Water Injection
Author
Discussion

piefacemate

Original Poster:

592 posts

194 months

Saturday 5th February 2011
quotequote all
What are the general thoughts on water injection with turbo charged MX5's? Seems to be popular over the pond but I've not seen that many here using water or ethanol injection.

I'm thinking that with my plans to track the Mazda, and desire to remap from my 'safe' map to a more aggressive 240-250BHP, that it could be a good investment to allow safer hard use on track.
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One specific question; will a Link ECU G4 manage a water injection system? Obviously, this is a moot thread if it doesn't as I'm not willing to replace the ECU.

rob0971

74 posts

191 months

Saturday 5th February 2011
quotequote all
The only negative with water injection is running out of water! & that can be avoided. Totally safe for the engine, think of driving on a cold foggy day.
I think its worth it purely for the knock protection.

MX-5 Lazza

7,954 posts

242 months

Saturday 5th February 2011
quotequote all
Yes it is worth it. I don't have WI so have mine tuned to be a bit rich at WOT to protect it on track. Using WI I could have the AFR mapped more aggressively for power and probably add in a bit more timing advance too. There are actually quite a few with WI, mostly Turbo but also a few SC. Take a look over on Nutz and you'll find plenty of good help & advice.

piefacemate

Original Poster:

592 posts

194 months

Friday 11th February 2011
quotequote all
Thanks, sounds like it's certainly worth considering. Anyone know the Link G4's capacity to manage such a system? Where in the North West might be worth considering to install and map?

MX-5 Lazza

7,954 posts

242 months

Friday 11th February 2011
quotequote all
Ask on Nutz and someone will probably offer to help - there are loads of FI Nutzers up your way wink

ETA: If the car will be regularly used on track I wouldn't tune it too aggressively. You need to build in a good margin as track use puts a lot more load on the engine than road use. Constant full throttle & high revs mean very high temps so use fuelling, timing and WI to make sure the car is safe rather than trying to extract every possible hp smile

Edited by MX-5 Lazza on Friday 11th February 12:36

piefacemate

Original Poster:

592 posts

194 months

Friday 11th February 2011
quotequote all
Bloody hell, I waste enough time on here without adding another forum to the mix.

They grown up a bit, or do they still spend half their time talking in kiddie speak and slagging each other off?

MX-5 Lazza

7,954 posts

242 months

Friday 11th February 2011
quotequote all
piefacemate said:
Bloody hell, I waste enough time on here without adding another forum to the mix.

They grown up a bit, or do they still spend half their time talking in kiddie speak and slagging each other off?
There is a bit of that on there but it's still the best place for FI advice. I don't get the time to visit much myself either - PH and PlanetMX5 is enough for me but I do pop over there whenever I need a bit of technical advice.

Richyvrlimited

1,870 posts

186 months

Friday 11th February 2011
quotequote all
piefacemate said:
Bloody hell, I waste enough time on here without adding another forum to the mix.

They grown up a bit, or do they still spend half their time talking in kiddie speak and slagging each other off?
The kiddie speak is something I absolutely detest and pull members up on to stop. I don't see anymore slagging off than other forums, (have you ever been on miataturbo.net? they don't put up with any crap there!)

RE: your original question, the LINK G4 STORM only has 4 injector drivers according to their website, unless there is a spare PWM output you won't be able to hook up an Aquamist fast acting valve and control water flow via it, (Though if you have an early 1.6 you'll only be using 2 of the injector drivers so in theory could). However you can use a completely standalone system, Aquamist sell varying degrees of complexity kit, some you can intergrate with your ECU, others tap into an injector PW signal and then use that to modulate water flow independant of the ECU.

The most basic of WI kits have a pressure based switch so they activate at a certain inlet tract pressure (that you set), and continusly flow water until that point is dropped past, they're not ideal but still work very very well.

The previously mentioned mt.net has a lot of knowledge on WI, I'd suggest searching a lot before posting though.


piefacemate

Original Poster:

592 posts

194 months

Saturday 12th February 2011
quotequote all
Richyvrlimited said:
The kiddie speak is something I absolutely detest and pull members up on to stop. I don't see anymore slagging off than other forums, (have you ever been on miataturbo.net? they don't put up with any crap there!)

RE: your original question, the LINK G4 STORM only has 4 injector drivers according to their website, unless there is a spare PWM output you won't be able to hook up an Aquamist fast acting valve and control water flow via it, (Though if you have an early 1.6 you'll only be using 2 of the injector drivers so in theory could). However you can use a completely standalone system, Aquamist sell varying degrees of complexity kit, some you can intergrate with your ECU, others tap into an injector PW signal and then use that to modulate water flow independant of the ECU.

The most basic of WI kits have a pressure based switch so they activate at a certain inlet tract pressure (that you set), and continusly flow water until that point is dropped past, they're not ideal but still work very very well.

The previously mentioned mt.net has a lot of knowledge on WI, I'd suggest searching a lot before posting though.
Thanks, very interesting.

I have a '90 1.6 so guessing I'm likely to be just using the two injectors. Is there an easy way to determine if this is the case?

Richyvrlimited

1,870 posts

186 months

Sunday 13th February 2011
quotequote all
Unless you've modified your car to be sequentially fuelled it'll be running batch injection.

If your really not sure just check the injector clip wires, the wire colours will match in pairs, (cyl 1&3 and 2&4 are fired together).

MX-5 Lazza

7,954 posts

242 months

Sunday 13th February 2011
quotequote all
I thought all Mk1/2/2.5 ran batch injection as standard. Pretty sure my 01 Mk2.5 does. Same goes with spark.

Richyvrlimited

1,870 posts

186 months

Sunday 13th February 2011
quotequote all
No only early mk1 - aka pre 93 - MX5's are batch injection, after that they are all sequential injection. Your MK2.5 is definatly sequentially fuelled wink

All MX5's are wasted spark until the MK3 which is sequential.

MX-5 Lazza

7,954 posts

242 months

Sunday 13th February 2011
quotequote all
Well there you go, what do I know jester

piefacemate

Original Poster:

592 posts

194 months

Monday 14th February 2011
quotequote all
All sounds very complicated does this, will do a bit more research on Nutz and see if I can get my head around it a bit better. CHeers for everyones input so far.

Richyvrlimited

1,870 posts

186 months

Monday 14th February 2011
quotequote all
WI can either be complicated (PWM controlled via either a standalone system or intergrated into your ECU) with lots of failsafes (low water switches that trigger a safe map etc.)

Or it can be simple, tank, pressure switch pump and nozzle. the former provides better gains and a more driveable car (you need less water at lower rpms, and ideal water %age varies depending upon load which is why PWM control of a valve is ideal).

It also depends on what you want from it, an added layer of safety, or a means to reach MBT at high power levels.

What you choose is entirely up to you, even the most simple setup provides a huge amount of detonation resistance.

It's well worth reading the Aquamist forums too btw smile