Long, slow build of my truck

[n8in8or]

Let's revive this thread, shall we?

Work has commenced on building an OEM-appearing center mount turbo setup.

I took my van manifolds to a local machinist who touched up the faces of the v-band flanges and cut the rear faces to sit better in the clamp. Appears to seal well so far. Flanges are just $20 eBay specials that I ordered. Seem to be decent quality. Anyway, the manifolds got blasted as well and are dummy bolted to the 6.2 for us to begin mockup. I need to order bellows for the up pipes and also try to source some pipe stock that has a thicker wall than standard exhaust pipe, for heat retention purposes. The up pipes will be wrapped anyway, but as we all know, every detail has to be correct to help these engines make any kind of power.

Yesterday we traced an intake manifold gasket to begin making a custom intake. We used 3/16" which I think will be thick enough. The machinist will likely get the finished product once it's all welded to face it and make it totally flat.

Not much else to report for now. Slow and steady.

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Good to see you're still at it! What are plans for making the up pipes clear the firewall?

 

[pacificdrumma]

Good to see you're still at it! What are plans for making the up pipes clear the firewall?

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[Husker6.5]

BFH always works to "massage" things into place.

 

[pacificdrumma]

So there is the need for some calculating to ensure that I use appropriately-sized material for the intake. I won't get too in-depth about how its going to look when its done - partially because even I am not sure how it will look - but I need to make sure the material is big enough to flow what is needed.

So here's where I am at, you guys tell me if I'm nuts.

Each intake port is 2"x1", or 2"^2. Eight ports at 2"^2 totals 16"^2 that needs to be fed by the intake. The basic concept is that there will be 2 intake runners that each feed 4 ports. The material coming off the ports will likely be 2"x1" rectangular tubing, though that is not set in stone yet. The calculations lie in the sizing for the runners. Using my collegiate mind, I can use the basic formula for the area of a circle (pi*r^2) to determine what I needed.

Say I use 2.75" 16ga pipe, .065" wall thickness, my ID is 2.62". I take my radius of 1.31, multiply by 3.14 and square it for a total of 16.9". So in theory if each runner was capable of flowing 16.9" and the intake ports can only take 16", I would be good.

Am I on the right track?

 

[Jaryd]

What in the heck did you just say.

You said to tell you if your nuts, your nuts for paying attention in math class. Or maybe I'm nuts for not paying attention in math class.

 

[KrisML]

If I'm picturing it right you're planning to basically make a pair of log style intakes and then join them somehow? Your math on the tubing size sounds fine and shouldn't be an issue. The challenge is making a smooth transition between the two sides of the engine and the single charge tube from turbo/intercooler.

 

[pacificdrumma]

If I'm picturing it right you're planning to basically make a pair of log style intakes and then join them somehow? Your math on the tubing size sounds fine and shouldn't be an issue. The challenge is making a smooth transition between the two sides of the engine and the single charge tube from turbo/intercooler.

You're on it. The joining of the runners (logs) will be centered to flow as evenly as possible. And if my ideas work, it will be "reversible" to either point rearwards to face the turbo, or frontwards to face the rad/IC.

 

[KrisML]

If you want the option of them to be reversible just put a small stub piece on each one that faces "in." You should be able to get a 2-into-1 silicon transition piece that would allow it to be faced either direction. I'm pretty sure that's what the 7.3 powerstrokes used. Hell might be able to use that piece from one, it's already made.

 

[n8in8or]

So there is the need for some calculating to ensure that I use appropriately-sized material for the intake. I won't get too in-depth about how its going to look when its done - partially because even I am not sure how it will look - but I need to make sure the material is big enough to flow what is needed.

So here's where I am at, you guys tell me if I'm nuts.

Each intake port is 2"x1", or 2"^2. Eight ports at 2"^2 totals 16"^2 that needs to be fed by the intake. The basic concept is that there will be 2 intake runners that each feed 4 ports. The material coming off the ports will likely be 2"x1" rectangular tubing, though that is not set in stone yet. The calculations lie in the sizing for the runners. Using my collegiate mind, I can use the basic formula for the area of a circle (pi*r^2) to determine what I needed.

Say I use 2.75" 16ga pipe, .065" wall thickness, my ID is 2.62". I take my radius of 1.31, multiply by 3.14 and square it for a total of 16.9". So in theory if each runner was capable of flowing 16.9" and the intake ports can only take 16", I would be good.

