, going from (say 100:1) idle, adding more fuel makes more power and eventually we see temperatures rise. If we continue adding fuel we reach a point of excessive EGT's (because there is no surplus oxygen) so isn't it logical that if we then add more oxygen as well, we can delay reaching that critical AFR?

Ooops I got my abbreviations mixed up, as I thought we were still talking about EGT's.

As we know, AFR's are determined by measuring oxygen vs fuel. In a diesel, going from (say 100:1) idle, adding more fuel makes more power and eventually we see temperatures rise. If we continue adding fuel we reach a point of excessive EGT's (because there is no surplus oxygen) so isn't it logical that if we then add more oxygen as well, we can delay reaching that critical AFR?
Yes now I realise we're talking about AFR's here and not EGT's
I was thinking of the nitrogen controlling the EGT by direct cooling, you're thinking of the indirect route.

slightly off topic but just got this press release:

http://www.turbosmartonline.com/index.php?id=328

I was referring to both Trev. Sorry I didn't explain my thoughts well enough, I need to get more learning done so I can use the right terms. I'll never make a good technical writer.

It's a moot point now anyway, as I realised it doesn't really matter whether it's nitrogen and/or oxygen that keeps EGT's reasonable. The idea I was trying to convey is that EGT's follow AFR's, until a certain (rich) point where EGT's then go through the roof.

I guess all this seems pretty obvious to you but there's an important distinction (which had previously eluded me) to be made between overfuelling (the term I've been inaccurately using) and a lack of surplus air

I hope that makes better sense.

Good on Greg, petrols engines have reached their limit, now it's time for the diesel engines to take it from here. Shame about his choice of nitrous though.

Lot of articles I have read lately express that sentiment.

some of the new diesel engines I have seen in cutaway are very nicely built,extremely nice looking 4-valve heads.How do they pump fuel at 25000psi?
Anyone got one of those subaru boxer 4's that we could put in a little rail?

To further help (me as much as anyone else that's interested) I've copied this quote of diesel website that gives a little insight into how EGT's vary massively with diesels and why. Although it's dealing with a specific vehicle (a Truck I think) the basics are the same for any diesel.

===========================
Here is a quote from Ted Jannetty of
Jannetty Racing Enterprises Inc.
about EGT's

EGT: or exhaust gas temperature gauge, measures exhaust gas temperatures leaving the combustion chambers. This is the window into the tune up of your engine, it will tell you everything you need to know, if you use the knowledge I will provide.

Average temps: stock truck (in degrees Fahrenheit -- ***

Idle – 250 to 450
Cruise no load – 400 to 700
Cruise with trailer – 500 to 800
Pulling hill no load – 500 to 1000
Pulling hill with trailer – 900 to 1250

Temperatures will vary whenever the throttle is moved or the terrain changes. The peak number is the most important while towing, the ISB can be safely run up to 1450 for short bursts and 1350 all day long. This number is strongly affected by modifications weather it be Air flow or Fuel delivery. If air flow and fuel flow are increased EQUALLY, (Very important words here!), we can increase power to very impressive levels with no increase in EGT or smoke. We will talk more about this later.

Sub 7 second diesel

http://uk.youtube.com/watch?v=X3nWNOEQDGM&NR=1

Pretty impressive! sounds like a jet when they wind it up?? I'd imagine ETs are really limitted due to gearbox technology..with so much torque but short "power band" they wouldn't be able to do it on single speed.What we need is a high strength cvt

but I bet He doesn't tow his own trailer to meetings! just found some more about banks' sidewinder... road legal drives to bonneville under it's own steam towing it's trailer

Unless that recording is damping it, it sounded far quieter than a petrol engine, so quiet you could clearly hear the turbo, as you say, sounding more like a jet turbine. It's a good point about the gearbox restricting times as I thought I noticed a distinct drop off of power or acceleration partway through. There must be a serious problem to overcome if CVT boxes can't be made strong enough, they totally eliminate gearchanges while insuring full power is being applied, efficiently, throughout the run, at any speed.

I read and saw that Banks stuff, the sidewinder is truly a MPV! I also understand Banks race diesel dragsters using nitrous. As someone else commented - it's the only way they can run those times (meaning it hides the fact their standard tuining products are impotent ). Interestingly, and I bet Banks don't use WON, they're reportedly said to have melted all the pistons in their "Duratech" - whatever diesel vehicle that is.