waterinjection.info  

Go Back   waterinjection.info > Injection Theory (what it is and what it does) > Intercooler Effects

Reply
 
Thread Tools Display Modes
  #11  
Old 30-12-2015, 05:30 AM
jondee86 jondee86 is offline
Member
 
Join Date: Dec 2015
Location: New Zealand
Posts: 77
Question Re: JET PLACEMENT FOR AIR FLOW (POST-MAF)

I have been struggling to find a good layout for the discharge ducting for
some time. One of the options would be to make an entry to the plenum
from below as you suggest. I will be using this discharge manifold...



In the available space I would only have room for a single short radius
90deg bend, and without any length after the bend for the airflow to settle,
I think that distribution into the runners would be unbalanced. I have been
wondering if some kind of "splitter" inserted down into the discharge end of
the duct could be used to help balance the airflow betrween 1+2 and 3+4 ?
The splitter could be attached to the blanking plate used to close off the
existing opening on the top of the manifold.

On the plus side the charger discharge manifold has a machined face that
looks to be suitable for mounting a single misting nozzle.

Cheers... jondee86
Reply With Quote
  #12  
Old 30-12-2015, 09:52 AM
rotrex rotrex is offline
Senior Member
 
Join Date: Jan 2014
Location: Germany
Posts: 181
Default Re: JET PLACEMENT FOR AIR FLOW (POST-MAF)

I now more see you point. You have a two 90 deg bends that are peripendicular towards each other.
Inserting a splitter or vane can have very detrimental effects on flow distribution.
Without experimentation or CFD, I'd not strap it on a engine. If you test on the engine, I would recommend monitoring the individual cylinders via exhaust gas temp, lambda in each primary or pressure in each runner before the intake port to get any idea on distribution.

Regarding a improvement or a way to fix this, I have to first think about it.
But usually air taking bends is not as bad as water / meth or fuel taking bends.

Airflow though a plenum on a inline 4 engine happens only through one runner at a time. This means that the flow distribution, both pressure and velocity, within the cross section of the central inlet and the runner won't change too much. Say the left half of the inlet pipe flows more than the right half. For the big part, the flow in each runner will be higher in the left half than in the right half, too.
Once you run the engine under power, you use excess fuel anyhow. a small deviation in air flow won?t make much difference. water makes the engine even more tolerant of AFR variations, especially on the lean side of things. if it runs very rich, it just loses power.

Most plenum chambers have a turn in the inlet pipe leading to a non-uniform velocity distribution. The air stream then has to take a 90? bend into the runners from a plenum chamber. The feed stream and its distribution of velocity over its cross section is the same for every runner (exception is high boost levels, here velocity variations also cause significant pressure variations).

if all runners would flow at the same time, things would look vastly different.

These video shows the effect to a degree: The air runs through mostly one runner at the time undefended of the flow mess before that
https://youtu.be/299Y50YWMGo
https://youtu.be/jm0b6udpW1c
https://youtu.be/X3ecq8MNfk0
https://youtu.be/6zUwJDUCZ08

Last edited by rotrex; 30-12-2015 at 02:41 PM.
Reply With Quote
  #13  
Old 31-12-2015, 12:00 AM
rotrex rotrex is offline
Senior Member
 
Join Date: Jan 2014
Location: Germany
Posts: 181
Default Re: JET PLACEMENT FOR AIR FLOW (POST-MAF)

have you considered cutting out the opening part of the intake manifold and place it onto the bottom? Kind of upside down. It is just cut and weld a square section by the looks of the manifold. this saves you the u-bend.
Reply With Quote
  #14  
Old 02-01-2016, 02:22 AM
jondee86 jondee86 is offline
Member
 
Join Date: Dec 2015
Location: New Zealand
Posts: 77
Smile Re: JET PLACEMENT FOR AIR FLOW (POST-MAF)

At the moment I am thinking of something like this...



I prefer a "bolt-on" solution rather that cut and weld, and I'd rather be
fabricating ducting that runs out in the open rather than hidden in behind
other parts. Just makes it easier to work on

This fitting would bolt in place of the OEM inlet neck and the airflow into
the plenum would be similar in direction to the airflow from the stock inlet.
It does mean that I will have two 90 deg bends and one 90 deg elbow in
the ducting, but when I look at pictures of other supercharger installations
I see a lot worse !!!

Cheers... jondee86
Reply With Quote
  #15  
Old 03-01-2016, 03:05 PM
HYDE16 HYDE16 is offline
Member
 
Join Date: May 2014
Location: Morris County, NJ
Posts: 47
Default Re: JET PLACEMENT FOR AIR FLOW (POST-MAF)

This video shows in yellow the highest velocity stream which would help atomize any water meth spraying inside of this intake pipe:
https://www.youtube.com/watch?v=OvprEu-yH-A
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 10:39 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.