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Making my own EFI intake... The First Casting


Derek

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Derek,

 

From the pictures it looks like you have a balance tube for each casting.

 

If you are going to control idle with an air valve of some sort you have to provide equal air to all cylinders. So you may want to plumb in air to each TB bank from a common source. Or tie both balance tubes together in the middle and keep your vacuum connection the same.

 

Pete

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Derek,

 

From the pictures it looks like you have a balance tube for each casting.

 

If you are going to control idle with an air valve of some sort you have to provide equal air to all cylinders. So you may want to plumb in air to each TB bank from a common source. Or tie both balance tubes together in the middle and keep your vacuum connection the same.

 

Pete

 

Hi Pete

The two manifold balance tubes are connected in the middle with a hose.

So I should be ok adding vacuum from one side of the manifold.

 

Thanks

Derek

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As you can see Derek, you are almost up there with my daddy. The reason why you are not passed him is because he is my daddy and he's pretty cool. Does a lot of cool stuff yah know... However he hasn't built his own EFI system which was the real boost for you, otherwise such high approval ratings would not be possible.Also, DragonFly would be passed you, after all, he did balance his valve train. Daeron, you're up there because you helped me through my stroker build. TonyD, you're up with the big dogs too because you are the king of big dogs. Don't have any hard feelings about people beating you, just remember that I still love you. :wc:

10zsgty.jpg

 

I tried to make a MAP 3D graph thing in Excell but I failed big time, couldn't figure out what my third axis should be... I did however make my Love Graph kind of 3D here. I also added the minor axis lines for you accurate people.

 

 

 

You're doing awesome Derek! :flamedevi

 

 

Oh, that is funny as hell. I must have missed something while working this weekend. Was someone being amused by something I said??? I can't see that Draxquoted item elsewhere so I'm figuring someting must have gone away. I'm trying to figure out what I could have said to elicit that response... (no steaming, flaming, latent hate-PM's waiting in my inbox...)

 

It's good to know I'm loved. Even if it is man-love, according to the graph at least.:P

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Ok I went back and re-read every single post on this build. One thing that jumped out at me was that I may be screwing up with the way I'm introducing idle control vacuum. As it's designed right now I'm just dumping it into the balance tube at the end of #6 runner. I'm starting to think this may be a mistake as this will cause #6 to run lean.

 

Would a better solution be to run 6 individual lines to each runner to introduce the vacuum. I haven't machined the log yet so this would not be a big problem to do

 

Any thoughts on this

 

Thanks

Derek

 

Hmm okay, my thoughts here. You're running the vacuum from bank1 and bank2, pulling vacuum from both manifolds via a tube by #6 horn, and your MAP in going to be in the log as well as your IAC right?

 

I don't think it would cause any one cylinder to run lean as all injectors would get their mixture based the effective draw from both manifolds due to your balance tube as read by the MAP. If you ran individual tubes to each horn, then you'd get a slightly more accurate draw on your vacuum across all the cylinders, and more efficiency but I doubt it would be measurable.

 

I don't think mixture will really be an issue if your compression is pretty equal across the engine (not really compression, but intake draw per cylinder, if you know what I'm saying) in that your mixture is based on the air pressure difference between inside the intake, and outside ambient pressure. Since your manifolds are balanced through the cast tubes, your injectors should be putting out the correct mixture.

 

Your IAC is going to be affecting how well your engine Idles, of course. So having a more constant vacuum for it to work with will make it easier to hold the idle at a consistant rate. When I swapped EFI into my jeep, I found that having the vacuum reservour connected evened out my idle in that the IAC wasn't trying to adjust for pulses in the vacuum. So that may be your only issue with only pulling vacuum off 2 manifolds IMHO.

 

looking at your design, I really don't see how it's going to be a problem, in that each cylinder draws air/fuel in one at a time, so if you've got the vacuum draw at your #6 cylinder, when cyl #1 hits intake, it'll draw air from the IAC past the closed intake of #6 and all the other cylinders mix it with fuel (measured for correct ratio by the computer reading the MAP) into the cyl for combustion... etc etc. Think of it on a momentary basis. If you're really worried, you can pull vacuum between the banks, but I don't think it's necessary. also the amt of air for idle is very small in comparison to normal driving.

