Plastic intake manifolds

69427

69427

The Artist formerly known as Turbo84
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Clinging to my guns and religion in KCMO.
Every time I see one of the lightweight plastic EFI manifolds I get a little envious. I'd sure like to shave a few pounds off the top of my carbureted antique by replacing the aluminum manifold with a plastic/nylon manifold. But obviously there aren't replacements out there. It's my guess that it's a wet flow issue that is the main deterrrent to making these, and secondarily the market volume is probably too small.
Am I correct about the wet flow problem, or is it some other reason?
 
That really is a fine question. While I doubt it's the "wet flow" issue that's the reason, when I go to SEMA in a couple weeks I'll ask the guys at Edelbrock and report back.
 
I'm pretty sure Wilson has a composite manifold, I remember seeing a 2 pc composite manifold too, was split down the middle for easy porting access and had a gasket sealing the 2 halves.
 
"AFR isn’t just developing heads, and of more interest is their Pro Flow Lite Manifold for the Small Block Chevrolet, a fiberglass plastic composite intake manifold which they claim outshines the competition. In addition to being 7 lbs lighter, the Lite also provides more horsepower and torque along the entire power curve and produced a maximum gain of 12 horsepower over the leading competitor. "
http://www.streetlegaltv.com/forum/sema-2008-friday-coverage-1698-2.html

Looks like they were working on one for the small block!
 
With composite there are two mayor problems :
- fuel ending up on the walls of a wet manifold
- engine blow back, with fire hitting the manifold.

The first one is easily solved with FI, the second probably with a composite that has a high heat risistance.
For the second thing, i would assume that carbon fiber is no good since mostly it uses epoxy resin, which catches fire...
 
Saw the AFR unit at SEMA today. Nice piece but surprisingly heavy. It's probably a pound or two different than a conventional aluminum manifold. Edelbrock and Holley both said they're both considering it but not even in the development stage yet.
 
In my opinion there is an other big issue.... thermal expansion.
Composite fibers have nearly null thermal expansion coefficient.... and this can be an issue with the conformation of the valley of a small block.
The solution can be a seal system like the one of LS1 engines.... and the intake must be ready to bear the related stretch.
 
I checked it out again today and I think I may have exaggerated the weight thing. It's still heavier than I expected but it's probably around 10-20% less than an aluminum manifold. The seal issue you mentioned seems to be addressed. It has embossed O-ring seals kind of like that of the LS engines. I didn't talk directly to the guys but TrackDog did and I think he was saying the torque specs are something like 9 inch-pounds.
 
composit manifolds

Pick up any of the latest magazines that ere on the shelves now and better than 50% of them have ads from a couple different companies offering them for SBC applications with a 4150 or 4500 series carb base. The ones I have seen recently are a 2 piece design with a seperate valley plate then the intake itself with 4 seperated individual runners to a mating flange per side that appear to fit on top of the valley cover actually sandwiching it between the head and the runner flange of the manifold wit o-rings sealing in all locations.
I have my own opinions regarding the thermal expansion rates between the composite and the A356 cast (supposedly) that most manufacturers say the use, and I believe the composite will do a better job of dissapating heat by design and materials. Hell, my RPM Air Gap actually rusts on the outer surface. I bead blast it once or twice a year to keep it clean. The manufacturer stated that it is actually not rust but a treatment inpregnated into the metal to protect it. I call BS, the aluminum is not "clean" as it would be if the recycling processed were completed to the correct standard for the specification for the type needed. I believe they are using the cheapest (most impure recycled crap) to keep cost down.

Enough rambling about my rusting aluminum.

I had a chance to sneak a peek at one on a SBC last weekend at Orlando Real Street World Finals. It looked like a very nice well uilt piece from what I could see with it installed on the car with a 4500 carb with scoop base in place and 4 kits plumbed into it. I spoke to a guy on the race team briefly about it and he stated that they are happy with the results so far with the largest improvement being a "drastic" drop in intake charge temps. I did ask for numbers but he was reluctant to pass the info along so I was polite and left it at that. A buddy of mine that is a professional engine builder(has competed in The Engine Masters Challenge on several occasions with a couple trophys under his belt was in attendance there and we discussed the manifold and he had only one thought on it , well actually two. The first being he considered would be substantial intake temp drops due to the design which looks to have more air circulation area around and under the runners and material itself will not act as a heat sync like aluminum therefore not getting the heat soak that aluminum will due to the nature of the material. Plus the composite will cool at a much faster rate with the wall thickness being to be quite a thinner in several areas on the intake. He has not used one as of yet on a carb application but will soon and he is interested as to just how much temp drop is achieved which in turn will lead to being able to applying more fuel molecules into the cooler air providing a more dense charge into the cylinder. The second of his thoughts was one I had not considered; It will be much easier and quicker to port match by being a composite but in the same sentence he stated it will also be easier and faster to screw up by cutting too much material if doing the porting by hand. At least in the aluminum Manley has us covered for the intake and a few 4043 rods and a TIG will correct the over zealous hand controlling the die grinder most anywhere else , provided you can get the base metal clean enough to get a decent weld on it.
He is going to keep me posted as to his findings on the dyno with a side by side comparison and I will post when I hear the news.
I will say though... it definately looks badd ass on the motor. That alone has to be worth a couple hundred horses wouldn' you think???
 
big2bird said:
I saw the unit at SEMA with clutchdust, and have to say if it seals, it is a killer deal. ;)

http://www.dragzine.com/features/se...ersatile-new-plastic-intakes-for-sbc-engines/
Click to expand...

Be slick as snot if they did a DPFI version of that top piece.....

stick a 1000 CFM t/body in the middle....:drink:

I know there are only 50 billion SBC's in existence, but outta production for some ten years now.....

makes me wonder how much longer before they go the way of the old Pontiac engines?? :gurney::ill:
 
That's an idea. Mount the base, and then have a selection of tops- 4150, 4500, open plenum, closed, 3" rise, 5", short runner, long runner, one could adjust the torque curve or volume as needed- and without much hassle.
 
TimAT said:
That's an idea. Mount the base, and then have a selection of tops- 4150, 4500, open plenum, closed, 3" rise, 5", short runner, long runner, one could adjust the torque curve or volume as needed- and without much hassle.
Click to expand...

Including my DPFI.....eh?? slick as snot....

:banghead::drink:
 
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