I've been toying around with the idea of mating S54 itbs to a M50 (and family) head for some time. I know it's not the easiest thing to do, nor, frankly, the most logical. Having a set of S54 itbs and a dead M50 head, however, I figured why not try? I know it's been done with Jenvey components, but I want to take it a step further.
I'm studying two different approaches, both of which do away entirely with a plenum and intake air tract: my preferred one would involve a short (~55mm) velocity stack, the throttle, then a ~150mm (from throttle plate to head surface) runner close to the original manifold's path down to the head, with the throttle sitting at a 60 degree angle relative to the head. I think this makes the most sense given the original dimensions of the manifold and air intake tract.
The second would involve a traditional manifold plate with the throttles bolted right up, then a curved velocity stack with a port length of about 15cm with a ~60 degree radius towards the driver side of the engine bay (and possibly slightly forward)
I prefer the first approach for three reasons: because of spatial constraints with the morass of hoses and wires under the M50 manifold (putting the itbs there would make the throttle linkage interfere with everything), because shifting the airflow cross-section from the s54 itb port to the wider and shorter M5x port within the thickness of the plate would negatively affect said airflow, and lastly for the admittedly vain notion of appearance.
This setup would involve the use of a six-port vacuum tank to maintain constant vacuum to the booster, and crankcase and valve cover hoses. In addition, it would include a twin-lever adapter to transfer the throttle cable travel from the pedal to the range of motion delivered by the S54's original fly-by-wire actuator.
The last key to the puzzle would be an Alpha-N tune or such eliminating the MAF and idle control, replaced with a throttle position, rpm and intake temp-dependent map, achieved using the S54's TPS and an IAT sensor mounted between two itbs for closest replication of temperature at the throttle plate.
I've drafted a CAD model of the runner/flange setup I have in mind; it's pretty complete, including all mounting positions, six vacuum takeoffs for the tank, and grooves in the M5x end flange for the original M5x intake manifold gaskets. The S54 end flange would use traditional plate gaskets. I plan on reusing the rubber interface between the itbs and my velocity stacks, which I've designed separately and am refining in accordance with my airflow calculations. As you can see in the attached pics, the runners use the full length to morph from the M5x port to the narrower and taller S54 itb port.
My question is as follows: would anyone be interested in such a setup? I obviously still have a lot of testing and refining to do to the design, but if it can be of interest to more than myself, I could adjust it in such a way as to make it more production-friendly. Any feedback relative to the concept or execution is more than welcome as well.
I am getting a 3d printer in the next couple of days and will start printing prototypes to confirm fitment. After that, I will start programming ECU maps as best I can, and install all components with the vacuum tank.
I'm studying two different approaches, both of which do away entirely with a plenum and intake air tract: my preferred one would involve a short (~55mm) velocity stack, the throttle, then a ~150mm (from throttle plate to head surface) runner close to the original manifold's path down to the head, with the throttle sitting at a 60 degree angle relative to the head. I think this makes the most sense given the original dimensions of the manifold and air intake tract.
The second would involve a traditional manifold plate with the throttles bolted right up, then a curved velocity stack with a port length of about 15cm with a ~60 degree radius towards the driver side of the engine bay (and possibly slightly forward)
I prefer the first approach for three reasons: because of spatial constraints with the morass of hoses and wires under the M50 manifold (putting the itbs there would make the throttle linkage interfere with everything), because shifting the airflow cross-section from the s54 itb port to the wider and shorter M5x port within the thickness of the plate would negatively affect said airflow, and lastly for the admittedly vain notion of appearance.
This setup would involve the use of a six-port vacuum tank to maintain constant vacuum to the booster, and crankcase and valve cover hoses. In addition, it would include a twin-lever adapter to transfer the throttle cable travel from the pedal to the range of motion delivered by the S54's original fly-by-wire actuator.
The last key to the puzzle would be an Alpha-N tune or such eliminating the MAF and idle control, replaced with a throttle position, rpm and intake temp-dependent map, achieved using the S54's TPS and an IAT sensor mounted between two itbs for closest replication of temperature at the throttle plate.
I've drafted a CAD model of the runner/flange setup I have in mind; it's pretty complete, including all mounting positions, six vacuum takeoffs for the tank, and grooves in the M5x end flange for the original M5x intake manifold gaskets. The S54 end flange would use traditional plate gaskets. I plan on reusing the rubber interface between the itbs and my velocity stacks, which I've designed separately and am refining in accordance with my airflow calculations. As you can see in the attached pics, the runners use the full length to morph from the M5x port to the narrower and taller S54 itb port.
My question is as follows: would anyone be interested in such a setup? I obviously still have a lot of testing and refining to do to the design, but if it can be of interest to more than myself, I could adjust it in such a way as to make it more production-friendly. Any feedback relative to the concept or execution is more than welcome as well.
I am getting a 3d printer in the next couple of days and will start printing prototypes to confirm fitment. After that, I will start programming ECU maps as best I can, and install all components with the vacuum tank.
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