 

 

One thing, Your MAP needs to read Vacuum from the Intake side or Booster side of the block, since it needs to read engine vacuum, not the needle valve side of the block. Maybe drill and mount it on the back lower section of the block. You can have it read vacuum from anywhere on the manifold too. I'd suggest a "T" between the two manifolds.

 

So don't worry I think your design is awesome. you shouldn't have any trouble.

 

 

Here's a cutaway shot. You can see the shelf under the needle valves that will allow filtered air into the valves. As the IAC raises it will dump filtered air into the vacuum chamber. ...

 

cutaway.jpg

 

...

Derek

 

God, I hope that made sense...

Phar

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Your balance tube has a port to each runner, and the balance tube is 1/2 I.D., it should be fine.

 

My Mikuini Manifold has 1/4" runners going to a 3/8" balance line, with the brakes hooked up at the end of that! Works fine.

 

Initial bypass for idle speed is what you need the individual connections for, from a common metered source. The IAC is for compensation above the initial set idle speed. Remember you want to be idling with all throttle plates closed, making the vacuum signal the strongest it can be in the balance log for a good MAP resolution.

 

So does the bonneville car with the IAC at one end, ducted similarly.

 

If you were ONLY letting air into #6 runner (like on the mikuini manifold for the brakes) then yes, there would be an issue. The only cylinder getting any airflow would be #6. By dumping it in the balance tube...it gets, er....balanced to the others by the action mentioned above in the previous post.

 

Remember there will be six cylinders sucking hard on that balance tube, when the throttles crack even a little bit it ceases to be much of anything more than something to look at and add weight. At idle, the balance tube makes all the air go to whatever individual cylinder is sucking hardest at that particular moment---which is why you want the 1/2" I.D....lets stuff move freely. And by making a small hole into the individual runner, you dampen the pulsations to the MAP sensor at the other end of the log through capacitance.

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Okay so you gonna do the install this coming long weekend? (assuming you're taking MLK day off) :icon10:

 

Phar

 

Not this weekend.

 

Just paid all the bills and checked the bank. YIKES!!! Warning...account below comfort level.

Probably going to take me a couple weeks to get back ahead of the curve.

 

 

 

Derek

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I'm doing a bunch of 3D scanning so I had some free time in between setups so I did the machine work on the log.

 

DSC_0007-1.jpg

 

 

DSC_0008-1.jpg

 

DSC_0012.jpg

 

 

DSC_0010.jpg

 

Now that's pretty tough looking!

 

The spring under the base idle screw will be replaced with something a little nicer.

 

The production model will have bigger mounting tabs as well as a second core for the vacuum side. I did a simple cross drill on this one but there was a large amount of mass in the casting which can cause problems in the metal.

The second core will lighten the casting as well as create a larger reservoir for the vacuum.

 

Derek

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Fantastic work, as usual Derek.

 

Pete

 

Thanks Pete.

 

Looks pretty darn cool! Me likee! I understand on the bank account side. it's after Xmas and $ is short all around :)

 

Looks like it'll work, How hard was the machining for the IAC at the base?

 

Phar

 

It was really straight forward. Drill a hole all the way through to the vacuum passage. pocket for o-ring, pocket for idle valve.

 

I could see TWM buying that piece and charging $1500 for it...

 

 

 

So If I charge $1400.00 I'll be giving everyone a bargain!!!

It does look spiffy though. Maybe $1450.00

 

 

Derek

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Just how in the hell am I going to synchronize these things!

I'm thinking my old Uni-Syn just ain't gonna cut it.

Motion Pro sells this:

http://www.motionpro.com/motorcycle/partno/08-0411

 

And Morgan sells this:

http://www.carbtune.co.uk/c.com/index.html

 

Obviously since they're for a four cylinder I'll have to do it in stages.

The Morgan seems to get generally better reviews.

 

Thanks

Derek

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