2.0, 2.2, 2.4-liter 911 engines should have routine maintenance performed every
6,000 miles (newer 911s can go until 10,000 miles before maintenance).
Engine oil and filter: Change
Transmission oil: Check level every 10,000. Change every 30,000 miles
V-belts: Adjust or replace as necessary
Fuel filter: Replace
Spark plugs: Replace and check compression
Valve clearance: Check and adjust
Rocker shaft tightness: Check and correct
Dwell and timing: Adjust using electronic equipment
Engine idle speed and CO%: Check with electronic equipment and adjust
Accelerator linkage: Lubricate
Brake pads: Visual check and replace if close to limit
Hand brake: Adjust if past 5 clicks
Exhaust system: Check for leaks or damage
Crankcase ventilation filter: Clean
Crankcase hoses: Visual check
E.G.R., OXY counter: Reset
clutch free-play : Check and adjust
Tire wear and condition: Check pressure (correct if necessary) and note condition
Ball joints and tie rod ends: Check
Front wheel bearing play: Check
Battery level: Check and correct
Filter for air pump: Replace
Air pump and control valves: Check
Air injection hoses: Check
911 SC
Exhaust System:
Replacing the stock 3.0 exhaust system with an earlier Porsche system (1974 or earlier)
The earlier system can improve horsepower by 17-22 hp.
Weber 40 IDA-3C Carburetors:
Before you do this conversion, it is best to check with the emissions
laws in your area. Replacing the stock CIS injection system with Weber 40 IDA-3C carburetors will produce about an
additional 10 horsepower (with proper tuning/jetting). The improvement in throttle response will feel like it is a
lot more than 10 horsepower. If this conversion is being done on a later 911 SC, you will need a distributor from
a 1978 or 1979 911 SC. The 1980 an later 911 SCs' distributor advance curve is too short to be used with carburetors.
Displacement Increase:
This can be an expensive way to get more power from the motor, and you either
need to be a very experienced mechanic (with the proper tools and facility), or have an experienced Porsche mechanic
do the work for you. With displacement increased to 3.2 liter, you can expect horsepower to jump to 220 (up from about
180 hp for the stock displacement engine).
911 Carrera 3.2
Modifications
Mass-Airflow Sensor:
3.2 engines can benefit from the installation of a Mass-Airflow Sensor.
Big Bore Throttle Body:
This is expensive from a dollars per horsepower perspective (5-8 horsepower).
The large throttle body obviously allows for greater air flow which equals more power.
Stainless Steel Heat Exchangers:
SSI heat exchangers and a good sport muffler will also help the 3.2.
Also, the stainless steel construction should last the life of the car. The cost is high up front, but cheaper in the
long run since most likely it will never need to replaced. As with the 911 SC, a 1974 or earlier exhaust system installed
on the 3.2 can produce horsepower gains of 13 hp or so. However, in order to install the earlier exhaust system, you will
need a pair of SSI heat exchangers, muffler, different scavenge oil line, and a few pieces to adapt the heater system.
Displacement Increase:
As with the 911 SC, increasing engine displacement with bigger pistons and
cylinders can be expensive. A popular conversion is the 3.4 liter. 3.4 liter conversions do not require machining of the
crankcase spigots. Any conversion larger than 3.4 liter, like the 3.5 liter conversion will need the crankcase spigots
enlarged to 105 mm (2 mm over). Depending on other engine modifications, a 3.4 liter conversion will produce 240-260
horsepower.
964 C2/C4 Series
EMS Chip:
A common modification for the 3.6 engine is a performance chip. The chip optimizes ignition
timing and fuel curve. The result is more torque and throttle (5-10% increase is typical). It is best to use 92 octane
fuel with the new chip to prevent detonation and internal engine damage.
Exhaust System:
The 1989-1994 C2/C4 Porsches have fairly restrictive and heavy exhaust systems.
Installing a free flowing aftermarket muffler will save a bit of weight, and it will add some power (4-5 horsepower).
Also, removing the tray under the engine will allow engine heat to escape easier (your engine will be happier).
993 Series
The 993’s have very well designed engines that are tuned quite well as they are delivered from Porsche. To extract more
power form these cars will be expensive, since certain changes can trigger "Check Engine" lights or be difficult to pass
emission tests. A free flowing exhaust (a street legal one) and maybe a performance chip is about all that can be done to
improve the car, and stay emissions legal.
996 Series
Similar performance modifications that are listed above (for the 993)can be performed on the 996. As with the 993, the
996 engine is even more technologically advanced compared to the 993, so not much can be done to improve the
996 engine besides the normal aftermarket exhaust, cold air intake, and performance chip. Those simple modifications can
improve horsepower by about 10-12%. Other modifications like cams with different profiles, head work, etc. is an option,
but very expensive, and then there is the question about emissions legality.
911 Turbo Cars
Extra special care must be taken (and a lot of restraint) when modifying turbo engines. Extracting more power from a turbo
engine is fairly easy. Adjustable waste gate, different turbo chargers, higher compression pistons, different cam shafts
can installed for more horsepower. A popular turbo replacement is the K27 series turbo. There are three versions of the
K27: K27-11/11 (the most popular) provides improved low-end power, K27-13 provides improved midrange power, and the K27-16
provides improved high-end performance. An adjustable waste gate allows for peak boost pressure to be set to the owner's
desire. With these modifications it is best to tune for reliability rather than all-out horsepower. Turbo engines are
especially susceptible to detonation. Crank up the boost a bit too much, and your engine will have a very short lifespan
(very expensive!). The same goes for high compression pistons in a turbo engine - too much compression will kill your
engine in no time. Always use 91 octane or better fuel in your turbo engine. Also, keep in mind, EMS (Engine Management
System) does not like drastic changes to the engine, so beware of a "Check Engine" light, and correct the problem right
away. Modifying turbo engines is best done in small increments, and test driving the car to check for detonation. At the
first sign of detonation, go back and make some changes (richen the air/fuel mixture, retard ignition timing, lower your
peak boost pressure, or use higher octane fuel. Start with lowering your boost first. Air/fuel mixture is generally on
the rich side on turbo engines, so richening the mixture even more may violate emission laws in your area. Retarding
ignition timing hurts performance, so this should be only your last resort. Higher octane fuel (higher than 91 octane)
is expensive (some high octane fuels cost as much as $30 per gallon) and hard to find. Also, many high octane fuels contain
lead (lead acts as an octane booster) which may not be legal for street use in your area.
NOTE: Another thing to consider is that modifications often bring down the car's resale value, because many
will view the car as having been "tweeked with." Simple modifications like a chip, exhaust, and cold air system seem
to be minor enough to not harm resale values, but always keep the original parts, so that a potential buyer will know
that the parts were not replaced due to damage. For example, installing aftermarket wheels may look great, but the buyer
may think that the original wheels were replaced due to damage. Also, the original parts often cost more to replace
than the aftermarket pieces.
*All aftermarket engine components that are installed in a state of California repair facility must be C.A.R.B.
certified, and the aftermarket component(s) must display an Executive Order (E.O.) number in order to pass the emissions
standards for a street-driven vehicle.
