Turbo intake manifold fabbing

[madkaw]

I have recently aquired a project off of flee bay from someone who was making their own turbo intake/plenum. It seems to be a good start to me and I would like to finsh and use it.

 

INTAKE:

As you can see from the pics the intake is a Cannon manifold which has been welded to the start of a plenum. The welding seems to be sound and air horns were incorporated into the entry of the runners. its seems to be nicely blended with a taper from 45mm to 37mm at the head side.

I will have to decide where to install the injectors. I was supplied 14mm bungs with the manifold that are cut at 45 degrees. I'd like to place them close up against the intake flange so the bungs are drilled to enter the port as high as possible. This will be installed on a early e-88 head that's NOT notched for injection.

 

PLENUM: the plan was to make a "shoe" shaped type plenum that is used on some RB manifolds. This design looks to be the easiest to finish from it's present state. The plenum area is 22"X 4.25". The tough fabbing will be incorporating the TB mounting to the plenum.

 

On the other hand, the dual plenum idea is also being considered. This plenum is not so far along that I could change directions and go with a dual plenum like;

 

http://www.racerxfabrication.com/page1/page5/page22/page22.html

 

It's obvious from Monzter's work and others that this plenum has significant merits. I can purchase the larger plenum extrusion from Ross Machine(mailbox extrusuion). The cone extrusion is a little more difficult to aquire-unless Tony's idea of a Louisville Slugger will work, then it's a piece of cake. Find a bat that will blend in with a 60mm TB and connect to the mailbox! I know I am simplifying things here, but I think you see the direction.

 

I'm posting up to get help from the members here. Please let me hear your input.

[madkaw]

Electronic Fuel Injectors 101-

 

Being a carb guy most of my life I know very little about FI components, but I am schooling myself everyday. Can someone give me a good link to page that lays out the whole- domestic/import -11mm-14mm injector stuff. I have been searching for hours for anything to do with a parts break-down of a modern fuel injector and the differences between injector sizes(physical size, O-ring types) .

Trying to lay out my stradegy for the fuel rail and injector selection as well as machining the intake runners and can't get past the fact I don't even know if 11mm or 14mm is regarding just the feed side of the injector or what.

 

I can find tons of info on properly sizing the injector based on HP needs, low impedance vs. high impedance, duty cycle, ect.....

but not much about machining and about the mechanical connections and sizes.

[evildky]

The 11mm vs 14mm refers to the diameter of the opening needed in the fuel rail to fit the top of the injector. The bottom of all top feed injectors are all the same, avoid side feed or dual feed injectors. SDS has some good reading on their site if you haven't read all that yet.http://www.sdsefi.com/techrail.htm

 

Ross engineering sells lots of injector bungs, drill bits for driling your own, and other bits for making intakes and fuel rails. http://www.rossmachineracing.com/injectorbungs.html

[madkaw]

Thanks for some feedback. Just that simple fact of all injectors being the same on the bottom side clears up a lot of things. So the 11mm vs. 14mm only has to do with the feed side-got it!

[Tony D]

Most will say use Teflon adapters on anything smaller than 14mm to allow you to run any injector you want.

 

Can put an 11 or 8 in a 14mm hole using a simple adapter and o-ring... But a 14 doesn't go in an 11mm ole!!!

[madkaw]

So I am ready to get serious about this intake. It's been a nice shelf ornament but I am ordering my MS2 and ready to proceed on with FI.

With Tony's comments it sounds like 14mm bungs are the way to go-I can always go smaller I guess. I haven't decided high or low impedance yet, but that shouldn't affect the build aspect. I will be getting a Pallnet fuel rail Assuming that if the injectors are mounted right up against the runner flange, that a rail made for a stock intake will work fine.   

I have also decided to finish out the design that's been started. I am getting some aluminum pipe and going to 'cap" what I have now. What I need to decide is the "angle of entry" for the TB. I think whatever that angle is will determine what pipe I order since I will use the mandrel bend to help blend the TB into the plenum.

I am thinking 75mm TB for now. I will initially running this on a NA motor, so I am trying to make this set-up versatile for both-turbo later! I don't see where 75mm will too big, and I can always reduce to 60mm with an adapter. I'm not sure what TB I will go with, but searching to steal one of a production car. I'd like to find an intake that I can steal the TB and be able to maybe cut off the thick flange that the TB mounts too(just to save from fabbing).  

 

Any comments or suggestions are welcome  

[Sam280Z]

Steve,

See post 35 in my MS3 thread. http://forums.hybridz.org/topic/102280-ms3-w-ms3x-install-l6-turbo-sequential-injection-boost-control/page-2

 

I've done essentially the same thing. I don't know if I like the extended injector bungs which are needed to clear the intake to head mount bolts. If you are going turbo, you will need large injectors- I'd be worried about fuel impinging on the sides of the bung. I cut the runners from a stock injected manifold and welded it on to the cannon. If I had it to do over, I would only change the top half of the runner - basically cut the runner in half lengthwise leaving the bottom of the cannon intact all the way to the head and only changing the top mounting locations and injector ports.

