Pre turbo nozzle placement

turbobooster · 05-14-2008

^^^Hey, that's me! Cool.

Terry Syd · 05-15-2008

Turbobooster, great to hear someone else is working through these fine points of water injection. Mate, I've got other things on my plate at the moment, so if you want to switch the positions of the DO1/DO2 to a DO2/DO1 and get back to us, I'd sure appreciate the feedback.

turbobooster · 05-15-2008

You may find this interesting, but I have since doubled the amount I am injecting. I am running a 2gph nozzle preturbo and a 4gph nozzle right before the manifold. No signs of quench, just more power.

Terry Syd · 05-15-2008

Actually, that is what I theorised may happen, but I needed some emperical evidence to support it.

My theory is that the liquid through the turbo becomes completely vaporised, and then the post-turbo nozzle dropplets make it to the engine largely intact. There would still be some vaporisation of the methanol in the post-turbo nozzle discharge as methanol can still vaporise in water saturated air.

Since I was using a M3 post-turbo before going to the M1/M2 combination, I might be able to get by with a M2/M3 combination.

Here is the problem I see with this set-up - pressure. As Dvldoc has mentioned the M1, M2, and M3 will work above 200 psi for good atomisation so that the droplets don't erode the compressor wheel. However, once we increase the flow above the M3 level the pressure drops below 200 psi. So, as in your case with the M2/M4 you are effectively running an M6.

Perhaps Dvldoc can give us an idea about droplet size at the pressure level of an M6.

dvldoc · 05-15-2008

Our nozzles don't make anything bigger than 30 microns at 100psi. For the most part around 17 to 18 microns for the 1 to 3gph nozzles.

Terry Syd · 05-15-2008

So then comes the next question, at what point does the dropplet size become critical to the longevity of the compressor wheel?

Admittedly, there would be large variations between turbos. A turbo working at higher speeds would likely face a greater chance of erorsion, a lesser quality of metal in the compressor wheel, etc. - but is there some rule of thumb that we can use?

Dust · 05-15-2008

Tests have shown that diesels can take quite a bit of water in the combustion chamber. I don't remember where I read it though, it's been a long time. Why not keep the M1 pre turbo, and bump up the post turbo nozzle. It will keep the little amount cooling the turbo, and the big amount cooling the engine.

Terry Syd · 05-15-2008

Dust, this is why I would like to see a dyno run of the M1/M2 configuration against the M2/M1 configuration.

The water going through the turbo drops the temperature so that the air is closer to ambient temperature as it comes out of the turbo. This decreases the work that the turbo has to do and opens the wastegate. It can also eliminate the need for an intercooler. This should be a more effective use of the water than putting it in the cylinder (unless we have high egts, then we have to dump in a lot of water)

We don't have any figures yet for the amount of water that can be put through a turbo. Perhaps in the future we may have some formula that relates to displacement and boost pressure. A formula would allow us to increase the flow into the turbo without causing an excess of water. An excess of water may accelerate compressor wheel erosion. It would be desireable to find the 'just right' flow for a given engine.

Having said that, if I swap the M2 to the pre-turbo position that will increase my water flow through the compressor by 100%. That is a significant increase of water and still allows me to keep the very fine water droplets. Perhaps it may exceed the 'just right' flow, however keeping the droplets very fine would mitigate erosion problems.

I will have to find the 'volume of a sphere' formula. There is a considerable increase in mass when the diameter of the droplet is increased.

I also think a small amount of methanol in the water is desireable for the pre-turbo nozzle installation. The addition of just a small amount (10%) will help to decrease the surface tension of the water. This may help to break up the droplets so that there is less tendancy for erosion.

Todd · 05-17-2008

Hi Guys,
Hope you don't mind me tacking on to your thread but I'm in the process of setting up water injection on my 7.3IDI with a Banks Turbo & you've got my interest about pre turbo injection. The calcultor shows that I need 11gph so I was thinking about putting an M3 pre turbo & an M7 in the Plenum spraying direct into the original intake. Any thoughts?
Cheers, Todd

Terry Syd · 05-17-2008

Todd, I'll jump in, but I ain't a WI specialist. As you have seen from the previous posts, WI pre-tubo works (and works well). The big issue is erosion of the compressor wheel blades from too large of droplets. If you are using one pump, then the M3 nozzle pre-turbo will not be running over 200 psi if you have another M7 running in parallel with it.

My initial impressions is to run two pumps, one for the pre-turbo M3 and another for the post-turbo M7 (or what ever you end up with). You could have them both kick in at the same boost pressure or at different pressures. The pre-turbo injection could come in a bit sooner than the post-turbo as you want to spool up as quickly as possible.

Just my impressions, comments are welcome.

05-14-2008	#11 (permalink)
turbobooster Water Injection Newb Year: 2000 Make: VW Model: Golf TDI Join Date: Apr 2008 Posts: 2	Re: Pre turbo nozzle placement ^^^Hey, that's me! Cool.

05-15-2008	#12 (permalink)
Terry Syd Alcohol Holic Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 104	Re: Pre turbo nozzle placement Turbobooster, great to hear someone else is working through these fine points of water injection. Mate, I've got other things on my plate at the moment, so if you want to switch the positions of the DO1/DO2 to a DO2/DO1 and get back to us, I'd sure appreciate the feedback.

