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Opeler
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Discussion Starter #1
I am working through all of the preparations to install dual DCOE's on my 2.2 GT. I have read about and have been suggested to unite/tie/join the intake runners together for vacuum purposes. Only 1 of my 2 intakes have been tapped for the vacuum port, the other has a spot where it could be tapped and a pipe installed. My question is, how do I tap the other runners and where on intakes would I do it? I ask this because the other runners don't have a predestined, or obvious spot.

I know I probably could have sent a few PMs but I thought this would be good info for other people to learn as well.

As always, any help is greatly appreciated!

Eric
 

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Super Moderator
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Here are a couple of ways I've done it.

The red ones use aluminum tubing custom bent with AN-style tube nuts and a mini vacuum plenum. I welded AN fittings (-6 AN) to the intakes.

The white ones use two of the original threaded ports, and I welded on two more female pipe thread fittings to the other bare runners. I tee'd them all together with hardware store brass threaded fittings I had nickel plated, and common copper plumbing fittings for the vacuum manifold. The copper fittings were silver-soldered to allow for powdercoating without melting the solder!







 

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Opeler
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Discussion Starter #3
Here are a couple of ways I've done it.

The red ones use aluminum tubing custom bent with AN-style tube nuts and a mini vacuum plenum. I welded AN fittings (-6 AN) to the intakes.

The white ones use two of the original threaded ports, and I welded on two more female pipe thread fittings to the other bare runners. I tee'd them all together with hardware store brass threaded fittings I had nickel plated, and common copper plumbing fittings for the vacuum manifold. The copper fittings were silver-soldered to allow for powdercoating without melting the solder!







wow. well, seeing as I don't possess any amount of skill close to doing something like that, how would you suggest I accomplish a similar set-up?? I am wondering where (what type of place) I could take the manifold's to have them drilled and tapped? Has any other non-super-hero (aka not RallyBob :biggthump) Opeler out there linked all the runners together??

Bob, thanks for showing me, and everyone else, what to shoot for....although, I know I'm incapable of pulling off your feats!

Eric
 

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wow. well, seeing as I don't possess any amount of skill close to doing something like that, how would you suggest I accomplish a similar set-up?? I am wondering where (what type of place) I could take the manifold's to have them drilled and tapped? Has any other non-super-hero (aka not RallyBob :biggthump) Opeler out there linked all the runners together??

Bob, thanks for showing me, and everyone else, what to shoot for....although, I know I'm incapable of pulling off your feats!

Eric
Easiest way I can think of to tie the runners together for a common plenum:

*remove the existing metal tube, and tap for a pipe thread.
*drill and tap for the same size pipe thread on the other intake manifold (this can be done with a hand drill BTW, no need for expensive tools! You will need a pipe tap and tap holder however)
*Use brass fittings and rubber hose to tie the two connections together
*drill a small hole in each intake manifold, near the cylinder head junction where there is a solid wall between the two intake runners. You can drill at an angle and connect each pair of runners easily this way. A 1/4" hole should suffice.
 

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Opeler
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Bob, what is the advantage of connecting the intakes? Is that really needed for a street use? Most of intakes are coming with just one hole for the booster (usually cyl. #1) and they work fine.
 

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Bob, what is the advantage of connecting the intakes? Is that really needed for a street use? Most of intakes are coming with just one hole for the booster (usually cyl. #1) and they work fine.
On a race car with no power brakes it's no big deal.

But with a street car, you are only getting all your power brake vacuum from one cylinder (25% of normal) with a single intake runner on twin DCOE's. If you have low vacuum from a big cam, then you can very easily run out of vacuum for your power brakes after 2 or 3 stops in a row. Many people use an aftermarket power brake reservoir to store extra vacuum for these situations.

But years ago I found that there was a better idle, more torque AND better power brakes by tying them in all together.
 

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Opeler
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Discussion Starter #7
Easiest way I can think of to tie the runners together for a common plenum:

*remove the existing metal tube, and tap for a pipe thread.
*drill and tap for the same size pipe thread on the other intake manifold (this can be done with a hand drill BTW, no need for expensive tools! You will need a pipe tap and tap holder however)
*Use brass fittings and rubber hose to tie the two connections together
*drill a small hole in each intake manifold, near the cylinder head junction where there is a solid wall between the two intake runners. You can drill at an angle and connect each pair of runners easily this way. A 1/4" hole should suffice.
Would drilling out and tapping the other pseudo-opening on the other intake be enough, leaving 2 runners tapped and the other two untapped? On your intake examples, you show the same type of tap at roughly the same place on the intakes...did yours come with a spot on all runners? If you look at my original picture, you can see what I'm working with. Would drilling through the top of the other side (where there isn't a natural spot) of the intake be a bad idea?

