marksportcts

Yeah, must be a big raised hood or something. Modified torque tube too. How does this affect the center of gravity? Seems like it would make the the weight distribution shift a bit more towards the front.

Markus951

we are talking about peak torque? what about the cruve?

Thats with turbo on the stock location right? What about relocated turbo, that should even emprove spoolup/torque?

toddk911

Pics of the intake side???

Chris White

Shifts the whole curve. Spool up time does not really affect the torque curve. Don’t mistake spool up time for the ability to make boost at any particular RPM.

Chris White

toddk911

Chris:

If you have more boost sooner you will have more tq sooner no??

Chris White

Yep, but how are you going to get more boost sooner?
Basically you get to tune the system to be efficient over a particular range. The S2/968 engines are tuned for the 4.5 to 6.5 range and the 2.5 is tuned for about 1K lower. Its not about when the turbo is spooled up, its about the tuning of the cam, ports and manifolds. If you put a turbo on a 16v head that is small enough to spool very quickly you will have the turbo running efficiently when the engine is not and by the time the engine is “up on cam” the turbo will run out of its efficiency range.

Set the turbo up to be efficient where the engine is efficient.

Chris White

turbo_porscha

good job devon....

Weissach Vampire

Here's a chart comparing the 3.0 8V Turbo and the 3.0 16V Turbo ("borrowed" from www.powerhaus.com).

I wonder what would have happened to the drop in power from 3100 - 4500RPM if the 16V would have used a 968 head with functioning Variocam? Has anyone heard of a Turbo 16V with Variocam? Any ideas why it is rarely used?

My wet dream, MID,3.1L,16V,Variocam,BB Turbo....Mmmmm.

evil 944t

Yes, I have seen variocam in use with this conversion. I don't have a dyno chart but it seemed to pick up some low end TQ.

Chris White

How about a dual cam drive with independently adjustable cam timing instead of the variocam? That way you can decrease the amount of intake/exhaust lobe overlap – something the turbos don’t like.

Might look something like this -

fortysixandtwo

Do those change depending on RPM, or are they locked in position?

Chris White

They are locked in position. But they are infinitely variable so that you can dial in the right timing. The stock system cannot be altered.

Chris White

Tom M'Guinn

I've never looked that closely at a 16v head. Are those the factory intake port sizes? Do the header-head ports use a 3-bolt flange? I hope you spring for a new t-stat after all that effort.

Chris White

Yep, very generous ports!

[QUOTE=Tom M'Guinn] Do the header-head ports use a 3-bolt flange?QUOTE]
Yep, it is a stronger mount but you can forget taking the headers off in the car!

Good eyes….except it is new – I test them in boiling water to make sure they open when they should – so it will get a little discolored 

Chris White

333pg333

Chris this is obviously for track only but with it's broad delivery is it not something that could be used on the road as well? What is the cost of having something like this built or is that something you would rather not calculate?