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Another approach to ITBs?


HoustonZ

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A little late night boredom has brought about this. It would be a real easy way to make an ITB setup. Instead of dealing with 6 different bodies, why not combine them? Of course it's not aligned to an L6 block right now, just 6 in a row to show the idea.The runners could be fitted with injector bungs and the welded to a custom intake flange. The butterfly valves would ride on a single bearing supported master shaft, with provisions at one end for a TPS.

 

What do you guys think? Does this idea have any merit, or am I just dreaming?

 

intake.jpg

intake2.JPG

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Guest TeamNissan
You mean like one of my designs?

 

I have this setup completed, atleast the throttle plate and butterflys are done, and tubing I just need to finish the flange, but other projects are taking time.

 

assem_of_modular_itb.jpg

 

assem_of_modular_itb-2.jpg

 

Projects like ground breaking L series dohc designs? psh lol

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Yea Ill snap some pics soon, heres one sorta what it looks like, heres a pic of the internal velocity stacks on my DOHC project.

 

FRANKINTAKE_001-600x450.jpg

 

Its like this. BUT you have to gundrill a hole through the plate, for the throttle shaft, we have gundrilling machines at the shop, so thats what I used.

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Projects like ground breaking L series dohc designs? psh lol

 

it's already been done before. let him take his time if he has to! :P

 

I was thinking of making a aperture-blade type throttle body.

I know it would be a lot of work, but the end result would be some cables attached to a single cable, that would pull them all and open the apertures evenly. the problem is the air velocity, and the thickness of each blade. I'm sure I can get it to work if someone cut the metal out for me, and I'm sure it would sound brilliant when on an RB30DE, but I'll have to wait to test my theory.

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With a common throttle shaft how can you accurately adjust the butterfly's(think synchronize) for consistant idle or is this mostly for racing at WOT? Without a procedure for butterfly adjustment I don't think this method would be to good for a street prepped car.

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The common shaft would have flats milled on the face to align all the butterfly valves. As long as you accurately do this, the angles of the valves should be extremely close to eachother.

 

Good point 1 Fast Z. It's almost a project that could be thrown together over one weekend, except for the gun drilling which I do not have access to.

 

Your project is obviously for race, where as mine is a daily driver. How well ITB would work for that, I have no idea. I suppose if it doesn't run too well for my purposes, it could be sold to a member here.

 

All the fun is in building these things anyway!

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Guest TeamNissan

I know os did it but try and find one lol. If a member descovers a way it may open a door for all of us to let our L series engines breath alot better. Hence, ground breaking.

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With a common throttle shaft how can you accurately adjust the butterfly's(think synchronize) for consistant idle or is this mostly for racing at WOT? Without a procedure for butterfly adjustment I don't think this method would be to good for a street prepped car.

 

 

Don't tell BMW!

 

The setup is similar to Eggers & Vickers Mechanical FI Manifolds from the 70's. Also similar to Knisler and Hilborn setups. Everything you need for making that manifold is available from Kinsler.

 

Synchronisation is not a problem, the throttles should be set to be closed, and with milled flats on a properly sized throttle shaft, deflection or bending of the shaft should never be an issue. The turning torque of those even with a 24" shaft is really not that much. If you are smart, instead of turning it from one end, you install a throttle quadrant in the middle to actuate the common shaft. This makes no untoward torsional requirements on the shaft end-to end compared to turning it from either end. Especially if one sticks for some reason.

 

Idle Air Bypass is done with a separate manifold and IAC Motor for best control of idle speed. Cracking six throttles open for idle speed control looses 1-3% resolution on the TPS map and you don't need/want that.

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I run a slide throttle assembly on my engine. 6 trumpets with injectors fitted into them mounted onto the slide assembly. At full throttle there is no throttle spindle to obstruct the flow of air. The throttles all open evenly at exactly at the same time and all operated on 1 cable.

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The turning torque of those even with a 24" shaft is really not that much. If you are smart, instead of turning it from one end, you install a throttle quadrant in the middle to actuate the common shaft. This makes no untoward torsional requirements on the shaft end-to end compared to turning it from either end. Especially if one sticks for some reason.

That was the concern I had, considering you want the smallest shaft possible to avoid air flow interuption.

Idle Air Bypass is done with a separate manifold and IAC Motor for best control of idle speed. Cracking six throttles open for idle speed control looses 1-3% resolution on the TPS map and you don't need/want that.

That was my concern about streetability. This same concept is used on engines with a/c to raise the idle when the compressor comes on. Thanks for clearing it up for me Tony.

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