Am I on the right track?

I don't think you need tubing that large. The reason I say that is because all 4 cylinders aren't sucking at the same time so the flow for all 4 at the same time isn't so important. Now will tubing that large hurt....especially in a boosted application? I don't think so. I think it comes down more to packaging - what can you fit along with everything else? At our power level I don't think intake size/volume is that important, but no it can't hurt. One other thing that may be a consideration is the time for the turbo to compress all that air in your intake - if you have a crap ton of air in between the turbo and the intake valves, all of that air has to be compressed before the effects of that pressure can be seen downstream - you may feel that more than you feel any restriction from an intake that's a little too small. Those are just my thoughts - build what you want and can, and let's learn from it. I'm sure others that know more than I will chime in and help you out. I'll follow along and see what you come up with!

 

[n8in8or]

I just had another thought. If we think about the pre-turbo intake as the limiting factor for airflow, then let's start there. If it's a 4" intake then the area is 4*pi. Half of that is 2*pi. That means the radius^2 = 2. So that means the square root of 2 is the radius you would want for half the air flow by area. Square root of 2 is 1.414. Muliply that by 2 to get the diameter and that is 2.828.......maybe you aren't too far off......

 

[Husker6.5]

For a circle, A=r^2×Pi So for an example for a 3" diameter tube, r=1.5" so (1.5×1.5)×Pi = 2.25×Pi = 2.25×3.1415 = 7.068 in^2.

So, @pacificdrumma , if your D=2.62" then r=1.31 thus (1.31×1.31)×Pi = 1.716×3.1415 = 5.391 in^2, not 16.9 in^2 as you calculated. Thought I would point that out before you progressed to far into this as a project. To get to a cross-sectional value of 16.9 you would need a pipe diameter of 16.9÷3.1415=5.380 (which is r^2). Square root of 5.380 is 2.320 so D=2×2.320 or 4.64". So,.a 4.75" OD pipe would work.

 

[n8in8or]

For a circle, A=r^2×Pi So for an example for a 3" diameter tube, r=1.5" so (1.5×1.5)×Pi = 2.25×Pi = 2.25×3.1415 = 7.068 in^2.

So, @pacificdrumma , if your D=2.62" then r=1.31 thus (1.31×1.31)×Pi = 1.716×3.1415 = 5.391 in^2, not 16.9 in^2 as you calculated. Thought I would point that out before you progressed to far into this as a project. To get to a cross-sectional value of 16.9 you would need a pipe diameter of 16.9÷3.1415=5.380 (which is r^2). Square root of 5.380 is 2.320 so D=2×2.320 or 4.64". So,.a 4.75" OD pipe would work.

Good eye. I missed the order of operations error.

And if you want to do a double log intake, each log could be half the cross-sectional area. So 16.9/2=8.45. Working backwards from there: 8.45/3.1415=2.6898. Square root of that = 1.6401 = r. So the diameter of each log then should be 1.6401x2=3.2802. So if you could find some 3.5" OD .120" wall tubing, you'd have it. But now I go back to my earlier thought: I don't think you need that much area/volume. 1000hp LS engines don't have intakes that big, and that sounds like a lot of tubing to package under the hood, along with everything else.

Ps. Typing math on a phone isn't any fun.

 

[Husker6.5]

Typing anything other than basic math on a phone (or on a computer for that matter) is a royal PIA. Even going to my extended characters on my phone, there's still no squared or square root key (although there's those plus all trigonometric functions: Sine, Cosine, Tangent, Secant, Cosecant and Cotangent, plus x to the y power and a couple of others on my phone's calculator).

You're right, Nate. The plenum logs do not have to be that big of diameter because at any given time on a bank only one piston would be on its intake stroke. What is desireable is to have sufficient volume in the plenum greater than the displacement of a cylinder so that the cylinder can be charged to capacity without any loss of pressure/charge volume in the plenum.

 

[n8in8or]

Typing anything other than basic math on a phone (or on a computer for that matter) is a royal PIA. Even going to my extended characters on my phone, there's still no squared or square root key (although there's those plus all trigonometric functions: Sine, Cosine, Tangent, Secant, Cosecant and Cotangent, plus x to the y power and a couple of others on my phone's calculator).

