Burning water

[Ruby]

Has anyone tried a water injection system on a turbo diesel?

I dont mean like this

http://www.spiritofmaat.com/archive/feb ... ns_doc.htm


Like this

And if so was it worth it?

It seems a little expensive

[andysimpson]

My 1.9TD has it, it certainly brings temperature down.

[HarryMann]

I've got an Aquamist system, and it should be going on soon...

Having a fitting made at the mo' for pre-compressor injection, initially starting with Richard's new .3 mm jet, which is rated at about 65 cc/min with the Aquamist Race Pump.. (think Andy has Sureflow pump).

For a 1.9 TD cruising at about 3 galls/hour (25mpg@75mph), this (65cc/min) represents about 35% water to fuel... For diesels, powerful ones running up to EGT limits, anything from 50~150% water might be injected post turbo, in fact even more... they won't flame out till about 400%, but we're being silly here!

There's an ongoing debate about pre/post trubo injection ... post turbo, post intercooler if you have one, is the norm. That was my original aim, not having an intercooler and liking the very neat and short hose from compressor to inlet manifold (negligible pressure loss), wanted to have the ability to knock high inlet temps on the head when cruising at high power (what most T25s pulled by diesels do, TD or not!). I'm now looking at pre-turbo options, to give what is called wet-compression in the world of thermodynamics and turbomachinery.

One of the debates is about compressor impeller erosion due to water droplets... but with properly atomised water or droplets aimed straight at the impeller nut, its unlikely to be a real problem. Fuel and fuel/water metering straight into the eye of the compressor has been used since before WWII on military aero-engines and Reno Air race derivatives of those... the RR Merlin was probably deriving a straight 15C charge air reduction from the fuel alone being delivered in this way, as good a reason as any for not persuing fuel injection ! And of course quite a wide range of other in-chamber advantages when water was being used too... one being that gross fuel enrichening to prevent detonation isn't necessary, reducing ridiculous fuel consumptions at full military ratings.

I may be a bit out, but I've just calculated that a 1.9 TD Diesel would be consuming air at the rate of maybe 5 to 7Kg/min at 75mph in a T25 (lots of assumptions )

That would give a water/air mass ratio of about 1~ 1.25% with the .3mm jet, the smallest ERL do. People are talking of figures of 2~3% for pre-compreesor injection on mad-ass turbo petrol engines, so its of the right order of things...

Some swear by it, others say they're not sure, but there's little doubt if nothing else it keeps EGT in check at higher bosst pressure.

Normal boost pressures to start introducing it are about 9~10 psi, else you can be using quite a lot of water.. ask Andy Simpson

I think the trick is to find the right injection rates and boost pressures to inject at, to give both cooling and in-cylinder advantages, without using tankloads of water... the above figures give about 1 gall/hr - but may not be enough for other than getting the compressor efficiency up a bit. Budget for about 2 galls/hr and you'll realise that this is not an inconsiderable anmount of watyer to be carrying about - both Formula One and WRC cars have both used WI - and for a F1 car to carry a lot of water about is a BIG penalty... I think those wicked turbo Renaults and maybe others certainly did just that!

[Ruby]

I thought it was simply buy it, bang a hole in the manifold, fill it, run it. At the volumes stated I would also need a larger tank then anticipated, I was thinking washer bottle.

So..a little more planning, a little more research and a lot more overtime!

Thank you guys.

[HarryMann]

If washer bottle quantities did the trick, and washer pumps then I think it might be fitted to all turbo cars as a safety anti-detonation device, now it can all be programmed into the ECU.

Ask Andy how much his kit cost, it's nothing like the price of ERL's Aquamist stuff, easy to fit and adjust. Some use the Sureflo pump and ERL's nozzles, possibly the best there are.

Aquamist equipment was developed for the race industry, works teams, WRC championship cars, where money is no object, or just a small one... I was lucky to find a basic setup with the race pump on eBay.

I have heard of one or two using a washer bottle and pump system triggered for kickdown only with manual cab switch... if I can find that thread I'll send you a link.

[Ruby]

AAH! No I don't think I'll be needing race kit

Happy to read that it may not be as expensive as I first thought!! I did realise that a high pressure pump was required, I'll keep my eyes on E-Bay


Thank You

[HarryMann]

The race pump is just what they call it... as Aquamist don't do a non-race pump as far as I know.

They engineered and supplied the water injection for the JCB world Diesel speed record holder, but didn't use their race pumps on it... they couldn't supply enough water I believe

[andysimpson]

I think HarryMann worked out my water consumption as something like 15.8mpg and fuel 24.?mpg.

My system is from coolingmist, can't remember exact cost but i did not get shafted for import tax.

[Ruby]

They engineered and supplied the water injection for the JCB world Diesel speed record holder, but didn't use their race pumps on it... they couldn't supply enough water I believe

mmmm...they wont be needing that motor again, so, if I volunteer for the back shifts and make a few adaptor plates.....

Hang on tho.. what did they use.. a very thin bloke and a long fire hose?

It's good to see transport oil doing the biz (who holds the record for veg oil? Is it me?)!

The off putting thing for me was the price,(read- wifey works in accountancy, can't get a fiver past her).

[Ruby]

I think HarryMann worked out my water consumption as something like 15.8mpg and fuel 24.?mpg.
.

Christ! the miles I do I'll drain the westy water tank before I get to the camp site!