first off i wanted to know if their is a name you have ITB with fuel injectors that are in line with each runner? for the best throttle response, you want the least dead air space between the throttle body and the intake valve? that goes for power as well right?

 

WHA?

 

This could be a good topic and very helpful. Can you possibly elaborate what your trying to say?

 

you lost me at "name". please rephrase.

 

ive heard injector placed farther back better power in hgiher band. closer the injector is low end is improved. that wut i heard not sure if its true. its easy to test what you want all you need is a car with itb and a dyno and enogh time to play with different injector locations lol.

 

I don't know if that's true or not, but im guessing it would have to do with fuel atomization. Injector placement isn't really a major power adder/detractor unless your talking about adding N02.

Still, you need to slow down and use punctuation when you type. Seriously.

 

Go to Jenvey.com and read the FAQ.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote">Go to Jenvey.com and read the FAQ.</TD></TR></TABLE>

'For performance at low RPM, economy and low emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.
For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be.'
- from da jenvey

at least wut i remembered wasnt wrong

 

You have to decide what kind of engine you are running a specific IM on. Every motor will need a different IM to reach its max eff. What you are talking about with the injectors placed firing into the runner throat is beneficial to high RPM engines because of the high velocity at which the air is entering the runner. Positioning the injectors like this allows for proper atomization of fuel in the air ( air becomes fuel saturated) as well as helps to cool the intake charge. When you place the injectors close to the intake valve on a motor making power to over 8000RPM dose not allow for proper fuel saturation. F1 uses a similar system where the injectors spray into the throat of the runner but they utilize variable runner lengths to maximize their usable power.

this is just and overview if you would like to konw the specifics of one of the areas i have touched on i will do my best to descibe in more detial.

hope this helps

Chris

 

Moving the injectors up also helps use less fuel on Honda motors. Especially for us N/A guys running wild cams with big overlap, when the injectors are too close to the cylinder a lot of fuel is wasted or never burned becasue it goes right out the exhaust before the valve has closed all the way.

 

what i mean by positioning of them is this,


Now, having less area between the intake valve and the throttlebody means beter throttle responce? what about fuel temperature?

i saw a picture of another manifold on HT, it looked kinda like this.
so the throttle responce wouldnt be as good but would it in theory have more power because the fuel isnt hitting the butterfly? would it be good for turbo then?



Modified by hks85 at 5:27 PM 6/24/2005

 

i thought of something similar to this last night, lol

 

Are you talking about these pics.this is the manifold to my head

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zad5 &raquo;</TD></TR><TR><TD CLASS="quote">

'For performance at low RPM, economy and low emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.
For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be.'
- from da jenvey

at least wut i remembered wasnt wrong </TD></TR></TABLE>

It makes sense that having injectors farther back (towards the intake tract) would be better for high rpm motors because the better atomizing of the a/f mixture could compensate for the lower piston speeds associated w/higher r/s motors (most higher revving motors=higher r/s=longer rods) longer rods means lower piston speed ATDC meaning less pressure differential between cylinder and intake ports ATDC. This would result in less port velocity and less atomization hence a less efficient burn, right?

If anything I said appears confusing or somehow incorrect, please correct me or chime in. Thats my 2 cents... for now. Beginnings of a good thread!

 

hey randy, what if there was a single throttle body in stock position, this would be nearly the same effect correct? i mean it wouldnt "blow" the fuel towards the driver's side would it
?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by veeetech &raquo;</TD></TR><TR><TD CLASS="quote">It makes sense that having injectors farther back (towards the intake tract) would be better for high rpm motors because the better atomizing of the a/f mixture could compensate for the lower piston speeds associated w/higher r/s motors (most higher revving motors=higher r/s=longer rods) longer rods means lower piston speed ATDC meaning less pressure differential between cylinder and intake ports ATDC. This would result in less port velocity and less atomization hence a less efficient burn, right?

