I don't know about the available part - I bought it year(s?) ago - at that time he said they made a limited run of them because they were going to market an MPFI system but they never did and they had some manifolds left over.... wether they still do with the injector pods drilled or not I don't know.

Some comments on it - the fuel rail is subpar. It appears to be a tube with fittings for the injector welded to it. There is no provision to clip the injector to the rail. You must make your own hold down mechanism, and this will intern keep the injectors in place. If you remove the hold down and remove the rail, the injectors are only held in by the o-rings. It also has 3/8" and 1/4" barbs. I was weary of wether the 1/4" would be too restrictive - for my motor it seems to do fine but for other builds....

One last thing - the pods aren't centered on the runner, IIRC #1 and #6 the pods are on the outer edges so atomization may not be the best.

For the price though, these are minor hickups. If you want perfect, buy a standard clifford manifold (or use a stocker) and send it out - I've gotten estimates from 2-400 to add injector pods and manufacture rail & hold downs.

If any are available, I wonder if clifford will sell them all to someone at a discount?

The reason I had been thinking about a scratch-built intake is that stock intakes have a couple of compromises from being designed around a carb. They're heated by the exhaust to keep the fuel from puddling, they have runners of different lengths on different cylinders, and a pretty small plenum. An EFI manifold would not be constrained by having to prevent fuel dropout, so in theory you could come up with a better design if it was meant for EFI from the get-go.

Although for a low RPM torque manifold, it might be hard to top reworking a Hyper-Pak reproduction for EFI.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Sam,

I'm not into having parts for the sake of having parts. If it's not worth building on a performance basis why discuss the optimum intake manifold at all? Just chrome something that exists, lift the hood at the car show and never bring up that you have no idea how fast it is because it's never been to the race track.

The goal is a faster car and since it takes power to go fast everyone builds for more power. The only way to improve power without increasing RPM is by increasing torque. My proposed intake manifold would boost torque beyond anything short of a tapered runner individual throttle manifold or variable length manifold.

I felt I explained myself reasonably well and made the 'why' clear without beating anyone over the head with MAXIMUM TORQUE, EASIEST TO BUILD, LOW COST MANIFOLD.

Individual throttle intakes (which are easier as all the parts exist and almost bolt together) have drawbacks beyond cost. BMW uses (or at least used to use) mass air flow for load sensing on their individual throttle intake systems as MAP sensing is less accurate. BMW also uses a very large plenum which leads to less sharp low speed throttle response.

I suppose it now falls to me to demonstrate that I do have a handle on what's required for an intake manifold and that I can successfully built not only a superior manifold, but a superior engine.

You had a big budget, spent a lot of money on turbocharging and electronic controls to boost torque. I don't have that budget, but I do have the ability to fabricate what I believe to be a superior manifold. If you aren't going to design and build it yourself then you're faced with substantial costs and more compromises if you try to drive the cost down. You may have a manifold that works, but that's not what this thread is about.

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Joshua

What about 2 throttle bodies manifolds....

Something like the 2 - 1bbl manifolds.

Each runner would be about the same length.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

And Josh, I would be happy to help you. Let's smoke a peace pipe here. I think the final product will be better if we share ideas and resources. Don't hear my questions as a challenge to your authority.. I don;t have any basis for judging your ideas. I don;t claim to be an expert on any of this. I just wanted to know more. And, if we get these ideas out there and talk about them openly, then we can get a better product, easier, and more affordably.

Josh, do you have any idea about what kind of improvement in torque we are likely to see with the split plenum. ? Will the curve be more flat, high numbers higher, etc, etc? Also, could you have the split run side by side and be fed by one TB much like a carb with a split plenum?

Now as I read these posts so far, the idea of a custom fabricated manifold has a number of supporting justification: Improved performance, availability, and maybe better configuration for underhood clearance. I'm not guaranteeing it, but I suspect that we could have this made at a fairly reasonable cost if we design it well. The idea of using tubes throughout is really clever. And it seems as if this should be fairly cheap in the end. Certainly it would be cheaper than bending and welding sheet metal.

I would like any and all with ideas on this subject to drop your two cents in here. There are a number of questions to be answered, and asking them is the start. For example, how would we want to mount the injector bungs? Is there a commercial product that would be preferable to use? My guy Tom actually would have real strong, and good ideas about that, as he has made these before.

