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Unread 05-08-2012, 11:52 AM   #1
Carl Fausett
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Default Stage II SC kit for the 968 New and Improved

We have just completed our re-design of our Stage II supercharger kit for the 968.

The design objectives for our Stage I kit, introduced 3/9/2009 were as follows:
a) low boost (and no special head gaskets)
b) use the stock injectors and ECU (no chip needed)
c) keep the Air Conditioning
d) ease of installation
e) low cost

The design objectives for this Stage II kit, are different, and are:
a) maximum performance
b) track-ready belt drive system

as it just so happens, we were able to again retain the air conditioner, although that was not directly a design goal.

another sub-goal was to provide an easy upgrade for owners of our Stage I kit or our first Stage II kit should they want to upgrade to this newer version.

As discussed on the Stage I kit forum, the Stage II kit is an ADVANCED kit. Not the simple bolt-on and drive of the Stage I kit. The Stage II kit does require modifications to the 968 fuel delivery systems to fuel the greater amounts of boost that this kit provides.

There are a number of ways that can be accomplished. You could go with large injectors, an FMU, and fight the IAC (Idle Air Controller) to get an idle that works. We chose to remove the IAC and the FMU, and instead use a modern engine management system to control all igntion and injector events.

The Tec-GT system we installed recognizes boost pressure in the manifold, and adjusts the fuel and ignition timing as needed for maximum output yet safety for the motor. The stock engine management systems cannot do that.

This provided the least tuning headaches and the greatest flexibility for the customer, because now he can continue to build on this platform if he wishes (agressive camshafts, etc) and he will be able to adjust his tune to any modification easily.

We did discover that the 40 lb/hour injectors that the customer had were adequate for this installation because he had fitted a 1:1 rising rate fuel pressure regulator. Conversely, a person could use 50 lb/hr injectors and the stock regulator with the TecGT system and also get a good tune. Electromotive does make an adapter that allows use of the stock IAC with the TecGT EMS, but as this is a track car, we chose to remove the IAC altogether. The Tec-GT also was able to use the stock throttle position sensor, the stock knock sensor, and the stock crank reference sensor, among others. This simplified the installation for us.

We did actually achieve 297 RWHP on a couple runs, but we had the ignition timing very finely tweaked to do that. That equates to 349.41 HP at the crank.
But with the timing so edgy, we thought one batch of bad gas could endanger the motor. We backed out a couple degrees of advance to add a margin of safety for the customer, and arrived at the numbers below.

The dyno we were using is a eddy-current dyno type, known for lower numbers compared to inertial drum (Dyno-jet) dyno's.

Our goal was durability and safety for the customer - he tracks this 968 - so we knew it would be pushed hard and long during road races. We ran the car under load in a numbers of gears at many different rpm ranges and throttle positions for more than two hours. We arrived at an extremely reliable installation with a tune that is exceptionally safe for this engine.

I hope you will also agree with me that the installation is clean and uncluttered.
Attached Images
File Type: jpg 968 Stage II HP andTorque for webpage.jpg (105.3 KB, 0 views)
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File Type: jpg 026 (Medium).JPG (214.9 KB, 0 views)
File Type: jpg 968Testing.jpg (194.6 KB, 0 views)
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