3D Printed Intake Manifolds

[ROB III]

I never ran any of my intakes on a turbo car. Interesting, however, that Porsche turbo racecars (and even the NA racecars) used the ITB's. 944GTR, 924GTR, all the water cooled R's and RSR's, 956, 962, etc, etc. This doesn't mean a single TB won't work well, only that Porsche saw some advantage to using ITB's. That said, there's an advantage to applying the KISS principle with a single.

Given what I suspect is improved efficiency, responsiveness, and accuracy of distribution from ITB, as well as improved delivery and control (possibly adjusting individual cylinders) of injectors of the ITBs, that might outweigh the KISS principle. In a pure race environment, finer control and increased response would seem to be the priority as miniscule improvements from all aspects of performance could result in a more cumulatively noticeable advantage. Look at the engines from turbo F1 era (BMW BT52 M12/13 4 cylinder), and most appear, to my untrained eye, to have ITB, but I might be missing something. Perhaps it gives greater access to optimizing average power in the different rev ranges of a race motor.
Now on a purely street car, maybe less influence on useable real world street performance making it harder to justify increase cost and complexity. Looks to be a widely debated topic for several years based on Googling the topic.

[333pg333]

Perhaps the difference is less nowadays with sophisticated ECUs and other electronics?

[Thom]

Under vacuum a single TB may never "bleed off" inlet air to all cylinders as quickly as ITBs, whence improved throttle response, for instance when blipping the throttle whilst changing the gears down. Inversely, lifting off the throttle, particularly when changing the gears up may cause a quicker loss of RPM due to the much lower volume between each inlet valves and its corresponding throttle plate. In this perspective I would imagine that switching from a single throttle to ITBs on a particular engine would have an overall effect similar to lightening the flywheel, and in this case ITBs may be preferable to lightening the FW to the point where the loss of inertia would be detrimental to engine load and cause a loss of torque which may be of paramount importance on a N/A race engine using a small-ish flywheel with a multi-disc clutch pack. With modern ECU softwares allowing things such as flat foot shifting through DBW getting close to the response of ITBs on certain engines may be possible with a single TB. Just off the top of my empty head anyway.

[333pg333]

That makes sense to me Thom. Would be interesting to read if anyone has actually done some decent back to back testing and what the results were.

[cp99]

Sharing a thread where someone has 3D printed an intake for the 944

https://rennlist.com/forums/944-and-944 ... st19580923

[michaelmount123]

I was recently contacted by a 944 guy in a far off land for help with an intake manifold design. I shared some drawings of ITB type manifolds which I had done years ago, and come to find out they will use 3D printing to complete the manifold. Since this is outside of my wheelhouse, I'll let him explain. Anyone familiar with this?

For this application the FDM printed would simply be for the core of the casting, like traditional investment casting but with a plastic printed part so would still result in a cast aluminum component just significantly less time invested.

To shine some light on 3d printing for you regarding appropriate materials, just incase you are interested.

We do a large amount of 3d printing for our vehicle's at XXXX cars . Our top printer is our SLS (single layer sintering) titanium printer that alot of components from suspension through to gearbox housings are done on.
Even managed to squeeze in component for my 944 strut brace in printed titanium, see attached photo.
But there are plenty of similar printers set up with the likes of aluminum ,stainless and inconel.
SLS is a very usable case now for parts like the manifold all be it at a higher price than traditional manufacturing like casting.

Today I have some ITB housings in the mill that were printed in Titanium that are extremely light thanks to being able to print it almost as a hollow item with essentially a 0.6mm thick skin around the outside and inside.

Sean.jpg (207.7 KiB) Viewed 1250 times

[mooreboost]

[endoquest]

Very interesting post considering my current application. My current off-season race car build will split between two classes. One will be the E Production 2.7 8V N/A with single TB/stock manifold and the other is a Super Production which allows ITBs. If it works out, I can swap configurations and tuning at the track within an hour or so.
MM is helping me with the project and this thread (3D printing TBs) will probably apply to the SP build.

[Energyhunter]

Design render vs partial print

944 Intake Manifold v2.png

PXL_20240620_165546817.MP.jpg

Hi,

I´m in the progress of making a custom intake for my P944T-16V 3,0L and I wonder if I could get my hands on the STL-file for the runners? Need them to optimize the plenum size, have a very large turbo so the space is very limited.

Regards

Björn Olander