GZE Questions

[Ben Wilson]

I'm injecting water before the SC to improve sealing and it seems to work OK. I've never tested it with the water off though.

[myne]

Rickq, have you considered simply fitting 8.9:1 gze pistons and a smallish T20 (or similar) turbo to your current engine?
You're likely to get similar response to the SC without the headaches of modding basically everything. You've also got a far larger range of turbos than you would SC's.
With the T2X series manifold, you can try everything from the T20 to the T28, and move your power band till you like it most.
As for implementation, it's remarkably simple once you've done the internals.
If you havent got an aftermarket ecu, you'd need to acqire a MAP sensed GZE ECU and appropriate sensors and wire it all in etc.
But you'd have to do that if you started with a GZE base anyhow.
With the GZE base, you have to find a spot for the SC, redo the inlet tract almost from scratch (due to the north south conversion)
It's a big job, and without other mods, you're likely to achieve a mere 100kw @ the treads.

In the future, once you've adapted to the power, and become bored of it, you're quite likely to try find an SC14, and deal with THAT headache, or go turbo anyhow.

It's up to you, but after watching a doco on jet engines and the huge fan efficiency improvements they've made in the last 5 years, I'm definitely thinking turbo's have to have come a long way too.

[nick.parker]

Howdy Ben,

I am really interested to hear more results about your car running with and without the water injection. I have tried water injection on my current setup with a 0.4mm Aquamist nozzle, and while it increases manifold pressure by 5 - 10kPa, and the engine feels smoother too, it dents the torque curve a bit. I treid adding a couple more degree when mist was on (after a short delay - custom ECU code) but that didn't make up the difference (maybe I needed to add more or lean my mix a bit or something).

I haven't given up its just on hold. Interestingly a few years ago when I used a crude windscreen washer pump, garden watering nozzle and stock ECU with a 165mm crank pulley I got a SOTP torque increase right to 7000rpm, its was really amazing. I did testing (different hills and roads) and data logging on inlet temps. It was incredible, flick the dash switch and get 5% more torque and a softer exhaust note!

All the systems I have since tried since (with finer mist) have always put a big dent in the torque - there must be something in that. I have always been injecting prior to the SC.

I am interested to know if it is not sealing, but actually the water vapour pressure increasing manifold pressure as at STP steam displaces more than 1000 times its volume (compare to its water volume) I think.

Cheers, Nick

[myne]

1600x
Amazing to think I could fill my 4age with 1cc of water.

You might have simply stumbled on something that accidently worked.
Theoretically, if you can keep the water and the fuel seperated in the chamber, you should be able to gain a shitload of power by using the explosion to heat the steam.
Was the old one using a topmount?

The other possibility is that one of the cylinders was detonating slightly with whatever shitty fuel we had back then, the water fixed that and the ecu restored the timing.

How long ago was it? What fuel? What happens if you fill up today with normal ULP and water inject?

[nick.parker]

Myne,
That is a possibility I have considered (regarding the knock sensor), but I don't think that is what I was fixing. It was when I lived in NZ a few years ago. I used 96 all the time, which I know was fine because once I used 91 and it was almost was fine (dont ask!).
Now in Perth with a slightly more modded car, I use 98 all the time, though 95 would be fine on my current 12psi. On 18psi I need 98! Anyway my ECU is custom, and currently without a knock input so I cant test that theory.

Edit: I just realised that I tried two systems on my old car. The coarser mist increase torque.
The fine mist slaughtered my torque by what felt like 20% at the time - a huge loss of torque - did back to back tests with the system off and on.

Cheers, Nick

[RonRob]

Nick, that is a very interesting find with the pre water injection mister. I myself have used water injection for years and have yet to use it in which I am benefiting from it. I am however going to tune on the edge with my water injection once I reach full potential to see what type of power I can get. I would like to think your loss in power is due to a richer mixture in which at that point timing can be added. It could also be possible that your nozzle for a fine mist was too big. I recall when I used a nozzle too big the car would bog down slightly. Do you have a wide band as I am curious to know what your afr are with and without the water injection.


Ron

[nick.parker]

Hi RonRob,

Yep, I have a wideband which I use to tune with. I will need to set up some experiements again (get my mist injection system out of the junkbox and re-install it - the compressor had a melt down about 6 months ago, so in needs some work).

I would love to get back those old results with more torque again. At the time I was so surprised that the extra power went through to practically red-line (or 7000rpm) as I expected that ignition advance would be required due to the (from my reading) cylinder pressure peak occurring later in cycle.

At the time it made my blood run cold..I was like what the????!!!! It was beautiful going up a hill under boost in 3rd, I could flick the mist on switch, and instantly the engine sound changed to a softer/more muffled sound and the effect of intercooler heatsoak would just vanish (instant torque increase), switch off and instantly the opposite would happen - less torque harsher exhaust note.

I know somebody who used to live in South Africa and his dad had a ute with carby.
He had water injection via venturi in the carb. And they always knew the water bootle needed filling because the ute because less responsive to drive... (no knock sensors there!)

Cheers, Nick

[RonRob]

Perhaps you where not injecting enough water with the fine mist. I forgot the outlet temps of the s/c12 and 14 do get pretty high. I have recorded 350f on the outlet of s/c12 and 14. I see you where running a 4mm nozzle. I am running a 6mm after the charger, but do not run it every outting. If I recall it was a 8mm nozzle that made the car bog, but then again that was with the s/c12 on a map based Ze which the stock ecu is rich up top so I am sure I was not helping much.

Ron

[camrygt?]

sorry if this is a bit off topic but on the subject of water injection, what would happen if I was to inject water with a high pressure pump into my exhaust manifold before the turbo?

I know this would cool the exhaust making its volume smaller but surely this would be offset by the increase in volume (1600x aparently) when it vaporises the water.

The higher pressure should spool the turbo faster and I imagine that even off boost the exhaust would have enough energy to vaporise at least some water.

People have injected water before turbos and superchargers on the inlet side of things so if its vaporised I assume the abrasive effect wouldn't detroy the wheel.

Any thoughts?

[Ben Wilson]

I think I'd ask that on the Aquamist forums:

http://www.aquamist.co.uk/phpBB2/index.php

I'm using a high pressure (9 BAR) pump and a fuel injector controlled by a Jaycar pulse modulator kit. That allows me to map the mixture fairly accurately, if I find a cheap fuel only ECU I'd try it out just to make tuning easier. I'm running about 12% water/fuel at WOT at the moment.

I've also got a little corrosion inhibiter added to the water to stop the injector/FPR from rusting..

[Starfire]

Mix up a batch of 60% water and 40% alcohol. Should have much better results. (keep the alcohol content below 50% though as after that it can burn )

[Ben Wilson]

I'm a little worried about alcohols effect on the bearing seals/rotor coating on the supercharger...

[RonRob]

Are you running your injection pre supercharger as well Ben? Have you noticed a difference in power doing this way?

Ron

[Ben Wilson]

I gained 1-1.5psi, and the inlet temps are pretty good, so I assume there was a corresponding power increase.

[Starfire]

The rotors are coated in teflon and the bearings are sealed running their own oil supply. There is very little danger of alcohol having any effect on it.

A replacement supercharger is pretty cheap anyway if you do have any problems (which you won't).