ITBs & injector placement
 

1st please don't flame b/c I read car magazines in dec. issue of HCI there was an article on their "KillerBee" b16a w/ forged rods & pistons & crane stage 2 cams w TWM ITBs - they repositoned the injectors and gained 14 whp with gains throughout the range...stated the gains were primarily due to better atomization of fuel (& air mix?) nice huh bas was 195whp before moving injectors & 209 after (no changes to fuel or timing tables) they did state that this would be a very hard-to-do mod with regular intake manifolds (basically only for those with ITBs) https://honda-tech.com/forums/images...es/emsmile.gif

Re: ITBs & injector placement (adirondackR)
 

I saw that too. But how would the car idle if the inj is before the throttle plate. It would be kinda dangerous.

Re: ITBs & injector placement (Tbone)
 

i don't know - i have the article in front of me - can you explain how it could/would be dangerous? you mean getting too much (or enough) fuel on the OR around the throttle plate???....i dunno know I think the velocity of the air would carry the fuel around the plate (maybe - kinda reaching here - i don't have experience in this area to really answer) anyone else?
edit: good point if the car is at idle :scratches head:

Re: ITBs & injector placement (Tbone)
 

i see what u are saying. a bunch of fuel puddling up on the throttle plate at idle. dont see how they managed to not get fuel all over the place...

Re: ITBs & injector placement (hybridKOOPHRI)
 

TWM's don't spray before the throttle plate. The injector is moved upstream, but not before the throttle plate. http://www.twminduction.com/Home/Hom...sale_page2.jpg

Atomization as well as cooling the charge is the reason for spraying upstream, but idle will suffer some due to insufficient (air) velocity.

Re: ITBs & injector placement (Benny Hinn)
 

Yes but in the article they made them spray upstream to the plates via a custom fuel rail. They sprayed directly into the air horns
I suppose you could run 2 sets of injectors via a sds unit and make the upstream ones only active at wide open throttle. That would be interesting

Re: ITBs & injector placement (Tbone)
 

ya..i also saw the article and said WHAT THE F*CK really loud in Borders when i saw this. hahah. I kept saying that out loud, while thinking, what is the purpose and left the store.

Does it really help? and i'm thinking that the injectors would get in the way of the airflow into the horn, but i think they said that it doesn't affect it.

Very interestingggg https://honda-tech.com/forums/images/smilies/embeer.gif

Re: ITBs & injector placement (Tbone)
 

what about the eldelrock victor x manifold, instead of using the traditional injector bungs. there is 4 more under the runners that are further away from the intake port. would it be a good idea to use these instead of the 4 up top?

here is a video showing injectors outside the air horns on itbs. I think F1 is where this idea came from. crazy video

f1 dyno Video



Modified by shant at 6:22 PM 10/30/2003

Re: ITBs & injector placement (adirondackR)
 

F1 style just like the Toda ITBS.

Re: ITBs & injector placement (SuperTwinz)
 

You could have a switch that was rpm dependant that would run the injectors at their stock locatin for low RPM, and then switch to the out board injectors at high ~7000~ RPM for the power/atomization.

I am going to do this very thing on my next setup, but that is still a little bit away.

We call that setup "Stand-off injectors".
(when they are firing directly into the velocity stacks.

Do you remember the AEBS twin throttle body, twin injector bank setup on the All-Motor CRX (currently in Larry Herring's GTP Racing CRX)

They were using a "staged" firing setup for that intake manifold.

As far as fuel "puddling" in front of the throttle plates.... ever hear of carburetors???

At "closed" throttle, usually, there is actually a very small openning that the air goes through, right around the trottle plate. Bernulli will tell you that at this point, air velocity is very high. Any fuel that "puddles" here will be sucked through, and can actually atomize and mix fairly well.

That being said, you'll probably end up with higher HC readings if you go to emission's testing like this. But this setup can idle ok, and have decent part throttle characteristics.

Re: (ProfessorNate)
 

ok let me clear this issue out for your guys...

It doesn't really matter where you place the injector in the specific air stream, but it does affect engine behavior.

fuel is fuel, not matter where it's being offered, once the injector is shot the vacuum wil pull it in for the correct stroke.

why they did with this to to monitor the gains to see if injector placement had a relationship due to distance to see the benefits of the fuel atomization. having it to far is useless...

the stock engines injectors fire directly at the center divider in the head which redirect the fuel directly on the intake valves, to help cool them and also promote swirl early in the cylinder head before making the piston continue the cycle. But because fuel is only seen 3 inchs of distance to atomize and then some swirl in the cylinder head it doesn't allow much room for atomization.. so they attempted this test...

but they failed to tell you the specifics...

look closely at the graphs they made.... look at 5000rpm and lower... you'll see the hp curve much much lower...

because for fuel at a distance to flow gracefully into the cylinder head you need a minimum flow force... if you don't have that enough, your not sucking in the fuel fast enough that it will run... which will MAY puddle and will run like the old style carb motors... honda place them at the edge of the head to have the best idle at any vaccum level...

so what i'm working on, is my euro-r is going to machine 4 injectors just at the edge of the runners, where you see the larges portion of the radius, and have 4 other hookups not at an angle but at horizontally...

and and fuel has different flow properties... fuel may not negotiate turns as good as air, so the more fuel you give , make sure theyre is not sharp turns... you may have some fuel that will run, but the most of the vaccum will lift it off the sides and allow it to atomize...

and to help more on this, i'm thinking looking at BIKE injectors since their tips are more advanced for atomization than most cars... the smaller the mist, the more power.

but bike injectors are lower in CC flow than most cars.

to activate them would be easy, engage them only on vtec, because on the low speed cam you don't need much fuel, but on vtec you would so put an rpm switch with another resistor box. and when the preset engagement hits, you'll switch banks...

if you do this right you would see similiar gains.. but you must ensure the manifold is not curbed to much and the pathway is clear...

I have hondata so i wanted to complete the manifold prior to dyno testing.

I studied this more than a year ago, when TWM had a small article on injector placement.. extremely interesting.

hope this helps.

Re: (HotWheelz)
 

The first thing I thought after seeing the article was
I wonder if some thing similar to this set up is under all that tin work on Leslie's CRX?

Re: ITBs & injector placement (Tbone)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tbone &raquo;</TD></TR><TR><TD CLASS="quote">I saw that too. But how would the car idle if the inj is before the throttle plate. It would be kinda dangerous.</TD></TR></TABLE>

nothing wrong with being placed before thr plate, as a matter of fact thats how the Toda ones are ... plus it shoots upwards ... all of which helps with atomization.

Greg O thanks for the fax.

Greg

Re: ITBs & injector placement (adirondackR)
 

Guys TWM Induction is having a sale on the B16, B18 & H22 ITB kits.
The complete kits come with ITB's, Injectors, Fuel Rail with Pressure Regulator, Air horns, TPS & Plug and linkage that will hook up to your stock cable.
They list for $2355.00 and are selling for $1695.00 complete or with Vac. Accumulator for $1895.00.
http://www.twminduction.com
805-967-9478