# W/M injection with Vagcom logs - "tweaking" advice requested



## Fast VW (Sep 24, 2002)

Ok first the setup (not much LOL): 
97 VW Jetta 2.0 
Neuspeed Supercharger with 2.4" pulley 
Autotech 270 cam 
Autotech 2 1/4 SS catback exhaust 
C2 30# injectors and tune 
Snow Performance stage 2 W/M injection based on MAF 
175ml/min nozzle 
Pump at factory pressure 
Start voltage of 2.8v 
Full voltage of 4v 
58% meth/42% water fluid mix by weight 
93 Octane fuel of course 

Ok so on these logs it was about 75 degrees out and I drove at highway speed for about 40 mins to make sure everything was hot, then I got off the highway and pulled over for about 10 mins while I turn on my lap tap and got everything ready to log info. Sitting for this time really allowed the charger to heat up because of no airflow. I started the car back up and did my first 3rd gear pull getting back on the highway. The area to look at is between the yellow bars. The blue bar is where the W/M injection turned on: 











Then I cruised on the highway for about 15mins to allow everything to cool down and did another 3rd gear pull: 











About 10mins later I did another 3rd gear pull: 











Then right after the third 3rd gear pull, I went from cruising in 5th around 75mph to 3rd gear WOT and 4th gear WOT: 










Looking at just the 3rd gear pulls (especially the 2nd and 3rd) I would say that I should turn up the pump pressure to get a little more water up top and leave everything else alone. But the last log I am not sure what to think any thoughts would be greatly appreciated! I am open to trying anything including messing around with the meth % again if someone thinks it may help.


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## Fast VW (Sep 24, 2002)

Another question is would there be any advantage or disadvantage to injecting less fluid with a higher percentage of water. Or asked directly, would my car run better or worse with a higher % of water but less fluid?


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## Fast VW (Sep 24, 2002)

OK I was logging some air temps and found my IAT sensor was bad. It was reading 50 degrees below ambient temperature. So I replaced it and switched to a 50/50 mix by weight. I also turned the pump pressure up 1 full turn. All other setting remain unchanged. 

Here are 3 new logs: 


WOT in 3rd gear: 










Another WOT in 3rd gear: 










Cruising in 5th and then down shift to 3rd gear WOT and 4th gear WOT: 









I think the logs look better but still need a little more. Any ideas?


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## Fast VW (Sep 24, 2002)

Just as an update to help anyone else. I experimented with different mixes ranging from 30% meth to 70% meth. I found the most detonation control and IAT control with a 50-50 mix (go figure LOL). I also turned the pump up to full pressure. So my final settings are:
2.8v start
4v full
175ml/min nozzle at max pump pressure
50/50 mix

Here is a cruise in 5th, down shift into 3rd WOT to 4th gear WOT:










Here is a 3rd gear WOT:









Now if I could only eliminate the knock in the lower rpm range. :banghead:


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## naemcivic (Aug 22, 2010)

thanx for all the real life data you have posted. it helps me out alot here! also, how much meth are you going through? I am running 40/60 WM here. and I got through 1 gallon really fast.


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## BLSport (Dec 24, 2005)

How much boost are you seeing down low where you're beginning to see the knock sensor activity?


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## Fast VW (Sep 24, 2002)

BLSport said:


> How much boost are you seeing down low where you're beginning to see the knock sensor activity?


About 3.5 lbs. Even before this car was FI, it didn't like much timing advance at light loads or lower rpms. 

To answer the other question, after 10 3 gear WOT pulls, I have used about 30 oz of fluid.


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## BLSport (Dec 24, 2005)

I imagine the timing written into the software rides close to the knock threshold in an effort to achieve best torque, and lets knock regulation keep things under control when conditions call for it.

