"my hats" just means the two ive built personally. They are anything pretty. They just work.

Yeh I messaged Holdener about that intake. If vortec was selling them , I wanted one. Sounds like it was just R n D.

 

NOT just R & D, third ~ The Power Hats have been available for (I THINK) at least 10 years. They're available from both Vortech AND Paxton. Unfortunately ~ like everything else nowadays ~ their price has increased dramatically (formerly about $275, IIRC).

The least expensive version I've found is under the Paxton name brand.......currently available from Jegs (linked below) for $374.99. When the "Vortech" name is applied, the price increases nearly 140 bux, to $513-ish! <eek> They're also available polished &/or with twin inlets.....for more $$.

Because of the large diameter, I suspect that they're very prone to "ballooning". Soooo ~ if I were gonna get one ~ I'd probably modify it with a few thru-bolts (studs) between the top and bottom......around the perimeter of the flame arrestor.

https://www.jegs.com/i/Paxton/769/8...1m9KSlFzQ00Z7eWqCikLwSDaTA0KuBpAaAtFFEALw_wcB

 

go to 9:16 of this video . This is the hat I am talking about.

 

I've never seen a Vortech hat/bonnet like that (below) before, third. Perhaps you're right about it being R&D/experimental.
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Here's an Engine Masters dyno test with a Vortech blower & (currently-available) Power Hat that was run at a fairly-low boost level:

 

The Vortech POWER HATS work because of a couple of things:
The Marine Flame Arrester (must have it installed) and a hat (not modified) with the "Air Brake"
removed (that caused the air to EVENLY FLOW around the circumference of the carb air horn
and enter all 4 of the throttle venturi EQUALLY).

Most carb hats are biased to flow more air to some portion of the carb air horn vs being equal flow to all
4 carb throttle plates.

And then people wonder why they have mixture issues to some cylinders with a blow thru carb.

Tom V.

 

.
Other than the SDCE or Power Hat.......can you name even ONE popular or commercially-available carb hat that provides satisfactory distribution to all the throats, Tom? I can't!

As an (the?) admin of this site......I'm sure you recall THIS old (Feb 2008) 15-page thread, where Scott from SDCE provided all sorts of charts & test data (ala Arlo Guthrie, lol) showing how his hat yielded nearly-equal distribution, plus a measurable increase in power when compared to the usual/popular varieties.

YET, that thread quickly evolved into a shit-slinging fest when virtually ALL the respondents threw him under the bus for a variety of reasons.......the first being that his hat was "fugly" <rolleyes> ~ and later, that [1] His data was either biased or flawed OR that [2] It blew apart (below) when a backfire occurred (DUHHH).

It never ceases to amaze me how respected engine builders like Steve Morris and others continue to use & sell the popular/customary "90°-elbow" carb hats and achieve phenomenal power figures & 1/4-mile times while using 'em. They MUST have exhaust temp &/or WBO2 sensors/instrumentation indicating their poor distribution (??).

OTOH ~ tho I wuz wrong once B4.......I doubt that ANY of those high-power blow-thru engines using conventional carb hats could compete at Bonneville, NOR run at WOT on a dyno for more than, say, 10-15 secs without melting a piston or two. My 2¢.......

BTW.........HERE is an interesting thread from (gasp) Speed Talk that discusses the same topic.

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Im 89shortbox in the speedtalk thread. RWtech and I emailed back and forth and he made suggestions and it helped me understand the air flow dynamics.

The hat above the I talked about is much like the design I was lead to by RWtech.
If vortec sold those, I would use them. It is time consuming to make one.

 

Due to the age of both threads (15-ish years), I wrote to SDCE (SD Concepts Engineering) outta curiosity and inquired about the availability of their hat. They responded by saying that they're no longer available for "public sale and only sell them to customers we build/tune in-house".

OTOH, I don't really see much wrong with the (currently-available) Vortech Power Hat, except that its' sheer size might cause it to balloon at boost levels above, say, 10-12 psi. However, if I were to use one, I'd probably install 3-4 "thru bolts" (studs) between the top and bottom, around the perimeter of the flame arrestor ("air brake", as labeled by Tom, lol). I would also increase the size of the central filter stud in the carb.

