DMS Porsche 996TT in EVO

DMS Porsche 996TT in EVO

Author
Discussion

grant3

3,640 posts

257 months

Thursday 8th July 2004
quotequote all
Stuh, margins aren't what they used to be, otherwise why would Porsche have upgraded the gearbox for an extra 30 horses on the X-50. Even though it's different, the standard Carrera gearbox has similar tight tolerances as Porsche have introduce a new box for the new 997 C2S because it's 350 horses (up 30 from old 996) was too much for the 996 gearbox.

GuyR

2,219 posts

284 months

Thursday 8th July 2004
quotequote all

Porsche and many other like to tell you they need upgraded parts for new models etc, but it's not always true. The Gearbox upgrade for X50 is only th input shaft and is probably designed to be a frightener to others and to help justify the enormous cost of an extra 30bhp.

There are many 996TTs that have been running 500-600bhp in Germany and USA for years without problems. Of course extra power means some extra wear, but Porsche is very conservative.

The weak part of 996TT and GT2 gearboxes is that they should not have loads of drop-clutch starts performed on them, as this may cause breakages.....

benr4513

7 posts

240 months

Friday 9th July 2004
quotequote all
GuyR said:
Sorry UV, but thats not quite right, you need to add the atmospheric pressure of 1.0bar (approx).

i.e. from 0.7bar to 1.0bar is in reality 1.7bar total to 2.0bar total ie an increase of 17.6% or from 420bhp to 494bhp.

In reality the turbos efficiency is reduced at higher pressures, so the air is heated slightly more, so the actual power gain is slightly less.


The actual pressure will be much as it says as when the car is going fast there is a reduced pressure in the engine bay although you also have the forced air from the air intakes. There is a fine ballance really which is something you will have to ask the experts about.
Regards
Ben

GuyR

2,219 posts

284 months

Friday 9th July 2004
quotequote all
benr4513 said:


The actual pressure will be much as it says as when the car is going fast there is a reduced pressure in the engine bay although you also have the forced air from the air intakes. There is a fine ballance really which is something you will have to ask the experts about.
Regards
Ben




Sorry to be rude, but you need to do some research first. Boost pressure is determined by the ecu and wastegate pressure/regulation, which holds a pre-determined amount of boost.

Positive engine bay and air intake pressures have no effect on turbo engines, unless the intake is running under vacuum ie there is a restriction in the intake piping. The only effect is air temperature in that it changes air density.

The 'ram-air effect' does work on normally aspirated engines though, but only works at high enough speeds to generate a pseudo-forced induction effect.

>> Edited by GuyR on Friday 9th July 12:19

iguana

7,046 posts

262 months

Saturday 10th July 2004
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Gazboy said:
the 996 cab on page 81



????

Do you mean left hand pic the non cabrio 993 in the pi$$ing rain?

If yes then its just a hoop spoiler, then can be bolted to retracting wing & fixed wing type, often have 3rd brake light in the middle.

Dunno why people fit 'em, look a tad chav charriot IMHO

benr4513

7 posts

240 months

Monday 12th July 2004
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Sorry Guy
Your probably right. But this may sound like a silly question. Where does the engine get its air from if the turbos arent running if not from the engine bay? Regards
Ben