my 3500 dual plenum intake, composite!!

[merlot566jka]

part lt1, part 3500. im waiting on my brother so i can get the pictures of the guts of this thing. i recived a cracked upper plenum and this is what i did with it. its not done yet, still have to make bosses for the bolts, plane the tb flange, make vacuum fittings, sand, paint....bla bla bla. but the structure is all there. the lid is made of mat and 3k twill weave, polyester resin, jbweld the base is obviously a 3500. i did hack a perfectly good lt1 manifold for this, but its been 2 years and the damn thing wouldnt sell.

the plenum volume is about 70 cu.in. per side, throttle bore is 48mm per side. iac and tps are stock lt1, the iac port goes to a chamber that feeds both plenums (plena?) and also shares the vacuum for the iac and brake booster. the individual plenums are fed by thier own pipes in a similar fashion to the stock 3500.

im not hoping to make any extra power, i just want to see what happens here. it was a fun project to knock out while i was waiting for my new 3500 intake to come in. i will use this one if all works out well

the paint on here was just to check to see if i needed to go further with the sanding....

[El_Diablo]

deffinetly interesting... thats for sure.... cant wait to see pictures of the interior

[Superdave]

nice!

that's kind of what i had planned for my spare plenum, good luck with it!

[ForcedFirebird]

Don't know about that color, but I like the idea. Looks like you pulled it off pretty good

[merlot566jka]

mid sneeze

[Mars]

Hmm, seems like alot of JB weld to let loose and wreak havoc inside an engine...

Cool idea though !

[RedBird]

Love the idea..... Just makes sure if you use it that you dont lean on it!

*leans in* Crackcrumblesuckstyrofoamintothemotorohnoes!!!!

[IsaacHayes]

I wonder if there will be any problems with the 2 sides separated like that? Essentially you have dual intakes and dual throttle bodies. I wonder if it will sound different/cool?

[merlot566jka]

i hope, got the idea from grapeaperacing.com should be no problems with seperate plenum, should actually help. ive got lots of numbers here supporting this endeavor

the photo of the foam was the mold for the plenum. i covered the foam with duct tape and layed up a thin shell for a frc mold. (melt away mold, use pva or brake cleaner) then from there i trimed and cut things and made the center divider and layed up layers of woven roving and mat untill it was about 3/4 inch thick. then every 20 mins i added a layer of resin. trim, sand, trim, sand, sand , sand, sand then practice paint. the jbweld inside the plenum collapesed before i even got to test it. apparently jbweld and playdoh dont mix. so thats made of cloth and resin as well. after both pipes end in the plenum there was a whole drilled infromt of them that leads below them. from there to the tb is the iac port, map and brake booster.

im hoping this sounds different. i know more sound will come out of the plenum than was retained by alum

[34blazer]

those tubes are going to create alot of unessessary turbulance unless you formed the ends to resemble trumpets. why did you split the center of the intake? wont that hurt low end airflow?

[latemodelnewbee]

it looks like it should act like a dual plane manifold small block chevy, it would pick up low end number but the top will kinda suffer. but it would have used alum. tubing and alum. sheet metal for the top piece so that you could have welded it all together other than its pretty sweet and it will be interesting to see the results

[95naSTA]

Cool project.

FWIW, the FWD Nissan VQ35 has a variable intake manifold that seperates the banks in the low end, connects during midrange, and seperates agian up top.
So, It may help out the low and top end.