Differences In Atomization Of Fuel Depending On Injector Orientation

[ADAM]

HERE IS A GOOD QUESTION,

I WILL BE PLUMBING IN MY NEW TURBO SYSTEM TWO 480CC INJECTORS JUST BEFORE THE THROTTLE BODY...APROX 5-8 INCHES AWAY FROM THE PLATE. THEY WILL BE INSTALLED IN THE STAINLESS TUBING THAT COMES FROM THE INTERCOOLER THAT HAS THE BOOSTED AIR CHARGE (AIR INTAKE OF THE ENGINE)

AT 10PSI I WILL BE FLOWING APPROX 380-450CFM THRU THAT STAINLESS TUBE WHICH IS 2.5 INCHES IN DIA.

NOW...SHOULD I ORIENT THE FUEL INJECTORS TO SHOOT THE FUEL

1=INTO THE AIR STREAM?
2=AGAINST THE AIR STREAM

SINCE THE GOAL IS ULTIMATE ATOMIZATION OF THE FUEL, THERE MAY BE BENIFITS OF GOING AGAINST THE AIR STREAM...IN A BOOK I BOUGHT BY CORKY BELL...."HOW TO DESIGN A TURBO SYSTEM..." HE STATES THERE MAY BE SOME BENIFIT IN SPRAYING THE FUEL AGAINST THE AIRSTREAM THOUGH HE HAD NO DATA TO PROVE IT.

LOGIC SAYS YOU WOULD SPRAY THE FUEL WITH THE AIR STREAM....BUT.....?

ANY COMMENTS...OR ANYONE WHO DEALS WITH AIR FLOW AND TURBULENCE?

ADAM

[Shaman]

There are three issues at play here:


you could risk blowing the fuel back into the nozzle and getting droplets formed, which is counter-productive
if you can force the fuel out hard enough, the fuel has to fight flow and has longer to travel
you may disrupt air flow by blowing it into the stream


I would personally consider a compromise and inect the fuel at a 90 degree angle, that way you should have the best of the two ideas. But you have to be careful that you aren't coating the opposite wall of the tube with fuel, you need it to go directly into the air stream (probably not an issue with the amount of fuel your motor is likely to need).

Hope I've given you some thoughts.

[ctenche]

Adam, where did you get the book? I've looked for it at Chapters and Indigo and it's a special order book (obviously they wouldn't have it in store). It's also damn expensive at approximately $52.

[ADAM]

shamen ...the injectors are on 45 deg angled bosses....

i got the book online from amazon...it came to approx 50 cdn with shipping...
it is a very very good book to have if you want to turbo charge...there is very good info on the internet as well....

if you have any questions i might be able to help?

[Theo]

I'd say go with the air stream.
Firing down I picture the fuel pooling on the opostie side of the intake tube.
Into the stream seems like overkill, and I'd imaging the injector would foul sooner than it would facing the other way.

Damn, I wish I could back this up with some technical data. My hunch is go with the flow.

[ctenche]

Thanks Adam. I have been thinking about turbocharging my car in the future (maybe next year?) but I have zero knowledge about it.

I have been pointed to Corky's book by a friend and I wanted to pick it up and learn all about turbos so I can make some educated decisions before embarking on the path to the "dark side."

If you have some Internet links that you think I might find interesting, please post them.

[ADAM]

here are some great links.....if you get serious...i could help you pick some parts...as i have spent the last year looking into all of this...and have become quite involved in turbo setups.

http://www.sdsefi.com/eic.html

(takes care of your fuel...and the FAQ section is great, i have this unit)

http://turbofast.com.au/javacalc.html

(can help pick your turbo setup)

http://www.turboneticsinc.com/

(the end all in turbos, got my wastegate here, but bought turbo locally thru one of thier distributors)

http://www.cranecams.com/ignition1/trc1.htm

(to help detonation issues on boost...i bought a msd version which is better)

http://www.spearcointercoolers.com/

(here is where you get your intercoolers)

http://www.vpracingfuels.com/fuels.html#unleadedfuels

(here is where you get your fuel if needed)

http://www.quancon.com/~gdrane/turbosys.html

(here is a page with some general info)

[JAMIE EASTMAN]

pointing the extra injectors with the air flow will help the fuel get sucked in having the inj.
at 90degrees to the air flow will make the fuel puddle up against the air duct wall I know from
past experimentation. Good atomization really helps the fuel\air mix to flow past a throttlebody
that was only ment to flow air. ALSO DO NOT FORGET THE CYBERDINE\INTELLATRONICS
AIR\FUEL METER 30$$ AT SUMMIT> OR EQUIVILANT>

[ADAM]

i have an autometer a/f ratio meter and it is usless...it basically jumps around, and at full throttle i think it is getting confused.

i will be dyno testing the system at several boost levels and octane levels, with a real tailpipe a/f meter that the dyno shop uses. so i will tune the proper a/f ratio in when the engine gets dynoed. i will keep it on the rich side just to be safe.

i guess i will aim the injectors to go with the air flow...as that will work well....

[JAMIE EASTMAN]

MY air\fuel meter jumped around untill I cleaned the O2 sensor with brake cleaner
although not recomended . My shelby drag race buddys say several injectors pulsed
for a light fuel mist works better 1 or 2 big ones. Cant wait to see the install. I have
some books and literature and will be in toronto sat or sun if you would like to see it.

[ctenche]

That's awesome!

Thanks Adam.