Useful Information for 944NA and 968 owners. Re posted from our web site

Or what you can do with your 944 type power plant .

Every day we are asked the same question about 944 modifications. You can perform most modification listed below, without expensive professional help.

Here is our take on this problem;

We assume your engine is in proper working condition, it has no major problems and is regularly maintained.

We also assume your oil pressure is from 3.5-5 when driving and not less than 2.5-3 when idling. Anything less than these numbers indicates crankshaft barring wear.

What would make your 944 run faster?

Change all fuel injectors to NEW and not rebuilt.
(Rebuilt injectors are fine if done by Python Injection. Python replaces inner parts to New. Only outside shell is re-used.)
Change the Oxygen sensor to a NEW one.
Change the fuel pressure regulator and fuel dampner. If your engine oil smells like fuel, it is further proof of malfunction.
Make sure your fuel filter is new.
Buy a high performance ignition coil and plug wires (do not install funky looking plugs. OEM works the best)
Change gear lube oil in your manual transmission to SWEPCO high grade racing blue oil. You will never hear your 5th gear rattle any more.
Change your paper filter box to an open K&N system with header’s heat shield installed to cut down on heat under the hood factor.
Install a Throttle Response Wheel on to your throttle body.
Install a new injector boot as well as new rubber hoses running to the manifold. Old rubber is usually hard and brittle. Microscopic cracks leaking air will lean out your mixture creating "underload" reducing engine’s pick up power.
Remove AirFlow meter. Holding it in your hands, move your ear to the plastic top . While listening, move inner vain door by pressing inward. If you hear faint scraping or squeaking noise, replace the unit. Yours is no longer sending correct information to your DME unit. The inner potentiometer has been scraped away. Potentiometer looks like a credit card with magnetic strip. Two cooper prongs move left and right on magnetic strip. Logic dictates the magnetic strip eventually will be scraped away.
Hard to start, rough idle? Examine or replace your reference sensors. There are magnetic pegs on the flywheel passing by the ref. sensor. These pegs send piston position to the DME unit. When information is inconclusive, DME will refuse to send the current to the coil, thus resulting in “no start”. In most cases the system fault is the result of the pollution. Small metal particles from the clutch and the flywheel are culprit. Consider changing these sensors and cleaning the side of the flywheel. Another suspect is your fuel pump's check valve. Replace one if you can.
Above changes will significantly improve your engine performance. Without these changes you cannot continue with further modifications.
All listed parts must be replaced. Do not assume they are ok. If they are original, they must go.

Further modifications

Replace Air Flow meter with a straight through system. (without the inner door) This modification will disqualify you from PCA racing events and put you in the "Modified" class with faster cars. No Good!
For 944 NA install 3" header header which must be pained with ceramic coating. (A MUST)
Combine above headers with Fabspeed’s 3" exhaust (NO CAT)
Install Weltmister or Authority performance chip in to your DME unit.
It is advisable to perform proposed changes before the "chip" is installed. The chip can be customized to reflect installed improvements such as less restrictive exhaust and mass air intake.
944T Consider Authority’s double chip system for great HP improvement. NOTE: an electronic BOOST CONTROLER will significantly reduce the life of your engine. You just have to except your "turbo lag". 944 4-cyl engine is too small for "aggressive boost".
Consider increasing your speed by reducing the vehicle’s weight. Replace rear hatch glass with a similar "Lexan" lightweight hatch. Replace your metal side fenders and hood with fiberglass ones.
Extreme modification would be considered installing a NITROS kit in to 944na. In fact it works very well. However, the down side, it will become "street illegal" in many states, unless you are good enough to hide your hardware. Also, 10 LB bottle is enough for 3 minutes of continuing boost. An increase of 170 HP. We think it is enough. However, the NITROUS could be set up to work in a TUBO mode by increasing gradually with RPM. Small bursts of energy for quick passing on the open road can keep your bottle filed for a month. In this case you would need PROGRESSIVE NITROUS CONTROLER. As far as a SUPER CHARGER, we believe selling your 944 na and adding $4000 for a would be supercharger, will buy you a nice original 944 TURBO.
Most of the above modifications are reasonably priced and available.

A Few Words for the 968 Owner
Porsche made a statement when they made the 968. It was to answer all of the 944 skeptics who blamed Porsche for the 944’s shortcomings. At it's inception no car builder had ever built more powerful 4 cylinder engine. Modifying a 968 engine is dangerous and not recommended, unlike the 944’s engine, the 968’s are modified straight from the factory. Any modification to the engine would shorten its life. It is superb and delicate vehicle.
Here are few tips if you do not know them already;

Porsche specifically tells you:
Never “jump” this car from a “battery booster” = DME damage
Never cross the battery wires = DME damage.
Do not attach anything to the ignition coil or cross its wires = DME damage.

Do not disconnect the battery’s wires while the car is running it will result in Alternator Death and DME damage.
The 968 is notorious for its electrical problems. Having a poor ground for prolonged periods of time eventually wear down many electronic control unit components around the car. If you encounter poor derivability issue with your 968, before you go to the mechanic there are few things you can do yourself:

1. Check your ground. It’s one of the single most important procedures. The 968 has 9 points of GROUND.
a. Get the diagram.
b. Remove each bolt individually.
c. Spray the contacts with contact cleaner, reinstall the bolt and tighten hard (just spraying the cleaner onto the bolt without removing it, will not do the trick. Pay particular attention to the battery ground wire behind the firewall and all of the ground on the engine itself. Some people add additional copper braids. It’s a good idea.

2. YOU MUST replace the DME relay! Regardless of your mileage, you should replace it to a new one.
3. Replace your oxygen sensor, temp gauge sender, DME temp sender, oil level sender. Tighten accelerator cable slack.
4. Replace your wires with OEM only, using non-OEM wires is not recommended!
5. Replace your paper filter with the same OEM K&N type oil charged filter.
6. Painstakingly examine your vacuum lines for cracks and brittle rubber, especially the line, which connects to the heater valve, on the top of the header.
7. If you are have overheating problems, replace your antifreeze with GM type (orange). It is much better than your green goo or add Water Wetter to your existing “green”. DO NO INSTALL A COLDER FAN SWITCH! Replace two fan resistors located behind the battery or at least clean their contacts.
6. Having alarm activation and or sunroof lifting problems?? That’s the result of an incorrectly wired after market radio!

Your comments are welcome