Questioning effectiveness of WI - only 5 celsius less!

[A4XRBJ1]

Hi everybody,


I'm so far quite disappointed with the effect that I see from installing the aquamist system 2D on my supercharged (Vortech stock with intercooler) Honda S2000, running with 8 PSI or 0.55 Bar, at this time running with water injection only, methanol still to come.

I did a quick test yesterday using the OBD sensors intake temperature and logging it. I've set the level to get the WI going on at 0.4 Bar, which means it only starts at about 7000 rpm's with WOT (car redlines at 9000 rpm's), so it's not injecting that much or for much time. I'll lower this today to get closer to positive pressure, seeing more injection and for a much longer period of time.

-> Any comments, what's the downside of injecting earlier or for a much longer time on WOT acceleration? Where should I start to inject, as the supercharger builds up the boost quite late?

Secondly, I only saw a reduction in intake temperature of about maximum 5 degrees celsius, mostly even less with 2 or 3 degrees celsius. You gotta be kidding if this is all that I could expect, for shelling out 900 bucks ?? I saw 42 degrees minimum on 22 degrees ambient temperature yesterday night, also due to efficient cold air intake and intercooler working well.

Any recommendations what is maybe going wrong? System seems to be installed properly, one injection with 0.7mm noozle on standard pressure right at the end of intercooler, about 15 cm away from the throttle body.

What kind of numbers have others seeing so far in regards to intake temp reduction?


Very disappointing so far,

Andreas

[simple]

I was always under impression that primary WI function is detonation suppression?..
Cooling effect is a bonus and depends on too many variables to rely on it. Say if intercooler is very efficient and ambient humidity is high WI cooling effect will be minimal.
Anyone to comment?

[JohnA]

...Any recommendations what is maybe going wrong? System seems to be installed properly, one injection with 0.7mm noozle on standard pressure right at the end of intercooler, about 15 cm away from the throttle body.

What kind of numbers have others seeing so far in regards to intake temp reduction?
Water Injection is not fitted for temp reduction primarely.
At least not in the way you've installed it. 15cm away from the throttle body is not much is it?
But fear not :wink:

1. Adding methanol in the mix will drop your temperatures further.

2. During hot, summer days the effect is much more pronounced. In the winter don't expect much difference, but then again temps are low anyway.

3. Water Injection has the main advantage that it provides IN-CYLINDER cooling. It is realised well into the compression stroke so your temp sensor in the intake won't register it. Your knock sensor will feel the difference though, mainly in the form of absence of knock (or serious reduction)
If your ECU retards ignition under knocking conditions then you will be spared that performance degradation - be safer away from possible damage as well.

[awdrocks]

I had the same problem with my test last night. I have a roots blower. I like 10cm before the throttle body and the water has to travel through my supercharder first then through my water intercooler... I saw NO drop in inlet temps. Also very disapointed. I live in Cancun and its very humid here, but also hot.

I did the test in nuetral and stationary.

But what you mentioned made sense. The effect will most likey be inside the combustion chamber, therefore the inlet temp senser not reading the lower temps. So my question is. If that the case would it be a good idea to get a EGT Guage to messure your exhaust temps to see if those are dropping conciderably?

[JohnA]

Correct, if the temperature of the water (being stored in the engine bay) is 60C and the intake temps are 80C, what sort of cooling would you expect to see after a brief contact between the two? a few degrees Celcius? Hardly noticeable eh?...

.... If that the case would it be a good idea to get a EGT Guage to messure your exhaust temps to see if those are dropping conciderably?
Funnily enough, NO :lol:
EGTs are not massively affected by water injection, strange as it may sound.
Piston crown, valve (and combustion chamber in general) temperatures do drop considerably but not EGTs.

The detonation threshold is lowered significantly, and that's what counts in the end.

[awdrocks]

Do you think I should get a EGT guage to furthure tune the motor and to make sure everything is safe? Or do you think thats just overkill if I already have a wideband?

[JohnA]

Wideband and EGT gauges compliment each other, the overlap is not large.

In my opinion, WB is higher up the priority list on a forced induction engine.

A decent way of knock detection is also very useful. On some engines KnockLink can be a useful instrument when fitted properly (may take time and experimentation though)

Be careful when using just EGT values for detecting lean conditions --- if you go very lean EGTs start dropping! It's easy to lose an engine from over-reliance on EGTs. They have to be interpreted in the context of the other parameters.

[awdrocks]

Wideband and EGT gauges compliment each other, the overlap is not large.

In my opinion, WB is higher up the priority list on a forced induction engine.

A decent way of knock detection is also very useful. On some engines KnockLink can be a useful instrument when fitted properly (may take time and experimentation though)

Be careful when using just EGT values for detecting lean conditions --- if you go very lean EGTs start dropping! It's easy to lose an engine from over-reliance on EGTs. They have to be interpreted in the context of the other parameters.

Right... I have a wideband and thats what I tune with. Im just wondering if it would be smart to get the EGT also. If im at a good A/F than there might not be any use to get an EGT.

If my A/F is perfect what can a EGT possibly be good for? What else can it help me with if my A/F is good?

[JohnA]

They are complimentary ---> you could be in perfect AFRs and as you get it to run at higher boost realise that EGTs are now getting out of hand.
That's when you revisit intercooling and ignition timing...

[awdrocks]

They are complimentary ---> you could be in perfect AFRs and as you get it to run at higher boost realise that EGTs are now getting out of hand.
That's when you revisit intercooling and ignition timing...

Cool deal. Im getting one.

[A4XRBJ1]

The car will be tuned again in about two to three weeks as I also have a new bored throttle body sitting here and I'm currently using a test pipe (with good results so far). We'll see how far we can change the timing and turn the fuel back, which is what really counts, I agree here.

I was only spoiled as on some webpages a large temp difference in intake temp was announced while using WI, which obviously was wrong or overstated.


I'll keep you updated,

Andreas

[ride5000]

Secondly, I only saw a reduction in intake temperature of about maximum 5 degrees celsius, mostly even less with 2 or 3 degrees celsius. You gotta be kidding if this is all that I could expect, for shelling out 900 bucks ?? I saw 42 degrees minimum on 22 degrees ambient temperature yesterday night, also due to efficient cold air intake and intercooler working well.

Any recommendations what is maybe going wrong? System seems to be installed properly, one injection with 0.7mm noozle on standard pressure right at the end of intercooler, about 15 cm away from the throttle body.

What kind of numbers have others seeing so far in regards to intake temp reduction?


Very disappointing so far,

Andreas

andreas, before you get too discouraged, i have to ask:

where is the IAT sensor on the car?

since you are using the oem ecu and obd2 to measure charge air temps, unless it is "downstream" of your point of injection you will see zero change in IAT.

it is not common to measure IAT post throttlebody. this is generally called CAT (charge air temp) or MAT (manifold air temp) and is really only useful if your ecu is running speed density as its load reference.

ken

[keithmac]

If you have an accurate and reliable way of measuring knock you`ll see a huge benifit, the right tune on water would be seriously bad for one without WI..