Sam

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Sam,

I don't have any numbers as for the torque improvement. The only way to know that is dyno testing. The more overlap the cam has the greater the benefit of the divided plenum. The torque curve should be higher throughout the RPM range due to the higher flowing tapered runners with the near ideal entry form and higher still at the manifold's resonant frequency which is dictated by runner length, inlet valve open duration and cylinder volume. The runner form (taper) is fairly easy to achieve, but requires fabricating a tapered tube. The runner inlet form is a little more involved, but if one is to use tapered tubes it would seem silly to give up the ideal entry.

Fabricating tapered tubes: http://www.streetrodderweb.com/tech/070 ... index.html

The plenum needs to be divided with 2 throttle bodies. A 180 degree V8 manifold really has 2 or 4 throttles if it has a 2 or 4 bbl carb. The left and right sides do not leak air between them. Dual throttle bodies are easy. 3.5 V6 motors in all the 1st Gen Chrysler LH cars like the Intrepid have them. Plenty easy to come by for little money.

The SDS article shows how to fabricate injector bungs and there is another article on their site on fabricating fuel rails. Of course there's is not the only way to do it, but if you have the time and skills it's probably the cheapest way if nothing used will do.

Joshua

So where do we go from here? Josh, do you want to do a preliminary, not-to-scale sketch but with dimensions written in? If so, I can go to Tom,a nd show it to him, and ask for a quote, or at least for him to think about the project and see if he wants to participate. Once we have some idea of cost, we can start a poll here on the forum and see if others are interested.

Sam

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I need to go over the math again and my notes are at home while I'm here at work. I have to calculate what size tubing to use for the runners to achieve the proper taper within the desired length. Calculate the plenum volume and see what size tubing works. Runners 3 and 4 need to angle toward the center of their respective plenums so their port entries are not compromised. Decide if the throttle bodies go on the top of the plenum or the side, etc.

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Joshua

I am insterested in working along here, and maybe providing organizational support if nothing else. Maybe it would be a good idea to put something here on this thread when you come up with the first, most basic design, and see what the responses are. You know, see if there are good ideas forthcoming to tweak the initial design. And, off course, every one does not have to be identical. It seems as if the design might allow for the fabricator to turn the TB this way or that. I don;t know, just thinking out loud here.

I totaly get the two barrel TB concept, and seems like the way to go since there is one available for adaption. Does it have a built in idle air control?

Sam

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I've got an idea for a low cost injector bung that could work on this manifold, as well as being something that could weld or thread into carbed manifolds in general.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

NOW Im interested!

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Yeah....Im the one who destroyed this rare, vintage automobile.....

We got so many requests for them at work that I'm planning on getting a batch of injector bungs made up. There's likely to be both rail type fittings, and railless designs that work with AN hoses.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Ok, I found my notes and went through the math again. MS Excel to the rescue!

The spreadsheet does many things for manifold design. Enter the intake valve duration, desired resonant RPM and pipe diameter to calculate the runner length. Calculates the plenum volume for the desired tuning RPM and find the length of 3.5" tubing needed for the calculated volume. Enter displacement, VE and max RPM to find the length of the inlet pipe to the plenum. Last, but not least using the intake port area the spreadsheet calculates the area of the large end of the tapered runners for both 1° and 1.5° tapers.

With all this data I know the tubing dimensions needed for the runners and the plenum.

As it turns out the manifold is quite long. Not unsurprising the length is close to that of a Hyper-Pak intake. Because of the length it appears the throttle bodies will go on top of the plenum and that a power brake booster may not clear the rear plenum.

The formulas used were taken from David Vizard's How to Build Horsepower Vol. 2. These are simplified formulas that have been proven in dyno testing. I am confident enough in the formulas and my results to spend the considerable time needed to fabricate a manifold.

Joshua

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Joshua

Can you make some rudimentary drawings, with dimensions? Why couldn't you put the TB facing forward with a goose neck adapter like some of the Fords I have seen. If I understand what you are saying, it would be out over , or near the driver's side fender.

I saw a new hemi for the first time yesterday, and the TB is in the middle, naturally, facing forward with an elbow tht turns towards the air cleaner box on the driver's side. Every new car has some ideas to be gleaned from it.

Sam.

