EFI on the log... Discussing injector placement

[RacnJsn95]

I plan on running a MegaSquirt system, so I'm trying to think of a way to rig up an injection system... I read the topic below about EFI on the log. That setup looks a little more difficult that I could handle. I was thinking of placing the injectors higher up on the log.

I've done a lot of research when I was into Z cars, and I was going to make a custom intake. The reason they put the injectors so close to the valve for emissions reasons. The farther you put the injector from the valve the fuel gets a better chance to atomize, and will make a little more power... So taking that theory into consideration, I think my injector placement would not only make a little more power, but would be easier (for me, and most people) to rig up, rather than to try the placement of the other injectors on the topic below.

What do you guys think?

 

[drag-200stang]

RacnJsn95,

Welcome to the forum. The problem with the location that you drew is that there's no way to guarantee the fuel will go down the port you want it to. With the one hole long log air density and velocities under boosted conditions will push the fuel to the next port. High exhaust pressures will cause reversion pulses which will push the fuel out of the port and who knows where it's going to end up? A tri-air intake like Dan Wagon's would help the condition but then the injectors and fuel rails would be kind of in the way. At the most 3" is the farthest you can move the injector. I'm not sure if that's enough to make much of a difference. Keep in mind I'm trying to make the best of what Ford gave me to work with. I'm not a big fan of chopping everything off. I want my engine to look stock and dumb. Tri power style air intakes work great with the log. Look at any of the fast imports - they all use short runners. The log will make incredible power your limiting factor is detonation. So my thought is to put the fuel as close to the cylinder as possible to cool the cylinder and curb detonation. My injectors are pointed just short of the short side radius of the port and valve edge where the highest port velocities are. Atomization under boost and the heat of the combustion chamber should work fine. Actually turbo engines are fueled rich to slow the combustion down to curb detonation. Also, with small ports fuel will displace air needed to make more power. I think an easier way would be to GB weld a boss slightly farther away and more straight up than what I did. Also the fuel rail can be made straight and connect all 6 injectors and not get in the way of your throttle valve(s). I hope this makes sense.

 

[RacnJsn95]

Some of what you said makes sence. I guess I got a little TOO into Z cars. Because of their individual runner intakes, there was no where else for the fuel to go except where it was supposed to go...

I don't think it's as far fetched as you make it though... I mean... Look at Lincs' turbo setup... Running through a 1v carb. You think that that dispenses fuel better than my proposed setup would? If of I6 engines is correct, wouldn't that make cylinders 1 & 6 lean still?

 

[Thad]

There has been extensive discussion here about efi on log manifold.
One line of thinking is that a TBI system may be the best.
Due to the construction of the log, air flow to each cylinder is not equal. But with a port efi system the fuel that would be delivered to each cylinder would be the same. Some cylinders would be rich and some would be lean. Would this be a measurable difference between cylinders?

In A TBI system, at any point in the cycle all the fuel injected would be mixed with all the air taken in, the a/r mixture going to each cylinder would be the same even if the volume wasn't.

 

[RacnJsn95]

That's an interesting theory. It does make sense. Even if the A/F ratio was the same, but each cylinder didn't get the same volume of the mixture wouldn't there still be a lean/rich problem between the cylinders? I like the idea of just being able to bolt it on... Hmmm, now I need to think about my plan some more.

I did a search, and read almost every TBI on the log topic I could find, and I saw that no one has ever done it, even though there was so much talk about how great it would be. Kinda makes you wonder... Would it really be as great is it sounds on paper (or in this car, on screen)?

 

[Thad]

TBI Throttle Body Injection. Air is measured at TB, fuel is injected at TB so the a/r mixture is homogeneous at that point. Even if different volumes are drawn in each cylinder the a/r mixture is still the same as originally mixed. Nothing has changed. So no leaner or richer mixture. Just some cylinder will get less or more of the mixture.

The Holley Projection has been used and some one used an adapted GM unit. These may have been posted before the crash.

This is the third incarnation of this forum. An earlier version crashed and the archives lost.

 

[RacnJsn95]

Just some cylinder will get less or more of the mixture.

Exactly, so wouldn't some cylinders will be richer or leaner? I think I'm going to buy the Clifford 2300 adapter, and use the Taurus (right? or is the LTD?) TBI setup, since it has the same mounting flange as the 2300.

