ALFAGTV6.COM

[MR2 Zig]

Thanks Duk!

I wondered about that as I am familiar with steam turbines (a little bit) and water coming out of the steam as it expands in the turbine, condenses and washes away the metal inside the unit. ( this while turning at below design running pressures).

I'm running normally aspirated at the moment, but I like to learn....

[gtv-racer]

Cool project! Wonder how it drives when finished. Al the horses at top rpm. Very NICE . And it's something different on an Alfa engine!

[MD]

"....Water Injection! What a subject!
I am really looking forward to seeing what can be achieved with water injection.... "

Irrespective of where the introduction of water is being made into the combustion process, don't lose sight of why you are doing it. You are looking to benefit from the properties of Latent Heat when liquid turns to gas. This is the critical reason why "water" in otherwise a burning process actually helps to improve combustion and reduce detonation.

For maximum benefit, this transition should completely take place in the combustion chamber.

Cooling the air molecules that enter the combustion chamber is helpful to increase O2 density but other than that, this has little to do with properties of latent heat taking place in the chamber.

Ever notice that your car runs better in the rain? This is due to a very mild form of water injection of sorts due to the humidity (and cooler air of course)

..er Duk, just don't be tempted to make your 75 amphibious without a snorkel, that would be taking water injection a tad too far..

[Duk]

Mr. D, thou art another who would benefit greatly from Mr G's tome on supercharging thy Alfa Romenof engine.

Seriosuly, Greg has explained in his book when, where and how water injection is so massively effective. It has precious little to do with other people's marketing of water injection kits and everything to do with what the engineers at NACA discovered during world war 2 developments of force fed engines.
I'm not going to sit here and type that you are entirely wrong about the crucial effectiveness of water injection, but mate, you're not entirely right, either

[MD]

Duk,

I am puzzled by your response which seems completely malaligned with what I said and so at the risk of more of the same, mate, I'll leave you to it.

[Duk]

Duk,

I am puzzled by your response which seems completely malaligned with what I said and so at the risk of more of the same, mate, I'll leave you to it.

Cooling the air molecules that enter the combustion chamber is helpful to increase O2 density but other than that, this has little to do with properties of latent heat taking place in the chamber.

Now I wasn't actually going out of my way to hurt your feelings there mate.

My comment is particularly aimed at your statement above.
While the air does get cooled with water injection, the air is now more humid and has very little extra air density. This is what the NACA engineers found out, that there is very little, if any extra air molecules inhaled when water injection is there doing its thing.
That is the opposite of what just about every seller of water injection will tell you, but I'd believe a bunch of engineers that weren't trying to sell something over some marketing drivel, any day.

Now 'cause I learned that from Greg's book, anyone who reads the above information is now obliged to buy it

[SydneyJules]

Nice going Duk!

I've driven a few potenziatas over the years- IIRC, they had different cams and a different map- resulting in 140kw- it was the rwd version of the 164q.

Didn't know they had a shorter diff in them... 3.9 out of a 1.8t would be the ultimate blown v6 ratio, but 3.7 is pretty good- much better than climbing a 3.55 to find some boost.
Paul k's sprintEx iteration of his 1.8 donk was fun, but in order to run high boost, he had low comp- it meant the engine behaved Like a peaky na donk, boosting right at the top of the rpm range.

How much boost you gonna run? It should sing up top!

Damn right, Kevin, I'm watching with interest! I will wait till
my rings go before building a blower donk...
Mine is in the panel shop as we speak- waiting on material from tomer so I can get thE interior done. New carpet coming next week, and looking at seals- mrfiat.com is not cheap!
Got some interesting stuff happening with this car.... Can't wait- piccies soon.
Ok- no hijacking-'over to Duk!

[Duk]

Nice going Duk!

I've driven a few potenziatas over the years- IIRC, they had different cams and a different map- resulting in 140kw- it was the rwd version of the 164q.

Didn't know they had a shorter diff in them... 3.9 out of a 1.8t would be the ultimate blown v6 ratio, but 3.7 is pretty good- much better than climbing a 3.55 to find some boost.
Paul k's sprintEx iteration of his 1.8 donk was fun, but in order to run high boost, he had low comp- it meant the engine behaved Like a peaky na donk, boosting right at the top of the rpm range.

I'm not a fan of overly low diff ratios. In my mind, it's got 3 litres worth of engine, it should be able to turn a reasonably tall ratio to give comfortable cruising revs and still give decent performance.

How much boost you gonna run? It should sing up top!