If anything I said appears confusing or somehow incorrect, please correct me or chime in. Thats my 2 cents... for now. Beginnings of a good thread! </TD></TR></TABLE>

im confused,
why would having a longer rod make the piston move slower? what is ATDC? @ TDC?lol I can't imagine why rod length would play a part in how fast the piston travels? enlighten me, what am i missing here?

 

randy tried to see if a honda engine can be a motorcycle race engine :D i heard it failed .....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hks85 &raquo;</TD></TR><TR><TD CLASS="quote">

im confused,
why would having a longer rod make the piston move slower? what is ATDC? @ TDC?lol I can't imagine why rod length would play a part in how fast the piston travels? enlighten me, what am i missing here?</TD></TR></TABLE>

Don't take this wrong,but you need to know engine design theory before you get into manifold design theory.Many things determine efficient manifold designs.That's why there are variable runner lengths and plenum volume designs on oem cars.There are lots of compromises made on fixed manifolds.
Glenn

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XtraFastCRX &raquo;</TD></TR><TR><TD CLASS="quote">randy tried to see if a honda engine can be a motorcycle race engine :D i heard it failed .....</TD></TR></TABLE>I must really be missing something here .Because I don't have the slightest hint what you are talking about.Can you enlighten me on this failure.So I don't do it again.

It would be fine having the TB on one end or the other.The reason the stock one is where it is ,Is for convenience.
HKS85 .You love that picture ,Don't you? That thing IS bad.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NJIN BUILDR &raquo;</TD></TR><TR><TD CLASS="quote">Don't take this wrong,but you need to know engine design theory before you get into manifold design theory.Many things determine efficient manifold designs.That's why there are variable runner lengths and plenum volume designs on oem cars.There are lots of compromises made on fixed manifolds.
Glenn</TD></TR></TABLE>

that wasn't what i asked,
looking into the physics of crank, rod & piston i do see where their being a fluctuation in piston speed. plz forgive me for my incompetence, about 99.9% of everything i know about engines is self taught. Don't get me wrong im not a complete idiot, Ive built a couple of motors (DRZ-400, GSXR 600 etc.) But never a FULL race motor. Ive just never thought to ask the Q: but i see where your cumming from now 100%

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RMF &raquo;</TD></TR><TR><TD CLASS="quote">I must really be missing something here .Because I don't have the slightest hint what you are talking about.Can you enlighten me on this failure.So I don't do it again.

It would be fine having the TB on one end or the other.The reason the stock one is where it is ,Is for convenience.
HKS85 .You love that picture ,Don't you? That thing IS bad.</TD></TR></TABLE>

yeah i do, i think the concept is great. Finding the exact size and placement of of the fuel injector, stacks blah blah blah is another story, but just looking at the think makes my mind run. Of course i cant see it having the same response as ITB but for a Turbocharged motor it looks like it would work.

anyone know if any professionals have used something like this before?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hks85 &raquo;</TD></TR><TR><TD CLASS="quote">anyone know if any professionals have used something like this before?</TD></TR></TABLE>

AEBS did it back in 2000

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hks85 &raquo;</TD></TR><TR><TD CLASS="quote">that wasn't what i asked,
looking into the physics of crank, rod & piston i do see where their being a fluctuation in piston speed. plz forgive me for my incompetence, about 99.9% of everything i know about engines is self taught. Don't get me wrong im not a complete idiot, Ive built a couple of motors (DRZ-400, GSXR 600 etc.) But never a FULL race motor. Ive just never thought to ask the Q: but i see where your cumming from now 100% </TD></TR></TABLE>

Motors with a lower r/s(shorter rods), will have greater piston accelerations.

 

Yes, it's not the speed, it's the acceleration. There is much to learn about engine geometry, some good threads here, lots more on the rest of the net. Engage search engine, captain!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drdisco69 &raquo;</TD></TR><TR><TD CLASS="quote">Yes, it's not the speed, it's the acceleration. There is much to learn about engine geometry, some good threads here, lots more on the rest of the net. Engage search engine, captain! </TD></TR></TABLE>

now i sound like a bigger idiot then before lol. i swore thats what i meant to say. in fact i could swore i typed the word "acceleration" which is much simpler then "fluctuation in speed"