Pre and post turbo injection in an audi b5 s4
 

Hello Everyone, this is my first post on the forum but have been lurking for quite a few years. First I have to say thanks to everyone who has contributed to this forum over the years and helped the development of water and alcohol injection.

Seeing as there is a limited amount of information being shared I want to provide some insight on what I have put together in this application in the event anyone else can benifit from it and ask a question or two.

The car is a 2001.5 audi b5 s4, I raised the compression rato to 10.5:1 and have bored the cylinders out to around 2.9 liters of displacement. The car is currently set up with 1000cc injectors for the fuel circut and the turbos are K24's. I'm currently running without intercoolers but plan to re-install them in the summer months and log the differences. The car is almost complete and I should have it on the dyno in a few weeks.

As for the water injection, I plan on running de-ionised water and isopropanol.*
The pump is the same aquatec unit that aquamist, aem and devilsown provide. The lines are all ptfe lined, stainless braided *in -4 with repect to the pre turbo T which goes from -4 to -2. Also worth noting, all of the -4 fittings are crimped, not the rebuildable type. I have placed two injectors, one for each turbo about 6" before the throttlebody using 550cc jets on each side. I gave a call to Jeff at howerton engineering who got me set up with a pair of the beautiful axial brackets which I first read about here (thank you Richard) and am using 150cc jets in each bracket.*

I originally set up the system with a solenoid consisting of two ports, one in and one out. The pre turbo injectors are aquamist and the post turbo ones are aem and have check valves integrated into the injector bodies.
I decided after bench testing the system that i was not comfortable with the way the line pressure diminished in all four injection points, the way it tapered down pre turbo specifically after the solenoid had shut. After searching around and making some calls I was able to have a custom solenoid made that consists of two seperate coils and plungers with the capability of controlling two injection points independently. The port configuration has one in, two outs and a common exhaust port shared by both outs in the normally closed state. My intent is to have the line pressure pre turbo and tb diminish as soon as the solenoid closes helping the check valves to actually shut instead of taper down leaving solid drops where they shouldn't be.

Just to elaborate alittle further,*
port 1 is the pressure source
port 2 is the exhaust port, which will run to the washer reservoir
port 3 is pre throttle body
port 4 is pre turbo

Question 1, Has anyone else set up a system similar to this?

Question 2, I am considering swapping out my manual transmission radiator and using one with a built in oil cooler with the intent of running the alcohol through it. I'm hoping the extra heat transfer will be of some benefit in regards to line pressure, atomization and poential ratios of water to isopropanol. Has anyone tried this?

Thanks in advance, Marc

Pics for the curious:

http://imageshack.us/a/img209/485/ja9g.jpg
http://i301.photobucket.com/albums/n...oads/image.jpg
http://i301.photobucket.com/albums/n...ds/image-2.jpg
http://i301.photobucket.com/albums/n...05AC5C6805.jpghttp://i13.photobucket.com/albums/a2...A893B127CF.jpg
http://i13.photobucket.com/albums/a2...3C699F98A3.jpg
http://i13.photobucket.com/albums/a2...6DB4B0F67C.jpg
-2 an line to pre turbo injectors was a perfect fit in the sai ports with a little massaging:
http://i13.photobucket.com/albums/a2...87309FA61A.jpg
http://i13.photobucket.com/albums/a2...2F9A15CCF0.jpg
I havent put back in the pre turbo and exhaust lines but you can get an idea of the setup:
http://i301.photobucket.com/albums/n...8BA1792CE5.jpg
http://i301.photobucket.com/albums/n...C83335A9E8.jpg
http://i301.photobucket.com/albums/n...EE788DF3A6.jpg
http://i301.photobucket.com/albums/n...B658E3EF0F.jpg

Re: Pre and post turbo injection in an audi b5 s4
 

Nice work on the setup, I'll be testing a small .3mm Aquamist jet pre-turbo on a TSI engine in my MK6 GTI. I don't have access to the turbine wheel like you do with my K04 turbo so I decided to set the jet way farther back right at post MAF. I'll trigger it at high boost with a boost switch a separate solenoid fed from the line pre-FAV (non-progressive basically).

Re: Pre and post turbo injection in an audi b5 s4
 

Hi Marc,

Nice work indeed and I am sure you thought much about it.

I didn't understood well the solenoid system although it seems a little complicated and prone to fail or else not be precise as it should.

I am not arguing about your system but maybe I could suggest you a better way of what I have in my mind for my current setup.

I am running a 1.5L GT28 turbo target of 340bhp @ 22psi. Currently using post water (only) injection but considering pre-turbo.

I have the AEM injection system running 350cc post turbo and thinking of 150cc pre-turbo. Now since I have no intercooler, I am starting injection about 3psi with a gradual increase until full flow @ 150psi pump pressure till 18psi boost. Now I wanted pre-turbo to begin at least @ 10psi boost.

I intend to use a variable cracking pressure check valve mounted directly with the AEM nozzle and thinking of setting 100psi cracking pressure. This way you simply make sure that injection is pressurized enough to mist preventing blade damage and maximum atmoization. You only need to adjust correctly the check valve.