You're right, Nate. The plenum logs do not have to be that big of diameter because at any given time on a bank only one piston would be on its intake stroke. What is desireable is to have sufficient volume in the plenum greater than the displacement of a cylinder so that the cylinder can be charged to capacity without any loss of pressure/charge volume in the plenum.

The turbo should reduce a lot of the plenum volume need, shouldn't it? Yes it will still need a plenum, just not one with as much volume as a naturally aspirated engine would need I would think - especially at our relatively low rpm. I feel like the extra volume would feely laggy too while you're waiting for the turbo to spool and fill that volume. Of course that would be less additional volume than an intercooler adds, so maybe it wouldn't matter that much.

I still defer to packaging. Build what you can fit that still has a relatively balanced configuration and I bet it works just fine.

 

[Husker6.5]

You would still want a plenum significantly larger than the volume of a cylinder running a turbo. While the intake valves on that bank are all closed the turbo would build pressure/charge density in the plenum (like an air compressor tank, which essentially it is) until an intake valve starts to open, at which time the pressurized plenum then starts to fill the cylinder as the piston moves downward. If the plenum has sufficient volume and pressure, as the piston begins its upward compression stroke and the intake valve closes the plenum should still have a higher pressure than the cylinder. This makes recovery in the plenum much faster, and with a properly sized turbo there should be no "lag". Think of it like this. Which would you rather do, all things being equal, fill a low tire on your truck (20psi) back up to 85psi with a 2 gallon 115psi compressor or a 50 gallon 115psi compressor? It's a question of reserve capacity.

Look at the dual plenum manifold Gale Banks has manufactured for his 6.6 Dmax project that is now a production engine.

 

[Will L.]

I dont know if it's good to think of it just as more reserve post turbo is the way to go...
If you are using a high psi turbo like the Gale Banks 6.6, then yes. Recover the higher pressure and keep it in the boost level as much as possible. One of the ways to do remote turbos effectively is have a blow off valve in the manifold, but let the turbo and ducting going from rear to front and through the cac stay at a higher than desired pressure.

To use the fill the tire example: fill the tire with a tank at 115 psi tank rather than a tank only at 85 psi. The higher pressure IS more air volume shoved into less space.

If you have more flow than pressure: using 1/2" air hose on an impact wrench instead of 1/4" air hose. The volume of air movement becomes far more functional than the psi. Try filling a tire with a 1/8" diameter 50' long air hose. If you have 200 psi you are still there all day.
So smooth flow of volume is where that ties in.

The Banks intake is big, yes- but it's flow characteristics amazing.

So dont give up a good flow pattern to achieve more available pressure. If just that would work, we would all have huge air tanks after our tubos. Think about cac draw back. Lag from moving air too far and around too many bends.

 

[pacificdrumma]

Good info there guys, thanks for the insight. I have some ideas for making the manifold flow well, fit well, etc. I am drawing inspiration slightly from a 6.4 PSD intake, but also now looking at the Banks 6.6 setup, I like the looks of that as well. The trick of course is going to be making room for everything; an S3xx charger, exhaust piping, and the intake stuff.

A little update: got some initial welding done with regard to the up pipes. Also purchased ingredients to make traction bars, and have a set of almost-new Bosch injectors from Kris to install. Should be a fun fall driving season ahead. Hoping to park the truck for most of winter... can you say SAS?

 

[WarWagon]

Slam Dunk point made here by @n8in8or and @Will L. Back in the Bad ole Days when the A Team was testing the ATT they found that an intercooler caused them more "lag" off the line due to the extra volume of the piping and intercooler air needing to be compressed and related restrictions.

Then you have the inertia of the air itself where you can tune the pipe for a specific RPM. Even boosted the air has inertia where narrow pipes can stuff more air in at low RPM but strangle you at high RPM. Big difference here when you are not under boost.

If you look at our vin F turbo manifold and a NA manifold you see the longer intake runners on the NA manifold that use air's inertia to stuff more air in as the intake valve is closing. Then the chain stretches and valve timing goes to hell...

 

[pacificdrumma]

Some progress on up pipes

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[3500_6.5]

I'll be keeping an eye on how you get this to fit at stock body height. I had to use the ole hammer to get a very similar looking manifold/up pipe setup to clear the cab with a 3" body lift. The clearance issue for me was the driver side v band and flange. Driving it around the yard (still can't test drive it due to tci incompetence), it still hits on occasion. I will most likely be cutting a section of the cab out and adding a large indent into the cab to insure clearance.


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