WI jets directly into the manifold ?

[Roger G.]

The question is would it make sense to inject water directly into the intake manifold after the throttle body instead of before ?

I aske because on my 3000GT/GTO the throttle body is 90? angeled to intake runners. Removing the plenum once showed that the first runners where cleaner than the rear ones, assuming that more water flows directly after the TB there and doesn't reach the rear ones.

What if I place three jets at the rear of the plenum to inject water directly into the runners ? (look at the pic)



Thanks for any ideas,
Roger

[robbilau]

IMO it would work - just make sure you have a check valve since the jets will experience vacuum now.

[TargeT]

from what im reading on other sites, its best to move the injection point as far from your throttle body as posible, allowing the water to cool the air as much as posible

[Roger G.]

TargeT, I need detonation control not cooling the air. This is done by the jet some inches before the throttle body.

But I really wonder if the temp would be too high there or if it is too close to the intake valves.

robbilau, yes, I always use check-valves on any application.

Thanks
Roger

[Charged Performance]

This design of dry manifolds does present this problem frequently - they were never intended to uniformally distribute fluids to all cylinders.

There are a few solutions:

The one you have proposed.

Move the jet further from the throttle body to permit more travel distance to improve the distribution of the mixture.

Put the jet in front of one of those cyclone induction inserts - while I question its other claimed benefits - brad has said it improves mixture uniformity very well in dry induction systems and it makes sense.

[Roger G.]

Thanks for the reply Ed.

Originally Posted by Charged Performance

Put the jet in front of one of those cyclone induction inserts - while I question its other claimed benefits - brad has said it improves mixture uniformity very well in dry induction systems and it makes sense.

Sorry, but I do not fully understand this one. Where exactly in my picture would you place the jet ? What inserts do you mean ?

Thanks again,
Roger

[Charged Performance]

OK I see that your jet is actually back away from the throttle body already pretty far.

Brad has suggested before that one of these can help keep a uniform water mixture better than you might think: http://store.yahoo.com/rodi/torfuelsav1.html

Sorry it was tornado not cyclone.

With a throttle body at one end of a long plenum you definitely want the water to be very well atomized and a uniform mixture by the throttle body or you will get rich and lean cylinders.

Previous experience has been with 4 cylinders and this setup - so water would still make it back to the last one on the line. Maybe getting past all those intake pulses on a 6 cylinder presents added difficulty in a dry intake. However properly atomized it should still make it to all cylinders, theorectically.

[AKWRX]

A similar even distribution issue on a Honda Jackson Racing supercharger surfaced because of the very short trajectory of the intake runners post SC. The solution was to use two nozzles evenly spaced between the intake runners at the outlet of the SC (on an all alcohol system in lieu of an intercooler). That is a similar nozzle location solution for a more even injection distribution as you are proposing for your application.

[Charged Performance]

As you came up with the three injectors across from the runner seperators likely is the most optimum solution. My listing of alternatives was merely to identify possibilities - not at all a discount of your initial thoughts. Watch your total flow rate through three jets though use size and pressure to make sure you don't bog the engine down with too much water for your tuning.

[Roger G.]

Thanks a lot for all the answers.

IMHO, avoid that tornado things. We measured nothing but added restriction in the air path.

The intake plenum will be removed soon. The bad thing is that on the back the aluminum is pretty thick. Dunno yet how far I can screw in the water jets. The MF2 will do nicely to avoid flooding

Roger