PROJECT, DCOE + MANIFOLD ( PhydeauX )

[PhydeauX]

I've finally got all the parts to start to build my manifold, so here is my first installment on how to do it.


The A20A DCOE manifold how to part 1: Getting your shit together.

The parts list for this is pretty short. All parts are aluminum to make the fabrication easier.

• 2 DCOE flanges. They are available from Pierce Manifolds. They are not listed in the catalog but the part number is 99005.147. These puppies are $42 a pop, but they make for a nice clean well fitting manifold.
• Tube. Onlinemetals.com is a good source, resonable prices and they deal in small quanties. Figure on about 2 feet of thick walled tubeing. I bought some 1/4" walled tube, and its a bit too thick, but don't go thinner then 1/8" this has to stand up to the vibrations of the engine. The tube should be about the diameter of the throttle plate of the carb. For a 40DCOE thats about 1 1/5", for a 45 just do the math.
• A flange to fit the head. The easiest way to get this is to just cut it off your old carbed manifold, or a spare one if you are still driveing the car while doing this. Don't use an injected manifold because you would have to plug up the ports for the injectors. Thats just more work for you.

The only real work thats been done so far is to chop up my spare manifold. I'm sure you can figure this out on your own but here it is anyway.

Mount the manifold in a vice.


Choose your weapon, this can mean the diference between this taking 5 or 50 minutes. Which do you think I chose?


When you're all done you should end up with something that looks like this.


And you can just throw this part away.



Next time I will be back with making the runners and maybe start the fitting.

andy

[PhydeauX]

I do plan on makeing those images smaller once I get photoshop installed again.

andy

[A20A1]

Hurry

[A20A1]

Hmm with the spare part of the maniflod you could do a quad exhaust... not sure if the aluminum would last

[carotman]

VERY interesting post. I ll look for the updates.

Once it's all done, I'll post this in the How-To section.

[PhydeauX]

I might end up having to order some thinner walled tube, wtf was I thinking when I ordered 1/4" wall. I don't know htf I am going to bend it into a nice oval, nothing short of a sledghammer is going to dent this stuff, its like a section of fence post. That will add another week to it unless I spring for express delivery. Then there is always the problem that I can only get intouch with the guy thats doing the welding when I don't have anything for him to weld. But I hope it doesn't take too long, I still have that nova I need to start putting more time into.

andy

[A20A1]

Damn that's the opening size of the fuel line...

[Don87LX]

Damn I want to do this...Andy your polluting my young mind!

[A20A1]

Originally posted by Don87LX
Damn I want to do this...Andy your polluting my young mind!

... and the environment. :lol

[Don87LX]

With the tubing, granted 1/4'' is pretty damn large, but couldnt you heat it with a torch and then crush it with your bench vise into an oval? could take awhile but the strength of the 1/4'' tubing might be nice. If you put a cheater pipe over the the vise's crank handle you could get the torque you need to flex the tubing.

Also what kind of angle are you cutting the runners at? our motors lean forward and the DCOE's have to sit flat correct? Are you going to make the carbs sit up any higher or just cut straight runners off the intake flange and then angle the dcoe flanges down the few degrees to compensate for the lean of the engine?

Are the runners going to be able to go straight off the intake at a 90 degree angle or do the two pairs have to angle away from each other to keep the doces from beings too close together?

How long are the runners going to be?

Am I asking enough questions?

[PhydeauX]

I left a about half an inch of the old runners on the flange when I cut it. I ground them down to a 10° angle with a grinder, pics to come in the next installment. I'm going to probably put the other 5° into the runners to make them sit level, though I could leave them at just the 10° I ground into the flange, dcoes have a +/-5° tolerance. I ordered some new 1/8" wall pipe, that 1/4" is way too thick. Yes I could bend it, I have access to a 20 ton hydraulic press, but its not going to be that percise. There is also the matter of getting it all welded. Its going to take a whole lot of heat to weld that 1/4" shit, its twice as thick as the flanges. I'd really be running a risk of them getting warped or worse when they're welded. I already ordered some 1/8" walled pipe and I decided to go with 1.75" I.D. incase I decide to go with some 45s later on. I'me haveing it shipped 3day so I don't have to wait a week for it. I'm going to have to slot that pipe and taper it a bit to have it match the head ports most likely, that will be explained in detail later. Its also better for the flow to have a tapered runner. I haven't decieded on the actual lengt of the manifold runners. I'll probalby see how the runners taper and bend into and tranition into a oval first. With a dcoe setup the carb and its airhorn are part of the runner as far as the flow is concerned so I can adjust the length by installing diferent length air horns. The runners have to angle slightly apart to allow the dcoe's to fit. If you remember this pic of the b16a manifold that I had the carbs are going to be spaced the same. They have to be angled apart slightly, but nothing drastic. The spaceing of the a20a ports and the bores of the dcoe's is just about the same so that makes things simple and its easy to keep the runners the same length (thats critical).

andy

[A20A1]

I better see your Setup in an import tuner kinda magazine...
Nothing flashy... just a list of mods and maybe a few good comments from the editor... or whomever.
The title of the artical can say '85 SLEEPER

[POS carb]

man you can't get into one of those magazines unless you've got a grand invested in a bumper and stickers. pussies.

