dr bob

OK. Go for it!

Remember that all you need is the bolts pattern for the hold-downs. Then Hans' flanges bolted to that. Then you can do whatever magic is needed on the AM metal so it fits onto the flanges. Once you decide to start welding the modified AM metal to the flanges beyond a few tacks, you'll need a pretty rigid jig to hold everything. The flanges are designed to accept a round tube, so your goal on the AM metal will be to accept that same tube in exactly the same alignment. This is something that a capable CNC person could set up for you if the AM metal is thick enough in the right places. You'll likely need to have your welder add metal to the AM manifold in the direction you want to "move" the runners. Then CNC the desired profile inside, making the hole to accept the connecting sleeve. At that point you could glue the thing together if you wanted, since lateral growth (shear on the connecting area) would be transferred via the tubes and not through a glued connection. That would solve a slew of access issues for welding the pieces together, and get you a giant step closer to a marketable product with lower fab costs.

Got that design effort going yet? Ready to get a set of the intake flanges from Hans?

blau928

MK,

I have a spare motor in my warehouse that you can use for a mockup.....

I might also have other surprises lurking in there

Text me or send a PM

Jerry Feather

Mark, what I did for a fabrication platform for my one-off S4 intake based on Hans' intake flanges, was to take an original S4 intake and place it on the quarter inch aluminum plate you see in the picture you posted early in this thread and copy the mounting holes. Then I drilled them and bolted the flanges to them in their respective positions. You can also see that I then made some legs for it and ran the bolts into the threaded tops of the legs.

One of the next things I'll probably do with the platform is trace the intake openings in the plate and then open them up. I think that might be helpful in doing the final fitting and welding/brazing of the tubes to the flanges.

mark kibort

Hi Jerry, that's what I was thinking, based on some of the pictures I saw. is there any draw back, if the intake holes from the stock S4 is the same? is the intake is perfectly level or is there a subtle angle from side to side. if not, it seems you would never need a complete block and heads to weld up the intake to fit correctly. certainly making room for the other items it would help.

James Bailey

So Mark do you have a spare S-4 intake to make your flat plate jig ?

Jerry Feather

I am reasonably certain that the bases of the S4 manifold are flat and on the same plane with each other from side to side. Look at Hans' thread about the development of his base flanges and you can see a lot of what he has designed into those.

The only thing that concerns me a bit is the different rate of expansion between the engine as assembled and the manifold that has a lot of fresh air flowing thru it. I think the Factory accounted for that by mounting the intake with some flexible bolt hole liners so that they could move at different rates. I think Hans has also incorporated that into the mounting of his flanges.

Even if you were to fab your intake on the block with heads installed, they are still going to change position when the engine heats up. I don't know just how best to account for that in making an intake; and I don't know just how the factory supposedly port matched the GT intakes and still accounted for that possible offset from heat expansion.

I suppose the best one might accomplish is to figure out where the offset is going to take place, and how, and then possibly adjust the port match so there isn't any sharp edge intruding into the air flow path when it takes place.

Imo000

He needs to start to get his hands dirty and make something.

The plan is extremely simple. Cut the AM intake legs off, make some bends and weld them to the bolted down flange from Hans or spare cut off S4 flanges. The cheapest way to do this is on the existing engine. The quickest way is on another engine (preferably still in the car to check clearances). I don't understand why he is going around arguing "planning" when all that has been discussed in this and other threads many times over by the same people. It's frustrating to see all the useless nonsense that Mark keeps posting just to keep the thread going. I hope this is nice enough of a way to say all this because I can't say any nicer than this (got penalty point for no playing nice for the previous post).

hacker-pschorr

Maybe saying nothing and moving on to a different thread is the best plan of action. Endlessly raging on someone for how they care to go about their project is more counter productive.

Yes I know Kibort can be a polarizing figure in our community, but last time I checked this was his thread and his car.

This goes for everyone else too. If you have nothing helpful to add to this project, just find some other thread to entertain yourself. Plenty of fun activities taking place right now in Off Topic, and that comes with a bonus of getting to play with Gretch!!!

dr bob

Jerry, Mark, Imo --

I have a lingering concern over using a 1/4" aluminum plate as anything more than a layout jig. Once you start welding or even just tacking the AM manifold to the Hans flanges, the uneven heat of welding will be pulling on the plate. It just isn't strong enough. A spare/sacrificial block and heads, on the other hand, takes care of any minor differences in angles, plus sinks heat as the outside-edge welding is done. There's still going to be that annoying issue of access to get to all the inner welding, and distortion will be a huge challenge. There's a huge case for stress-relieving the whole assembly after the welding is completed, then milling or even Blanchard-grinding the mating faces as one to offer flat flanges for the gaskets.

Once the AM runner modifications are defined, I'm of the opinion that some fill welding and a bit of CNC milling in the transition zone will be the best possible manufacturing method. Include connecting sleeves in the design, and you'll be able to glue the pieces together rather than weld. The only welding needed then would be to build the runner walls where they need to be "moved" in that transition zone, something that can be relatively easily done after the AM mounting flanges are removed. This would be a great test of your 3D cad skills, but done once it will transfer easily to the next and the next. A user could buy the pre-modified AM manifold from you, a set of flanges (perhaps with the mating sleeves already formed) from Hans, and glue it all together on their own engine.

