Supercharged Porsche 928 S4

[ngenius1]

Hi all,
Wonder if anyone can shed some light on why this supercharged kit has no management system ?
Have been doing some work on above car and noticed other than larger injectors and water cooling and fans to cool charger and intercooler,
No stand alone management or tuning of original system needed.
How and why ?

 

[gsxr]

It almost certainly has a re-programmed engine management computer. I find it extremely hard to believe the stock, unmodified ECU can accommodate the change to positive pressure intake.

 

[asultan]

It almost certainly has a re-programmed engine management computer. I find it extremely hard to believe the stock, unmodified ECU can accommodate the change to positive pressure intake.

this guy boosting says otherwise



Admin edit: Skip to 14:00 in the video below:

 

[Jlaa]

this guy boosting says otherwise

He's gonna run 8psi without any fueling system changes? Not even hack-style additional injectors, or even more-hack-style rising rate fuel pressure regulator?

 

[ngenius1]

I've read the the install book so I could see how the fans needed to be wired, 5 in total.
No mention of anything relating to a management system or otherwise.
Spoke to the guy who installed it and he said what you see is it, no other components.

 

[Jlaa]

Hi all,
Wonder if anyone can shed some light on why this supercharged kit has no management system ?
Have been doing some work on above car and noticed other than larger injectors and water cooling and fans to cool charger and intercooler,
No stand alone management or tuning of original system needed.
How and why ?

I looked at the manual online: https://928motorsports.com/wp-conte...-95-32v-Stage-2-Supercharger-Installation.pdf

It looks like, on page 47-48, that they are mechanically increasing the fuel pressure to the injectors -- using a rising rate fuel pressure regulator.

 

[ngenius1]

The question is, could this system work on our cars ?

 

[gsxr]

The question is, could this system work on our cars ?

A supercharger system? Sure, the problem is engine management. And no, you cannot use 928 S4 management. The 928 has an older, more crude version of LH which batch-fires injectors. The M119.97x has LH-SFI with sequential injection that is far more sophisticated. Most of the forced-induction M119's that I've seen use either a 9th injector to richen the mixture under boost, or change to complete aftermarket ECU control (Megasquirt, etc).

 

[gsxr]

this guy boosting says otherwise

He's dealing with CIS, which is a mechanical injection system. I honestly don't know how much CIS can accommodate forced induction, but it sounds like it may be able to compensate for a modest power increase. He's brave only using a narrow-band O2 sensor (worthless IMO)... why would anyone not pay the extra few bucks for a wideband on a forced induction build?

Engines with electronic injection (Bosch HFM, LH, ME) are a different animal. There must be some method to adjust fuel delivery for the increased airflow / positive manifold pressure.

I looked at the manual online: https://928motorsports.com/wp-conte...-95-32v-Stage-2-Supercharger-Installation.pdf

It looks like, on page 47-48, that they are mechanically increasing the fuel pressure to the injectors -- using a rising rate fuel pressure regulator.

Ah! Rising-rate FPR is crude, but may be effective (enough) on a batch-fire system. It likely will be limited to relatively low boost / lower power output kits.

Anyone know the claimed power before / after on the 928 S4 kit? I'm guessing <30% gain?

 

[asultan]

He's dealing with CIS, which is a mechanical injection system. I honestly don't know how much CIS can accommodate forced induction, but it sounds like it may be able to compensate for a modest power increase. He's brave only using a narrow-band O2 sensor (worthless IMO)... why would anyone not pay the extra few bucks for a wideband on a forced induction build?

Engines with electronic injection (Bosch HFM, LH, ME) are a different animal. There must be some method to adjust fuel delivery for the increased airflow / positive manifold pressure.




Ah! Rising-rate FPR is crude, but may be effective (enough) on a batch-fire system. It likely will be limited to relatively low boost / lower power output kits.

Anyone know the claimed power before / after on the 928 S4 kit? I'm guessing <30% gain?

outside of adding a cold start injector or two and running them on a boost controlled circuit, i can’t see much in the way of tuning on the A/F or timing side (sounds like a waste of energy and time to me)

 

[alabbasi]

He's dealing with CIS, which is a mechanical injection system. I honestly don't know how much CIS can accommodate forced induction, but it sounds like it may be able to compensate for a modest power increase.

CIS just dumps fuel so I expect that it can. Porsche used an 8 cylinder fuel distributor with two lines capped off on the 930.