 

Your choice between high and low impedance injectors will be driven by your choice of management system. Almost all can drive high impedance. 

 

Sam

[madkaw]

Sam,

I have much to learn, but I'm not sure what you mean by impinging fuel on the bungs.  

I was considering placing the bungs at about a 45 degree angle centered between where the runner meets the flange. I would be shooting to have the fuel spray come out in the middle of the head port(whatever that angle might be). The bungs supplied with the intake are a bit long, but I thought that was due to make them adaptable to whatever set-up. 

[Sam280Z]

Compare the Cannon to a stock FI manifold. Note that the manifold mounting holes on a carbed manifold are directly in line with the injector ports. This creates interference with bolts that hold it to the head. 

 

The spray from the injector widens as it leaves the injector. If the bung is too long, the spray will hit the walls of the bung, wetting the walls and reduce the atomization. This will be markedly worse if you choose an injector built for a dual port (4 valve) engine because they have an extra wide split spray pattern.

 

You want the tip of the injector as close to the valve as possible. - While this isn't optimal for max HP, it makes for ease in tuning idle, cruise, and transients.

 

Sam

[madkaw]

I had planned on getting things as close to the valve as possible just for the reason of idle and tuning. I think I can work around the bolt issues. In fact when I looked at the manifold and the angle of the injector and bung, I didn't think it would be an issue at all-especially if I run studs like on my mikuni's now. I was more worried about how I was going to secure my fuel rail on this Cannon manifold.

I also noted that some injectors spray at an angle-as much as 25 degrees-which I might to be able to use to my advantage.

[NewZed]

Isn't there a little more to it than just pointing the injector at the back of the valve head?  Spray pattern, sequential versus batch, time of injection even if sequential is used.  In batch mode, firing off of every third spark, only one cylinder might have an intake valve open (I haven't tried to calculate it exactly), even that might change with advance curve action.  A sharp stream impinging on a closed intake valve might not be as desirable as a cloud of fuel created and waiting for the valve to open.

 

Just something I've pondered before.  For the best balance and effectiveness between cylinders, it seems like injection should be timed to the intake valve opening.  Maybe not when it's actually open, but at some definite period before or during.  In batch, there are three injection positions, with pairs of cylinders swapping a position.  I think it might one reason the injected straight sixes have a not-so-smooth idle.

 

Having the injector as close to the back of the intake valve as possible might only matter if you have the EFI system to take advantage.

[Sam280Z]

Isn't there a little more to it than just pointing the injector at the back of the valve head?  ...

 

Having the injector as close to the back of the intake valve as possible might only matter if you have the EFI system to take advantage.

 

Yes and no. There is a lot more to it than the location of the injector. Having it close to the valve reduces the effect of a lot of variables that add confusion to tuning idle, cruise, and transient states. An EFI system to take advantage allows you to tune for a different injector location, but does not make it easy.

 

Spraying on the back of a closed, hot, intake valve does a lot for atomization. However, lots of valve overlap can send that nicely atomized fuel straight out the exhaust. There is a reason that nearly every factory port injection EFI has the injectors in the same place.

 

For mounting the rail, I made some dummy injectors out of wood to hold the fuel rail and fabbed up the aluminum blocks that bolt to  the throttle linkage mount holes. You can see the mounts in the following pics.

 

https://plus.google.com/u/0/photos/110595327894846974778/albums/5827006289261665345/5827937482721907826?pid=5827937482721907826&oid=110595327894846974778

 

https://plus.google.com/u/0/photos/110595327894846974778/albums/5827006289261665345/5827937481614790706?pid=5827937481614790706&oid=110595327894846974778

 

Stud and nut mounting may work, but I'd get the injectors as close as possible.

 

 

Sam

Edited May 27, 2013 by Sam280Z

[Sam280Z]

One reason not to use studs at the top and maybe why the factory used bolts, is that you can assemble the studs, washers and nuts for the mounting locations shared with the exhaust manifold, slip the intake in and then tighten. You cannot slip the intake on with studs installed in the top and nuts/washers installed in the bottom. You will have to put the shared washers and nuts on while the intake is in place. While doable, this is not easy.

[NewZed]

 There is a reason that nearly every factory port injection EFI has the injectors in the same place.

You may be right.  Probably so that they can lower emissions.  Lower emissions was one of the key drivers for EFI.  If that's the goal, then the closer the better.

[Tony D]

"There is a reason that nearly every factory port injection EFI has the injectors in the same place."

