993 TO 993TT ENGINE DIFFERENCES??
 

I searched...

I want to know what differences there are in the 993 to 993 internal differences?

Block, crank, rods, cams, heads, etc.

All they all the same long block except for higher compression? Do they have different blocks or heads?? Anyone know all the differences?

Rods and crank are the same. Heads, pistons, and cylinders on the 993tt are different. 993tt pistons protrude into the combustion chamber to reduce stress on cylinders during combustion, the cylinders are shorter, pistons have a flatter top for lower compression and the heads are single plug with different size valves than the twin plug 993. Maybe someone else (like Steve W.) will chime in with more detail.

:cheers:
Jay

The rods are reinforced as well.

So it is possible with a rod and piston change to essentially be able to throw twins on it and have a tt car with a motor that will last.

why not just buy a tt to begin with?

you would also want to add the forged cylinders.

i imagine the cost would be more than buying a TT. Also I really doubt resale would come close to equalling a TT.

Agree with above. If you just want to go down the bolt on path, starting with a TT or trading in a NA car to get a TT would be far wiser. If you want to build something unique then start with whatever base you wish.

Nope, bottom end is the same except for a few studs.

p/c are different as are heads(single plug on tt), valves, guides, cams, carriers etc. all different

Now why wouldn't you want to use twin plug heads on a turbo? The extra plug would let you run an extra point of compression for better response, or more boost. Is there some critical weakness in the twin plug heads that make them unsuitable for the TT?

Protomotive has been (low-boost) turbocharging the stock 964 and 993 engine for a long time without problems (i think for around $8k).

I do not have first hand knowledge.

I am quoting Motor Trend:
"The Turbo's powerplant is basically the same as the powerplant used in the Carrera, only with lower compression, reinforced connecting rods, and upgraded engine cooling systems"

And Road & Track:
"The engine itself receives special tweaks to live under the maximum 11.6 psi of boost; Compression ratio is lowered to 8.0:1; and connecting rods, piston crowns and cylinder heads are reinforced"

It is quite possible the magazines were given the wrong information at the time and just quoted the spec sheets they were given.

Bill Verburg is giving the correct answer.

To get the complete list just look in the PET engine section for the turbo engine type designation M64.60 on the far right column next to the part description.

Rods and crank are identical. Same part#'s too.

Extensive machine work will be required for it to be identical to a TT engine. A good machine shop can do pretty much anything I guess but it's not worth it IMHO, better to just buy a TT engine.