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Top speed just needs power, the torque is not especially important.
You need to gear the car so that at peak power (say 6000 rpm) you are doing around 200mph.
I reckon you need 450-500bhp.
Power is how much work the engine will do, and is force x distance in a particular amount of time. In other words it is proportional to torque x revs.
If you have a flat torque output from the engine, then the graph of power against revs goes up at 45 degrees.
This is the ideal, and variable lift and timing on the cams, plus variable inlet tracts help to achieve this (hence the reason Porsche use them).
The issue you have is that at some point in the rev range, the torque starts to drop off. As it falls away your power stops increasing until eventually you actually generate less power as the revs rise.
If you can keep the torque up, then the more revs you have, the more power you have, which is why Ruf, Gemballa, 9ff, can raise the rev limit on your TT. But if you look at the peak torque, it only goes up by about 10%, they just manage to achieve it higher up the rev range, which is often at the expense of torque lower down.
For the 944T, you could raise the rev limit, but it may do you no good.
You will need to make sure you can move the torque peak further up the rev range.
You will need more valve lift (i.e. wilder cams), which may require stronger valve springs to close them again. It may now run a bit more lumpily at tickover.
It would be easier to just get more torque lower down and change the gearing.
You need to increase the boost and increase the fuelling.
You will need to watch the cooling, since you are going to generating a lot more heat than the cooling in the block was designed for.
You may also need to consider how to keep the pistons cool (since they may not be splashed with enough oil).
Getting to 200 is probably best done on a long straight 3 miles or more (try Fairford), or a large circular track, such as Nardo. You don't want much of a corner, since it creates drag and heats the tyres.
If you are going to run for some time, then things are going to get warm.
Of the 500bhp, probably more than 100 is being lost in the transmission.
This will make the gearbox and diff hot. This is why the gearbox has an oil cooler on TT and GT2/3, plus you have individual oil sprays on the gears in the GT2.
You really should lower the car, plus fit a larger air dam, to reduce airflow under the car.
At 150 you need to pay some attention to the aerodynamics, at 170/180 it is pretty important, but at 200 it is pretty serious.
(I read somewhere that an early 911 with no rear spoiler, would be getting about a third of a ton of lift at 150 - I will check. Hence the tea tray.)
This will increase drag, but will stop you losing control.
The door mirrors should come off too (or at least be smaller).
Saving weight by stripping the interior, will make no difference to the top speed, just how fast you get there.
Of course another way you can get to 200 without modifying the car, is to follow another car very close (a few feet away) and slip stream it.
You should be able to do 200 with 250 bhp then.
But you will need to be careful not to rear end them if they lift or brake.
You need to gear the car so that at peak power (say 6000 rpm) you are doing around 200mph.
I reckon you need 450-500bhp.
Power is how much work the engine will do, and is force x distance in a particular amount of time. In other words it is proportional to torque x revs.
If you have a flat torque output from the engine, then the graph of power against revs goes up at 45 degrees.
This is the ideal, and variable lift and timing on the cams, plus variable inlet tracts help to achieve this (hence the reason Porsche use them).
The issue you have is that at some point in the rev range, the torque starts to drop off. As it falls away your power stops increasing until eventually you actually generate less power as the revs rise.
If you can keep the torque up, then the more revs you have, the more power you have, which is why Ruf, Gemballa, 9ff, can raise the rev limit on your TT. But if you look at the peak torque, it only goes up by about 10%, they just manage to achieve it higher up the rev range, which is often at the expense of torque lower down.
For the 944T, you could raise the rev limit, but it may do you no good.
You will need to make sure you can move the torque peak further up the rev range.
You will need more valve lift (i.e. wilder cams), which may require stronger valve springs to close them again. It may now run a bit more lumpily at tickover.
It would be easier to just get more torque lower down and change the gearing.
You need to increase the boost and increase the fuelling.
You will need to watch the cooling, since you are going to generating a lot more heat than the cooling in the block was designed for.
You may also need to consider how to keep the pistons cool (since they may not be splashed with enough oil).
Getting to 200 is probably best done on a long straight 3 miles or more (try Fairford), or a large circular track, such as Nardo. You don't want much of a corner, since it creates drag and heats the tyres.
If you are going to run for some time, then things are going to get warm.
Of the 500bhp, probably more than 100 is being lost in the transmission.
This will make the gearbox and diff hot. This is why the gearbox has an oil cooler on TT and GT2/3, plus you have individual oil sprays on the gears in the GT2.
You really should lower the car, plus fit a larger air dam, to reduce airflow under the car.
At 150 you need to pay some attention to the aerodynamics, at 170/180 it is pretty important, but at 200 it is pretty serious.
(I read somewhere that an early 911 with no rear spoiler, would be getting about a third of a ton of lift at 150 - I will check. Hence the tea tray.)
This will increase drag, but will stop you losing control.
The door mirrors should come off too (or at least be smaller).
Saving weight by stripping the interior, will make no difference to the top speed, just how fast you get there.
Of course another way you can get to 200 without modifying the car, is to follow another car very close (a few feet away) and slip stream it.
You should be able to do 200 with 250 bhp then.
But you will need to be careful not to rear end them if they lift or brake.
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