And forgive me for the elementary question, but wouldn't drilling through the wall between the runners defeat some of the advantage of the DCOE and the individual runners??

Eric
 

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Another area that you might want to think about is the cold start.

With my fuelie I've learned to get a high vacuum by tapping the throttle for a couple
seconds BEFORE I get to the end of my driveway.
If I don't there's very little power assist on the binders.

Once the engine builds up some heat thereby less idle air bypass it's not ....
Oh yes I really need a canister to store some suction or a vac pump.

Here's how Bob tied my intake together.
 

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Opeler
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Discussion Starter #9
other dual carb questions

I have been doin more research and planning about going dual carbs. Has anyone on here ever done a dual carb set-up with an automatic transmission? I haven't found anyone in all of the threads that has mentioned this combo. I'm thinking that the trans filler tube/dipstick is going to be in the way of the carb or manifold. I'd hate to get going down this road and then the darn set-up won't physically work bc of having an automatic transmission.

I'm also wondering if going with a Getrag 5-speed (my wife would also prefer a manual trans in the car) will make this swap not only easier, but better performance and driveability. Thoughts?
 

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I'm also wondering if going with a Getrag 5-speed (my wife would also prefer a manual trans in the car) will make this swap not only easier, but better performance and driveability. Thoughts?
Yes, of course.
 

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Just Some Dude in Jersey
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I have been doin more research and planning about going dual carbs. Has anyone on here ever done a dual carb set-up with an automatic transmission? I haven't found anyone in all of the threads that has mentioned this combo. I'm thinking that the trans filler tube/dipstick is going to be in the way of the carb or manifold. I'd hate to get going down this road and then the darn set-up won't physically work bc of having an automatic transmission.
I too have the same question and will have the same set up, with shorties. I won't be starting my install until after this weekend, but I'm going to bolt the carbs/intakes on, after I pull the stock style intake/carb off, to size a few things up. I suspect that the dipstick/fill tube WILL come awfully darn close.

One solution I envision is to simply trim an inch or two of the tube off. In my 30 year experience with automatic GT's, I've found the dip stick to be absolutely useless at determining fluid level. It wouldn't bother me one bit if I had no dipstick in that tube at all and just had a plug in the tube. I could just trim back the dipstick to match how much I trimmed back the tube.

Of course, once I know where the carbs sit, I could remove them and easily remove the fill tube and bend it a little in whatever direction I need to to make it not hit anything and still be able to fill the tranny.

I could always use a hose fed into the tube if I have to shorten it or bend it to where it's not accessible with a funnel and stick the funnel in the hose.
 

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Bob, on the red ones, why not put that manifold thingy in the middle, run shorter tubes, less bouncy?
Mike why should it?

If you follow the firing order...you'll notice the dips with the vacuum when the intake
valve opens.
 

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Bob, on the red ones, why not put that manifold thingy in the middle, run shorter tubes, less bouncy?
It's actually quite rigid, not as flexy as you might think. I can pick up the pair of manifolds via the reservoir and tubing no problem.

Aesthetically, I wanted it to line up with the back of the valve cover so it's a straight shot from the vacuum reservoir to the brake booster.
 

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Opeler
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Discussion Starter #15
I am working through all of the preparations to install dual DCOE's on my 2.2 GT. I have read about and have been suggested to unite/tie/join the intake runners together for vacuum purposes. Only 1 of my 2 intakes have been tapped for the vacuum port, the other has a spot where it could be tapped and a pipe installed. My question is, how do I tap the other runners and where on intakes would I do it? I ask this because the other runners don't have a predestined, or obvious spot.

I know I probably could have sent a few PMs but I thought this would be good info for other people to learn as well.

As always, any help is greatly appreciated!

Eric
Easiest way I can think of to tie the runners together for a common plenum:

*remove the existing metal tube, and tap for a pipe thread.
*drill and tap for the same size pipe thread on the other intake manifold (this can be done with a hand drill BTW, no need for expensive tools! You will need a pipe tap and tap holder however)
*Use brass fittings and rubber hose to tie the two connections together
*drill a small hole in each intake manifold, near the cylinder head junction where there is a solid wall between the two intake runners. You can drill at an angle and connect each pair of runners easily this way. A 1/4" hole should suffice.
Would drilling out and tapping the other pseudo-opening on the other intake be enough, leaving 2 runners tapped and the other two untapped? On your intake examples, you show the same type of tap at roughly the same place on the intakes...did yours come with a spot on all runners? If you look at my original picture, you can see what I'm working with. Would drilling through the top of the other side (where there isn't a natural spot) of the intake be a bad idea?

