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Making my own EFI intake... The First Casting


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My God.... It's full of STaRZ!.. Derek, that's an amazing manifold. please please get it going soon, the suspense is deadly... all I can say is WOW.

 

For the back triple I guess it wouldn't work to cast the same upside down. since the Injector bosses would be on the wrong side then. Perhaps in the production casts, you could make them swapable. Though I suppose it's just as easy to make the 2nd cast unique..

 

So once these are figured, what would a ballpark cost be if say we wanted to order a set?

 

Phar

 

"pardon my drool..."

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Anybody remember the old CAN-AM or Formula cars with their stacks all askew? That's what this reminds me of, I love the look!

 

The performance and sound are frilly intrinsic benefits for motorheads!:icon6:

 

This is exactly how I describe my design concept to my friends. Like the "old CAN-AM cars"

I guess I got pretty close then!

 

My God.... It's full of STaRZ!.. Derek, that's an amazing manifold. please please get it going soon, the suspense is deadly... all I can say is WOW.

 

For the back triple I guess it wouldn't work to cast the same upside down. since the Injector bosses would be on the wrong side then. Perhaps in the production casts, you could make them swapable. Though I suppose it's just as easy to make the 2nd cast unique..

 

So once these are figured, what would a ballpark cost be if say we wanted to order a set?

 

Phar

 

"pardon my drool..."

 

Making the patterns for the rear manifolds aren't that big of a deal. All I do is mirror the design in the 3D program and add the additional bosses.

Since there seems to be a fair amount of interest in this thing I'm making some changes so that the machining can be a little easier.

 

The cost is going to be a little pricey. Most certainly more expensive than the TWM setups. But I like to think your getting a lot more for the money!

 

 

Thanks again everyone for the kind words. It really does help on a large risky project like this.

 

Derek

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You do know, that butterflys are NOT round correct? You can make them on a 4 jaw, or a buck chuck, but will require a few setups, to make them in a lathe. They would be easier to be made on a mill, yes it can be done on a manual mill, with rotary tables, but I would do it on a CNC.

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You do know, that butterflys are NOT round correct? You can make them on a 4 jaw, or a buck chuck, but will require a few setups, to make them in a lathe. They would be easier to be made on a mill, yes it can be done on a manual mill, with rotary tables, but I would do it on a CNC.

 

Yep I'm aware of the oval shape. If it's round it won't close as well and has the potential to stick. My problem is my mill isn't as fresh as it was when it was new. It has a little backlash and while perfect for pattern work trying to make a butterfly fit properly is a bit of a problem. I'm thinking of making a mandrel for the lathe that has a 14 degree face on it and 2 screw holes to hold the butterfly blank. I'll machine the blanks a little oversize in the mill and then screw them to the mandrel and make a finish pass with the lathe. This should also cut a knife edge on the leading and trailing edge of the butterfly.

In theory this should work but of course we all know I live in theoryville!

 

I wish I knew how much gap I could get away with but I figure it's easier to do it right and just be done with it.

 

Derek

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You are gonna want NO gap, or atleast plan for not gap, or you will never get your idle down low enough. The best way is to have no gap, and do all of your idle controll through a bypass valve. I have build a few ITB setups for L28's, and it is always a pain, getting everything syncronized and timed correctly. What is the ID of that machined hole where the Butterfly has to fit? I ask this, because you can rob butterflys from other throttle bodys, with the same id, and it already has the cam, built on the butterfly, and the two holes, and you would be ready to go. How do I know this? Because I came accross the same dilema a few years ago, when designing ITB setups for these motors.

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You are gonna want NO gap, or atleast plan for not gap, or you will never get your idle down low enough. The best way is to have no gap, and do all of your idle controll through a bypass valve. I have build a few ITB setups for L28's, and it is always a pain, getting everything syncronized and timed correctly. What is the ID of that machined hole where the Butterfly has to fit? I ask this, because you can rob butterflys from other throttle bodys, with the same id, and it already has the cam, built on the butterfly, and the two holes, and you would be ready to go. How do I know this? Because I came accross the same dilema a few years ago, when designing ITB setups for these motors.

 

I'm controlling the idle with a IAC. The bores are 1.495. I just need to get through this one as I'm going to buy pre-made butterflies from Kinsler if I do any kind of production. They have a 1.523 as a stock size and they'll make any size you want. I'm also going to make everything work with their throttle arms and shafts. No need to reinvent the wheel. Their stuff has a really nice old school feel and will work well with the style.

 

Derek

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A bit of welding on the ends to accept a plenum, and there is no requirement for this to only be N/A...

 

Though seeing a custom-cast ITB N/A setup that puts TWM to shame really does have it's allure... :mrgreen:

 

Anybody remember the old CAN-AM or Formula cars with their stacks all askew? That's what this reminds me of, I love the look!

 

The performance and sound are frilly intrinsic benefits for motorheads!:icon6:

 

I've been thinking the exact same thing since I saw his design, but couldn't recall which cars they were :D

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I will second Bryan's comment of shooting for NO gap. The bypass is your idle control. Frank280ZX just went through this on his ITB setup and wasn't getting an idle below 2300, after screwing them down to even a paper-thin opening (like less than 0.003" cracked, it was still idling the car at 1700 rpms.

 

Normally a fixed bypass orifice sets the 'no stall minimum idle speed' (say 700rpms) and the IAC makes compensations ABOVE that point---so even iwth an IAC, you are wise to incorporate a fixed or variable bypass orifice from the external air source to keep the IAC working near it's seat, instead of much wider open...makes for better and smoother PID control of the IAC when your A/C kicks on (or whatever). Working the IAC near seat keeps air velocity up and helps prevent buildup. You will be cleaning your IAC if you don't have a good air filtration setup!

