12 valve port and runner intake Q

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porschecoyote

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Starting my first real 12 valve engine build
Purchased a ported o ringed intake removed head from fellow comp d member
I am going to build my own runner intake for the motor. Unfortunately the truck will be used occasionally in the winter, therefore the intake will require a grid heater part of the year.

I purchased motor sport diesels intake flange. I had head and intake machined.

My initial thought on the main intake runner is to run a square tube that is congruent to the size of stock grid heater. Seems like the volume will be about the same as a zz fab.

My question is why is no one running a square runner?

Second question has to do with placement of intake to runner
I was discussing intakes with guys at industrial injection at sema show and one of them suggested I run the heater and intake on the side of intake behind pump. This will certainly make fab simpler but then I have an extra 90 for air to travel. He thinks that at 60 psi angels in an intake really don’t matter. Any thoughts?

Third and final question are in regards two cylinder port 3 and 5 both have a bit of a hump that protrude at the bottom of the port. Is there a reason they where left protruding? if I take them down will I hit a water jacket picks of port attached.
 

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Good questions always been curious myself.Instead of mounting a grid heater in your intake mount it in the intercooler pipe tight after the the intercooler. So if you decide later on to change it up some for a more competitve use it would be easier to delete.
 
They will start in the winter without a grid heater. How cold does it get where your at? I dont think the square is gonna flow as smooth as a round pipe would. Because of the corners in it, but who knows, i think the square tubing would be better than stock though
 
I would guess a square port is more of a concern when you have a wet flow port and localized velocity differences can cause havoc with fuel suspension. I can't say for certain how it would impact air flow by itself but again I don't think it would be as much of a concern as it would be in a gas motor injecting fuel at the mouth of the port or in the intake via carb.

Its up to you but you don't need a grid heater to start the truck in pretty damn cold weather as previously pointed out. I've started mine in as little as 5 degrees F but i've always run good injectors which I think have more influence on this than anything else aside from things like compression drops, different pistons, etc (my compression and short block are stock).
 
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I will be running mahly pistons and stock head gasket so compression should be close to stock. I have not decided what injectors to run but I will definitely look into cold start performance before I buy. Truck will be used to pull snowmobiles to Wyoming so temps will be in the negatives with no block heater so that's why I'm so hell bent on heater. Makes for a long night if she won't fire.
 
Bump still looking for input on how far to take down humps in intake that are for water port anybody have good pics of intake porting on no 1 with intake off ?
 
porschecoyote said:
Bump still looking for input on how far to take down humps in intake that are for water port anybody have good pics of intake porting on no 1 with intake off ?
Click to expand...

the humps are just casting's for bolt holes in the stock intake log grind them right off. be careful to not port too far into the intake runner, the headbolt and pushrod holes sometimes have casting shifts that make the placement of them iffy, just dont go too far.

grind away
 
ahale2772 said:
the humps are just casting's for bolt holes in the stock intake log grind them right off. be careful to not port too far into the intake runner, the headbolt and pushrod holes sometimes have casting shifts that make the placement of them iffy, just dont go too far.

grind away
Click to expand...

porting into the headbolt is actually a good practice if your wanting cfm.
 
porschecoyote said:
I will be running mahly pistons and stock head gasket so compression should be close to stock. I have not decided what injectors to run but I will definitely look into cold start performance before I buy. Truck will be used to pull snowmobiles to Wyoming so temps will be in the negatives with no block heater so that's why I'm so hell bent on heater. Makes for a long night if she won't fire.
Click to expand...

Why no block heater?

Other than that nothing to add.
 
A diesel fired recirculating block heater works awesome in cold weather. Either an Espar or Wabasto.
 
Lenahan what is your thought on putting the intake for the runner on the side of the log as apposed to front or back? Seems like I have lots of room behind pump. My thinking is intake side of plenum flat the exhaust side curved and individuall runners tapered from size of runner tube to intake flange. Also if the air is entering middle of runner should I tapper runner on each side ie front and back or provide same vollium to all runners ?
 
porschecoyote said:
Lenahan what is your thought on putting the intake for the runner on the side of the log as apposed to front or back? Seems like I have lots of room behind pump. My thinking is intake side of plenum flat the exhaust side curved and individuall runners tapered from size of runner tube to intake flange. Also if the air is entering middle of runner should I tapper runner on each side ie front and back or provide same vollium to all runners ?
Click to expand...

side feed will be better than front. i dont know much about manifolds but id taper from plenum to port entry on the head. its all really pointless putting a runner on unless your flange matches the intake port or is slightly smaller than port opening. to fix the 12v head issue with a runner, the port needs filled with epoxy on the entry to make it worth your time imo. otherwise, its just a nice boosted whirlwind.
 
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