And forgive me for the elementary question, but wouldn't drilling through the wall between the runners defeat some of the advantage of the DCOE and the individual runners??

Eric
Just bumping this again to figure out which way would be the most effective approach, from a skill standpoint and from the driveability standpoint. Bob, does drilling through the wall of the intake runners defeat the purpose of each cylinder getting its own air/fuel feed? Would the side with the pipe fitting pull more vacuum than the other?? I want to do this RIGHT and trying to figure out how to make it right without screwing up the whole set-up and my manifolds. Bob, I'd be willing to send you the manifolds to have them done-up RallyBob style if you would be up for the job...obviously would pay for your services as well.

Thanks for any help and insight...

Eric
 

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Opeler
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Discussion Starter #16
I am working through all of the preparations to install dual DCOE's on my 2.2 GT. I have read about and have been suggested to unite/tie/join the intake runners together for vacuum purposes. Only 1 of my 2 intakes have been tapped for the vacuum port, the other has a spot where it could be tapped and a pipe installed. My question is, how do I tap the other runners and where on intakes would I do it? I ask this because the other runners don't have a predestined, or obvious spot.

I know I probably could have sent a few PMs but I thought this would be good info for other people to learn as well.

As always, any help is greatly appreciated!

Eric
Easiest way I can think of to tie the runners together for a common plenum:

*remove the existing metal tube, and tap for a pipe thread.
*drill and tap for the same size pipe thread on the other intake manifold (this can be done with a hand drill BTW, no need for expensive tools! You will need a pipe tap and tap holder however)
*Use brass fittings and rubber hose to tie the two connections together
*drill a small hole in each intake manifold, near the cylinder head junction where there is a solid wall between the two intake runners. You can drill at an angle and connect each pair of runners easily this way. A 1/4" hole should suffice.
Would drilling out and tapping the other pseudo-opening on the other intake be enough, leaving 2 runners tapped and the other two untapped? On your intake examples, you show the same type of tap at roughly the same place on the intakes...did yours come with a spot on all runners? If you look at my original picture, you can see what I'm working with. Would drilling through the top of the other side (where there isn't a natural spot) of the intake be a bad idea?

And forgive me for the elementary question, but wouldn't drilling through the wall between the runners defeat some of the advantage of the DCOE and the individual runners??

Eric
Just bumping this to try to get an answer on drilling through the intake runners wall...I'm real close to giving this project a GO and would like to sort this issue out. Does drilling through the walls of the intake runners provide more benefit than harm or more harm than benefit!

Eric
 

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Opeler
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Discussion Starter #17
Just bumping this to try to get an answer on drilling through the intake runners wall...I'm real close to giving this project a GO and would like to sort this issue out. Does drilling through the walls of the intake runners provide more benefit than harm or more harm than benefit??

Eric
Anyone?? I've asked this question about 3 other times with no relevant replies.

If anyone can provide an answer to this question, I'd really appreciate it.

Thanks,

Eric
 

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Anyone?? I've asked this question about 3 other times with no relevant replies.

If anyone can provide an answer to this question, I'd really appreciate it.

Thanks,

Eric
Without knowing how thick the wall of your inlet is ...... I would just drill and tap the one that's been prepared for this

Personally I've never done this and either ran with just the one connected, or not at all

Sorry to be so vague but that's the best I can do
 

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Opeler
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Discussion Starter #19
Without knowing how thick the wall of your inlet is ...... I would just drill and tap the one that's been prepared for this

Personally I've never done this and either ran with just the one connected, or not at all

Sorry to be so vague but that's the best I can do
It's okay Goy! I appreciate you providing any amount of insight that you've personally experienced. My manifolds have 1 of the ports already tapped, but that's it...RallyBob chimed in very early on in this thread but I haven't heard anything more in reply. Through all of the threads about DSD's that I've read, several members reference connecting the individual runners together, but don't show any pictures or talk about completion. While some other members that have DSD's have ran their set-up with just the 1 tapped intake runner.

I'm just trying to have the best set-up that I can have.

Thanks again for your reply Goy!

Eric
 

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Just Some Dude in Jersey
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In another thread concerning electric engine mods, it was brought up that, since there is no vacuum generated by an electric engine, an electric vacuum pump and tank is installed to assist the braking. This sound like the far better idea than all these hoses and drilling of intakes.

What do these electric vacuum pumps cost and what size would be appropriate?

Are there any other ways of "brake boosting" that don't involve engine vacuum hoses?
 
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