building an intake manifold, input needed

[DEI37]

Custom is nice but almost all the custom ones i've seen kinda ruined the drivability of the car... there was a few done a couple years back..

maybe swapping over to the 3.4 iron head stuff would yeild better results?

http://www.turboz24.com/Pics/Current_Engine_32.JPG

^^ Sexxy

That is a cool pic. Definitely easier access to the coils rather than the location down on the block under the front exhaust manifold.

[Superdave]

with all the work into that engine.. just a 3400 top end would put you into the low 14's easy...

I understand about wanting to keep those heads though.

what about a LIM for a carbbed application, then run a TBI setup on it.. you should be able to find something like that at the junk yard.


Plus you could use a Hilborn scoop then

[sharkey]

the stock middle intake is just tiny, like i said, between the middle and upper intake, the ports are 1.25x1" with no room to realy do more than gasket match. also welding cast aluminum isnt great, id rather start from scratch.

swapping to the 3400 top end is out of the question, id have to change out my forged pistons to make it streetable, as well as i have over 20 hours of porting in the heads alone. i know the heads flow decent, but trying to suck air through that horrible middle/upper intake transision is killing it. from what i have heard, the stock 3.4 intake doesnt flow much better, and i would have to get an external crank trigger and run dis (or ford edis).

now when your trying to cram air down its throat, thats a different story. this is actualy a plan of mine eventualy, however i do want to have a 14 second time slip n/a, and if i can make the intake flow better to feed it n/a, it will also make a big difference with boost.

[Superdave]

Custom is nice but almost all the custom ones i've seen kinda ruined the drivability of the car... there was a few done a couple years back..

maybe swapping over to the 3.4 iron head stuff would yeild better results?

http://www.turboz24.com/Pics/Current_Engine_32.JPG

^^ Sexxy

[john_V63400]

Why not bore the hel out of a stock one and build from there

[1988GTU]

I dont know how much you'll actually gain, but maybe contact boostedrs since he does custom MPFI upper intakes. IMHO forced induction or 3x00 upper end swap is the way to go for the 2.8/3.1MPFI's since they have small lengthy ports.

[sharkey]

ive decided its time to build my own intake. ive been tossing this idea around for a while now and with no real gains from everything i did last winter (tranny swap, megasquirt, big tb, some other things) i started looking at my intake and thinking of how little air can be pulled through those 1x1.25" holes between my middle and upper plenum, never mind the 180* corner its gotta flow through.

what im thinking is using 1.5x2" rectangular tubing, bringing it out overtop of the valve covers (much like stock), and then build a plenum, basicly a big box, to bolt to the middle intake. i will be using the 60mm jeep throttle body im running right now, i figure itll flow plenty for what my little 2.8 requires.

any thoughts on runner length??? i know longer is better for low end. i figure i can have the runners 7-8", coupled with the lower intake that ends up around 12-13" to the head. also plenum volume im not quite sure of. depending on runner length, the plenum would end up at 12" wide, 10-12" long, and i figure i have room for 2-2.5" tall. this would end up with a pretty good volume, mabey to much??? also, whats the thoughts on diverters to direct air towards the runners???

any input would he helpful. also, if anyone has built a custom intake, post up some pics, i wouldnt mind having a look.

btw: my motor is a 2.8l ironhead, 9.5:1 compression, comp cam, ported heads, ect.