StavFC

Im not sure if this is on or off topic anymore, lol (good reading btw, keep going, my question was answered already ), but I have some actual results if anyone cares...

AFRs are mid 12s to mid 13s on idle and cruise.
AFRs are from low 11s to mid 10s flat out. Generally about 0.3 richer any any particular point using water injection.
Had it up to 1.45bar peak 1.35bar held with no fueling issues at all, but then **** jubillee clips and popping boost pipes stopped play.
Nowhere near fast enough for my liking, ill try up to 1.5bar held once I get the boost pipes to stay on ok, maybe more if its feeling strong, but im not holding up much hope its fast enough to keep me happy; I sense big big turbo time...

j9fd3s

iTrader: (3)

what kinda timing is it running?

thewird

iTrader: (8)

Hmm, thats strange. I've observed the opposite once with a water injection system. AFR's would lean out 0.2 just by turning the water on with nothing else changed.

thewird

rx72c

iTrader: (8)

thats what happens when ignition cant handle it. goes richer.

haydenw

http://www.efi101.com/forum/viewtopi...er=asc&start=0

StavFC

Ignition cant handle it? Hmm, interesting. Well it didnt seem to affect performance, I tried it off and on each time; no change.
Was a lot of water mind, about 600cc pre-turbo.

arghx

iTrader: (3)

You're running enough boost that the quality of couplers, clamps, and hoses become a big issue. Do you have T bolt clamps on everything? Do your pipes fit closely? How about your vacuum lines? One option is to pull all the factory vacuum nipples and tap for AN fittings. Another simpler option is, strangely enough, to superglue your vacuum lines. It sounds stupid, but it actually works pretty well. Silicone hoses will stick decently with superglue but usually can still be removed with enough physical effort. Neoprene and rubber may have to be cut off.

StavFC

To be honest, this is pretty low boost compared to other cars ive built (25-35psi is much more me) but im having to upgrade the boost hose connectors even at this fairly low level compared to the skinny little things that was on it in japan; it's not exactly the parts i'd have chosen.

Never been too happy with how they did the vac pipes, so I've been sorting that from day 1.

At this stage I sense a big turbo swap coming, and if thats the case im going to re-do the whole IC pipework regardless as though its all custom TIG stuff, it seems to have been done by Stevie Wonder while Ray Charles pointed out where he should weld.

thewird

iTrader: (8)

If it goes richer or leaner? I assume when it goes leaner, ignition is ok since water contains o2 but haven't had enough experience with it on many different cars to say for sure.

Nothing in that thread really advances your argument. The people that say it changed weren't sure how accurate their AIT correction tables were. I read the whole thread. They did mention how its important to have your FPR vacuum line sourced at the correct spot important (which is important regardless of altitude >_>)

thewird

rx72c

iTrader: (8)

Ignition is a problem when it goes richer. This is a definite as i had the same problem at one stage and after running ignition at 18v it went back to around .1 points leaner then it was before the water came on compared to around .3 points richer after it was on with the old ignition system.

Hope thats not confusing.

turbotoaster

id assume richer because the ignition spark isnt strong enough to burn all the fuel because of the water blowing it out so more fuel in the exhaust gas showing up on the afr gauge maybe

haydenw

Ok,

Being a tuner yourself you would of heard of the terminolgy of VE= Volumetric efficency, and that everything from the air filter to the exhaust tip effects it.
The part you are not thinking about is the exhaust, you are only thinking of the intake , Yes if you have a jar of air at a pressure of 10psi and take it to the moon there is still only 10psi of air in it but a engine is not a jar, its a air pump. All you are doing is factoring in density which is only part of the equation. You need to know the MASS and for that you need to know the Volume and the density as MASS= VOLUME x density
Now what happens if you put a nice shiny exhaust on a car and all of a sudden its made more horsepower , you didnt increase its density in the inlet manifold but you increased its Volumetric efficency.
Now in that mind set you drive up a big mountain and now theres less exhaust back pressure say 70kpa instead of 101kpa what do you think that has done to the volumetric efficency of the engine. Its increased!!
But the ecu only has a feedback of inlet manifold pressure and not Baro pressure so while the ecu thinks yeah ok its only at 70kpa it calculates what you have entered at that load point in the base map but has not factored that your "air pump" just filled with air a lot better than at sea level causing a lean condition.
Sure there are plenty of other factors like air inlet temp blah blah but that is all under the density equation of 2.7(aP/aT) and not volumetric effiency

thewird

iTrader: (8)

Yah, thats what I said lol

thewird

haydenw

And to further elaborate from my previous posts why it only effects the vaccum part of the map up to 101kpa is that for Example of a 2litre engine has a fixed volume of 2 litres which makes that 100% volumetric efficient, now anything above that (So boost region of map) you are changing density of the air as the engine cant take a larger VOLUME than that 2 litres. So remembering that MASS= Volume x density, it is calculated in the density side of the equation in the positive guage pressures of the base fuel map.

:scra tch:

haydenw

So in all that.
SPEED DENSITY systems which use a MAP sensor needs to have a BARO sensor to correct for altitude

arghx

iTrader: (3)

Barometric pressure sensors on MAP based turbo cars are helpful but not strictly necessary. Again, GM did just fine on the Syclone without one.

haydenw

Sure, with a little "that will do" attitude, And thats why technology advances.
For ACCURATE AFR control you do!

Jimmy2222

iTrader: (3)

I think there's one thing you guys are forgetting when talking about altitude, there is less oxygen the higher up you go. I know air pressure is different and varies much more than oxygen content in the air, but once you hit a certain point, you're going to be burning less oxygen because there's less of it in the atmosphere to take in.
Also, to the jar w/10psi comment, that may be true, but it's a bad example. With a motor, you're constantly taking in air and it's being compressed, it's not the same.

haydenw

that is not forgoten at all.
That is all read by the map sensor in 2.7(aP/aT)