Your latest logs don't look too bad, I wouldn't get too concerned as long as timing pull doesn't get too much higher than that; would be interesting to see if that goes away when the ambient temps drop a bit more. In the meantime, you might be able to take advantage of the extra timing; have you given any more consideration to lowering your injection start-point (lower MAF voltage), and adding a boost-triggered relay between your controller's output and your pump's input? You had mentioned that the only reason you have the controller adjusted where you do, is because it comes on too soon under light load/no-boost conditions if adjusted any lower.


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## Fast VW (Sep 24, 2002)

I would still like to try something but I need to find more information on the controller. As an example, how does the controller control the spray amount? I do not think the controller varies the voltage to the pump but will the "information pass properly through a relay? What happens if the main power line to the system is used? Will the controller provide proper information it it turns on and sees a non-idle MAF voltage?

I am not sure where to get this info and I do not want to break something experimenting.


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## BLSport (Dec 24, 2005)

I believe most controllers these days vary their output via pulse width modulation, rather than a variable analog output, however the result at the pump motor is effectively the same; the modulation varies, producing variable average output voltages to the motor.

In this respect, it's not really a signal per se, but rather variable DC output voltage/current. A relay (appropriately rated, of course) between the controller's output and the pump's input should conduct this "signal" just fine. The only question that remains, would be the potential effect on the controller or its output (if any), that may occur when the load (pump motor) is connected when the controller's output is already in an active state; i.e., wherever in the output map it would be at the time the relay activates. My gut feel is that the controller is designed such that it would tolerate this without issue, but it would be nice to know for sure before experimenting. :beer:


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## Fast VW (Sep 24, 2002)

Ok, I wanted to post an update plus get a little more help. I have been getting some pretty erratic results, so I thought. What has been happening is the outside temps have been changing pretty significantly from day to day and from morning to night. This has been influencing my logs more than I though it would. When the outside temp has been lower, I have needed substantially more fluid. From looking at my logs, the colder air is showing as a higher engine load. I am therefore assuming the colder, DENSER air is causing higher cylinder pressures and the need for higher octane is greater.

I have also been on the phone with a tech at Snow Performance and have learned that in some cases over injection of fluid can cause knock sensor activity. Not true detonation but causing the flame front to not "travel smoothly" and thus "trip" the knock sensor. I have been able to show this by over injecting and getting worse knock on my logs.

*Where I am somewhat stuck is what will happen next summer when the temps go from 40-50 degrees like they are now to 70-80 degrees. Will my need for fluid stay high because of the hot intake air, or will it go down because of the decreased cylinder pressure?*

Here is a log with the 225ml nozzle at full pump pressure, notice the engine load highlighted in orange and notice how good the knock sensor activity is:










Here is a log with the 225ml nozzle at full pump pressure, notice the HIGHER engine load (caused by colder air temps) highlighted in orange and notice how the knock sensor activity has gotten WORSE:










Here is a log with the 375ml nozzle at 1 turn up on pump pressure, notice the engine load highlighted in orange and notice how good the knock sensor activity is:










Here is a log with the 375ml nozzle at FULL pump pressure, notice the engine load highlighted in orange and notice how the knock sensor activity has gotten WORSE with increased fluid flow but no increase in engine load:









Any more input would be greatly appreciated!


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## Fast VW (Sep 24, 2002)

Ok after more tests/logs today, I almost have this. Today I tested with the 375ml nozzle, 2.9v start, *4.25v*, 1/2 turn up on the pump and then 1 full turn up on pump. The 1 full turn up was better. Still some knock on highest of engine loads.

Studying the logs according to engine load and NOT rpm is key. Raising the full voltage from 4v to 4.25v made a nice improvement in my ability to get more flow at higher engine loads while not "drowning" at slightly lower loads. Sounds very basic and elementary but when looking at rpms instead of load things just didn't add up. I still need more at higher engine loads so I am going to turn up the pump and raise the full voltage more.