I realize that the flame arrestor (air brake) presents a slight restriction to airflow ~ BUT.......so do intercoolers, tube bends, throttle blades, the tubing itself, etc., etc.. It's just a means to the "end" (uniform distribution) that might require a slight WG adjustment to overcome.

BTW, as a preemptive strike, I have absolutely NO affiliation with Vortech or SDCE, lol. I also realize that this discussion has migrated to a topic better suited to the "Carburetion Nation" sub-forum, since it has little to do with manifold design, lol.

 

Been a bit of a lurker and just reading on here for awhile taking in all the information I could but I figured it was time to actually make an account so I could get some insight on manifold design. This thread alone has provided a lot of great information that I am really grateful for so, thank you for all those who contributed. Throughout this thread most of the manifolds have been for gas engines but this would be for a diesel application so no throttle body or injectors to worry about, among other things. I assume a lot of the theory and such is the same between diesel and gas but I figured this would be the place to find out. This is probably going to turn into a long post due to all the information I have based on what I’ve seen discussed throughout this thread.

The engine is a 4BT Cummins, the 4 cylinder version of the 6BT that most people are familiar with. For those that aren’t familiar with it, it is a 3.9L 4 cylinder with essentially everything being mechanical. You can run them with just a can of diesel and no electronics once you get it started (depending on what injection pump you have). Stock they make 105 hp and 265 lbft with a redline of 2300 rpm (lol). New goal has been 600 hp and 1000 lbft, mainly I just want 4 digit torque numbers.

My initial setup made 360/560 to the tire on a mustang dyno and was more or less thrown together so I could take it to a dyno day, so I was pretty happy that it even made that for being essentially a stock long block with unknown miles. With that being said, this new motor is far from stock, which is another reason for the new intake manifold. The other reason is the current manifold on the motor does not fit under the hood, which defeats the entire focus I have had on keeping the car appearing as stock as possible from the outside since it is stuffed in a Prius, yes. This new motor setup made 477 hp at 50 psi on a single turbo and needed more air so I am taking my compound setup from my old motor and putting it on the new one.

Here is some of the more motor specific information that I have seen requested throughout the thread for the design of the intake manifold. If I am missing something, just let me know.

Displacement: 3.9L (238 in3)
Redline: 5000 RPM
Head: crossflow 2V (1.870 intake and 1.750 exhaust)
Cam: 200 intake duration, 220 exhaust duration
Turbos: Both sized and spec’d to be approx. 3:1 pressure ratio, made over 100psi on previous motor but it was fairly restrictive so we will see what they do on this one. Mass flow rates based on 600 crank hp.

The factory head has an intake shelf cast into it and is quite restrictive. Plenum volume I would estimate to be maybe 80 in3 from the 3D model I have, if even that. Clearly it wasn’t something meant to make big power at all. Here is the factory head with the intake shelf circled.

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This new head has that shelf machined off and is drilled/tapped for mounting a new manifold. It is heavily ported, has larger valves, fire ringed, etc so it is ready to party. The current manifold has a large plenum and slightly tapered individual runners, which I do have some issues with. The volume is approximately 490 in3, again based on the 3D model I made from it, so approximately 2x the displacement (238 in3 displacement). My main concerns with this manifold, besides physical fitment, are the head/intake flange interface and how the ports match up, the large volume, and poor cylinder distribution.

The head/intake flange interface is my biggest concern since, to me, it looks like it would cause quite a bit of turbulence and pretty much nullify the effects of the tapered runners because it isn’t the prettiest transition. Here are some pictures of what I have going on. The runner outlets going to the head are 1.680” wide by 2.275” tall with 0.5” corner radii. The partially brown part is the 3D model I have of the head. I transferred the dimensions/locations of the ports onto the model for a reference location. The pinkish color is the 3D scan that I did of the actual head. Then the grey part is what the current flange is. When overlaid, you can see the odd intersection between everything. Technically all the ports are connected with how the head is machined (you can see the recessed portion between all the ports in the pink model), so I would think there really isn’t much of a point to having individual runners.

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My initial thought was to redo the plenum somewhat like the 2jz intake manifolds that were posted earlier and maintain the tapered runner shapes. Then after looking at the head/intake mating face more I was thinking I should just forego the runners overall and make it that same plenum style but bolted right to the head. The runner style is more common on the huge horsepower drag or pulling trucks but the plenum only style is somewhat common as well, mostly due to packaging, I think.

