3.2 short stroke porting/setup.
 

Hi,

I am on my way to build a 3.2 short stroke engine, the donor engine is a 3.0, 930/10. To my surprise the heads had 39/35 ports, P/N 930.104.329.2R, must have been swapped as a 930/10 engines are equipped with 34/35 ports?

I want the engine to be road driveable, compression is 10.5:1, close to S-cams and double plugged. For management I will use data, both for fuel and ignition. HK target is 260+

First of all I want advise about head porting? I am also grateful for advise regarding managment systems, is PMO the first choice?

3.2 short stroke porting/setup.
 

Hi.

This is my setup, it's a very strong engine and works very well.

930/10 engine with heads like yours.
98mm Mahle RSR p/c's with 10.3:1 cr.
Webcam 120/104 cam, much like RSR cam, but still very drivable.
46mm PMO ITB's
Twin plug
DTAfast S80Pro full sequetial ecu
Eisenmann exhaust with 39mm primaries.

Power: 290+hp
Torque: 345Nm / 254 ft lbf

The 39/35mm ported heads are great for a build like yours. Porsche did a very good job with the port design.


Tuned for 98 octane.

It's very strong all over the powerband.

The car is faster than a 930 Turbo and has a top speed of 270+km/t , 168mph

930/10
 

Hi Arild, not sure where you got your info from but a 930/10 is a 81-83 euro which has 39/35 ports and a 9.8:1 CR. In the SC family, 78-83, all of those engines have the 39 mm intakes except 80-83 USA versions.

+1

+1 as well, have an '83 euro SC with 930/10, 39/35 ports

Hi and thank for your reply,

And you have not ported any additional above the 39/35?

Arild.

No, no additional porting.


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If you feel like it you are welcome to come home to me and join me for a test drive in my 911. It will give you a good experience of how my engine set up works.

There are several benefits to a set up like this that has to be seen, heard and felt.

Eskild


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How much to you think you really need the twin plug? This looks like a great set up and something I have been considering for a while now. Though I have SC small Port heads :(

3.2 short stroke porting/setup.
 

It depends on what kind of parts you want to choose.
Twin plug ignites the fuel / air mixture from both sides and gives a faster travel of the flame front. This is beneficial on the ignition timing.
With twin plug you can go higer than 10.0:1 on CR.
You can choose pistons that will give you the possibility to use much more radical camshaft profile.
You can use a bigger bore.
All these things are stuff that will give more power.

It is many good things to read regarding these things on the Rennsport Systems web site. Steve Weiner is a very knowledgable Porsche doctor.



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3.2 short stroke porting/setup.
 

From the Rennsport Systems web site:

https://rennsportsystems.com/featured/gasoline-detonation-timing-and-twin-ignition/

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I am not affiliated with Rennsport Systems or Steve Weiner.

Heia, så det er du 😂😂😂

3.2 short stroke porting/setup.
 

Jepp, det er meg [emoji23][emoji23]

Question for Litle Brother: I am planning a 3.2SS with my '83 Euro 911SC which is nearly identical to yours. I see in your photos you are using coil packs in your setup. I was thinking of using a Coil-On-Plug arrangement, thinking it might be a little better or perhaps more reliable over the long term, but I don't really know.

Any thoughts or comparisons about your setup vs COP? Thanks.

I use COPs for my twin plug arrangement. Just make sure you use good ones (Bosch) and you'll be fine.

3.2 short stroke porting/setup.
 

Hi.

I have only used coil pack not COP, and I am very happy with that. The Electromotive coil packs works very well for me. I have heard that if one is going twin plug the lower COP comes quite near the exhaust and thus can be exposed to too high temperatures. From what I have also read it is important to use high quality COP if going that direction.


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Thanks for your responses.

For your P&C, was that part number PS98-014? I am in the process of a rebuild of a 79 sc and have purchased the PS98-014 I will be running twin plug and PMO carbs. cams are reground to 964.

Hi.

Here’s what I bought:


https://www.fvd.net/de-en/10010303204/mahle-32-liter-rsr-piston-cylinder-set-911-30-l-cis-98-mm-big-bore-1031.html

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