Water Spray/ water injection?
20 July 2002, 11:13 AM
#1
Scooby Regular
Thread Starter
Join Date: Jul 2001
Posts: 1,534
Likes: 0
Received 0 Likes
on
0 Posts
I think I know how water spray works, water is sprayed as a fine mist over the intercooler. Heat is taken away through evapouration. Howerver, I cannot get my head round water injection, how does this work?
20 July 2002, 11:22 AM
#2
Scooby Regular
Join Date: Mar 2002
Posts: 4,604
Likes: 0
Received 0 Likes
on
0 Posts
20 July 2002, 11:39 AM
#3
Scooby Regular
Join Date: May 2001
Posts: 1,835
Likes: 0
Received 0 Likes
on
0 Posts
Chaz,
water injection works by literally having an injector spray a very fine mist of water into the induction system (like a fuel injector) at around 8bar.
The injectors are very small 0.4mm to 0.7mm and have a complex mechanical element to create a very fine spray.
The way it works is that it increases the nominal RON of the inducted charge - water has a very high specific heat and so it cools the in cylinder charge and reduces the speed of the flame front - all of which enables higher boost pressures and increased advance - without getting the resulting det.
On my car - the use of water injection is like increasing the nominal RON rating around 6-10RON. The downside of course is that water is not combustible in an engine and so at peak power the required amount of water - in terms of latent heat loss is around 6-10bhp - however if you have a mappable system you can more than compensate for this with a more advanced map.
Or - if you have a standard ECU - the WI will prevent a much greater loss of power due to retardation and boost cut in extreme circumstances such as on a track day.
On the road a standard car would not really benefit from WI - however if you are tuning over 300bhp and have a mappable ECU then WI is a good investment.
The other factor to take into account is that if you map this way you are now dependent on the water system which may fail.
There will be two effects of the water system failing - first of all the protection offered by water will be absent - but also the car will run leaner (you need to map in less fuel when you have water) and you will then get more heat due to lean running and *POP*!
So if you run water you need a knocklink or a display showing knock count - and if they suddenly start to rise then you need to back off until you fix it!
You can of course run water purely as a protection - for example of you do lots of track days.
Overall I would recommend a non-mappable WI system for cars around 300bhp - especially if they are tracked - a 0.4mm injector will be fine - but will need to be cleaned/replaced regularly in case it gets blocked.
For cars above this level - with mappable ECUs then the mappable system is a nice luxury and will enable you to have some groovy parts on you car that are also found on the WRC cars - which includes a high speed valve system which gives pulsed injections. This enables the water to be mapped against boost pressure, engine speed, throttle position - etc, etc.
In addition you will need a tank, primiing pump and a few other bits and pieces - expect it to cost between £500 and £1,000 for a decent set up!
Trout
water injection works by literally having an injector spray a very fine mist of water into the induction system (like a fuel injector) at around 8bar.
The injectors are very small 0.4mm to 0.7mm and have a complex mechanical element to create a very fine spray.
The way it works is that it increases the nominal RON of the inducted charge - water has a very high specific heat and so it cools the in cylinder charge and reduces the speed of the flame front - all of which enables higher boost pressures and increased advance - without getting the resulting det.
On my car - the use of water injection is like increasing the nominal RON rating around 6-10RON. The downside of course is that water is not combustible in an engine and so at peak power the required amount of water - in terms of latent heat loss is around 6-10bhp - however if you have a mappable system you can more than compensate for this with a more advanced map.
Or - if you have a standard ECU - the WI will prevent a much greater loss of power due to retardation and boost cut in extreme circumstances such as on a track day.
On the road a standard car would not really benefit from WI - however if you are tuning over 300bhp and have a mappable ECU then WI is a good investment.
The other factor to take into account is that if you map this way you are now dependent on the water system which may fail.
There will be two effects of the water system failing - first of all the protection offered by water will be absent - but also the car will run leaner (you need to map in less fuel when you have water) and you will then get more heat due to lean running and *POP*!
So if you run water you need a knocklink or a display showing knock count - and if they suddenly start to rise then you need to back off until you fix it!
You can of course run water purely as a protection - for example of you do lots of track days.
Overall I would recommend a non-mappable WI system for cars around 300bhp - especially if they are tracked - a 0.4mm injector will be fine - but will need to be cleaned/replaced regularly in case it gets blocked.
For cars above this level - with mappable ECUs then the mappable system is a nice luxury and will enable you to have some groovy parts on you car that are also found on the WRC cars - which includes a high speed valve system which gives pulsed injections. This enables the water to be mapped against boost pressure, engine speed, throttle position - etc, etc.
In addition you will need a tank, primiing pump and a few other bits and pieces - expect it to cost between £500 and £1,000 for a decent set up!
Trout
14 March 2003, 01:27 PM
#5
Scooby Regular
Join Date: Nov 2000
Location: 32 cylinders and many cats
Posts: 18,658
Likes: 0
Received 1 Like
on
1 Post
Trout do you have any before/after ignition numbers where you pushed it right to the edge? If you are adding so much effective octane I would expect about 5 or more degrees and over 20 BHP imrpovement even considering the losses? Any data to share? Thanks, John
Thread
Thread Starter
Forum
Replies
Last Post
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
28 December 2015 11:07 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM
Pro-Line Motorsport
Car Parts For Sale
2
29 September 2015 07:36 PM