Here's how the current plenum sits in relation to everything and some of my clearance limits I have. It is made from a 6in diameter stainless tube essentially. The top plane/line is my hood clearance just in front of the motor (I just did a straight plane back so it looks like the fill on the valve covers doesn’t clear, but it does. It is about 5.5 inches from the top of the front gear case to the underside of my hood. The angled plane/line is my clearance to the injection pump, mainly due to the oil feed line that is on that side and ensuring I have access to the nuts that hold the pump on. You can see the clearance in the last picture along with how the head looks with the intake shelf machined off.

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Here is what my current rough design is so far, but it is just a little over 200 in3 and I would like to get it closer to at least the 1.3x displacement number that has been discussed before. I don’t have any of the fancy CNC equipment like some have to make those gorgeous manifolds so I have to be mindful that I can actually fabricate it as well.

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The inlet of the manifold would eventually be a 3in tube with a vband and go off to the right. I planned to try and angle the inlet more to give a straighter shot for the air instead of having to make a bunch of turns. Somewhat like the manifold below but no runners since I have to connect to my intercooler piping there anyways. It does help that the intake ports in the head are angled towards the front too.

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It seems the main consensus is to try and slam the air into a wall opposite the runners, but I don’t think I have room to make a manifold that allows me to kill all the air velocity like that. I am hoping that directing it as much as I can will work. I saw the idea of putting vanes in the plenum to direct some of the air was discussed and that was another thought I had, but it sounds like it won’t really work (at least that is how I am understanding it). I am all ears if anyone has any better suggestions though.

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I think you're missing a brain (just kidding), BUT......I can certainly understand your reasoning for choosing the "Mad Scientist" moniker as your username, lol.

A couple of random observations:

1. I'm reasonably sure that air-charge distribution is just as important/critical for diseasel engines as it is for their gas or alky-fueled counterparts.
2. It looks to me like your hood-clearance issue will remain, regardless of intake design, since the front v/cov "module" interferes with the hood w/o any manifold at all. Can the engine be lowered, OR can the frt v/cov be modified with a sloping front, w/o interfering with the rockers?
3. The ports appear to have DRASTIC (and differing-sized) tapers at their "mouths". I ASSume they were made that way to help "gather" the air from within the cast factory plenum? Since you've milled off that plenum and you're making your own manifold with individual runners.......I suggest making a different flange to accommodate manifold runners that are closer in crossectional shape/size to the inner portion of the head port. I would then use A-B epoxy putty to fill the heavily-tapered outer sections of the port, in order to yield a consistent shape/size port from the flange-mounting surface inward.
4. As for manifold clearance next to the head.......can I ASSume that the injector pump is mounted to the backside of that front gear case? If so, can the pump be "clocked" to a different position (CW, as viewed from the front)? Even if you could clock it only 45°.......you'd gain a lot of room "over there". Of course, doing so would require you to make new injector lines from some kinda whatup gee-whiz thick-walled tubing.

I'm curious to see what others recommend, BUT.......I suspect that your initial concept of using a largish plenum to feed individual runners (having inward-projecting velocity stacks) will be the design of choice. The problem, however (as always), is "how to feed the plenum" without skewing distribution to the runners. I doubt that it would be "from the front", but I also concede that you have some significant packaging challenges, lol. GOOD LUCK!

 

I'm sure I can't help with this unless you need parts machined but can we get a build thread or a social media photo channel of this build. I'm intrigued.

 

A few of my friends have called me a mad scientist, or just insane, many times so I figured it was rather fitting haha. It was either going to be that or something engineer related, since I am an engineer. Being a fab guy/mechanic and engineer is a bit of a dangerous combination as you can see lol. I feel like I have a good grasp and knowledge of a lot of this but I know there is always going to be things to learn and I have no hesitation on diving into something to learn more from those who know more than I do. That's one of the reasons that I have enjoyed this site since it seems like there are a lot of people who are willing to help/teach/share knowledge if others are willing to listen, so here I am.

1. I assumed the charge distribution thing was the same but I wasn't 100% sure if some of the other considerations came into play since there never is any vacuum in a diesel, essentially runs like a throttled motor at WOT all the time.