I wonder what would be the easiest unit to use. A ford unit, GM, but I wonder which model. Anyone know the injector flow rates of any models? I'd have to try and find something that is high enough, that I could adjust it for running high, or low boost, and still have it flexible.

 

[rbohm]

8) since you are going to run the megasquirt system, why not use 3 tempo tbi throttle bodies, and set them up like a 3 one barrel carb system that offenhauser designed years ago. the only difference here would be that you would set the system to open all the throttles at the same time rather than progressively. that would give you one injector for 2 cylinders.

 

[RacnJsn95]

8) since you are going to run the megasquirt system, why not use 3 tempo tbi throttle bodies, and set them up like a 3 one barrel carb system that offenhauser designed years ago. the only difference here would be that you would set the system to open all the throttles at the same time rather than progressively. that would give you one injector for 2 cylinders.

It sound's great, but it's more work than I would like to do. I'd like to just get one big TBI setup and run it like that, for simplicity. If Linc's 1v setup can run fine, I'm sure I can run 1 TBI, and be just fine.

 

[Asa]

Linc, as far as i remember, is just doing destruction testing on that engine, seeing how much boost a completely stock system will take (what was he up to? 15PSI? something relatively insane i thought)

a single 1bbl will work, as has been evidenced, but for better power, future upgradability, and better fuel dispersal, i'd go with multiple units

plus, it looks cooler

 

[RacnJsn95]

What about using 1 TB, and Linc's idea of having a "second log" that ends up delivering the fuel to 1 & 6?

Yeah, That... I know there was seculation that the long trip in the second log might cause fuel to pool up, and not stay atomized, but I don't think that would really be a problem, under boost. Seems like a good idea to me.

I can't find how people are putting multiple carbs on one log through the search. If you look at danwagon's latest post on his tripple carb setup, it almost looks like that log was MADE for 3 carbs... I wonder how he did that?

 

[Asa]

look up the Offy 3x1 intake
google should turn up pics, as should ebay

or, wander around here
http://kastang.net/

as for danwagon's post, i assume you mean this one
http://fordsix.com/forum/viewtopic.php? ... highlight=
look closely at the log, the center carb has either a Clifford or Stovebolt adapter on it, i can't remember which orients the carb like that
the other two have adapters as well, but those were installed via boring a carb hole, then adjoining bolt holes that were tapped afterwards

as for Linc's additional idea, it just looks too complex to me, it should be easier to do something similar

whenever i get home (lord knows when that'll be) i'll take some pics and show you what i'm planning

 

[RacnJsn95]

If you look at the log in dan's post, it almost looks like the log is raised, like if something is supposed to go there...

 

[lightnin-boy]

That looks like a sketch that the Mustang Geezer came up with a few years back, we muised about forming the calimari induction corporation....

Kirk

 

[Asa]

the center section is raised up a little bit because of the old 1bbl mounting point
however, the outer carbs are raised up because he has (if i remember correctly) volkswagen stubby intakes bolted to the bottom of the carb

the log isn't designed for it, just has some machining and a few interesting intake ideas

 

[Thad]

First I heard injector placement for efi, then TBI, now someone mentions boost. Think I lost content somewhere. What are we building????

Turbo'ed efi small six? Draw through TBI, good fuel mix, all cylinder load to max due to boost---sounds good if you can get it to work.

What kind of fuel system did the Buick GNs use, IIRC, draw through TBI.
If so then that would be the system to plagerise.

Racn Jacn your question "rich or lean". The mixture below the TBI will all be the same. Due to the flow characteristic of the log manifold internal flow some cylinders will have better or worse volumetric effeciency, say cylinders 1 and 6 will get only 95% of the volume of air and fuel that cylinders 3 and 4 get. This is in an "unboosted" situation, "boosted" all cylinders would get much the same volume of air/fuel mix.

 

[RacnJsn95]

Yes, I'm build a turbo, EFI, small 6... Either a 200, or a 250 I haven't decided yet. I'm leaning towards a 250 though. I don't think I'd really trust a draw through system... Seems pretty sketchy to me...

But you said it yourself... All cylinder load max due to boost. So a single TBI should be fine.

 

[Thad]

There are several configuration of TBI just like carbs, 1v, 2v and 4v. A 2v, 1 tb with two venturii and injectors should do for the small 6.

