Porsche Turbos -"The GT1 block"
 

Knowledgable 911 Turbo owners, particularly 996 and 997 model owners seem to enjoy talking about the heritage of their engine always in terms of "the GT1 block"

Whilst this is correct surely the block for this engine dates back much further than the GT1. I am not sure how far but isn't the block very similar to what was being used in the 80s models and certainly the 930s ?

I feel that Porsche Marketing have been doing their usual BS tricks in working the company's racing heritage to the max since they also mention the "GT1 Block" in plenty of their publications. To me Porsche are conveniently hiding the fact that actually ALL Porsches pre 996 actually had that block and it was only when they went for the big profit margins and gave their ignorant consumers the current "non GT1 ;)" throw away engines that they decided to call the once mainstay block the "GT1" so they could big it up and throw some magic dust on the tt/GT models....

Next time a 996tt/GT or 997tt/GT owner mentions "GT1 block" I am going to tell him it is actually a "911 SC block" from the 80s - Is this about right ? :)

Toby the engine block that we have in the 993TT, 996TT, 997TT and GT series come from the 964 beginning in 1989.

There has been gradual upgrades to the design from the 964 to 993. Then a few more minor casting changes for the 996TT and GT3. However, in production year '04 Porsche changed the casting and reinforced the lower case to suit the water-cooled engines. Same design but reinforced the case and added support for the new GT3 oil pump. From 1989 to 2003 the engine case had the 964 part number on the case...

Different casts have been discussed in the 996 GT3 forum quite a bit, including what parts where taken from the 964 stock, motorsport stock and newly produced. A quick search should reveal some info about it.

IIRC the later 996tt blocks were reinforced for the Gt2 and Turbo S, and the rest of the line were able to benefit

Porsche went to Spain to have a new casting manufactured. The old castings were wearing out. The GT2 was around in '02 along with the X50 coming as a option. There are many early GT2's and X50 cars running the old 964 based engine case.

OK, showing just how ignorant I really am....... what are the big differences between the 964 "block" and the 3.2 Carrera/930/911SC "blocks" which immediately preceded which made the 964 one so tough ?

The 3.3 or 3.2 case was a diiferent animal. The 964 was a increase to 100mm pistons, the head stud spacing needed to be increased. The chain housings and oiling to the valvetrain was also re-designed for the upgraded new design.

Sadly enough, there is rumour over here that Porsche will stop using the engine block M64 (alias GT1) with the new model following the 997 - this means that GT3, Turbo and GT2 will most probably get the current M97 from the Carrera (inheriting all its problems...) :crying: Reason for this: better margins :banghead:

Porsche is moving to a direct injected engine. Cylinder heads have to be redesigned. The engine case will need to be designed. Porsche has made other engine designs in the past that aren't to shabby.. 906 to 917, then the 928> the Carrera GT.. I think that it's going to be a change but all for the better.

Aren't these quite minor "details" ? The chain housing and oiling was changed because it was a crap design - I know I paid to get the mod done on my '81 SC !

But surely the 3.3/3.2 have the same inherrant qualities which make the 964/GT1 "block" so sturdy - eg the dry sump ?

We know tuners were winding the 930 engines up to 700hp in the late 80s (with only the electronics holding them back when comparing to post Motronic tuned engines)
The cars in this thread were running serious outputs on their basic 930 engines:
https://rennlist.com/forums/showthre...=391580&page=2

Yes, the basic structure is the same. Porsche reinforced the 3.6 case, for the larger spigot bore, infact on the RS and factory race engines there was enough room to oring the spigot bores. It would be a very tough job to stretch it to 107mm and oring it on the older case. Every model or case design had new features and improvements. We see this from the 2.0 ltr case to the 964 based case.