2. The front valve cover doesn't actually interfere with the hood. The "hood clearance" plane I made in the 3D model is just a general guide I put that is the clearance from the top of the gear case "green circle" to the hood line. It is actually the point at the very front of the gear case, not the middle like my crude drawing here.

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You can see the hood has quite a bit of angle from there back but it was just quick guideline for me in the design. If I have to, I will try and scan the engine bay without the engine in so I can have exact package limitations. I just got my 3D scanner so I am still learning how to use it. The engine location can't be changed anymore as I have the rest of the drivetrain designed/built around that location and the new oil pan I built is already a tight fit with the front subframe.

3. You are correct on the vastly different port openings and I assume, like you, that was done to help with the factory plenum. These geometries are one of my main concerns with the individual runner style intake. FWIW, I did not make the runner style intake that I took off, nor did I do the headwork. However, this is a very common modification in the high horsepower applications of the 6BT. After taking the intake manifold off and seeing how it actually looks, the gears started turning in my head, and I wanted to do better. It is just odd to me how this is a very common thing in other trucks. The epoxy thing is something I have been toying around with quite a bit actually. I have been trying to read more about it since I haven't done anything like that before. If I had a billet head, I would for sure be doing a individual runner style intake because I could have the intake ports however I wanted. With doing the epoxy, I assume I would need to remove the head to clean everything up before and after the epoxy, which honestly, I would rather not do at this time. Do you have any insight on this at all? I was going to do some sort of epoxy anyways around the outer edges of the flange to create a larger flat surface so I could use an o-ring seal on the intake instead of the RTV that is always used. This is kind of why I have been leaning towards doing more of a plenum style and leaving the ports alone.

4. Yes, the injection pump is bolted to the back of the gear case. You can see how it sits in one of the 3D models. The pump in the model is not exactly the same as mine since mine is larger, but it is close enough to get me what I need. I plan to try and modify the file so the pump is closer to correct, but this will do for now. Unfortunately you cannot "clock" this pump at all with the mounting studs. Timing adjustments are made on the front with the gear. In addition to specific support brackets that are already there on the pump, there really isn't enough material on the mounting tabs of the pump to machine slots in to clock it either. For reference, the pump sits at 35° from vertical. I already have straight sections of injection line so I can bend them up however I need when this is done

I don't have a build thread for this but I can probably put one together. I will keep the machining part in mind though as I'm sure I will run into more things I need done haha. As for social media, I just have my instagram that I post to, schulzb. I haven't posted in awhile as the project had to go on the backburner for a bit due to other cars I had to get done and life in general. The pictures I posted above aren't even on there yet. Some of the videos of the car come up when you google "Cummins Prius" too but most of those videos were from when it was very much incomplete, but complete enough that it would drive, barely (lots of zip ties and bungie cords haha).

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......• I only ASSumed hood interference b/c of what appears to be a pic of the hood being held open due to direct contact with the front valve cover.

......• I haven't used A+B epoxy putty in a couple of decades, BUT ~ it was and, AFAIK, still IS.....used extensively by professional head porters to reshape, resize, raise, etc. cyl-head intake ports and manifold plenums/runners. The last time I used it was to extend/reshape the divider walls in the manifold plenum for the BBC in my Super Gas Vega (an NHRA class). I got it from Aircraft Spruce & Specialty, but nowadays just about everyone carries it.
........It came (comes) in two foil-wrapped sticks that presented as thick "Playdough". Equal parts of A & B were then kneaded together until "homogenized". IIRC, it has a working time of approx half an hour ~ during which I molded/applied it to the ends of the existing dividers to lengthen and "bullnose" 'em. During the curing process, I could smooth it very nicely with water-wetted fingers. When cured, it was as hard as ceramic and I used cartridge/sanding rolls on a die grinder to finalize the desired shape and finish.
........Your inclusion of the two manifold examples implies the use of individual runners. BUT.....w/o making the head ports uniform in size & shape, your flange-mounted manifold runners will dump the charge air into drastically different-size ports and immediately be faced with "mini plenums" behind the flanges that neck down into smaller sizes. I'm no CFD expert (or even novice), but that seems very "turbulence-inducing" and counterproductive to me!
........As for the need to remove the head for protection against fouling the cyls ~ simply back off or remove the intake rockers to tightly close the valves (whack the v/stems a couple of times with a hammer to ensure positive valve sealing). During the application, reshaping, and sanding of the epoxy.....only dust and possibly a few flakes/artifacts of epoxy will settle into the port behind the valve ~ which can be blown out with shop air.