I think the correct settings are going to end up at:
375ml nozzle
full pump pressure
2.9v to 3v start
4.5v to 4.75v full

I will post my final results (at least for colder weather)when I am done just in case this may help someone else. I will be putting the car away for the winter very soon so I will test the final cold weather settings with the higher air temps next summer to see how they fair.


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## naemcivic (Aug 22, 2010)

I have turned my full settings at 4.25V for a while and it seems to help alot in the colder climates we are facing here. 0c at night. By the way what is the HP you are making with your 97SC 2.0 8V?


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## Fast VW (Sep 24, 2002)

I do not know how much hp this set up has. I can tell you it doesn't have enough to run a 375ml nozzle. It must just produce a lot of heat.


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## Fast VW (Sep 24, 2002)

Here are the results of today's tests:
375ml nozzle
2.9v start
4.5v full (I tested 4.75v but it was not as good)
Full pump pressure
50/50 mix (by weight)

First 3rd gear WOT pull: 











Second 3rd gear WOT pull: 










5th gear cruise to 3rd gear WOT to 4th gear WOT: :banghead:











Some things about the log above. Notice how high the load is; this is the highest load I have seen yet and I just didn't get enough detonation control. I think this one can be improved by lowering the full voltage to 4.25v. I made a chart for the MAF and the total knock (all 4 cylinders added together) for this run; see below:










Notice how the knock peaks right at the beginning of 4th gear. I think that with a full voltage of 4.25v instead of 4.5v will help bring this area down by allowing more water/meth sooner. This will be my next set of logs. After that I will have to wait until summer to see how these settings do when it is 80 degrees instead of 40 degrees like it was today.


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## Fast VW (Sep 24, 2002)

Here are the results of lowering the full volatge to 4.25v:









Definitely better. Now if only the temp would go up so I could see how this will work in warmer weather. For now I am done unless someone has any ideas on how to improve the logs even more.


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## naemcivic (Aug 22, 2010)

thank you for all the posted logs. a little off track here, have you ever get a cloud of black smoke behind you at WOT off lift? I had a cloud of black smoke on a 3rd gear WOT pull the other night.


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## Christiene (Nov 9, 2010)

thank you for the posted logs .


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## Fast VW (Sep 24, 2002)

I have never seen a cloud of any type behind my car.

One thing to mention is that I do realize that I am sort of tuning the W/M injection backwards. For any one not familar with W/M injection here is the correct procedure:

Get the car set up and running well (i.e. AFR, timing boost levels, no knock, etc.)
Install the W/M injection kit and then lean out the AFR 1/2 to 1 point.
Turn on the W/M injection and increase flow until AFR returns to the "ideal" level.
Start adding boost and/or timing until knock appears or until no more HP is produced.
Reduce timing and/or boost back to where max HP without knock was achieved.

Unfortunately I do not have control over AFR or timing. I basically had everything running well, installed W/M, put the smallest pulley I could without exceeding the S/C max rpm, and then turned on the W/M to eliminate knock. Not the ideal way to go about it but I am sure there are many others who must do it this way.

I do have a cool Excel spreadsheat that I found on line that helps to calculate a lot of items for you. I would attach it for people to down load and check it out but I cannot/do not know how to attach a file. Here is a screen shot:


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## Fast VW (Sep 24, 2002)

Just out of curiousity, I installed the 625 ml nozzle to see what would happen. 
1. The injection turned on around 3300 rpms. 
2. I had slight knock in cylinder 1 that went away right after the W/M turned on
3. By 4000 rpms the motor felt slow
4. By 4500 rpms the motor was bogging
5. At 5000 rpms the motor started to misfire
6. CEL light came on

Here is the log:











I would think that if excessive fluid was causing knock in my set up, it would have shown up here. Especially since a scan of the ECU showed the misfires were in cylinder 4. I am putting the car away for the winter tomorrow so I am done until summer. 

As of now my best over all logs came from:
1. 375ml nozzle
2. 1.5 turns up to full pump pressure
3. Full voltage between 4.25v to 4.5v


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