 

EFI is designed to idle with the throttle closed for maximum intake manifold vacuum off-idle. You can always make a non-linear throttle actuation to help tip-in form a low idle, but you will play hell trying to get your idle down to reasonable levels with the six throttle plates open.

 

A simple 1/4" vacuum hose is what I have controlling bypass air to all my engine, and with a reworked 82/83 NA idle air bypass needle valve through that 1/4" hole I can raise the idle to over 2200rpms easily. They don't take any air at all to idle!

 

Kinsler throttle plates, why make the jig...they're cheap!

 

I heard you could get the same grey sealant that was OEM on the Nissan TB's for total sealing once the T/B is staked to the shaft. Nissan guys got ahold of some, ideally that is the way to go, than way you can use a slightly 'loose' butterfly and minimize the chance of Sticking when it gets hot or loaded with debris...like some of the TWM bodies are known to do...

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I will second Bryan's comment of shooting for NO gap. The bypass is your idle control. Frank280ZX just went through this on his ITB setup and wasn't getting an idle below 2300, after screwing them down to even a paper-thin opening (like less than 0.003" cracked, it was still idling the car at 1700 rpms.

 

Normally a fixed bypass orifice sets the 'no stall minimum idle speed' (say 700rpms) and the IAC makes compensations ABOVE that point---so even iwth an IAC, you are wise to incorporate a fixed or variable bypass orifice from the external air source to keep the IAC working near it's seat, instead of much wider open...makes for better and smoother PID control of the IAC when your A/C kicks on (or whatever). Working the IAC near seat keeps air velocity up and helps prevent buildup. You will be cleaning your IAC if you don't have a good air filtration setup!

 

EFI is designed to idle with the throttle closed for maximum intake manifold vacuum off-idle. You can always make a non-linear throttle actuation to help tip-in form a low idle, but you will play hell trying to get your idle down to reasonable levels with the six throttle plates open.

 

A simple 1/4" vacuum hose is what I have controlling bypass air to all my engine, and with a reworked 82/83 NA idle air bypass needle valve through that 1/4" hole I can raise the idle to over 2200rpms easily. They don't take any air at all to idle!

 

Kinsler throttle plates, why make the jig...they're cheap!

 

 

Hi Tony

I'm absolutely not going to have any air gap on the butterflies. I can see the cumulative effect of a little gap on each one time six! I can also see the benefit of having the bleeder.

 

I'm in a catch 22 situation on the butterfly jig. In order to make this manifold work I have to make the jig. If I go to the trouble of making the jig I might as well make the butterflies. I called Kinsler and they want $16.00 each for the butterflies. $96.00 is close to the tipping point anyway for me to MFG them.

 

Can you go into a little more detail on this:

 

 

I heard you could get the same grey sealant that was OEM on the Nissan TB's for total sealing once the T/B is staked to the shaft. Nissan guys got ahold of some, ideally that is the way to go, than way you can use a slightly 'loose' butterfly and minimize the chance of Sticking when it gets hot or loaded with debris...like some of the TWM bodies are known to do...

 

 

Thanks

Derek

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Take a look at any Nissan T/B and you will see a grey substance around the edges of the butterfly and a corresponding grey substance around the periphery of the T/B where the butterfly mates to it. Almost like someone took a q-tip and swabbed the whole diameter of the Butterfly with something.

It's a persistent sealant that Nissan Uses to seal out the imperfections. Where they get it, I do not know, but someone at Nissan Motorsports told me they did acquire it for 'overbored' T/B's used in SS racing (cheating)...

 

I don't know the composition, but it's persistent and won't come off unless you sand it off with something abrasive---carb cleaner won't touch it! Neither will chlorinated solvents, alcohol, or brake cleaner.

 

Real thin coating, fills all those little imperfections!

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sounds like some magical freakin stuff.

 

TonyD....

 

Are you for real??

 

You sure you aren't some twisted sort of computer program, being run from the scanned memories of Mr K, Pete Brock, Bob Sharp, and Paul Newman???

 

 

He is for real. I have hung out with Tony at a couple of conventions, and had dinner with him once. He also makes a good human gas tank strap :mrgreen:

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Take a look at any Nissan T/B and you will see a grey substance around the edges of the butterfly and a corresponding grey substance around the periphery of the T/B where the butterfly mates to it. Almost like someone took a q-tip and swabbed the whole diameter of the Butterfly with something.

It's a persistent sealant that Nissan Uses to seal out the imperfections. Where they get it, I do not know, but someone at Nissan Motorsports told me they did acquire it for 'overbored' T/B's used in SS racing (cheating)...

 

I don't know the composition, but it's persistent and won't come off unless you sand it off with something abrasive---carb cleaner won't touch it! Neither will chlorinated solvents, alcohol, or brake cleaner.

 

Real thin coating, fills all those little imperfections!

 

if you had to guess, what comes closest? we could narrow it down that way.

 

is it a resin? an aluminum like substance similar to an anti-seize compound that dries thin? a solder of some sort? I bet there are resins that are impervious to gasoline and hot air charges that could be used, and would fill those gaps just as well.

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Just thought of this... you could probably get away with glass-chip resin. it's UV-Cured, and hard as ever. I wish I could get the stupid nissan vintage cd working on the FAST system, i would be able to look for sealants. Im going to check the RB26 throttle plates to see what I can find.

 

EDIT:

 

Trying to help out with some alternatives here:

 

http://www.ellsworth.com/display/productdetail.html?productid=1134&Tab=Products

 

http://news.thomasnet.com/fullstory/465265

 

The 3M one looks to be promising. :)

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