[PhydeauX]

Maybe I'll get it featured on hybridhonda.com. After all its built with parts from 3 diferent honda models (5 if you want to count the steering wheel and seats, 6 if you really want to nit pick), and the carbs are from an alpha romeo. It doesnt realy get more hybrid then that. But its not a vtec b-series into a civic/integra so it probalby wont count as a true hybrid.

andy

[MoonScryer]

Grassroots Motorsports will probably give ya a pic and paragraph...

[PhydeauX]

I finally got photoshop reinstalled and I resized the pics. Oh and here is a teaser of the cut flange after I angled it. It kinda looks like an artsy shot.



Oh and kiss my sig goodbye for now, it wouldn't compress well and I coudln't get it down to the limit with out sacrificing too much quality.

andy

[PhydeauX]

Here is the long awaited second installment of my DCOE manifold howto, forming and fitting.

Last time I got all the parts together and cut the manifold apart. Then I had to put it on hold while I waited for the right sized tube to come. (Note to anyone doing this, don't use 1/4" walled tubing, 1.75" ID X .125 wall is perfect.) I've got the right stuff now and I am back underway. The tools you are going to need for this part are just a saw and an angle grinder. I already leaked this first shot but the first step is to angle the flange. You need the carbs to sit level but the a20a sits tiped 15° forward so you have to compensate for that somewhere. Idealy the runners haveing a smooth bend in them would be best, but thats hard to do with the shape the runners have to be formed into. Its alot easier to leave some of the old runners on the flange and go after them with the angle grinder.



Next its on to the runners. This is where most of the work is. First I'll start with how not to do it. Don't cut off a piece like this and put one end into a vice/press to squish it.



You will end up with something like this.



You need a bit more finesse then that. I found the best way to do it was to get out a nice big hammer and pound it into shape. Its very time consumeing and it gives you alot of time to get in touch with Thor, Viking god of beating metal with a big hammer, but you get alot more control and come out with a much better piece. The hammering helps keep it from cracking, but if you hit it to hard it still can crack. Don't use a sissy little carpenters hammer for this, you needs something big with a large flat head like a smiths hammer or a small sledge. It also helps to shape the runner before you cut it from the tube. It gives it alot more strength at the round end to keep its form. I went for 2 1/5" runnres and they bent quite nicely, but I wouldn't use this method for anything shorter then that.







Now comes the fun part, final shapeing and fitting of the runners. The a20a lucks out in haveing its ports spaced the same as the DCOE's barrels which simplifies things greatly. They are spaced too close to clear the linkages so the runners have to be angled to place the carbs furhter apart, but since the spaceing is the same as that of the carbs all of the runners are identical. That translates into all the runners being even shapes and equal lengths with out any special planning. I basically just took the angle grinder and ground the runner into a trapazoid shape. Its not going to be perfect, I'm going to come back later after its welded with some metal filler and a aluminum head porting kit to smooth it all out, but where the runners and flanges meet need to line up as close as possible.

The runner on the left is unfinished and the one on the right is finished.



The more time you spend here the better everything will fit. Its best to make a jig with the carb flanges and trial and error the runners untill everything is just about perfect.



The actual spaceing of the flanges will depend on your throttle linkages, but about 2 1/4" or so is good.

I'm not quite finished with this step yet, still have 2 runners to shape but here are some shots of some trial fits of 2 of the runners.





andy

[A20A1]

Looks like everythings coming along pretty well. Good work

[MoonScryer]

That is the shitz man. Hmmm...my DX hatch may need a new life before too long...

[PhydeauX]

I finished up the runners but I didn't take a pic. Now all thats left is the welding. I should have something to show for my work soon.

[edit]
Ok, so I broke down and took a pic. It looks like a manifold now .



[/edit]

andy

[carotman]

That's sweet, now I gota buy another accord and install dual webbers on it

[PhydeauX]

I droped it off with my buddy this afternoon. He's going to tack it up and bring it back to me for a final inspection. I put so much time into this that I'm not going to let him do the final welds with out me makeing sure everything is in the right place. I'm also haveing him weld in bosses for nos fogger nozzels. I don't have any plans to juice it yet, but who knows, this way if I do I won't have to pull the manifold. Hopefully this will get finished up for the weekend, but he said no gaurantees that he will be able to have it done by then.

andy

[POS carb]

I think I would've taken a slightly different approarch... I was thinking if I went to sidedrafts that instead of using a dx/lx manifold I would use an LXi one because its shape is smoother and it looks like you canuse the injector holes for nitrious jets. Whadda ya think?

[PhydeauX]

The .5" or so of the runners on the factory carb manifold that you keep can easily be smoothed out. The casting on the efi manifold I have is the same as the carbed. You cant use the injector bosses for nitrous, nitrous nozzels goes in perpendicular to the manifold, the injectors go in angled. You would have to have the injector bosses welded over.

andy

[Don87LX]

You need to have this motor dynoed when you are done. I have to know what kind of power we are talking here....I want to do this so bad it itches.