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High Output Alternators for Porsche® 928

New guy to the Forum here. 15 year 928 owner. I recently purchased and installed the 928 Motorsports alternator upgrade kit. It was the easiest project I've ever done to this car. The kit, the instructions, the power of the added amps, it all worked. It went together so well I had to triple check to see if I had missed something. The most difficult portion of this procedure is removing the original factory alternator. As for the power output; primary and secondary electrical component operational improvement is quite noticeable: fans, windows, starter, battery charge. Weight savings felt like around 15 lb. I should have done this 14 years ago. Tony D.
I have had several alternators on my 1984 928S over the years. It came with an Audi alternator which failed. I used one of Carl's high output alternators, which needed a rebuild after 5 years. I tried a OEM style Bosch, which failed after one year. I am back to Carl's aftermarket item. Christian R.

Carl, Let me begin by thanking you for all of your support on the alternator upgrade. I have the new pulley installed and I am getting a good charge even at idle unless I have "everything" going and even then it's far better than the stock set up. Steve LP

Video for this product is available Product Installation Services Available

The power to drive the Accessories you want!

Application: Porsche® 928 1978 through 1995 all

Background: The first Porsche® 928's were introduced with 90 amp alternators. When these were found to be too weak for the options-ladened Porsche® Luxury Sports Sedan, they upped it to a 115-amp alternator to try to solve the problem.

Today's 928: Even in ideal circumstances on a new 928, the 115-amp alternator was too small. Now, 20 years later - with older wiring and higher impedance - its way too small. PLUS - you may have added big stereos, cell-phone chargers, radar detectors, and other accessories to our beloved 928 that did not even exist back then.

Many 928 owners report that their alternator will not even charge at idle - they must rev the engine to get it to charge at all. This kit will fix that - and the difference in the electric windows and sun roof, headlamp brightness, etc is AMAZING.

Better Design, Better Materials: You know that the world has not stood still since our 928's were born... but continuing to install factory-replacement alternators in your 928 is preventing you from accessing any of the new alternator technology. Our alternator is made from ALL NEW PARTS, is more compact, and is more durable. The cooling "bucket" on your old alternator is no longer needed and can be removed. Our custom 928 alternator mounts up to the stock 928 brackets without modification, and uses the stock wiring harness too.

New Ground Post and Cable Provided: Each of our alternators is fitted with an external grounding stud and a new heavy-duty grounding cable for it. We do this because many 928 owners have found bad connections and corrosion at the old engine ground strap, and the alternator, ignition, sensors and gauges cannot perform to spec if the engine is not grounded well. Adding this new, second ground insures the best performance for your entire 928. This is a 928 Motorsports exclusive!

Two Models Available: The 150-amp model will charge more at lower speeds (like idle) than the 200 amp model. So if charging at idle in city traffic is your main concern, choose this one. It is about a 150% improvement over your old stock 928 alternator. But if you've got that mega-stereo and a lot of gadgets, then go with the 200 amp model to feed that hungry electrical system of yours.

We even provide a 1-year free replacement warranty with each alternator sold.

Our Alternator Kit Includes:
  • NEW custom 150 amp or 200 amp SAE-rated alternator
  • Custom welded Porsche® 928 mounting adapter bracket
  • Wiring Harness Adapter
  • Alternator-to-ground cable
  • Complete Installation Instructions

If your alternator has a 4-rib or 5-rib pulley: Simply remove the V-Belt pulley provided and replace with the ribbed pulley from your old alternator.

Our Alternators are Tested and S.A.E. Rated: Our alternators are SAE-rated, just like the OEM Porsche® alternators are. When you receive your alternator it will be carrying a tag on it that shows the results of the dyno test on this alternator before it left our factory. It's your certification of quality and performance!

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* Domestic US shipping shown. International shipping will be calculated based on location.


Phone: (920) 485-0928
Email: info@928motorsports.com

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