......• I'm a lifelong (retired) professional mechanic and, even tho I haven't worked on this specific engine, I would tend to disagree that the pump can't be clocked. The studs that presumably pass thru slotted holes in the pump's mounting flange could simply be relocated (new holes drilled & tapped) to the desired position on the gear case ~ between the existing stud locations? AND, the pump gear could be re-meshed/timed to engage in the proper location for correct timing ~ easy peasy.

 

I wouldn't bother epoxying the ports. I assume they are similar CSA as you get closer to the valve. Just try to get the blend radius on the entry to each port reasonably similar.

A 6" dia plenum will have fairly low velocity (about 8m/s (26'/s)) so air distribution should be OK - provided the plenum intake is a smooth transition (a 3"-6" step would introduce a high velocity stream to the plenum). Ideal is a 3" - 6" conical diffuser, approx 10 deg (I appreciate that is probably not going to fit).

A gentle chamfer at the front for hood clearance won't affect things much.

 

A Bit more info on the Paxton and Vortech Aluminum hats, (NOT THE KNOCK-OFF) LOOK A LIKE HATS):

I HAVE PERSONALLY TESTED THE VORTECH ALUMINUM HAT TO 18 PSI WITHOUT FAILURE.
Many dyno pulls. As long as you have the marine flame arrestor screen properly installed the system easily made over 860 HP at 5300 rpm on a low compression basic 455 Pontiac Engine at just 13 psi of boost pressure. SO MUCH bad information out there concerning these parts.

Tom V.

 

THANX for including your personal experience, Tom. The (fugly?) Vortech/Paxton hat design seems to offer much better distribution than the typical 90° variety that virtually everyone insists upon using.

My reasoning for the addition of "thru bolts" (studs) and increasing the center-stud size, was/is simply due to math. Even at "only" 13psi, a hat diameter of 14(?) inches......imputes a force of [gasp] 2,001 pounds (18psi = 2771 lbs) attempting to balloon that hat & simultaneously rip the center stud outta the carb!! <eek>

 

Hmmm........I invite you to look at the OP's picture & 3D scan(?) below of the head surface, to which the intake will be bolted, gruntguru. Then, kindly advise how you intend to.......

1. Equalize the 4 port entrances (especially #1, at left, that lacks the sloped "lead-in") without hitting water.
2. Make a flange with large enough openings to encompass the mouths of the 4 "similar" funnel-shaped port "mouths".
3. Attach a 6-in plenum without using runners as large as said port mouths.

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All good point. I was envisaging a plenum feeding the ports directly - no runners. Oh wait - no need to machine the original "plenum" off the head. Should have read the posts more carefully.

To put individual runners in that head perhaps mill a consistent cross section with step into each port entry. Then create a manifold with runner stubs that push up to that step and with oring groove on the outside of each stub.

Seriously, at 5000 rpm I doubt there is much to gain creating individual runners when they are so restricted on length. I would just bolt a big enough box on top of the original head flange and add the 100+ psi.

 

Ok, lots to reply to. I greatly appreciate the feedback

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1. Altho my previous thought about re-clocking the inj pump by moving the mounting studs is still valid, I've since discovered that those studs are screwed into "bosses" that are ribbed/reinforced on the inside of the gear case. It could still be done, but it would require a little ingenuity, fabrication, and possibly some welding. However, the cam does NOT need to be removed and the pump's drive gear can easily be re-engaged and timed to match any amount of pump clocking,
2. I hate to say it, BUT ~ you already HAD a "plenum-style intake" and ~ IMO ~ the "ship" has pretty much sailed on your ability to fabricate a new plenum-only intake that will simply bolt onto your modified head. In retrospect, I'm beginning to think you shoulda left the stock "shelf" intact. If you wanted more plenum volume, you could've just bolted on a custom "box", in lieu of the stock (flat) top. Obviously, you don't need a throttle body ~ since diseasels are "fuel-throttled" rather than "air-throttled". My 2¢......