MFI Turbo Engines - Lot of pics

[slingshot-930]

Hi gents,
some days ago, I visited a very special Porsche wizzard, named Gerhard Stahl, at his shop in Northern Germany. Mr Stahl is an absolute Porsche maniac, with a particular addiction to MFI and turbo-technology. In 1972, he built his first Porsche MFI-turbo engine and a lot of projects followed. His creations aroused the attention of Hellmuth Bott, the legendary former Porsche R & D boss (responsable for countless Porsche competition programmes, from 906 to Group C and also TAG F1), who asked him to join the Weissach team. Finally, Gerhard Stahl decided to continue with his own shop and that was the beginning of a long lasting He is very modest and always flew under the radar, but several Porsche shops still rely on his magic hands.
Unfortunately, with my poor knowledge, it was pretty difficult for me to follow his “lessons“ about certain technical details and solutions, such as the space cams, which he custom made for his applications. His creations may look simple, but let‘s not forget that some of the engines are already several decades old and can be considered the great-grandfathers of what we see today. In those days, there was a more mechanical approach and modern electronic engine management systems, knock sensing and all the modern (usefull) gimmicks had still to be invented. He had and still has a stunning talent of improvisation and you‘ll see what I mean. BTW, the whole Stahl family seems to be affected by the Porsche virus. His 75 year old brother regularly participates to marathon tours around the globe, such as the Hamburg – Shanghai journey or the Namibia-Southafrica round trip. Needless to say, in an old MFI Porsche....
I‘m going to show you some examples of his work, and I will add more details, later. I hope you like this time-travel and I thank you for your time.

G

First DIY wastegate made of a Porsche head and a Mercedes part on top..



DIY engine dyno – lever and weight not attached - with a very old 2.3l MFI-turbo engine

[slingshot-930]

3.3 MFI turbo with Audi intake plenums and twin throttle bodies





3.4 MFI-TT-ITB

[slingshot-930]

3.6 MGI-TT-IT-ITB

[6771911esses]

Funny,

Just this am I was thinkg about retrofitting a MFi engine with some take off 911 Turbo parts. I have a complete 3.3 T setup that just came off for a header + K27 swap and though about the 3.2 Carrera Turbo I sold last year to a friend of mine. This car only runs 0.5 bar boost but what a boot to drive.

I have several MFI engines, i.e. 2.4E, 2.2S, 2.7RS (911/83) which would be fun to turbocharge. My only guess is who would be able to re-calibrate the injection pump and injectors to richen the system appropriately.

Do you have contact info for G. Stahl in Germany? Would be great to pick his brain about this.

Great post.

Cheers,

Mike N.
Madison, CT

[jsveb]

I love the way he has utilized parts from other cars. Very cool

Is the first one a Carrera 3.0 by any chance.

Where in Germany is he exactly?

[Tippy]

Like the Audi plenums......very cool as how it allows a central IC.

[slingshot-930]

I'm glad to see that you like the pics. I will post more interesting details of the 3.6 TT, soon.
His shop is located close to the city of Hannover. The contact details are:
Gerhard Stahl
Peiner Landstraße 220
31135 Hildesheim-Drispenstedt,
Tel: 0049 (0)5121-52152
E-Mail: gjf.stahl@hotmail.de
As he's not a computer wizzard, email answers are not "immediate", but he's a very nice person and a wealth of information.

[Flieger]

Cool!

[einsteiger]

What innovation. Intercooler too big to lay down? Stand it up and modify the lid!!

I would love to see #27 in person.

[slingshot-930]

As promised, I give you some additional info on the 3.4TT and the 3.6TT. These things are light years away from today‘s CAD solutions, but they seem to work, nonetheless. I like this old fashioned “coarse“ workmanship, put together by oily hands.

The 3.4TT came up by welding together the front and the back of two different cars. A coupe roof replaced the original targa version and it got a 964 RSR style body. He pretty successfully raced the car in German Porsche club racing events, until the mid 90‘s, when the rules changed. I have taken some shots of the MFI pump, intake plenum and the plumber-style details, such as the air ducts from the rear wing inlets to the turbo.

[slingshot-930]

The #27 3.6TT was born as a 964 and it received a 959 style body, as it offers a lot of room for the lateral IC configuration. The intake plenums are from a 3.2 and you can see the attached vent valves
The original pistons were machined to reduce the static compression to about 9.0:1and they got the valve pockets. The piston top and the ringland were also reinforced, by adding some material from inside. Boost is below 1 bar. He also adds a cam driven oilpump for an additional cooling and oiling of the valvetrain. The initially used K26 turbos were replaced by “Volkswagen“ units. He never dynoed the engine, but he‘s pretty satisfied with the power. In a direct comparison with his 997 Supercup racecar at the Oschersleben track, #27 was faster on the straights.

[slingshot-930]

With the green handwheel he can adjust the LSD, the red one is for the brake bias and the black knob is for the boost setting.


Some details of the front trunk with catch mod for the fuel tank, the oil tank and the engine breather tank.

[vas930]

Awesome!
Thanks for sharing.

[JBL930]

That vertical cooler, is it two 930 units welded together? Love the pics, all very different approaches, love it!!!!

[MikeD930]

It's amazing that the CIS gets dumped for MFI especially on a turbo! Everything looks so raw but innovative. Talk about very unique builds! Just wow.

[Speedy Squirrel]

The force is strong in this one. Thanks much for the pics.

[vas930]

Originally Posted by Speedy Squirrel

The force is strong in this one. Thanks much for the pics.

hehe

[Costa P]

Slingshot-930, you are a very fortunate chap. It really is an honour, to meet and learn from living legends. It must have been a wonderful experience talking to him.

Respect to a true Porsche Meister, Herr Stahl.

Doesn't it make you wish that you could just soak up, like a sponge, his wealth of Porsche knowledge?

[Costa P]

In the spirit of this thread - MFI Turbo Engines & Pics;

The below pics are of one man's dream turned into reality;
Building a true-to-the-original replica of the '74 Carrera RSR Turbo







Relevant tech info:
- 930 based engine
- Kugelfischer MFI (with customised space cam!)
- Inlet manifold and IC true to the form of the original (do you recognise the donor intake runners?)

For those of you thinking that the engine pics were taken at the Porsche museum......you can read up on this build here


More action shots here

[crimson ghost]

I'd be happy just knowing how everything works in order to design mods like that.