water injection + failsafe

[antnicuk]

sounds to me like its getting a bit more complicated than it need be......

[NixRX7]

Complicated for sure, but then having a WI system that also has a failsafe built in is never going to be easy to do.

Nick

[antnicuk]

the more complicated you make it the more likelyhood there is something may go wrong,  especially DIY jobbies that arnt tried and tested.   Aquamist seem to think that a flow indicator is all that is needed.  i dont think many of the people using w/i to run seriously fast cars have much more than that.

I was quite lucky as the TII has a headlight washer bottle with a low level indicator in it and a warning light on the dash board.  I removed the low level sensor and fitted it in my w/i bottle.

You gotta remember that you only get a light on your dash if you oil runs out in most cars,  Rx7 also have a buzzer.   Your engine may survive without w/i but it wont without Oil.

I\'m sure it would be very simple to wire in a buzzer and light with a low level sensor.   That together with your flow sensor is more security than you get for anything else on the car failing....

Just my thoughts and experiences though.

[NixRX7]

I quite agree Ant, my WI when i fit it will have the clogged nozzle detectors and low level warning and thats all.

But the original post was asking how to make a WI system with a failsafe and thats never gonna be an easy thing to do and the only way i can see of doing it is to have it connected to a boost controller of some sort.

Be nice if there was an easy non complicated way of doing it tho.


Nick

[Prof]

All valid points chaps - and I do subscribe to the Keep It Simple Stupid school of thought.

The simpler a thing is, the more likely it is to work.  That said, the worse performing part in any control system is usually the human/machine interface. :Hammer

There are probably lots of simple things that can be done to prevent a WI system failing and possibly doing damage to an engine, which don\'t involve a human having to do anything.

Don\'t forget even Mazda put some fail safe features on the REX - if the boost solenoid dies you get spring boost only, if too many sensors register problems the ecu goes into limp home mode, there\'s the disastorours rear rotor fuel cut, apparently even the rotor housings were teflon coated - when the engine is first run, the teflon melts into the micro pores in the surface, and if the engine overheats, the teflon comes back out in an attempt to stave off an oil loss overheat.

For me the best form of failsafe is one that operates its own control - not tied into any other system so it\'s not dependant.

Be intersting to see what results ?  

[kev-yorks]

Running a two stage system on mine i\'ve wired two mega bright LED\'s to each boost switch a red one when its off and green when its on. So as i come on boost i can see when each stage comes on line as the led\'s switch from red to green, also makes it easy for tuning the system as you can see each switch on point. Don\'t forget if running W.I. and you start running a methanol mix that its corrosive to Aluminium so your as well using the plastic washer bottle with the bonus its got a low level light. If your worried about capacity you can always get a second bottle with built in pump plumbed into the main one. I use a gen 1 one Then when you get a low water light its just a case of flicking a switch to top up on the move from the reserve bottle.
Kevin

[vxer]

I also agree that simple is best. However, i still can\'t see the problem with my original proposal?

All the components already exist, its just a sensor change and a remap parameter - you may even be able to adjust the setting through the commander!

Job done?

Ta, Paul.

[maximtaylor]

Nice thought, but......

If you tune fully for the full advatanges of water injection as you suggest, that\'ll mean running far leaner than you would otherwise, as well as running more advance.

Using the Air temp retard function as you suggest would work for timing (what about heat soak, hot days??), but you would still need to somehow work out a way of either dumping the fuel back in if the WI system fails, or automatically lowering boost.

As NixRX7 has said, you need to detect blocked jet, water out, pump failure and you could link this to a boost controller.

As Vxer has said, the technology does exist.

Most boost controllers such as the Greddy Profec b have a connection for a remote switching harness (to switch remotely between high and low boost).

Most WI kits can be supplied with means of detecting blocked jet and no flow with an output signal which could be linked to this switch.

Do some hunting around and I\'m sure you\'ll manage it in the end!

[maximtaylor]

Et voila

http://www.aquamist.co.uk/cp/806-425/806-425.html

Look at this diagram and you can see what you need to do:

[vxer]

If you tune fully for the full advatanges of water injection as you suggest, that\'ll mean running far leaner than you would otherwise, as well as running more advance.

Using the Air temp retard function as you suggest would work for timing (what about heat soak, hot days??), but you would still need to somehow work out a way of either dumping the fuel back in if the WI system fails, or automatically lowering boost.

Ah crap. I\'d forgotten about that pesky fuel thing! Heh heh, guess thats why i don\'t tune my own cars, huh?

Its a shame i have to invest in a boost controller... Actually, if i could lower the boost when i needed to, would that cover the possible lean condition?

Cheers, Paul.


edit: i\'ve just realised that its obvious that it would sort the lean condition! Duh. Anyway, i wonder if there is a way to get access to the PFC\'s second boost setting and automatically triggering it somehow....?

[maximtaylor]

edit: i\'ve just realised that its obvious that it would sort the lean condition! Duh. Anyway, i wonder if there is a way to get access to the PFC\'s second boost setting and automatically triggering it somehow....?

yes there is, but you\'d need the datalogit box to do it with!

[vxer]

If i were to run water injection *without* tuning for it, i\'m presuming the ECU can adjust fueling to compensate for lower AIT (since it would need to cope with winter, for example) and therefore gain performance*?

The question is, if i was able to tune for WI what margin of power difference are we talking about?

Cheers, Paul.

*) Currently 50 degrees AIT is the coldest i get during a run(!)

[maximtaylor]

The Power FC corrects for air temperature, yes.

You could probably gain around 5-10% power by leaning the a/f\'s out.

But you are low on safety margin if things go pete tong

[Fish]

What are people using as water tanks and where are you fitting them?

Thanks
Fish

[Mr J.T]

im using a ali fuel tank in the boot a 4.5lt one only usin the wi for a safety feature, not to tune too |:)