Resurrecting Porsche 911SC-Leistungsgesteigert

[Henry Schmidt]

Porsche 911SC-Leistungsgesteigert (Performance increased)
We're starting a simple 911 SC rebuild and resurrecting a little known option offered by Porsche by in 78-81.
Here's some information.

Engine type 930.03 or 930.09 * 3.1 *
Engine displacement: 3122 cc
Bore x Stroke: 97mm x 70.4mm
Power: 210 hp @ 5900 rpm Binary: 280 Nm @ 4300 rpm
0 at 100 km / h: 6.4 seconds Max speed: 230 km / h


The Forgotten 911SC-L
Porsche's 1st factory tuning engine kit that was NOT in the option list for those years (Dealer Secret)
Rolf Sprenger, The Father of the Porsche MFI for the road cars and the Slant Nose 930
Designed this 3.1, 210hp Tuning kit for customers that were not happy with the output and performance of the normal 911SC 3.0 78-81
This tuning kit has a output of 210HP @5800 RPM and 206 Torque @ 4700rpm
Roth used 97mm 3.3 Turbo Cylinders with 9.5:1 compression Pistons made it 3122CC
3.1-L Engine Leistungsgesteigert or Increased Power
Bosch reworked the CIS injection with new Distributor
Taller 5th gear and larger oil cooler from the race department
3750.00 dollar Option in 1978
ONLY spread word of mouth at Porsche Dealers showroom
when customers voiced displeasure of the performance of a normal 911SC
Never was available in the USA only Europe and ROW and only a Letter from Rolf was included in the glove box with this upgrade
No way of knowing how many of these tuning kits were made
Some estimate 200-300 unit made
Roth Sprenger Personal notes and Porsche refusal to Market the SC-L
almost left no documentation to this special rare 911

We're making sets using 95mm cylinders bored to 97 and plated by Millennium. CP X-brace pistons are then custom fitted.
The pistons are designed to use 3.3 liter turbo rings so replacement is cheap and easy.






I have a set for sale Remanufactured 911SC 3.1L pistons & cylinders

[Trackrash]

Cool. So what CR will you be using? 9.5? Will this motor have the CIS and SC cams?

[Henry Schmidt]

The Ps&Cs are designed to produce 9.5:1. The build has not yet been finalized but we're thinking MFI.

[racer]

I had a Euro 1978 SC that was imported in 1984 and was subsequently rebuilt to similar specs. The Euro car had an adjustable fuel distributor iirc. What was nice about it was that the CIS was maintained, which made passing a "visual" inspection easy. I would encourage a kit that is CIS compatible for the California crowd still concerned with emissions.

[lvporschepilot]

Extremely neat! I love the back door options so many had back then. Ferrari did something very similar offering a 'sprint pack' on 308s in the late 70s Euro market cars only. Practically unstreetable P6 Cams, forged pistons, carb jets, and supposedly black cam covers. Claimed output was 280bhp (up from claimed stock 255bhp), but real output was maybe 265bhp (actual stock bhp was 231bhp per Fia homologation which cannot be fudged).

[Henry Schmidt]

Originally Posted by racer

I had a Euro 1978 SC that was imported in 1984 and was subsequently rebuilt to similar specs. The Euro car had an adjustable fuel distributor iirc. What was nice about it was that the CIS was maintained, which made passing a "visual" inspection easy. I would encourage a kit that is CIS compatible for the California crowd still concerned with emissions.

There is nothing about our kit that will be a concern for CIS or smog considerations.
If a wedge piston is desired we can do that but it is by no means a necessity.

We also have a program that makes smog a non-issue on the 78-79 911SC.

[markhoward]

Originally Posted by Henry Schmidt

There is nothing about our kit that will be a concern for CIS or smog considerations.
If a wedge piston is desired we can do that but it is by no means a necessity.

We also have a program that makes smog a non-issue on the 78-79 911SC.

Would like to learn more about the program that makes smog a non issue for 78-79 SC's.

[Henry Schmidt]

Originally Posted by markhoward

Would like to learn more about the program that makes smog a non issue for 78-79 SC's.

Give me a call

[QueWhy]

Resurrecting this thread to see if this package is still available

[safe]

I once meet a guy that had an SC with that engine.

[Henry Schmidt]

Originally Posted by QueWhy

Resurrecting this thread to see if this package is still available

Yes , the kit is still available but we only stock a couple sets at a time so there may be a slight waiting period (4 weeks or so) if inventory runs out.

By popular request the compression ratio is now 10:1(calculated) but we can also order custom compression ratios if desired. At 10:1 with a .040" deck, the compression can easily be reduced with a thicker base gasket. .050" deck gives you around 9.75:1. .060" gives you around 9.5:1. We have custom base gaskets so excessive stacking is not required. (.25mm, .50mm and 1.0mm)

[QueWhy]

Thanks Henry!

I’m not in a hurry, fortunately my engine is still running strong but a bit high in oil consumption and mileage. It’s had a (unverified) valve job many years and miles ago but it’s going to need a refresh at some point.

I’m just trying to find the right path forward and start accumulating parts. It’s a lot easier for me to spread things out rather than say “Hey hon, I’m going to spend $10,000 on the Porsche and no it still won’t have air conditioning”

Currently it’s a stock US spec ‘82 SC with SSIs and a M&K 2-1. My next step is to ditch the CIS for a set of PMO or Webber’s. I know to take full advantage of the carbs I’ll need new cams and pistons. Then it’s a matter of deciding how deep I want to go. The two options I was kicking around were a 3.2ss or sticking with 3.0 and getting some more appropriate pistons and maybe upping the compression (twin plugging) as a path to more power. This 3,1l kit seems like a perfect compromise.

It’s a street car so mid range torque is more important than top end HP but I love winding the engine out so more of both would be ideal. I’d like to keep the exhaust I have now and need heat. With that constraint would 40mm carbs, cams, and this 3.1 kit be a viable solution or do I have to port the heads and go to a more free flowing exhaust to take full advantage?