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Porsche 928: Performance Modifications

With some subtle upgrades which should improve engine note, throttle response, low-end torque, and peak horsepower for minimal costs in the $500 range, the 928 can be easily modified into a tarmac-churner.

By Thomas Parry - April 14, 2015

This article applies to the Porsche 928 (1979-1995).

By today's standards, the Porsche 928 isn't considered a powerhouse, despite being the only modern Porsche coupe with a front-engined V8. That said, there are avenues to upping the power in your nimble, little steed. Simply by improving the aspiration of the engine, significant gains can be found. With X-Pipe exhausts, freer-flowing headers, and aftermarket air intakes, the 928's V8 sings, stomps, and stirs the emotions of the driver. Read on to learn more!

Performance Modifications

For the 1978-1986 928, the 4.5 and 4.7 liter engines can be pepped up with the addition of headers, exhaust, and intake. Not only will these mods sweeten up the appearance of your engine bay, but they can sharpen throttle response and increase torque and horsepower. Also, if you're looking to make a strong and impressive bellow emit from the rear end of your 928, this is the way to go.

Figure 1. Porsche 928 V8 engine.

MSDS Header System

DIY Cost – $500-$1,000

Professional Cost – Depending on the layout, this can add up to 5-6 hours of labor time.

Skill Level – Difficult; the 928's engine bay is very cramped and needs the crossmember removed to install.

Headers from MSDS can be ordered nickle-plated and ceramic coated. When added to the older 16-valve engine, this header system is reputed to offer ~40 additional horsepower. The installation requires removal of the front crossmember and other suspension components. This allows you to fit the headers from the bottom up.

Motorsports X-Pipe Exhaust

DIY Cost – $628

Professional Cost – Depending on the headers, adding a new exhaust is a mere 1-2 hours of installation.

Skill Level – Designed to reduce hassle, an X-Pipe exhaust is great for additional horsepower without needing to have a custom set of headers added.

Generally speaking, adding an X-Pipe is a simple and hassle-free upgrade that provides a significant amount of power, especially for the 12-valve engine, and doesn't require a set of aftermarket headers.

Kuhn Twin Filter System

DIY Cost – $425-$625

Professional Cost – With this engine layout, adding air filters takes less than an hour. An ECU recalibration may be necessary depending on where you live.

Skill Level – Easy, as it's located in front of the engine.

These fiberglass filters, made with a strong epoxied resin, are good for two reasons. For one, they improve airflow. The more expensive oval filters flow more than the cheaper circular filters. Secondly, the filter position is relocated to an area in front of the radiator that allows for more direct airflow.

Pro Tip

Whenever changing the airflow of an engine, be it intake or exhaust, a computer recalibration is often needed. More often than not, improved breathing goes unnoticed by older ECUs and therefore leads to a lean situation, causing the engine's air-fuel ratio to become skewed and the engine to run dangerously hot. Finding a tuning shop that will recalibrate your ECU and upgrading the fuel supply is necessary and can piggyback on the already impressive gains from the better breathing.

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