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Interesting series of posts. In my first attempt at a blower manifold for a GM M90. I ran into problems. On a '65 Dart there are certain limitations that will affect a manifolds design. Here are my thoughts on the subject.

So, lets set some ground rules.

I will use a standard 65mm, Ford 5.0, throttle body. The are as common as dirt and just about as expensive. Ford, 19lbs injectors are just about as common and are reasonably priced, used on Ebay. They should be good to about 180hp. Ford, 24lbs injectors are slightly less common, but are good to about 220hp. Which should satisfy most \6 builds. The Ford injectors are just standard Boush stuff with a Ford part number.

The manifold itself will be made out of cheap muffler pipe. Which is easy to weld, easy to shape, and easy to bend. Using Aluminum would triple the cost.

The intake runners will be 1 1/2" and the plenum will be 3". The end plates will 16g mild steel on one side and 1/8" plate on the other. The head flanges will be made out of 3" x 1/2" plate. Total cost of these materials will be less the $50. When you do a "google" for "mild steel bungs" a place in Spokane WA. pops up. They claim to make steel bungs as described on the SDS site. They want 6$ apiece. So raise the price up to $90.

So for less then $100 dollars you can build an intake manifold. Add the cost of the TB and injectors, you should be at less then $200.

Sandy should be happy and smiling right about now.

Now to answer the question of what dimensions you can use.

A standard intake port measures 1 3/8" x 1 1/4". The 16g, 1 1/2" exhaust pipes inside diameter is about 1 3/8". Close enough for government work. The head flange measures 3" x 2" x 1/2". The hardest part is locating the bolt holes and making the opening for the pipe in the flange. I have a diagram on my web site that show how.

In my first attempt at making flanges I was using 1 5/8, 1/8" wall aluminum tube. So I used a 1 5/8 hole saw and drilled half way thru the flange. I then used a 1 1/4 hole saw and then drilled from the back, This left a nice face to braze the 2 together. Worked great. Then you just blend the resulting hole to match the intake gasket. With my new, mild steel set, I will probably use the same strategy.

The SDS site says the plenum should be a least 1/2" past the end runner. There is 19" to the outside of those runners. So the plenum needs to be at a minimum 21" long. That places the ends, very close to the firewall and radiator hoses and fan. So TB mounting now becomes an issue.

Next is the runner length. The SDS site recommends 9". OK. If you are using Doug's castings, like I am, you need a minimum of 7" to clear the tail pipe flanges. If you go any longer then 9" you will start to run into the shock tower, master cylinder and battery tray and only one of them is easily moved. You also have to have room to bolt the damn thing on. God knows what a chore that can be. So 9" is the longest particle straight length that you can use.

If you really want to go longer, you need to but a bend into the tube. Unless you have a mandrel tube bender, you have just tripled the cost of your runners. Summit and the local Napa store would be more then happy to sell you J-pipes for $12 a pop. For comparison, a single 10' length of straight 1 1/2" pipe is $20.

So you really want that mythical 14" runner, just like the Hyper-Pak. Well here is something to think about. On a '65 Dart there is 9" between the upper role of manifold bolts and the hood. Sounds like a lot, but its not. To get to that 14" you need to do a 180* bend. The radius of the above mentioned J-pipe is 3". The puts the top of the pipe at around 4" above the top bolt. The top of the plenum would then be about 1 1/2" higher for 5 1/2" height. The base of the Ford TB is 4 1/2". So add another 1 1/8" for a total of 6 5/8". Depending on how you mount the TB, you may need to add 1 1/2" to 2" for IAC clearance, throttle linkage clearance, PCV hose clearance. So, allowing for engine movement, there goes that 9" of clearance.

The next thing to worry about is where to mount the TB. If you mount it facing the passenger side fender, you will hit the fuel rail. If you mount it facing the front of the car, there is radiator hoses and fans to worry about and the length of the cable also becomes a concern. There is no room facing the firewall so that is out of the question. So about the only place to mount it is facing the drivers fender. Which would require a short piece of 2 1/2" pipe to clear the upper length of the runners.

So for under $200, a typical DIY should be able to build an intake manifold. There is a lot of theory, speculation and "gee I should do this because the Vizard book says so", but there are certain practical limitations on what will really fit in our cars. So keep that in mind when talking about intake manifolds.