A 1996-1997 993 Twin Turbo is one of the most exhilarating cars to own. In its stock form, the engine produces 400HP with 400 foot pounds of torque. Combine this power with a great suspension, and you have one of the most awesome cars that's ever been produced. The 993 Twin Turbo was the last of the air-cooled Turbos Porsche manufactured.Â
When looking at a 993 Twin Turbo for purchase, first and foremost be sure to have it checked out by a good Porsche mechanic that understands Turbos. If you don't know of a good mechanic, a good source to find one in your area is to post on the Rennlist Porsche Boards. You can ask there if anyone knows of a good Turbo mechanic in your area. There is a 993 Board and a 993 Turbo Board. Here's the URL... http://forums.rennlist.com/renforums Scroll down until you see the 993 or the 993 Turbo Board.
For the most part, the 993 Twin Turbos have had a very good mechanical record if the previous owner took good care of the car, and hasn't drag raced it. Above and beyond the normal things a pre-purchase inspection should look for, there are a few items the mechanic should specifically check for on a used 993 Twin Turbo.
Warped 1st Gear shaft - If the car was drag-raced, the 1st gear shaft could be warped. Have the mechanic down shift into 1st gear at 25 MPH and verify that it goes into 1st easily. Also have him listen to any strange transmission noises when down-shifting. Note: The 1st gear shaft was improved in the 1997 model.
Worn Turbo Bearings - If the car has been driven very hard and the previous owner didn't let the turbos cool off before shutting off the engine, damage to the Turbo bearings could occur and start to leak. Have the mechanic check the Turbos for oil leakage. If the bearings are leaking, the Turbos must be replaced. They aren't cheap.
Clutch - If the previous owner was drag-racing, the clutch can fail on a low-mileage Twin Turbo. The Twin Turbo is an all-wheel drive car and standing starts are hard on the clutch. Since it's hard to spin all four wheels, the clutch usually gets warn very quickly. Have the mechanic check it carefully.
Clutch Slave Cylinder - A problem with a some of the 993's is a defective Clutch Slave Cylinder. When depressing and releasing the clutch pedal, if a "Click" is noticed or if the pedal seems to 'hang-up', the slave cylinder is probably defective. It doesn't cost that much to have it repaired, but I would have the seller get it fixed before I purchased the car.Â
Proper Boost Levels - Have the mechanic take the car out and floor it in 3rd gear above 3,000 RPM. The boost should build quickly and the digital boost gauge should read .8 BAR. If the digital boost gauge reads a maximum of .5 BAR, the Motronic ECU is going into the "Limp" mode protecting the engine by limiting the boost. This is an indication of a possible severe problem. If .5 BAR is the maximum boost produced, the car needs to be taken to a dealership and the fault codes should be read to find what's wrong with the car.
Check Engine Light - If the mechanic sees the check engine light on, this means that something in the engine's pollution control system is defective. This could be something as simple as a defective oxygen sensor, or more serious as a defective catalytic converter. It could also be as simple as a defective gas cap.
Carbon Build-up Problem - Additionally, the engine light may come on because of a problem with some small holes in the air pump lines getting blocked because of a carbon buildup problem. If a dealership discovers this anomaly, they will try to sell you a remedy that will usually include a valve job, cleaning these clogged holes, and probably additional expensive fixes. The dealerships make a lot of money on these repairs. Are they necessary? Maybe so, maybe not....
There are some products on the market that are very effective cleaning the carbon out of these holes and around the valves. One of the most popular is Techron sold by Chevron. A typical application is to pour a can of Techron in the gas tank when the tank is ½ full. It may take more than one application to clear the carbon. After the Techron application(s), it’s best to have the oil changed as some of this cleaner will end up in the oil. (Not a good idea)
If that doesn’t work, your local Porsche mechanic may have what’s called a MotorVac. This is a unit that will force a cleaner through the fuel system under pressure. If the MotorVac treatment doesn't work, you are probably looking to have a valve job done.
It’s a good idea to run Chevron gas most of the time because it contains Techron in small amounts that will continuously clean the system as the car burns fuel. It’s also a good idea to apply a can of Techron just before your oil changes to keep the fuel system clean.
1996 -vs- 1997 Models - The 1997 model has a few improvements. These include:
- An ECU that can be modified and re-programmed for much higher HP
- Stronger 1st Gear Input Shaft
- Upgraded Turbo Hoses
1997 Turbo "S" - The 1997 Turbo S was the final upgrade Porsche made to the air-cooled Twin Turbo series. It included:
- A modified ECU to provide 424 HPÂ (A Chip Change)
- Added an additional oil cooler
- Air inlets on the real quarter panels
- Lot's of Carbon Fiber in the interior
- A different front bumper with additional air inlets
- A different rear Turbo Tail
- "Turbo S" scripts on the Tach and on the Tail
- Yellow Brake Calipers
- Originally sold for around $155,000.00
Where to look for a used 993 Twin Turbo:
I added several links to newspapers, special interest 'for sale' sites, and Porsche used car dealers. Keep in mind that dealerships usually sell these cars at a high premium. There are some very good deals out there if you have the time and patience to look. I hope these lists will be of some value. Some of the sites to look at are:
Newspaper Classified Ads
Specialty Ads
Dealers - New and Used Inventory Listed
Porsche Brokers
These companies can help you find the Porsche you are looking for
Other PCA Clubs For Sale / Want Ads
Good Luck in your search!!
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Last updated: March 25, 2009