Dual injection for twincharger

[dlheman]

Hi all,

I have this idea of going for dual injection for my VW Golf MK6 1.4TSI Twincharger. The goal is to cool down the supercharger, and I hope I can get an input if my idea is ok.

Below is a diagram I made:



And here is the engine


As of right now I already use 1g/h nozzle right after the intercooler outlet. It works great and to cool down the air charge and enough to allow me to run safely on Revo stage 1 98ron map on 95ron fuel.

But I am wondering what if I inject pre-supercharger, and if I do it would it be ok?

I only plan to use a small size 1g/h nozzle, just enough to cool the air intake entering the supercharger. But at around 3000rpm, the supercharger is turned off, and the bypass valve re-route the air intake to the turbo.

I read for pre-turbo it is best to have the nozzle very close on center. Now since I am spraying before supercharger with small 1g/h nozzle, I think by the time the air intake reaches the turbo it should already be fully vaporized and it should be safe for the turbo.

What do you guys think?

Please assists~!

[Flr Power]

Roots supercharger do not spin fast compare to turbo, so spraying right in front of them is not a problem. But why 3 IAT sensors?

[parmas]

Originally Posted by dlheman

Hi all,

As of right now I already use 1g/h nozzle right after the intercooler outlet. It works great and to cool down the air charge and enough to allow me to run safely on Revo stage 1 98ron map on 95ron fuel.

But I am wondering what if I inject pre-supercharger, and if I do it would it be ok?

I only plan to use a small size 1g/h nozzle, just enough to cool the air intake entering the supercharger. But at around 3000rpm, the supercharger is turned off, and the bypass valve re-route the air intake to the turbo.

I read for pre-turbo it is best to have the nozzle very close on center. Now since I am spraying before supercharger with small 1g/h nozzle, I think by the time the air intake reaches the turbo it should already be fully vaporized and it should be safe for the turbo.

What do you guys think?

Please assists~!

Hi DLHeman,

Since you have 3 IAT why not begin by giving us the temps you are seeing on each IAT at various RPM / BOOST ?

You could make a chart for us one with water injected @ ?flow while another chart with same titles but only inter-cooled. That would help us understand more your setup.

Also what water injection system do you have and what nozzles ?
(1Gal/hr seems too low) A picture could help

What about the bypass valve leaving it closed? Would that be possible or is it stock ecu controlled?

[dlheman]

Hello~!

Hmmm, I do not know why there are 3 IAT sensors, but I am guessing:

IAT 1 : measure air tempt coming out from S/C
IAT 2 : measure air tempt coming out from I/C
IAT 3 : measure air tempt inside the manifold

The twincharger is factory equipped, and I have no mean to control the bypass too. I do know that the S/C bypass valve re-route the air intake to turbo at 3000rpm and at that point the s/c is off.

I am using a simple boost triggered system by Devils Own, and 1g/h nozzle is (surprisingly) enough to drop down the IAT (based on VCDS datalogging software) to 2deg C above ambient from previously 15 to 20 Deg C.

To further justify this nozzle size there is no knock retard, and during the first log pull (3rd gear, full throttle from 2000rpm to rev cut) the AFR richen. On third pull the ecu adjusted the AFR and it advances timing also. I need to find the data somewhere in my PC as it was a long time ago when I did this. Perhaps this is because it is only a 1.4L engine, so 1g/h nozzle is enough. Oh, and I am on 30% methanol by weight.

Now although there are 3 IAT sensors (note: i read this somewhere, and I can see the 2 sensors except the one on the manifold as the manifold is close to firewall), the VCDS software only shows 1 IAT parameter. So I do not know what are the three individual IAT are reading.

Suffice to say, the ECU is happy with the introduction of 1g/h WMI fitted on post intercooler.

But since there is a S/C, and it is very hot in where I live, I thought maybe it is a good idea to cool down the S/C too (this is the main goal) and honestly I don't know what to expect, except I figured cool air surely is good for the S/C. Afterall much of the driving is within the S/C zone. And surely cooler air is also good for the turbo. At least that's what I think.

My only concern is, would the WMI be bad for my turbo since it is placed far away? Or, would it be ok since I only inject 1g/h and it would evaporate by the time the air reaches the turbo. My brain said is ok, but then I have never done anything like this before when it comes to WMI.

I will try dig for some picture later, but it is a pretty basic install with nozzle right after the intercooler outlet.

[parmas]

What is your ambient temp actually?

From above it seems you are below 15C of temp into intake plenum?

[dlheman]

Oh yes, I am sorry I didn't mention the ambient tempt.

Ambient based on the dash reading is, say 33deg C. On engine it can get to 36deg C - based on log pulls.

Here is a couple of shots from some logs I made a long time ago:

Without WMI


With WMI 1g/h


I am guessing this is the reading from the IAT sensor inside the manifold. There is only one IAT field available to be log.

[parmas]

What is the max boost pressure you are running ? Also if you put the gear at 4th @ 1000rpm with full throttle pressed, how much boost will you see at 2Krpm / 3Krpm etc..?

At what boost or rpm are you injecting water ?

Is the water injection system constant pressure or variable according boost?

Make sure which IAT is that you are reading from. Do you have realtime air temperature readouts ?

[dlheman]

I don't know how it is if I do 4th gear full pull from 1000rpm, but why at such low rpm and such tall gear? Besides, the DSG will kick down a gear or two if I try to do that.

But on 3rd gear pull from 2000rpm the boost looks like below:


(I believe this log was done with 2gh nozzle)

The injection is progressive, and right now I just set mine to start at 4psi and max at around 16psi. I believe max rpm boost is about 18psi.

The IAT value from the VCDS is for sure inside the manifold. It has always been the value to refer to regarding intercooler effectiveness.

[parmas]

Originally Posted by dlheman

I don't know how it is if I do 4th gear full pull from 1000rpm, but why at such low rpm and such tall gear? Besides, the DSG will kick down a gear or two if I try to do that.

The 4th gear is normally the 1:1 ratio. Full throttle at 1Krpm on 4th gear, will understand how much quickly boost is generated. Since you have a supercharger + turbo that should work quite good.

But on 3rd gear pull from 2000rpm the boost looks like below:


(I believe this log was done with 2gh nozzle)

First the ignition timing seems too low. Idle @ 13Deg at transient throttle goes -6Deg seems out. Also @ 4.5Krpm still @ 0Deg with a total of 7Deg @ 6.3Krpm. Or your engine is vhigh compression or your engine is overadvanced internally.

Fuel table seems not that bad although it can be improved according your setup

Figure 3 only shows Boost duty of the solenoid, there is no actual pressure values. That chart is only good to verify ecu pressure value vs actual pressure value.

The injection is progressive, and right now I just set mine to start at 4psi and max at around 16psi. I believe max rpm boost is about 18psi.

I believe you need a Boost gauge to be sure.

The IAT value from the VCDS is for sure inside the manifold. It has always been the value to refer to regarding intercooler effectiveness.

IAT 2 is also a reference after the intercooler which it is also just after the water nozzle. From experience, with that diagram you will get colder temps on IAT2 than on IAT3.

[dlheman]

Ah ha, thanks for the input.

The software is by Revo, so I've no idea what was done to it. Though the car is very smooth and no problems. And the log method is by them too.


So what do you think? You think it is ok to add 1g/h pre-charger nozzle? And do you think it will cause problem for my turbo since I am injecting so far away from it?