250 EFi Questions

deano, apart from the EF-BF intake, have you seen the intake that some of the rotary racecars have?

Speaking with A7M a while ago, he was saying that they have some kind of lengthening and contracting device just behind the air filter, to optimise ramtuning to the max...



BTW, I thought XR6T and Typhoon have the dual length intake aswell? I've seen it in magazines, and the BA Typhoon I saw had one too..
 
:stick: I can't remember the exact details but according to Wheels and AMC, it doesn't have the full dual resonance intake.

That could be

a) no flap inside the intake manifold.
or
b) The twin pipe intake with the resonator isn't included.

I'll have to study the articles before STEVEN. gets them.

Smalll print ramble so I don't post hog...
There is an interesting issue with single throttle body injection (not similar to a single carb), and multiple throttle body EFI (very, very much the same as a port on port independent runner set-up you'd find in a 1980 AM V8 Vantage, or Lamborghini Countach S).

StrangeRanger or Thad was the one who talked about the trumpet which had dynamic resonance tuning. They were able to plot the thottle openings and power curve verses runner length. On a rotary, with next to no low speed torque, it would pick up a large percentage power increase.

Its do-able on any single or mulitple carb,
any single or multiple throttle body port EFI,
or any single or multiple pi$$ and dribble TBI or CFI system.

David Vizard in a 1988 publication previewd one for an HS4 equiped Leyland Mini 1275, and just by altering the length of a long piped ram tube to a box already equiped with a small velocity stack. He was able to pick up sligtly less air flow than with an K&N fliter, but picked up a about 10 to 15% more midrange torque with no power loss up high. The key is creating the least turbulance, and the best mid range torque.

Carb makers Amal, DellOrto and Weber, plus gurus like Vizard did some work on velocity stack length. Some of the carby stuff is well over 50 years old and still relevent. I'm certain we've lost about 20 years of knowledge becasue of Federal Emissions regs which have forced US makers to focus on single throttle body set-ups, and have focused on 12 inch primary runners, and whatever HDPE or rubber tube you could package. Everything is a compromise!
 
hmmm, lots of interesting info there.
For now, Im gonna use some bits of drain pipe i have floating round....

Then I'm going to fab up my own set of primary runners.
What its gonna end up looking like (and hopefully I can make a mock-up of it), is, dual TB, maybe dual MAF sensor (unless I can figure out what resistance a single one needs to put out to get right fuel).
The MAF's and filters, will be in a box ontop of the rocker cover, something along the lines of V8 small supercharger style with injector hat, fabbed from a sheet of stainless.
The dual MAF's inside that, lead to 2 pipes on the outside which the dual TB's will be bolted to.
So that makes the complete bit that will be the most important.
And, from there, the primary runners:
They would curve down towards the dizzy, then do a wide 90degree bend back up to the bonnet, then curve towarss the TB's, 3 into 1 TB, 3 into the other.

Looks good in my head! :eek:
And the way that I'll have it, I can unbolt the primary runners and swap over sets, hopefully I'll beable to get the length sorted for midrange power, could be longer ones like above, or short ones similar to stock.
 
He he he. I've messed up your X-mAs plans, now you're thinking as wacked out as I do.

my job is done!. ;)
 
Hehehe, are sure bout that?
Damn, sleepless nights! Gota get me a Tig welder, pipe bender, and alot of time.

My plans are even more spaced out now, dual runners, 2 lengths, flaps in 2 boxes, somehow rigged for rpm switch.
It would be servo opperated...

And, my 3d modeling artist mate here, is gonna do a few 3d models for me based on my mockup versions.
And, while i was in the dairy, the guy working there offered me a bunch of parts, so on the line is some more doors, an XB bonnet and hopefully a tailgate. Sweeeeet!!!!
And super majorly hopefully, I can get her rego'd and wof before christmas, theres gonna be cops around, and roadblock checks between where I want to go and here.
 
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