Injecting prior to turbo comp' impellers

[rarson]

The problem I see with that is, by directing it toward the wall like that, I think you'd have the puddling problem with water streaming down the pipe as hotrod explained. I agree that your second picture seems accurate, that the water would not flow straight, but I don't think the third picture solves the problem.

I honestly think the best design, for a system with less than optimal atomization, is a nozzle very close to and aimed at the shaft nut. Not only would the nut help "atomization" but it would also alleviate injecting water at the blades... it would seem to me that the water would more likely go through them instead of at them.

[JohnA]

Originally Posted by rarson

The problem I see with that is, by directing it toward the wall like that, I think you'd have the puddling problem with water streaming down the pipe as hotrod explained.

Maybe it won't be aiming at the wall, this is a rough sketch to show the idea of offset aiming.

As the water is at a pressure differential of over 10bar it should have strong resistance to the air rush that is below 1 bar (precompressor, so no boost!)

Has anybody measured the vacuum before a turbo?

[cheekychimp]

Having just worked my way through all 15 pages of this thread, I feel somewhat reluctant to pose a question that is moving away from the CURRENT focus of the questions at hand. That said, having gained a huge amount of really useful information by following this thread for so long a very crucial matter is staring me right in the face and I really just have to ask.

Most MAS systems place the MAS immediately after the air filter and prior to the turbo. A lot of DSM vehicles are however using the larger bore and less restrictive GM-MAS with a MAF-T in what is generally referred to as a 'blow through' setup. That is it is placed in the intake tract between the intercooler outlet and the throttle body.

My question here is that since this is essentially a hotwire MAS, is any WI whether it be pre-compressor, pre-intercooler or post-intercooler but PRIOR to the GM-MAS going to have a detrimental effect on the MAS readings and consequently going to cause problems with the A/F ratio that the ECU calculates?

Paul

[masterp2]

really good question

[hotrod]

Hot wire mass air flow systems will not tolerate any liquid mist in the air stream. I can say this from personal experience having gotten a bit of water inside my air filter box which got pulled past the air filter under high intake vacuum. It led to an instantanous CEL and fuel cut. The engine would hardly run until the system dried out.

In the tests on wet compression, only a fraction of the water is evaporated in the compressor proper, so I would expect some small dropplets to survive.

You might ????? get away with one down stream of the intercooler. But I have my doubts. I know it would not work just down stream of the turbo if any mist survives the trip through the compressor scroll. As far as WI post intercooler, and before the blow through sensor --- don't even try it ----- won't work.

Larry

[cheekychimp]

Hot wire mass air flow systems will not tolerate any liquid mist in the air stream.

I am not going to dispute this, because I quite see the logic, but then what happens in rain, fog or high humidity conditions? At least some water must get into the intake tract? If not, how would we ever know to make a comparison between the effects of using WI and driving a car on a cool misty evening in autumn?

Like I said, I am NOT disputing this, I just want to know if injecting water at a very high temperature as was suggested above (i.e. at boiling point and under pressure) would result in sufficient evaporation or if the particles of water/alcohol would be of sufficiently small size to negate any adverse affect on the readings of the MAS.

[Richard L]

To day, we had a chance to experiment on fabricating a holder for pre-turbo injection.

Haven't yet finalise the method of clamping.

Here are a few pictures:

[JohnA]

very interesting.
How about an aluminum fitting to replace the hose sitting in the pressurised airstream? Would the standard bits survive the conditions?

[Richard L]

Originally Posted by JohnA

very interesting.
How about an aluminum fitting to replace the hose sitting in the pressurised airstream? Would the standard bits survive the conditions?

The air pressure will be less than a bar. The intention was to use two jubilee clipd, one to clamp the disc bracket and the other clamps the silicon hose to the turbo flange.

We might try to make a lip to go over the turbo flange (interference fit). This bracket will be tested on a twin turbo skyline about 800 horses. The car in concern has inlet heat soak problem becuase it has pot injection fitted.

The goal was to achieve 900 horses with twin 400bhp turbos - it will show if the pre turbo idea work of not. We have found that running 3 boost yields less power than 2 bar boost - nearly 70 horses loss!!!

[JohnA]

Correction: I said 'pressurised' but technically it will always be in vacuum of course.
Still, it won't be sitting in engine bay under atmospheric conditions like it normally does, will it?