05-15-2008	#13 (permalink)
turbobooster Water Injection Newb Year: 2000 Make: VW Model: Golf TDI Join Date: Apr 2008 Posts: 2	Re: Pre turbo nozzle placement You may find this interesting, but I have since doubled the amount I am injecting. I am running a 2gph nozzle preturbo and a 4gph nozzle right before the manifold. No signs of quench, just more power.

05-15-2008	#14 (permalink)
Terry Syd Alcohol Holic Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 104	Re: Pre turbo nozzle placement Actually, that is what I theorised may happen, but I needed some emperical evidence to support it. My theory is that the liquid through the turbo becomes completely vaporised, and then the post-turbo nozzle dropplets make it to the engine largely intact. There would still be some vaporisation of the methanol in the post-turbo nozzle discharge as methanol can still vaporise in water saturated air. Since I was using a M3 post-turbo before going to the M1/M2 combination, I might be able to get by with a M2/M3 combination. Here is the problem I see with this set-up - pressure. As Dvldoc has mentioned the M1, M2, and M3 will work above 200 psi for good atomisation so that the droplets don't erode the compressor wheel. However, once we increase the flow above the M3 level the pressure drops below 200 psi. So, as in your case with the M2/M4 you are effectively running an M6. Perhaps Dvldoc can give us an idea about droplet size at the pressure level of an M6.

05-15-2008	#15 (permalink)
dvldoc DevilsOwn Staff Join Date: Apr 2005 Posts: 2,043	Re: Pre turbo nozzle placement Our nozzles don't make anything bigger than 30 microns at 100psi. For the most part around 17 to 18 microns for the 1 to 3gph nozzles. __________________ Currently deployed to Ramadi 1 battalion 12th Marines Task Force MP

05-15-2008	#16 (permalink)
Terry Syd Alcohol Holic Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 104	Re: Pre turbo nozzle placement So then comes the next question, at what point does the dropplet size become critical to the longevity of the compressor wheel? Admittedly, there would be large variations between turbos. A turbo working at higher speeds would likely face a greater chance of erorsion, a lesser quality of metal in the compressor wheel, etc. - but is there some rule of thumb that we can use?

05-15-2008	#17 (permalink)
Dust Alcohol Holic Year: 1999 Make: Daihatsu Model: Move Join Date: Mar 2007 Posts: 330	Re: Pre turbo nozzle placement Tests have shown that diesels can take quite a bit of water in the combustion chamber. I don't remember where I read it though, it's been a long time. Why not keep the M1 pre turbo, and bump up the post turbo nozzle. It will keep the little amount cooling the turbo, and the big amount cooling the engine. Last edited by Dust; 05-15-2008 at 07:32 PM.

05-15-2008	#18 (permalink)
Terry Syd Alcohol Holic Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 104	Re: Pre turbo nozzle placement Dust, this is why I would like to see a dyno run of the M1/M2 configuration against the M2/M1 configuration. The water going through the turbo drops the temperature so that the air is closer to ambient temperature as it comes out of the turbo. This decreases the work that the turbo has to do and opens the wastegate. It can also eliminate the need for an intercooler. This should be a more effective use of the water than putting it in the cylinder (unless we have high egts, then we have to dump in a lot of water) We don't have any figures yet for the amount of water that can be put through a turbo. Perhaps in the future we may have some formula that relates to displacement and boost pressure. A formula would allow us to increase the flow into the turbo without causing an excess of water. An excess of water may accelerate compressor wheel erosion. It would be desireable to find the 'just right' flow for a given engine. Having said that, if I swap the M2 to the pre-turbo position that will increase my water flow through the compressor by 100%. That is a significant increase of water and still allows me to keep the very fine water droplets. Perhaps it may exceed the 'just right' flow, however keeping the droplets very fine would mitigate erosion problems. I will have to find the 'volume of a sphere' formula. There is a considerable increase in mass when the diameter of the droplet is increased. I also think a small amount of methanol in the water is desireable for the pre-turbo nozzle installation. The addition of just a small amount (10%) will help to decrease the surface tension of the water. This may help to break up the droplets so that there is less tendancy for erosion.

05-17-2008	#19 (permalink)
Todd Water Injection Newb Year: 1991 Make: Ford Model: F350 Join Date: May 2008 Posts: 6	Re: Pre turbo nozzle placement Hi Guys, Hope you don't mind me tacking on to your thread but I'm in the process of setting up water injection on my 7.3IDI with a Banks Turbo & you've got my interest about pre turbo injection. The calcultor shows that I need 11gph so I was thinking about putting an M3 pre turbo & an M7 in the Plenum spraying direct into the original intake. Any thoughts? Cheers, Todd

05-17-2008	#20 (permalink)
Terry Syd Alcohol Holic Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 104	Re: Pre turbo nozzle placement Todd, I'll jump in, but I ain't a WI specialist. As you have seen from the previous posts, WI pre-tubo works (and works well). The big issue is erosion of the compressor wheel blades from too large of droplets. If you are using one pump, then the M3 nozzle pre-turbo will not be running over 200 psi if you have another M7 running in parallel with it. My initial impressions is to run two pumps, one for the pre-turbo M3 and another for the post-turbo M7 (or what ever you end up with). You could have them both kick in at the same boost pressure or at different pressures. The pre-turbo injection could come in a bit sooner than the post-turbo as you want to spool up as quickly as possible. Just my impressions, comments are welcome.