custom upper half efi intake?

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Sep 15, 2009 | 05:06 AM

muscletruck7379

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From: Harrisburg, NE

custom upper half efi intake?

I don't remember where i saw it at, but somebody with an efi big six had replaced the upper intake with a custom made piece that was fabbed out of aluminum, it was basically a 2"x2"x (however long it needed to be). the guy did a good job and it really helped clean the engine up.

my question is how much do you think the loss of runner length would affect the powerband of the engine? they seem to do good enough with carbs.

common theory is that short fat runners move power up the powerband, while skinny long runners help with low end torque.

anyways, enough mumbling. bottom line, it probably won't help or hurt any. but what do you guys think about a setup like that?

Sep 16, 2009 | 06:48 AM

BigBlue88

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From: Northern Virginia, USA

Interesting. Would probably work just fine. Like a log manifold, but with better flow & longer runners. Where would the throttle body be located? I'm wondering about air charge distribution effects with an upper intake that small. A larger upper intake (4x4 or 3x3, even) would provide more of a common buffer for all the runners to pull from, "disconnecting" them from being directly affected by the throttle body. But if you go too big, it starts to look like a Trick Flow Box-R manifold (for 5.0L, but same manifold design- short runners, big open plenum), which is designed for top-end power.

http://www.themustangshop.ca/product/303570/300338

Sep 16, 2009 | 07:04 PM

300 Buster

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From: Hudson,Michigan

I like hearing someone wanting to modify the EFI, I still marvel at the precision of it and I think it has a lot of potential.I think changing the runner length will probably have effects on the character of the engine,but if your going to build it,why not go from the head out?You have an excellent chance to polish the inside of the whole thing and do away with a joint that messes with the flow.Support for it would be a must,otherwise intake gasket would suffer.From what I have seen,the closer you keep to equal length on the runners,the better and the plennum could be made so you could un bolt the top and clean it.As far as size and shape,I don't know,but I do know that every Ford EFI plennum/manifold that I have seen taken apart,with miles on it,was nasty inside,probably due to crankcase ventilation and no gas through it.I'm to old to play like this anymore,but I sure like to see others do it,keep at it,if it don't work,find out why and fix it,but keep in mind that Ford probably spent a bundle on the whole EFI thing (design and research) so improvements may not come easy.They just come out with a little V6 SHO engine boasting 365 HP and getting green gas milage,where would a person start with mods on that one?

Sep 18, 2009 | 10:46 PM

muscletruck7379

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From: Harrisburg, NE

http://fordsix.com/forum/viewtopic.p...=56075&start=0

found it...

i guess he used sheetmetal instead of aluminum (which i might try finding some to use). this would also allow me to mount the throttle body anywhere I needed it, as i have been considering pulling air out of the cowl to help prevent it sucking water while fording.

buster, thanks, if you noticed my sig i am going to be using a megasquirt computer. but i am also planning on using a wide-band 02 sensor (which will allow me to run as lean or rich as i want), and im also going to DIS ignition, so all my distributor is gonna do is drive the oil pump! although if i thought i could do it i would go to direct injection like the gxp solstice had...

im gonna do the head, but not right away, I would like to get it on a dyno first, then do some port and chamber cleanup and bump the compression up a point or so first.