Look... (And please, don't take this the wrong way.).....I appreciate both of your thoughts here...But between you flooding me with indirect solutions to a direct potential issue,..and Joe waving the red " You're gonna hate that" flags....I'm now the guy caught in a revolving door.
Here is a fact: I don't wanna keep doing junk over.
#1. If there are negative reversion issues that'll come as a byproduct of attaching the TB's directly to the head, that's fine...but please,..Between the two of you will somebody tell me what they think about how BMW did it on their engine with success. I need to understand how so many examples of direct TB injection, and the scores of Webers carbs placed either directly over or beside the intake port didn't suffer from all of this calamity before I find it out the hard way.
#2. If I have to scrap my cutting board sandwich idea, and go back to a tube between the head then thats fine too, I really kinda wanted to orient them straight up in the first place...but that'll mean using a "j tube" to drop the runners under the row of ITB's and turning the tube 90 degrees into the port from there...in effect..ill have probably 12" of additional runner before the port entrance.
( it'll also mean that I'll have to weld up the injector bungs that'll now be on that plate bolted to the head)
Or...
#3. I can use a 90*, or 45* bend and turn a much shorter version up directly from the port..probably adding 2-3" of runner length.
Ideally it'd be great if I could make the tube transitions adjustable, and use silicone couplers so I could adjust the runners simply by removing or adding rubber. Then I can make stacks that are attached directly to the head, and to a plate attached to the bottom of the ITB's...and simply insert or remove whatever length of tubing is required until I get the engine to do what I want it to.
The problem with that is I don't have that much room between the head and the brake booster to be all that adjustable in reality.
Or....
#4. If the problem can be solved with a common air box placed on top of the row of ITB's mounted directly to the head,..( Cause that's the way it is on the BMW engine) then I can do that too...Solves the " What am I gonna do for an air cleaner"?, and "Do I really want the engine breathing all of this hot under hood air?" issues perfectly.
Man, you just gotta wave the finger to what you don't like, stamp that nasty spider like Mr X, and then build what you WANT to do.
I believe in anectol proof. The risk is you kill some poor guy with fully automatic gunfire. But they are blanks, and its just training.
Sadly, your tough, resisilant and darn smart, so you get it with both barrels. I've tried it elseware for 17 years on another forum, and people who actually think are rare.
Look at any motorbike engine, and the ITB's are Mikuni and Kehin replacements. So thats all you are doing. Get a copy of Tunning For Speed, Phil irving.
The only thing with canted valve in line six cylinder engines is you might loose mid range torque somewhere, like Phil E Irving did when he did some dyno work on his High Power head back in the late 50's. The solution in that case is to contain fuel stand off and you do that by adding or subtracting total intake runner volume from the head to the air inlet. But that is rare.
End of over thinking that direct mount Oh my G""d If just Shunt Funted my brand new hand made Intake runners, SOB, I'ma gonna have to do it again because some dirt bag didn't JUST answer a simple question I asked five times....
1. No reversion issues. Reversion is a fuel stand off and containment issue. You'll have fuel standoff on back up the throttle body to a point 13 inches back in some situations. Ask 5 liter 630 hp AVESCO drivers what they smell, and its fuel load, even at 7500 rpm. All Port EFi engines bheave like Independent Runner Carbed engines at various points in the rev range, esepcailly on on off the gas.
Direct solution is ITB's to the head as you are planing, and then playing with the tunned length to the ITB. Anectol, in 1993, Larry Perkins went right back to that Jag D type slide throttle crud because he had to package his engine first with no hood scoop. When Rover and Tom Walkinshaw did the Group A 1984 Rover 3500 Vittese and the 1988 VL and 1990 VN Holden 304, they were forced to relocate the throttle bodies a mile away from the intake valves. Where the throttle bodies are just doesn't matter, thats a packaging issue. The black eyed Scottish dude Tom put two mechanical secondary throttle bodies upstream like a giant oversized Varajet 2-bbl carb, just so they could package it. Fuel containment and fuel standoff were then and are now controlled not by the distance of the throttle body to the intake valve, but by the total lenght of the combination.
2. If you have something that has 12 inches between the head and throttle bodies, then go do it. The bend radius is limited if the runner is filled with atmoised gasoline. But look at the late 90's Mazda Rotary and BMW V12 Lemans racers, they have up stream injection, and Trumbone extensions to the bellmouths, and vary them to suit the engine speed. Depends whatcha wanna do. Visualise the old XJ12 quad Stromberg CD175 carbed XK-E. Nothing to have 12 inches of intake runner. Build it, and Shoeless Joe Jackson will zoom arm breaking speed balls by ya half dozen one foot tubes, make everyone else look like a fool, boy. If Jaguar in 1956 were silly enough to point the injectors in the wrong direction, you can too.
3. You could slipper joint and patent the worlds first swing arm 45 to 90 degree sweep, variable runner lower ITB mount.
4. David Vizard had that very issue when he put a 2-bbl IDA 48 Weber on his 1435 cc Mini. The bellmouths came through the hood, and he had a mide range and high rpm problem with fuel delivery, and wanted the free cool air, but couldn't figure out how do do it right. So he made a Cowl induction hood cover.
You cannot Tuck Fhis up. Build it the way YOU want, and the Horsepower will come.
, won $$$$ every Saturday night on the 1/8th mile.