Jfrahm

Sounds right. A quote from a 968 turbo site, http://968turbo.homestead.com/

"In 1992, Porsche introduced the 968 Turbo RS racecar which it developed to compete in the new ADAC GT racing series in Germany. The car was based on the 968 coupe with limited lightening due to the regulations of the series which had a 4kg/bhp power/weight ratio limit."

-Joel.

333pg333

I would agree from the sidelines. Perhaps also based on application. LeMans car had 16v. Horses for courses.

333pg333

Looking at that still doesn't mean that you have to have 8v vs 16v does it?

MPD47

over under 8 pages?

I'll take under, anyone care to bet?

333pg333

'nuther 5? I think you may win.

fortysixandtwo

I'll take it another post toward a higher page count. And probably spur some additional responses.

In either case, 8 or 16 valve, the engine bottom end needs to be built to the hp level you ultimately want the engine will produce. If your goal is at a level that will require upgraded rods and pistons for an 8 valve engine, the cost for the S2 engine bottom end will be about the same. The real price difference is the additional cost to rebuild the 16v head (which can be just a stock rebuild), sourcing some 951 parts to make adding a turbo easy, and the cost of fabricating the intake and exhaust plenums.
What I think drives a lot of peoples 16V conversion budgets out of control is the idea that they need all the ancillary items to support what the 16 valve head is capable of producing. While this approach is fine if you have the financial fortitude to build the engine out to its max potential, it’s not the only why to get into the 16valve turbo club. You don't need a 3" exhaust, bigger intercooler, fancy pulleys, intercooler pipes, fuel rail, etc..... Will you be leaving horse power on the table? Absolutely, but you will still have more power than a lot of 951's on this forum. Plus you will be able to drive and enjoy your car without spending as much as you could have. When you decide you want more power, get the parts needed to reach the level you want. At this point, its all bolt on up to the level the bottom end was built for.
Even if you have to buy all the stock 951 parts, get them all used from any of the multiple listers parting cars these days. When it comes time to replace them, guess what? They're still used 951 parts, just like you bought! Heck, just the fact that they came off of a 16 valve turbo engine should add some mystique value and warrant a higher resale value.

SprintStar

A 4kg/bhp power to weight limit. Hmm.. So, that can mean the 16V is capable of much more power?

Sprint.

Dubai944

I am researching this also. I thought S2 pistons were forged, at least that is what I have read in several places?
I understand the rods are the weakest link. For extra insurance on a low boost setup on an otherwise healthy S2 motor why not just change the rods?

Mikes3.0cabturbo

no they are cast in the S2, easy to drop a set of S/H 951 rods in there if you really want, but if you keep the boost down to 7psi or so you very likely can run the stock engine pistons/rods, I would be careful of the exhaust though, under boost the stock S2 exhaust creates a lot of backpressure, I have measured this.
rgds
mike

bitburgerluvr

dont "change" that beautiful car!! love the wheels.

Get a beater 944 with bad engine, and install LS chevy engine. Beat on this one and keep the white car for pure enjoyment, long trips etc. Youll have two cars for the same amount of cash invested.

Look, I still feel that these cars will be collectors in the future and this is why Im saying to leave the current car stock. Why will they be collectors? Try to find one that has zero modifications. It is getting harder and harder to find these days. Maybe Im dead wrong but youll still have 2 cars.

But if you must turbo, I like the 8v head on the 3.0L. They still can make enough power to destroy transaxles........ 16v looks meaner to me though and Im sure it make a little more power.

FRporscheman

I just started tearing down my spare 951 engine last night, so I can bastardize some parts for my 968 3.0L turbo conversion. After 2.5 years of driving and servicing a 16v engine, it was a supreme relief to work on the much simpler 8v engine. Especially in an application where stuff is liable to break and blow, this mechanic/student would much rather deal with an 8v engine.

nick_968

8v 3.0 will make 400hp. How much more can the car lay down on the road before you hard earned just leaves your rubber on the highway. Sure 16v will make more power for more $$ but do you really need it?

SprintStar

Is there a big difference in the servicing and maintenance? What's involved? What can break? I've been thinking 16V when I rebuild my 951.

Sprint.

FRporscheman

The cam chain, the cam sprockets, the hall sensor, the fact that there is twice as much valvetrain... I like that on an 8v the cam comes off easily with the housing. And parts are cheaper.

333pg333

I think that many of us in here may not have been in or driven a decently modded 8v with more than 350whp. You'd be surprised just how quick these can be. A 3L 8v can be made from mild to pretty wild for a lot less ca$h. If you go for something +/- 400whp you will need to allocate a lot of funds to supporting components like suspension, brakes, wheels, tyres etc. You can do all of this for less than a decent 16v engine will wind up costing....or do the 5-7psi thing and hope for the best.