3.0 intake port to boxster manifold dimensions

[jhelgesen]

Hey guys, had some spare CAD time on my hands lately, started working on my 3.0 to boxster manifold project again.

Does anyone have a 78-79 3.0 head or engine around that they can measure the intake port? Mine is still in the car and in storage 2 hours away.

I need to consider how to transition from the oblong hole shape of the boxster intake to the round 911 port.

This is the shape of the boxster intake.

[jhelgesen]

Here's what I came up with today.

I layed out the boxster flange against the 911 intake ports, estimated a 35mm port opening on the 911. The oval/triangular shaped gasket on the boxster intake hung directly over the studs for the 911 intake, so I shifted the boxster part over 8mm. I then put a surface between the two openings and extracted it, and made a cut out for the injector spray angle.

My concern is will having the angle of the port do anything strange to the incoming fuel/air pattern.

Overall view.


Close up of port shape.


Top view of boxster gasket against adaptor.

[juicersr]

Neat project. Just curious as to why you are mating a boxster manifold onto your SC engine (other than the fact that it look cool)? Where in NC are you?

[jhelgesen]

I'm mating the boxster intake to simplify the installation of a megasquirt EFI system. I don't like the looks of the hacked up CIS airbox, and just happened to have the Boxster intake. Might be able to use the fuel rails for the injector installation. Best of all, the intakes say "PORSCHE" on the top of them.

Oh yeah, I'm about an hour east of Ral, in Kinston.

[juicersr]

John, installed the tbitz MS EFI last winter... you'll love it. Makes the 911 into a whole different car. Agree about the hacked airbox. Next project is a turbo conversion, and your boxster manifold 'graft' would work great as a turbo manifold. Hope it works as i might be interested in a manifold adapter too. Do the boxster manifold inlets line up on the SC 3.0 manifold studs without modification (except port adapter of course)?

[jhelgesen]

Cool, I can hit you up for tuning files when I finally finish my EFI, built my own megasquirt box, just need to build my wire harness. Saw a few guys on the MS forums that sell wire harness kits.

No modifications would be needed to the 3.0 heads, should just bolt right on. Thought it was kind of cool that the boxster and 3.0 intake spacing was the same at 118mm.

I would expect that the adaptor would work with 996 intakes as well, I believe they had two runners going between the intake halves. I would hope with the number of early boxsters out there, grabbing parts from the junk yard wouldn't be too hard.

If I can get the geometry figured out, should just be a matter of finding someone to cnc cut them.

[Elombard]

Wont that be pretty big money to have cut out? I have a bud that can estimate the cost for you if you need. That is going to be a huge hunk of Aluminum!

Too bad there is now way to do something with a flat 1/2" plate and a little porting on the 3.0 heads (with out removing them) and the boxster intake.

Very cool if you can make it work w/o too much expense!! I will have to look for your previous posts on this I am probably restating stuff.

[juicersr]

Good luck..keep us posted. Happy to share MS files to get you running.

[jhelgesen]

I'd love an estimate on cutting time. I did a little optimizing on the size, got it down to a 18x80x340mm blank. Two could be cut from a 3/4" x 4"x36" 6061 bar of aluminum. Price on that piece is $60 at Mcmaster.com, which is overpriced, but not too bad. The maching time is what is going to be pricey.

I could probably thin it down a little more, might get it to a 5/8" thick blank.

[Elombard]

One you are happy with your cad send it to Billy and tell him you need some ball park numbers. I bet you are looking at $500 each!!! seems like you start getting into TWM territory at that kind of money?

mrc@mrcmfg.com

Billy is the owner and a very talented machinist. He loves prototyping type work. Very good guy he might be able to give you some pointers for getting it done cheaper. He does not actually do that much machining any more but he has the capability and is a serious car enthusiast and racer.

If the price is not to bad I want to have him do 2 sets!!

[jhelgesen]

Thanks, I should have the cad finished up in a few days, then I can send it out for quotes. Before it gets cut, I might get a rapid prototype made, SLA, FDM, etc made to tripple check it would fit right. Working with a few companies here at the office, might let them take a look at it.

[Elombard]

Cool, I figured you were in the biz some how since you were familiar with the cad stuff. Really looking forward to it. Next you can just put a radiator in the front and slip a boxster motor in there!

[randywebb]

generally, avoid any tight curves, edges, corners, etc.

w/o more data, I'd just make it as smooth a transition as I could

Here is a little ditty that is not as helpful as a numeric model, nor as flow visualization techniques, but still true:
"air doesn't like to turn corners"
and a lemma, "air with particles in it likes to turn corners even less"

particles will include fuel microdroplets...

[jhelgesen]

Thanks Randy, I tried to make the transition as straight as I could. Would have been a straight drop if I didn't have to clear the intake stud on the outside.

[sc]

VERY COOL!!!!

Please keep us posted!

[jhelgesen]

Thanks to another Pelican, and looking in Waynes engine bible, found intake port dia is 39mm. Update the adaptor to this dia. Measuring area of both shapes, they come out about equal.

Thinking of modeling the rest of the intake, boxster parts, and the Ford throttle body I have. I think the Boxster TB is probably too big a diameter.

Todays progress:

[Lukesportsman]

John,

You did reference the year of your 3.0, correct? There are small port and large port heads.....earlier ones are the large port (39 from memory).

[jhelgesen]

Hey Luke, my 3.0 is from a 79 sc, so the large ports. 80 and up are 34mm.

Thanks!

[Wrecked944]

SWEET! I love these Pelican Mad Scientist Projects - especially since they so often produce awesome results. Please keep us posted! I want to live vicariously.

[randywebb]

"I want to live vicariously."

- It's a lot cheaper that way.


Post any dyno results. You might strike hp gold...