 

Yep, Emissions.

 

Search on "tau layer" and the "wet manifold" starts to make sense. Tuning for transients is actually working to preemptively soak the wetted portions of the manifold to keep the tau layer constant. TBI existed on V8's for so long because the evolution of the wet-flowed manifolds by use with carbs for 40+ years at that point was such that putting TBI air doors on with essentially the same placement of fuel but far more precise control of amount introduced really made tuning relatively easy.

 

As for ordering a Pallnet fuel Rail and hoping it fits....WHY GUESS? Box it up, ship it to him, and let Pete make a rail that FITS?

[madkaw]

"There is a reason that nearly every factory port injection EFI has the injectors in the same place."

Yep, Emissions.

Search on "tau layer" and the "wet manifold" starts to make sense. Tuning for transients is actually working to preemptively soak the wetted portions of the manifold to keep the tau layer constant. TBI existed on V8's for so long because the evolution of the wet-flowed manifolds by use with carbs for 40+ years at that point was such that putting TBI air doors on with essentially the same placement of fuel but far more precise control of amount introduced really made tuning relatively easy.

As for ordering a Pallnet fuel Rail and hoping it fits....WHY GUESS? Box it up, ship it to him, and let Pete make a rail that FITS?[/quote

 

 

Good point, but didn't know he did custom applications.

[madkaw]

Actually, the more I read , the less I'm getting hung up on exact injector placement. I'm not ever going to make such a cammed mister that it won't idle good and if I did then two sets of injectors would be in order.

I'm going to shoot for packaging and the easiest method of securing the fuel rail against te Cannon manifold. If that means being 1-2 inches down the runner- so be it. I will shoot for 45 degree angle or more.

[Sam280Z]

A bit back from the head may not make much of a difference. Before going through the trouble of welding the bungs, I'd verify the spray pattern with your chosen injectors. Those bungs look long and I'd be concerned about a wide spray pattern hitting the sides of the bung.

 

http://www.google.com/imgres?sa=X&rlz=1C1CHFX_enUS454US454&biw=1366&bih=681&tbm=isch&tbnid=k6kqo2bJgGteqM:&imgrefurl=http://www.blackstoneautomotive.com/Blackstone-fuel-injection-service.html&docid=_51HcBK6OoeR0M&imgurl=http://www.blackstoneautomotive.com/custom/Spray-pattern.jpg&w=300&h=208&ei=1RekUfKUGYua8wTgrIHwDA&zoom=1&ved=1t:3588,r:2,s:0,i:89&iact=rc&dur=410&page=1&tbnh=166&tbnw=237&start=0&ndsp=15&tx=64&ty=20

 

 

If this happens, it will have two effects. One, the fuel that hits the sides will come out of atomization and stick to the side, delaying its availability to combustion. And two, that fuel will then drip in later, adding an extra bit of fuel. This will quickly equalize and have no effect for steady state conditions (except for the large droplets which will not burn efficiently), but the switch from lean to rich under transient conditions can be difficult to tune (can require enhanced acceleration enrichment to attempt to track the tau layer)

 

FWIW, Tau layer and wet manifold behaviour is markedly different in a V8 TBI system than in a 6 cyl individual runner port injection - especially port injection with large injector. TBI V8s effectively have a constant stream of fuel being supplied into the airflow, much like a carburetor.  Port injection with large injectors has small injection events which can be very sensitive to timing, hence the movement towards sequential and the gains in drivability and efficiency during transient conditions.

 

 I'd put the injector tip as close to the manifold port as possible. If the spray pattern doesn't hit the bung walls, I'd say you are golden.

 

HTH,

Sam

Edited May 28, 2013 by Sam280Z

[PMC raceengines]

 

I made this one about 7 years ago , and fitted the injectors in so they would fit lol and it idled like a stock engine , engine made 400kw and drove nice , and was easy to tune , some times you just need to build them and see how it works , all the theory people said it wont work and it wont be good and will not idle , bla bla bla , give it a go and see how it goes .

[Tony D]

There are TBI inline sixes as well...

 

Tau is Tau

 

Soaked into the deposits on the back of the valve... On the long side radius...

 

Port injection does NOT eliminate the effects of the Tau Layer, only where it occurs.

 

The tuning of transient response IS the tuning of Tau Layer.

 

Unless I missed it, and we switched discussions to a direct-injection setup...

 

Wanna know why manufacturers are switching to Direct Injection? After the obvious reason of hardware now being available to do it...

 

(Hint: Look at the Last reason! It totally eliminates Tau-Layer transient tuning complexities. What you put in the cylinder is what goes there....no vagary of an evaporating puddle of petrol somewhere exhibiting variable-enrichment/enleanment rates...)

Edited May 28, 2013 by Tony D