Here is the check valve in subject : http://www.ham-let.com/catalogue/product/7853

Regarding question 2 :

I tried to use the same theory but instead of radiator heat turbine exhaust heat !

I used a braided pipe from pump to engine bay and converted to a stainless brake line. Welded bracket to the brake line to a spacer that fits into three bolts of the turbine housing.
After testing, it eventually gave no positive results but instead exhaust heat was actually heating the intake through the line and nozzle!

To make sure the thoery of heating the liquid could make a difference .... try this as it was eventually easier to do !

Boil the distilled water using a kettle and pour nto the empty tank. Heat enough water and go for a ride immidiately after to test it.

I did it and eventually gave negative results of increased air temps by 10C !

Good luck

Re: Pre and post turbo injection in an audi b5 s4
 

Parmas,
Thanks for the input, I was thinking a check valve would be essential but wasn't sure on cracking pressure yet, i'll order some of those check valves and see how it functions again soon. With the check valves, the line sould keep filled and only discharge the line pressure back through the solenoid and into the washer res. To make sure it donen't drain the line between the solenoid and injectors, introducing air - I made sure to have the exhaust line higher than the rest of the circut.

Today I decided to do a threshold test on a stock audi radiator with an integrated gearbox cooler. I cut down the flanges and tapped the ports for -6 and put it on the test bench, It held up to 700 psi and ruptured internally at 800.
I don't expect that the trans cooler portion of the radiator would ever see more than 300'ish psi in operation, but we'll see what happens once it's set up.

Very interesting setup with the braided line, do you have any pics? 10*c is a huge rise!

More to come soon...
http://i301.photobucket.com/albums/n...8DFE810298.jpg

Re: Pre and post turbo injection in an audi b5 s4
 

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Re: Pre and post turbo injection in an audi b5 s4
 

Parmas,

Thanks for the formula and That car of your looks like a rocket, what does it weigh?
I'll be sure to set everything up with the check valves once Iv'e optimised the injection start points. The ham-let check valves are really nice, just waiting for them to email back so I can get them ordered.

The radiator would be used to heat the alcohol line, I'm going to conduct my first set of tests on the dyno without it and come back to this concept after everything else is dialed in.

Re: Pre and post turbo injection in an audi b5 s4
 

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Re: Pre and post turbo injection in an audi b5 s4
 

Parmas,

I got abold of somone over there, will see them in about five weeks or so.

You were right about the water and kettle trick, too close to the boiling point was a negative effect.
Wasn't sure about having an alcohol mix in it but I definately agree that heating iso would also be a very bad idea.

Re: Pre and post turbo injection in an audi b5 s4
 

Thank you for trying my suggestion. Now i am sure the theory is like that.

Also do not try to cool the water as I tried it aswell and was a negative result!

For once it seems that better leave it to whatever the ambient temp is

Re: Pre and post turbo injection in an audi b5 s4
 

I have tried precompression injection with a Rotrex C30-74. I took pictures of the turbine wheel before and after some use and could not spot a single difference except the blades looked more clean.

Powerwise I did not make any feelable difference comparted to direct port injection with similar flow. I injected 300ml/min.
The sound of the supercharger changes a bit. You can hear more of a noise. Intake asir temps drop to ambient using 50/50 water methanol.
The nozzle was positioned about 5" away from the intake that was S-shaped. I positioned in a way it would not pool on a wall.

Re: Pre and post turbo injection in an audi b5 s4
 

This is exactly what I'm going for.

Re: Pre and post turbo injection in an audi b5 s4
 

Did you used only Pre-Turbo injection during this test ?

If not, how much did you inject pre turbo?

What about spool up time ?

Could you explain exactly the noise you noticed? is it whining or scratching ?

Re: Pre and post turbo injection in an audi b5 s4
 

Yes, I have only used pre-turbo injection during this test.
I injected about 300ml/min.
I have no spool time as I use a mechanically driven supercharger, a Rotrex C30-74 at the time. It spins to 120000 rpm. The compressor wheel plus housing itself is actually from Garret.

The noise is a white noise sound. It sounds like a small boost leak or a compressed air blow gun being opened in your engine bay.
No scratching or whinning. It is a flow related noise. It is more a altered turbine sound rather than a additional noise. It completely changes the thermodynamics of the compressor, so that may as well induce a different sound.
My car has no sound insulation besides one piece of carpet on the fire wall . You cannot hear the radio past 30mph. But your hear everything that happens in the engine bay. The engine sits right behind the seats.

Re: Pre and post turbo injection in an audi b5 s4
 

Could be surge noise?

A picture of the Pre-compressor setup would be nice

Re: Pre and post turbo injection in an audi b5 s4
 

No surge, the (smallish) compressor was operated near the choke limit. Too much flow with too little pressure. A C30-74 is too small for a well flowing 1.8l 16V engine revving 7000+ rpm. I only got 0.6 bar out of it at max turbine revs. That's why I now run a C30-94.
Pressure did not change as did mass flow. Why should it. 5g/sec extra is not much at 200g/second.
The noise was not loud either, but you could hear it as there is no other intake noise.
I don't think it is something critical. Could be just the noise of fluid being "processed" by the turbine.
I don't have a picture. It is just a nozzle on the side of a pipe.
Throttle body-----horizontal straight pipe-----45?bend---short straight pipe with nozzle on side---45? bend back to horizontal---supercharger inlet.

