Short runner manifold

[striker]

looking at it, I wonder if you won't get into trouble on the length of the runners and them being equal, since the headports are further appart than the 2 by 2 holes in the flange you have, and you plan on very short runners.....

argghh what am i saying you'll get around it, but it won't be easy though.

grtz Thomas

 

[JustenGT8]

They won't be equal but will be close enough. If this was for a 9000rpm screamer then i would be concerned but we are just looking to see what gains we can get from a short runner manifold with plenum and single TB on a 6500rpm or so redline.

If it works then i can invest serious effort into developing something flash

i don't do bodge so even this 'experiment' will still be pretty sweet....can't tell me the flange isn't a nice bit of gear

 

[striker]

it sure is!

you said something about the injectors needed to come back 2mm, and that won;t affect the seal, I have small clearance problem also in that area, are you planning on laying down into the valley or do you make them more upright? the extra 4mm would do it for me, but won't the angle of injection become to steep?

grtz Thomas

 

[JustenGT8]

I'll try and get them as close to stock as possible so won't know for sure until they are in. The rubber seal has a fair bit of play so moving the top of the injector a little shouldn't effect the seal.

As for angle...i don't see this as a bit issue for power. Ideally the spray would be carried in suspension regardless of injector angle....the only prob is if part of the spray makes it to the port wall as then you will have some condensation. Still not much of an issue for performance but would hurt economy and the worse it is the more it may effect driveability.

All pretty much suck it and see at this stage

 

[Zuffen]

The angle the injector holds to the port isn't too critical as long as it doens't hit the wall.

I've seen injectrs where the spray pattern is 180 degrees from the port. In other words firing toward the t/b but obviously it works.

 

[striker]

ok thanx for the intel.

keep us posted on the mani,

grtz Thomas

 

[cjsupra90]

The angle the injector holds to the port isn't too critical as long as it doens't hit the wall.

I've seen injectrs where the spray pattern is 180 degrees from the port. In other words firing toward the t/b but obviously it works.

That is actually done quite often on race motors and has proven to provide better air fuel mixing (more evenly mixed) and and thus less likelyhood of detonation and more power. Doesn't work to well on low RPM engines as the fuel has a tendency to fall out of suspension at low flow rates and gives somewhat poor idle quality.

Another thing that has been done quite often on N/A race engines that has the same effect is mounting the injectors before the throttle plates on ITB sutups. This does also help the idle quality a very small bit and does have a better low to mid range mixture quality.

 

[striker]

CJ I understand what you're saying in the first bit,
but the part about injectors moving further from the intake ports has to do with atomisation at high rpm, it defenatly doesn't aid Low or midrange torque at all.
there are several motorcycles like the MV augusta's that have 8 injectors, in in the heads (like 1uzfe) and 4 outside the sliding trumpets inside the airbox, ala F1. the outer ones take over at 8100rpm, the reason being servere atomisations problems in the speeds of the air entering the engine.

Grtz Thomas

 

[torquefab]

hi guys im a new member noticed you talking about making a manifold ive just made one for a customer using the bottom stock runners fabricating a new pleneum with a intercooler inside and am112 s/c on top it works very well

 

[cribbj]

hi guys im a new member noticed you talking about making a manifold ive just made one for a customer using the bottom stock runners fabricating a new pleneum with a intercooler inside and am112 s/c on top it works very well

Welcome, but please post pics!!! Also to avoid thread drift, I'm going to move your post to the FI area where people are looking for supercharger manifolds.

Hmm, easier said than done; our post moving tool isn't working today.

 

[torquefab]

yer ive got plenty of pictures ill put some up but ill have to work out how to do it

 

[cribbj]

Well, until our thread tools start working again, why don't you start a new thread here: http://www.lextreme.com/forums/forumdisplay.php?f=17

And call it something like "New Supercharger Manifold", etc.

 

[cjsupra90]

CJ I understand what you're saying in the first bit,
but the part about injectors moving further from the intake ports has to do with atomisation at high rpm, it defenatly doesn't aid Low or midrange torque at all.
there are several motorcycles like the MV augusta's that have 8 injectors, in in the heads (like 1uzfe) and 4 outside the sliding trumpets inside the airbox, ala F1. the outer ones take over at 8100rpm, the reason being servere atomisations problems in the speeds of the air entering the engine.

Grtz Thomas

When you fire the injector in a reverse mount congif, it is almost impossible to not fire it somewhat at a intake runner wall. By moving then up, out side of the throttle plates, this allows for you to mount is centered in the bore and therefor not spraying at a wall and thus not causing nearly as much to drop out of suspension. This help low and mid range over reverse mounted injectors.

Were you thinking that I ment in general? If so, sorry for the confusion. I was meaning just when compaired to reverse mounted injectors. For low and mid range, the closer to the cylinder the better. Hense the reason for direct injection.

 

[striker]

Hey Chris,

Yes I more or less was,
but you're adressing a problem that is fixed by the way you describe, and I wasn't. a correct placed injector facing the intake valve up-close is better able to provide low and midrange torque then an upstream mounted one, unless you have a problem in that place to fit it. like you said

I was talking about the reason to mount an injector completly outside of the intake system, above the intake trumpet facing down into it, this way of opperation is normaly only used in very high RPM applications, and on street driven machinery is almost always used in conjucntion with head mounted injectors aswell, both banks opperating within their own RPM area.
the best way to have it overall is injector facing the intake valve the relatie angle to the port itself of of lesser meaning as I understand.

not to go to far of topic,
but take care when trying this on any engine, the form of the bellmouth in the trumpet can be very mean to you when the engine spits back on closing of the intake valve, and set the airbox or filters on fire..... the best way to overcome this is to have the bellmouths incoporated on a flat piece/plane (F1 airbox like) and not suspended in open air.
I found out the hard way.....

Grtz Thomas

 

[cjsupra90]

Yeah, I agree with you 100% it is just better then a reverse mounted injector being that it is fired into the air streem vs. against it. and partly at a runner wall and thus improves low speed mixture quality or the reverse mounted unit. Sill should only be use in high RPM situations.

I cant agree more with you on the fire hazard with the trumpit mounted injectors.

 

[4000GT]

Any update mate?

 

[JustenGT8]

Yeah i've gone with a supercharger instead

Actually i will get back to this in the near future but obviously have been distracted with the SC proj which just unexpectedly popped up....one of them things

 

[4000GT]

lazy......

 

[JustenGT8]

Hiya all,
apologies for the delay, as most are prob aware i got a little distracted with a twin-charged SC setup

Anyways, intake is basically done, just nee to clean up one of the injector bosses as the weld bead intruded. We managed to keep the stock fuel rails...just, but we did have to relocate the mounting tabs. I think it's actually a better setup than stock now

I have a track day soon so manifold will go on as is...i can already see some areas for easy improvement. Will be dynoed as well of course against my benchmark 12psi 315rwkw run.

Pics tomoz with luck.

 

[4000GT]

Cant wait to see this!