Marti

It’s a great result for the intended application and just shows how much the stock manifold is affecting the power potential. Big motivator for me to get on with testing my prototype

Strosek Ultra

There is no law against letting long trumpets extend through the hood.
Åke

Strosek Ultra

The difference between a race camshaft and a S4 standard camshaft (both intake).
Åke

SwayBar

Have you installed the 'race' camshaft yet?

Because of their size, they look more like a 2v camshaft.

hans14914

I am working on getting another batch of intake lowers made here shortly. I find that the real limitation for intake design is actually fighting the stock water bridge for intake runner #1. That always requires a wonky runner and the placement of the bellmouth would steal from either #2 or #5 depending on how you route your runners.

I am close to having a replacement water bridge designed that will allow for a less restricted path for cylinder #1 and also have a bit more room behind for the plenum. Hopefully I will have something workable for my machinist to review by mid week, and then I can place a purchase order for another batch of lower intake stubs with a slight redesign. On this batch, I am either going to turn some internal threads so I can screw in either trumpets, runners sections, or a v-band ring for a tubular upper, or have a simple 2-bolt flange backcut on them. I need to get pricing, but the threaded interface would be much less expensive than a flange, so the likely option.

I will share some concept drawings when I get a bit closer.

Strosek Ultra

No, due to many reasons, this project has not progressed for some time. The cams are intended for a 7 liter stroker build. The base circle diameter is unchanged, that is why they look big.
I had to make a special tool in order to cut the heads for clearance.
Åke

Strosek Ultra

The lift diagrams show the difference in overlap and lift for stock and race camshafts.
Åke

ptuomov

The people who designed the S4 intake manifold and it’s near impossible to beat for the average torque under 4000 rpm. So it’s about the intended use.

Strosek Ultra

ITBs will reduce torque below appr. 4500 rpm compared to the stock intake manifold. The torque can be well compensated by building a larger engine.
The below picture show how Porsche has designed a more modern intake manifold for the Cayenne V8 which Mr. Brown has copied for the 928 (second picture).
Åke

SwayBar

Are the profiles from an existing 32v engine?

ptuomov

No there isn't, unless the rules state otherwise. In the case of John Gill's engine, he should definitely experiment with different trumpet lengths as long as the engine redline is kept at 7000 rpm.

A good video of how intake length and shape impact the torque curve:

john gill

My engine is a long way from being calibrated correctly , the itbs require that I go from map load sensing to tps and map (3d) which requires basically complete change , the mid range and most of the map is a tidy up of the fueling requirements , the ignition cal map is a carry over from the previous engine , so I would expect some other significant gains when I take some more time , I want some track time so I do not scare myself as the gains are significant over the previous engine .

SwayBar

Excellent video.

Strosek Ultra

Ferrari 550 GTS Maranello intake.
Åke

belgiumbarry

sorry , of topic, but that is Havik Racing Solutions , was a shop from Rob van Kol in Belgium building mostly race 944 cups.. ... that yellow 928 is his brother's car , seen it many times in his shop.
That's the shop who was building me a "race" engine years ago... after having already "20k €" payed in the project , he went broke and disappeared with "my" engine ! Never heard of him again...
Sad story for me..... as engine was almost finished..... a sleeved 6l 16V with ITB's as in the pic. 944 heads , custom pistons , dry sump..etc...he "was" a specialist in 928 engines... sadly it had to end that corrupt way .