This sound pretty much exactly like it
https://www.youtube.com/watch?v=LO0MGrkEWzI

Re: Pre and post turbo injection in an audi b5 s4
 

Thanks for that video. Although I do not like the sound it is making. Maybe you are injecting too much water ?

Could you re-test with a smaller nozzle and check if it makes noise aswell?

Re: Pre and post turbo injection in an audi b5 s4
 

I tried different jets. The noise is always there.
I'd not worry about it. It is likely fluid hitting the turbine casing wall at high speed.
I do not use pre-compressor injection in the moment. I use direct port injection.
Car is off the road until March. It's a roadster on UHP types and it is winter over here.

Re: Pre and post turbo injection in an audi b5 s4
 

I have tried different nozzles, there is hardly any difference.
The noise is most likely fluid hitting the compressor housing wall at high speed.
My intake uses a closed airbox. You don't hear the compressor with the roof off.
The airbox dampens the turbine's sound pretty well. This leads me to concluding it is the turbine housing as sound cannot not transmit through the intake air.
When I used a open cone filter at the beginning, it sound like a jet fighter or a XXL industrial vacuum cleaner on steroids in the engine bay. It is pretty loud.

Re: Pre and post turbo injection in an audi b5 s4
 

When I test my pre-turbo setup, I will post my results and note if any noise is heard.

Re: Pre and post turbo injection in an audi b5 s4
 

can't wait!

Re: Pre and post turbo injection in an audi b5 s4
 

any update?
my car is still in winter storage until March

Re: Pre and post turbo injection in an audi b5 s4
 

I have been working on it and tested it.

Currently injecting 350cc post turbo and 50cc pre-turbo @ 10psi till 18psi.

Ambient temp is 15C. Injecting 400cc @ 18psi result 35DegC on first run climbing to 45DegC on consistent runs.

After throttle is closed and cruising, air temp keeps a steady 15-20DegC. Note this is all without intercooling.
The crazy thing is that with water injection I am loading engine on boost from almost stoich at low boost while from 10psi+ running 13.5AFR and lots of advance !

Now I am working on wheel alignment issues so until then... no updates.

Next up... increasing Pre-turbo injection to 150cc total of 500cc

Re: Pre and post turbo injection in an audi b5 s4
 

Is there a way to block the post turbo jet to see the effects of only the pre-turbo? I'm installing a .3mm pre-turbo to start but I forget what the cc rating is.

Re: Pre and post turbo injection in an audi b5 s4
 

It is very easy to block the post turbo jet. Just a tap on the water line makes it running pre-turbo only.

The only issue is that I don't want to inject much pre-turbo so I am trying keep the post nozzle fixed while changing pre-turbo flow.

When I reach my goal of lowest air temp at max boost of 18psi, I will make 3 tests.

1. Post Turbo only
2. Pre-Turbo only
3. Post+Pre Turbo

With AFRs used / Ignition Advance / Air Temps @ Throttle Body / EGT readouts / Spark plug readouts including datalogs and graphs

Re: Pre and post turbo injection in an audi b5 s4
 

Is your pre-turbo progressively controlled by the FAV or is it running off of straight pump pressure, non-progressive?

Re: Pre and post turbo injection in an audi b5 s4
 

I am using the AEM progressive control system. Starting injection at 5psi and full at 10psi. Both nozzles use the same pump system and are connected with a Tee-fitting.

The only difference is that the pre-turbo nozzle has a custom made adjustable check valve in order retain it from injecting at low boost. The drawback of the nozzle is that it is more bulky than stock due to the springs.

Check out the attached Plug at last tune. Heat Range is 6 gapped 0.7mm.

AFRs are :

17-19 IDLE
16.5 - 17 Cruising
14s 0-5psi boost
13.5-13 6-18psi boost

Re: Pre and post turbo injection in an audi b5 s4
 

Seems to be a lot of soot on the firing ring.

Re: Pre and post turbo injection in an audi b5 s4
 

I agree ! And that is at 13.5 AFRs on load.

It surely will work with 14 AFRs

Re: Pre and post turbo injection in an audi b5 s4
 

Did you tune engine ignition on a dyno?
Did you try reaching MBT on the dyno as well?

Re: Pre and post turbo injection in an audi b5 s4
 

No dyno, tuning is done on street and datalogging.

Re: Pre and post turbo injection in an audi b5 s4
 

How much miles/Pulls did the plug's have seen?
I also agree, that this is a lot of soot for 13.5:1 AFR.

Mine look much cleaner on the top of the thread plateau even with 12:1 without WI activated.

Re: Pre and post turbo injection in an audi b5 s4
 

Maybe 200km with mainly high revs.

My engine is 8.5:1 compression with stock head and GT2560R turbo.