When injecting into a pressurised port additional fuel pressure will be need to over come boost pressure. Example normal aspired injector fuel pressure 50 psi, boost 12 psi. Fuel pressure required under boost 62psi. Engines running turbo or blowers with port injection uses boost pressure to adjust the injector fuel pressure.

In a draw through system injection of fuel is in ambiant air so no additional or adjusting fuel pressure is needed.

Not expert on EFI but don't think speed density (MAS) system will work pressurize. Most TBI are speed density. Another reason to go draw through.

 

[drag-200stang]

Depending on how far you want his jaw to drop, most OEM style injectors on one TBI won't flow enough fuel to take care of any 302, at least not around here. A carb has better atomization characteristics than a TBI. There are truly wet flow issues with the log - not so much air flow issues. Wet flow air/fuel separation is not a problem at low HP levels. But the more power you make, the more fuel you have to supply and the more issues you have. Inline 6's love tri-power and as Execute has said before what works for NA is multplied by boost. And Linc did have issues - look at the picture of #6 piston on page 3 of his post. He talked about #6 the most so I'm assuming it was the worst. (This ought to get Linc posting again ) The fastest Grand National Buicks were port injected and intercooled. A lot of the new ECU's offer individual injector trim. Mega-squirt probably does too. I wouldn't be going through the work of making a tri-power style direct mount air/water intercooler for my new build when I already have a single hole one made if I didn't think it would be worthwhile. While I'm stirring up trouble , the fastest engines are 200's. Addo put up an Aussie link that proved it.

 

[xctasy]

Keeping the terms of reference to just a non turbo engines for a moment


Re-read FrenchTown Flyers advice on what was observed during the Brand F**d small block 5.0 engine program. CFI has a very poor fuel atomisation, or 'roosters tail', while the 4180 Holley is one of the champions. Yes, CFI or TBI work well enough on a non turbo, and can yield good power with two injectors. Yes, 120 to 140hp form a smog 302 is okay. Same for 205 hp from a 1982 and 84 Corvette 350 Crossfire, or 180 hp from a 305 or whatever from a TBI 350, or the 140 or so from the 3.8 Taurus yada yadayada. But guess what? They used single plan, open chamber plenumbs on equidistant engines with a cylinder a stones throw away.

Not a labyrinth of bends and curves.

Even the best US D8 I6 and on heads were a little 'bendy' in the port approaches.

Changing the terms of reference of this discssion to include turbos, then you just need to append the evidence.

Realio trulio little red dragon Turbo 200's like drag-200stang's beast, or even a milder 250 I6 like Does 10s, and certainly the radically boosted 1-bbl 200 Foxstang like Linc 200's, have the same things poping up. One carb doing a high pressure mix of fuel to six cylinders. If its carburetor, it may just work without detonation issues in the 12 psi area. If you add a TBI or CFI unit, it will form a more poorly atomised fuel distribution, it will be more likely to detonate with a single TBI or CFI injector.

If either of these three gentlemen had used pee and drible single CFI set-up, then there engines would be scrap right now!

Even if you richen up the fuel delivery by increasing pump pressure, injector size, or whatever, you won't improve tha atomisation charateristics because a venturi does a better job than EFI in atomising fuel.


To do a Turbo 200 justice, you'd need to run the sort of system drag200stang is looking at now (hint hint!), or a triad of CFI thottle body EFI units, like this.

If you were to use carbs, such as the Holley 2300 series (or 2150 or 2100 series 2bbl Autolite or Motorcraft, or 3 38 DGAS Webers), then you've got to have have something like this in a high boost situation

.

Or at the very least, two CFI units or two 2-bbl carbs like Mustang Geezers.

I guess anyone who has destruction tested there 200 (Linc200, drag200stang) have sort an American Idiot Red Heart,

and they automatically should be benchmarks we should listen to. Rather than being idiots, you guys are wise beyond your years!If your not blowing up engines, your not learning anything!

As for why 500 hp 3 liter and 3.3 litre turbo engines are a real force in Aussie racing, its simple. Most of them are cheaper and easier to get, and when you blow one up, you just get another block form the junkyard, and start again. In Aussie, the Ford guys have to use 4.1 (250) cube engines to beat Datsun 3.0 and Holden 3.3 turbos, but only because there Ford Falcons are 6 inches wider in the track and wheelbase, and a lot heavier than equivalent Nissan Skylines and Holden Commodores.


Enjoy yourself fellows!