It's a bit of trial and error with supercharger drive ratios The compressor map I got my hands on is for the same model SC but a different trim. That and I just took a guess at the engines volumetric efficiency.
I'll be tiding the ports up when I overhaul the heads and that will probably lower boost pressure a little bit (less resistance to flow), too. But I do think that 10 or so psi should work and add nicely to the cars performance.

[killaz]

Nice project!!!

Can I ask, are those rear springs Eibach too..? And specs, please?

[Duk]

Nice project!!!

Can I ask, are those rear springs Eibach too..? And specs, please?

Cheers .

Yep, those rear springs are Eibach, 175lb/in, 5" in diameter and 11" long.
They do require locating bushes to fit properly on the spring seat and up under the chassis. I machined some from a 19mm thick Nylon chopping board. Cheaper to get Nylon that way than buy 5" diameter bar.

I haven't driven the car with the rear springs or the newer front coil overs yet.
I did drive the car with some 105lb/in springs in there, but they would have only added about a third more wheel rate. I'm after 2.5 times the standard front wheel rate (about the same wheel rate as 28.7mm torsion bars) so I really need about 360lb/in, not the 225lb/in I bought when I stuffed up the motion ratio calculations.
If I calculated the rear motion ratio correctly, the rear suspension will have a natural frequency about 10% higher than the front's.

[Duk]

Another water injection video I tripped over on Youtube that I thought I'd post. It shows a pre-compressor water injection system. What I found interesting about it is the compressor surge (probably from releasing the throttle) that started at the 1:01 minute mark and how violent it was.

http://www.youtube.com/watch?v=F51xymg3 ... re=related

And while I'm at it, from http://autospeed.com.au/cms/A_110369/article.html:

"Evaporating a kilogram (ie a litre) of water requires 2257 kilo-joules of energy – and that’s a lot! If the nozzle flows 400 ml/minute, and if all the water evaporates, each minute 903 kilo-joules of energy are extracted. One joule per second is the equivalent of 1 watt, so fully evaporating 400 ml/min of water provides a cooling power of 15 kilowatts!"

[SydneyJules]

Cool video! the surge is him backing off the throttle.

You can hear fluttering- sounds like wastegate- but obviously, no BOV. Charge is hitting the throttle plate and causing the surge.

On a side note, some guys at work had a compressor surge at 68kts on takeoff out of LAX last year- GE-115BL- 115,000 Lbs of thrust per side.

They said it felt like they drove over a car. Apparently she snapped about 15o sideways! The low speed meant that there was no aero loading on the tail, so the asymmetric thrust overcame grip until both thrust levers were retarded.

Understandingly, GE were pretty keen to examine the data, and issued a change to compressor wash procedures as a result.

Duk, please don't do what a reasonably well known Sydney BMW workshop did a few years ago.
They tuned a centri blown E46 325 with water injection running and the owner accidentally ran it dry and put a hole in 2 pistons!

Apparently these days, they tune it without the injection running... which, IMO, allows a bit more room for error!

[SydneyJules]

Ahhh idiot- just read the comments- a quirk of the dyno, apparently?

[MD]

...

the owner accidentally ran it dry and put a hole in 2 pistons!

All that could have simply been avoided by installing a low level float switch coupled to a warning light.

[Duk]

...

the owner accidentally ran it dry and put a hole in 2 pistons!

All that could have simply been avoided by installing a low level float switch coupled to a warning light.

Even better will be dual maps, 1 tuned for water injection and 1 tuned without water injection. A low level switch will give an input to the computer to swap between maps. So if I run out mid fang, computer just switches to the other map.
As Greg said, the biggest potential problem is from nozzle blockage. Good filtration of the water that goes into the pump should keep on top of that.

For anybody who checked out that Autospeed article, I have those same pump and nozzles (bought after I read the article ages ago) and hooked them up the other day, when it was surprisingly warm. The discharge air from the out side unit of the split system air conditioner, was a digital thermo couple measured 47*.
Ambient air was 36*. This is under my back veranda, so not in direct sun light or anything. Air movement was minimal and the humidity felt quite low. Lower than most of summer was, that's for sure.
I held the spray nozzle perpendicular to the A/C's condenser fan about 45cm away from the fan's centre and allowed the water to spray into the air the fan was pulling in. Some water was collecting on the wall of the house.
After about a minute of this water mist, condenser discharge air at dropped to 35*. So just below ambient air temperature.
No noticable water was coming out of the condenser's exhaust air but some water did start draining out the bottom after a while.

Now obviously I'm stating the obvious here, but it is a very good reminder of how effective evaporating water is at absorbing heat.