pt holt,
Water spray and water injection are two TOTALLY different things NOT to be confused.

Water spray is where water is just sprayed onto the intercooler to help the air to cool it down.

Water injection is where water is sprayed directly into the engine with the charge air. The idea is that in the process of it evaporating (heat exchange) removes the heat out of the air and cools the intake charge allowing a more dense charge to be crammed into the engine.

However, if the water does not evaporate sufficiently, the addition of this into the combustion process will LOSE you power (as you would expect - fire and water don't mix!).

This is why the rally teams use two controls to operate the water injection. If you just inject the water on a boost pressure switch, obviously under certain conditions you are injecting water into the engine when it doesn't need it and thus losing power (as the charge air temp is not sufficiently high to evaporate the water). Obviously the second control is therefore heat. On the Cosworth / Zetec rally engines, the water is injected into the inlet ONLY if the charge air is above 42°C AND the boost is above 7psi, if either of these parameters are dropped below, then the water is switched off.

Through rigourous testing it was discovered that if you inject the water before the air can climb in temperatue it can be controlled to the optimum level. However, if the water was injected into the charge air at 60°C, the air temperature would still continue to climb, but could not be reduced down to a safe temperature. This is why it is injected "early".

I would NEVER use water injection as an anti-detonant as it doesn't work the way you think it should and if it fails your engine goes pop. WI should only be used as an ACT control (as has been discussed at length before on 22.com).
Best regards
Mike

Well water injection sounds completely out of my meagre mechanical mind to make sure its operating correctly, any other suggestions ?

pt,

a couple of thoughts

- first of all the HKS downpipe will give you cat free benefit - but it has a poor flange and the gas flowing of the joints is also poor - so replacing it will help a little http://bbs.scoobynet.co.uk/smile.gif

- if you think you need a remap then this can make a huge difference - in my own experience optimising the map from winter to summer made around 20bhp difference - and that is a lot of add ons http://bbs.scoobynet.co.uk/smile.gif http://bbs.scoobynet.co.uk/smile.gif

- finally before replacing the manifold/headers think about gasflowing the heads - they are fairly constricted - with different routes out the cylinder (with a 90 deg bend in one!) I think it is about £400 plus getting the heads off and on again http://bbs.scoobynet.co.uk/smile.gif http://bbs.scoobynet.co.uk/smile.gif http://bbs.scoobynet.co.uk/smile.gif

R

J.

With all that extra water you must be carying, do you have a weight disadvantage http://bbs.scoobynet.co.uk/smile.gif

Hi folks, I have hit a barrier when it comes to buying things to make my car go quicker and I would be very interested to see what the general opinion is, in what way to go next.

The car is a 98 sti 5, full HKS decat exhaust (inc downpipe - ss one coming soon), possum link (tho this needs remapping which will be done soon), blitz induction kit, AP clutch.

I have had two alternatives offered so far, both being major work and both quite expensive.

1. replace manifold/header area for one with much larger ports to allow gas to escape quicker thru the above mentioned exhaust - approx 1700

2. replace the standard intercooler with a front mounted one for a simliar amount of money as number 1.

I am unsure which way i should go and what the benefits will really be.
I have seen people talk about replacing the turbo inlet pipe, is this something i should consider ? What would the benefits be ?

please help as i'm getting a little too bored and have some money burning a hole in my pocket that my wife is trying to use to have wood floors put through the house !

http://bbs.scoobynet.co.uk/biggrin.gif

Decisions..decisions... lol

Do what I did...

Fit them all.. http://bbs.scoobynet.co.uk/biggrin.gif

And then some.. lol

J. http://bbs.scoobynet.co.uk/wink.gif

Water Injection like Mark (R19 KET)?

Firefox,
My kinda attitude! http://bbs.scoobynet.co.uk/biggrin.gif
LOL
Mike

Ah yes i forgot water injection.

I've played with it in my friends evo 6 and it doesnt seem to make any difference at all ! (well other than covering the intercooler in windscreen washer bottle fluid lol)

Anyone tell me what the benefit of this is ? And whether it actually does anything.

yeah but like you said, thats in an evo. http://bbs.scoobynet.co.uk/biggrin.gif Talk to Harj about his water injection or give Powerstation a ring and let them tell you about it. Im thinking about that after Unichip.
Stu

But if i do go the front mounted intercooler route, can i still use the water injection ?
Or will it be wasted when i move it ?

Fancy a group purchase on one stupot ? :>

Guys..

WI can serve several purposes... either det, intake temps..etc... do a search... it has been covered. http://bbs.scoobynet.co.uk/smile.gif

In respect of det control ..water injection wont as such give you power... if you just inject water..you will find you will probably loose power.

The water allows you to tune the engine to obtain more power... so there is a comprise... where at one point you will loose power... then you might break even.. and the ideal result is that you obtain more power...the water moves the det threshold... allowing more advance..or more boost..

using it as a cooling medium will produce more power...*not always the case though).

The amount of water being injected and the location of the jets is important to...very inportant http://bbs.scoobynet.co.uk/smile.gif

Basically..what I am trying to say.. is check to see if you actually require it... if you arent getting det and your intake temps are fine.. then dont fit it.

I would suggest investing in a decent intercooler setup.

J. (Front mount I/C..with water spray.. thermal coatings on all pipes...twin water injection system) http://bbs.scoobynet.co.uk/smile.gif

Yeah, what J said! http://bbs.scoobynet.co.uk/wink.gif
I think perhaps water injection and I/C water spray are being confused here - hence 'covering intercooler in windscreen washer fluid' - which implies you are talking about spray.
Cheers
Chuck

chucky..

Well spotted...

He is confusing water spray and water injection...

The Evo's and type R's have water spray on the intercooler... no water gets into the actual intake system.

What Mark has is water injection..where you inject water into the intake.. mixing with the air..and then the fuel...

I run both.... yes I am greedy.. :-p

J.

yeah you're right chuck, i hadn't noticed the injection part and only thought of spray.

Didn't even know there was a water injection option !

Maybe i should just try to but firefox's car off him http://bbs.scoobynet.co.uk/smile.gif



[This message has been edited by ptholt (edited 10 August 2000).]

What extra water? I use the windscreen washer reservoir (with no washer fluid - just water).....

Mike..

I have a tank in my boot.. which feeds both spray and injection...

It helps keep the back of the car down... Tank on one side.. battery on the other... http://bbs.scoobynet.co.uk/smile.gif

J.