Water Injection :)

[sdminus]

Wow this thread has gone a long way. I wonder where it will end up LOL

Scott

[fro]

Wow this thread has gone a long way. I wonder where it will end up

probably going round and round in circles as usual

[BlitzBoy]

Wow this thread has gone a long way. I wonder where it will end up LOL

Scott

probably end up closed Scott lol :rollin

Scott do you think having a slow acting temp sensor would cause det? I dont think it would because the water itself would hopefully fight off det

[sdminus]

probably going round and round in circles as usual

LOL. lets give it a twist.... anybody got a dog LOL :Snoring

Scott

[sdminus]

probably end up closed Scott lol :rollin

Scott do you think having a slow acting temp sensor would cause det? I dont think it would because the water itself would hopefully fight off det

Not really. IMO if the air going in is colder than what the ecu thinks it is then  its only a matter of a few seconds till it reacts. So unless you are right on the edge ( i doubt many are ) i cant see it will matter... bottom line is dont boot ya motor if the temps are crazy. I dont even tune my own car to the last 1 percent it can take so i doubt if anybody else does..

Also if the air is colder of denser i would say that possibly it would be safe anway

Scott

[BlitzBoy]

So Scott anything below 40 degrees say before booting it you are quite safe in having the water injection switched on?

[sdminus]

I wouldnt bother even at 40 deg. i get worried over 35 deg C.... but im an old woman and panic LOL :rollin

I see there are a few good guys watchin this so they would know better... que max que brian

 :cool

[maximtaylor]

In the example I used you very often find that the sensor warms up through heat soak, not necessarily the intercooler itself. Especially so if you run a front mount intercooler.

So when you do move away from standtill, although the sensor is reading high the real air temp plummets quickly, the sensor catches up.

In both cases, the sensor is always playing catch up. More dense air than the ecu thinks is going in.

I\'ve run W/I for around two years now, and my wideband has never really had a scary lean moment as per your example. Sure it does lean a bit, but not much.

 

I believe you are mistaken.
I am warning that the moment the water switches on the temperature of the charge drops instantly as the water vapourises (latent heat of vapourisation). The ecu will find out much later as the temperature sensor is slow acting. You then run lean for a period of time at say, 0.85barWOT. This could cause det.

At the lights the intercooler and sensor both heat soak. As you drive the intercooler gradually cools and the charge does too. The sensor cools with it and the ecu corrects the fuelling at the same time. You don\'t have the same level of fueling mismatch.

In any case most tuners will have a 15% safety factor in their MAP to accomodate these shortcomings.
A better solution would be to have a fast acting sensor.
You would expect to be avble to see the inlet charge temp fluctuate with rpm and boost as the intercooler cannot cool linearly with flow rate. You do not see this because of the sensors large time constant.

If you want serious power you need to get closer to the detonation threshhold and thats when this type of water injection system could prove dangerous.

Jon

[sdminus]

I

If you want serious power you need to get closer to the detonation threshhold and thats when this type of water injection system could prove dangerous.

Jon

I presume that you are either tuning back to stoich and repalcing fuel with water. In which case you could have probs.

Or you are making crazy advances in the ign timing. ( above the ceiling in which  engine would normaly run)

I have the answer to all this temp business. Ditch ya intercooler and petrol and run strainght methanol.. :burnout

[BlitzBoy]

If you were tuning back to stoich(14.7 afr I believe) using WI, therefore say leaning out from 11.1 to 12.1 would you see the biggest increase in power as opposed to the next stage from 12.1 to 13.1, is there diminshing returns going leaner and leaner?

[bnaellis]

I wouldnt bother even at 40 deg. i get worried over 35 deg C.... but im an old woman and panic LOL :rollin

I see there are a few good guys watchin this so they would know better... que max que brian

 :cool

What I do is this. I have a v mount so my intercooler gets hot a lot quicker than a front mount does. I can sit in traffic and quicly see 50+ ait on a hot day. At those temps I don\'t boot it. I just need to get moving and my ait drop quite quick. When my ait gets to say 45deg I will plant my foot to the floor but with minimal load on the engine 1.e 1st or 2nd gear. I only need to put my foot down for literally 3-4 secs and my ait are back down to around 27deg. Then I can plant my foot down like normal and put load on the engine  i.e 3rd or 4th gear.
Different people have there cars setup different, but in general you will find minimal difference in afr when water is being injected, unless you are quenching.

[sdminus]

Yeah. i think the 0.85 L mark is the palce to go rather than leaner. unless you are using a blended fuel in which case it would alter the stoich. ie 10 % meth mixed with 90% petrol gives about 13.8 afr to 1 L

I was making more of a point than fact if that makes sense

Scott

[BlitzBoy]

so a good combination with a bit safty and a good power with WI 12:1 afr should be good?

I know without WI and high boost 10.8ish afr is as lean as you wanna go with Pump fuel

[sdminus]

so a good combination with a bit safty and a good power with WI 12:1 afr should be good?

I know without WI and high boost 10.8ish afr is as lean as you wanna go with Pump fuel

I have done lots of testing over the past few months and found 12.0 afr at peak tq at 16psi of boost was ok with the correct ratio of water. I also found this to be quite quick but only a tiny amount. It didnt seem worth while to me for the extra danger.

Scott

[Jonathan_F]

In the example I used you very often find that the sensor warms up through heat soak, not necessarily the intercooler itself. Especially so if you run a front mount intercooler.

So when you do move away from standtill, although the sensor is reading high the real air temp plummets quickly, the sensor catches up.

In both cases, the sensor is always playing catch up. More dense air than the ecu thinks is going in.

I\'ve run W/I for around two years now, and my wideband has never really had a scary lean moment as per your example. Sure it does lean a bit, but not much.

Ok Max. Well I\'m coming from a theroetical point of view and your coming from the real world. I know enough to know that real world experience is worth ten in the bush!

Jon