Mark -- Make some silicone "plugs" of the existing runners [silicone molding compound] on a simple [plywood with waxed paper] base, then compare that with a similar set of plugs from the correctly-spaced intake openings in a 928 head. Maybe a piece of clear acrylic instead of the plywood, so you could see in 3D where you will need to make adjustments to the AM runners.

mark kibort

Im not a fabricator, so if the planning takes a little longer or im thourough, and possibly redundant with the other thread, its only to make the job easier.. if it was EASY, you could just do it and send it back to me!
so, the reason there is "planning " and discussing (not arguing) is that this is a simple solution with some complicated conversions. nothing is planned yet, even now, we are debating on whether to use a dummy engine/w heads or a piece of flat metal. you cant use the S4 intake flanges as the material probably wont weld well. but i could use the holbert intake.... ha, that will never happen.... the S4 intake is a disaster for flow.. the lower intake runners for cyl 2-3 are almost at right angles to the flow to the heads. horrible. this is why the design will work so well. i could never make problems with joining the runners, as the stock manifold already has with horrible angles.. sure, if i could just lap off the bases, i would have the Hans adapters .. but i need hans' stuff, because we need to do some welding. is the 85 manifold aluminum or part magnesium like the S4?

Great thoughts Bob........i especially like the concept of making some inserts that are glued in, and then using flexible rubber adapters, like what we have on the S2 cars? is that the idea? that way, we can weld it all up, fill in gaps and then anyone can just take the modified lower manifold parts and join them to the modified AM intake.

there is decent room for the intake to be mounted front or rear ward. compared to the stock intake, i have about 1.5" clearance from the stock manifold now, which makes a huge difference on what might be needed to be moved on the engine. most all the water manifold parts are well below it, however the two sensors will need to be moved, along with the oil filler. other than that, the stock fuel rails look easily reused with lots of mounting surfaces to attache them. the only variable is possible moving out the damper, and use an extended length fuel hose to accommodate that. (bending the line might work if safe) it doesnt have to move out very far.....just a corner looks to be in the way.

I think to do this right ,im leaning toward a dummy block and a set of dumny heads.(and water intake manifolds, along with the oil filler manifold idea.

in looking at the am intake , it looks like it can be mounted frontward or backwards. there is something cleaner looking about having an intake mounted reverse with a throttle body and air filter just in the AC area (that is empty) but, facing forward, makes the design more compatible for anyone to use. all that would be needed is a tube from the TB, which will be located about where the water hoses go into the engine..and the filter to be mounted down in front of the radiator . similar to joe fan and mark's design for their intake systems.

mark kibort

Sizing things up a bit. things look a little better than my first measurements and comparisons.

dr bob

No rubber adapters. The AM manifold gets some fill welding done in the transition area at the bottom end of each runner. You'll CNC the transition zone, including a relief so that a sleeve can fit in each runner at the interface point. That sleeve is either part of a revised Hans mating flange or a separate piece that fits in both. Hans' part is already set up to receive a sleeve at the end of each runner, part of the runner really. Your AM manifold will then sit on top with a runner with the sleeve inside, bottom end of the sleeves fitting in Hans' parts. With a good fit, you can glue each sleeve into the AM runner and the port flange on the Hans adapter. So no welding on the Hans pieces at all. Keeps it all flat and free of weld-induced distortion.

I propose the silicone plugs for the AM manifold runners and from Han's adapter, glued to a piece of acrylic, so you can see in full 3D reality where the runners are relative to the ports. That would help guide your efforts for the fill welding and subsequent CNC work on the AM manifold. Nothing gets done to the adapters -- just fit 8 connecting sleeves and a little Elmer's to hold it all together.

V2Rocket

have to say, that does look pretty kick-*** under the 928 hood.

can you come up with a way to measure the plenum volume, and length of those runners?

mark kibort

yes, it does look good! this is a Well designed intake and will be a HUGE improvement over stock.

I can easily measure the runner volume and length. length is a snap, but the volume ill fill with water and empty.

i would not be too concerned for the length, but they are quite long and should have similar results to what GB and others have done on their designs. again this slapping on an engine with 4.3 to 4.7 Liters and it gets stock, 340 (4.3L) to 360rwhp (4.7L), not even looking at the shape of the HP curve. I think the only downside would be the torque loss in the 3500 RPM range , due to the flappy based / S4 intake systems and design. Look at how those runners are straight and how LARGE they are. pressure drops willl be minimal through these runners. I might bench flow it if i get a chance too. probably getting a dummy S4 intake from anderson too for set up and comparisons

EDIT: dimensions: runner length 11" exit to the head width is 1.5 x 2" and bell mouthed inlet is 3.5" x 2"

how about reversing the mounting orientation?

V2Rocket

what you're going after is clean flow (not convoluted runner shapes) and more importantly, the tuning effect for higher RPM power boost.

engine displacement doesn't really matter for tuning runner length - that comes into consideration when deciding runner diameter.

there are lots of approaches to the runner formula, some more generalized/ball park than the actual helmholtz formula, but one rule of thumb from tuning guru David Vizard goes something like,
"start with 7 inches for 10,000 rpm, for every 1000rpm below that add 1.7 inches"

so your AM intake has 11" runners but we don't know the length of the runner in the AM head. so let's substitute the 928's in-head runner length, 85mm = 3.375".

11+3.375 = 14.375.
14.375-7 = 7.375..
7.375/1.7 = 4.34 = 4340 rpm below 10000 = 5660 rpm "tuned length"

now again this is VERY generalized/ball park and you need to really know cam timing events to get the most tuning effect. looking at some AM4.3 dynos the HP curve (line, really) is VERY smooth and linear, presumably a desirable aspect AM programmed in taking advantage of fuel, spark, and cam timing...since you don't have VVT the power increase should be more predictable.


*edit* i mentioned this previously in the Ferrari thread.