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Yessss - I'm baaack ... until you understand that the entire length of the OEM S4+ intake tract - air filter to inlet port - is a choke point - you will spend many $$$ on both simulation software and shiny metal bits (not counting repair costs of holes punched in walls) for very moderate bang-for-buck returns.
I really do wish I could convey an understanding of the subtleties of intake airflow aerodynamics to those folk here looking for gains in engine performance.
You need to understand aero breathing principles beyond the concept of bigger TB's, cams, ports, headers, injectors etc. Great things happen once both are combined.
Here's my experience re S4 manifold breathing mods, emphasing all else re engine is totally stock, c/- Foghorn:
Now there Boy, aaahhhh say, Boyyy ... you got that? Everything else totally stock? (Dang boy has a mind like a carrot grater ...)
Yessss - I'm baaack ... until you understand that the entire length of the OEM S4+ intake tract - air filter to inlet port - is a choke point - you will spend many $$$ on both simulation software and shiny metal bits (not counting repair costs of holes punched in walls) for very moderate bang-for-buck returns.
I really do wish I could convey an understanding of the subtleties of intake airflow aerodynamics to those folk here looking for gains in engine performance.
You need to understand aero breathing principles beyond the concept of bigger TB's, cams, ports, headers, injectors etc. Great things happen once both are combined.
Here's my experience re S4 manifold breathing mods, emphasing all else re engine is totally stock, c/- Foghorn:
Now there Boy, aaahhhh say, Boyyy ... you got that? Everything else totally stock? (Dang boy has a mind like a carrot grater ...)
There's a FIA Group B document that gives the S3 flange dimensions, but those need to be adjusted for the angle to get the csa normal to the flow.
while searching around last night, I found an old post by PorKen with a CAD drawing of a S3 intake port gasket.
the gasket is of course larger than the port but the rough dimensions of the "hole" were about 52mm x 46mm.
here's a photo someone took of an S3 head next to a 944S head, which should be more or less the same casting as the 928S4...the S3 gasket is much larger than the port!
while searching around last night, I found an old post by PorKen with a CAD drawing of a S3 intake port gasket.
the gasket is of course larger than the port but the rough dimensions of the "hole" were about 52mm x 46mm.
here's a photo someone took of an S3 head next to a 944S head, which should be more or less the same casting as the 928S4...the S3 gasket is much larger than the port!
So who's been letting you in here for all these years?
):-[
You're engaged in a systematic and intentional campaign to span unrelated threads with your intake manifold project. That's very different from my natural tendencies to go off on tangents and drift off topic. That's all.
Looking through that document more...was this for a race series?
They show pictures of manifolds and stuff..but the pictured head on page 12/13 is an S4+ piece, and there is an intake manifold (page 13) unlike anything I've seen on a 928.
You're engaged in a systematic and intentional campaign to span unrelated threads with your intake manifold project. That's very different from my natural tendencies to go off on tangents and drift off topic. That's all.
Except that my intake manifold 'project' actually delivers - you know - much improved performance for a reasonable cost.
What my project performance has shown is that the entire intake tract (air filter to port) is actually a giant choke, so ... there is little logical point in finessing port flow c/- CFD analysis, while an upstream flow choke is swamping the reliability of your design results.
Re my "systematic campaign" ? Gee Ptuomov - I thought Rennlisters following this type of thread were looking to increase the engine performance of their cars (at minimal cost), irrespective of the method: eg cams. port flow, air filter flow, header design, plus X or Y pipe, and so it goes ...
While I acknowledge your analytical efforts, unless they eventually result in construction of shiny metal performance bits, what is their point?
I was totally lucky, in that Porsche had done such a horse's *** of a job within the aero flows of the S4+ manifold, that even blind Freddy, (missing one eye and blind in the other), could have managed some sort of flow improvement. Which I managed. Whew.
I seem to remember, in our earlier discussions, that my intake flow mod was the only mod to be found on the 928 forum that actually delivered a no-kidding, economical, bang-for-buck, grin on your face, performance gain.
Nothing magical about what I have done (unless you count the endless hours studying CFD analyses, plus the resulting understanding), except that I was lucky enough to be in the right place/right time to benefit S4+ owners.
Whether your mods deliver or not is a separate question from whether they belong to every single engine performance thread. I have an opinion that they don't belong to every single engine performance thread. Others may disagree, or agree.
Originally Posted by UpFixenDerPorsche
Except that my intake manifold 'project' actually delivers - you know - much improved performance for a reasonable cost.
What my project performance has shown is that the entire intake tract (air filter to port) is actually a giant choke, so ... there is little logical point in finessing port flow c/- CFD analysis, while an upstream flow choke is swamping the reliability of your design results.
Re my "systematic campaign" ? Gee Ptuomov - I thought Rennlisters following this type of thread were looking to increase the engine performance of their cars (at minimal cost), irrespective of the method: eg cams. port flow, air filter flow, header design, plus X or Y pipe, and so it goes ...
While I acknowledge your analytical efforts, unless they eventually result in construction of shiny metal performance bits, what is their point?
I was totally lucky, in that Porsche had done such a horse's *** of a job within the aero flows of the S4+ manifold, that even blind Freddy, (missing one eye and blind in the other), could have managed some sort of flow improvement. Which I managed. Whew.
I seem to remember, in our earlier discussions, that my intake flow mod was the only mod to be found on the 928 forum that actually delivered a no-kidding, economical, bang-for-buck, grin on your face, performance gain.
Nothing magical about what I have done (unless you count the endless hours studying CFD analyses, plus the resulting understanding), except that I was lucky enough to be in the right place/right time to benefit S4+ owners.
thought you guys might be interested in this.
made a simple "sandwich adapter" plate that will allow a 944-4v intake manifold to seal up to a 928S3 head.
The gasket shown is a 944-4v gasket. the plate is wide enough to seal the whole 944 gasket. underneath the plate is a 928S3 gasket against the S3 head. without the plates the gaskets don't overlap enough.
the purpose of this is to be able to run a standard 944-4v intake for preliminary tuning under the new head, as well as smog visual test. i know there is a big step in runner size which is far from ideal...but it will work.
i bet something similar could be devised for putting S3 intakes on S4+ heads, or S4+ intakes on S3 heads. this is 0.090" aluminum, took 2-3 hours to get right using drill press. copies will be much faster since i can use this one as a template now.
11-24-2015, 05:57 PM
