Woodster

Gentleman, if I may ?

Pole Position although abrasive, always has very good knowledge on a subject.
Here is my thinking (bench racer extraordinare'),
Please do not use the fastest ever Stage 2 car as an example,
I believe you speak of Divexxtreme's car which ran an 11.65 @ 126.
Very, Very good run on perfect day (55 degrees cool). This is a poor
example of this set-up because most Stage 3 and Stage 4 cars struggle
to break below 11.5. This is a fact!
Hell look at Buddy G's car (Very Modified, Very Good driver) ran a 11.3.
My conclusions: Similar to Pole Position K-16's Max out at about 500
SUSTAINABLE HORSEPOWER. We are not talking peak horsepower on
a 20 second dyno run. K-16's run out of air at the higher RPM's generally
required to build 500 + horsepower in our motors. A good running
Stage 2 car "might" keep up to 997TT ?? we shall see...

Ruiner

Woodster, trap speed matters more so than ET. I've got friends running 12s @ 130-135mph only because they cannot get traction. I also know of domestic cars running 10.9 @ 123 because they get insane traction and 60fts.

If you can get a 122-124mph trap in a 996TT, then you are obviously making 500bhp+; especially with our weight. I think that we can all agree on that, correct? As for the K16s running out of air, I truly believe that they should be able to hold good, efficient boost to around 1.1 bar, max. After that, I would agree that they are out of their efficiency range on the 3.6L... They might be at their limits, true, but I think that they are still inside of them.

Perhaps you can educate me on this: What boost can you hold to redline? I only wish that I could see a boost curve for a K16s @ 1.1 bar across the rev range. I really need to look at the compressor map in further detail.

Here it is if you would like to make some calculations as well:

robertp

There are always a few people in the crowd that are going to refute, antagonize and batter everyone else’s opinions and beliefs. We are dealing with high end cars and even bigger egos.

pole position

Trapspeeds will differ from track to track due to location,altitude, "fast" surface etc so it is not the ultimate answer to performance. The Ruf Yellowbird ran in the 130's with less than 500 hp(claimed) with the help of some weight reduction and a Carr GT runs in the 130's without the help of R tires or racegas and matches or beats tuner cars with a claimed 200-300 hp advantage.

Compressor maps represent what the turbo is capable of under ideal and controlled condtions on a bench. Those condtions can not be duplicated once installed , the turbo becomes a piece of the puzzle . A map can be used to narrow the desired features down but it is no guarantee that it will work as intended or perform as the map suggested.

Dock

pole position - does increasing boost do anything to the power output?

Ruiner

There are all different types of variables, however...

"Now, are you telling me that a jump from, let's say 9.4psi to 15.9psi doesn't produce a rather large power difference on a 3.6L engine with a 9.4:1 compression ratio?? That's a 6.5psi increase..."

Please sit down and explain this to me. Remember, the K16s will hold that boost to redline (a VERY important fact). They do not "die" off. The compressor map will tell you if they are in or out of their efficiency range as well.

Kevin

We also need to inject outside temps into the mix.. The standard K16 comes with a K24/2006 (yes it is actually a K24 wheel)compressor wheel.. This wheel will sustain boost to redline only to a certain extent. Let's look at it this way.. In sixth gear flat out this compressor wheel will not reach redline, however, if you install the same wheel that is the GT2 or X50 driven by the same K16 turbine wheel you will be able to hit redline.. Disclaimer, I haven't done this, but I am quoting one of my customers..

The 2006 compressor wheel will provide boost to 1 bar and 1.1 bars.. It will hit 1.2 bar however, not without generating heat.. Heat that places a greater load on your intercoolers.. If the outside air temps are high/hot enough the delta between ambiant and heat generated from the compressor wheel will cause the ECU to pull timing and thus limit your engine output.. So in effect you can make more power at lower boost levels with this turbocharger..

Look, I love the K16 platform for building hybrids, I think that as we get into the sunshine states we should limit the boost output between 1 to 1.1bars max.. One other fact is that the K16 is really cranking it's RPM's at 1.2bars.. At 1.2 bar it is running very close to it's critical overspeed threshold..
Stepping up to the K24 compressor wheel, will lower the RPM of the shaft.. This is true with every increase in wheel diameter..

Ruiner

Kevin, thank you for your input and you said exactly what I was looking for: the psi at which the K16s begin to lose their efficiency and instead, blow hot air. I was taking an educated guess that 1-1.1 bar was at that borderline, if not theoretical limit, but just under. Your statements seem to confirm my beliefs. Thus, if we sit at no more than 1.1 bar, then we are still w/in the theoretical efficiency of the K16s (assuming that the ambient air temp isn't 100' and the intercoolers are not suffering heat soak).

With that said, would you agree that 500-520bhp (with exhaust and perhaps intake) is possible and sustainable for the K16s on a 996TT at the upper rpm range? No more than 1.1 bar, as that would be the max peak boost that I would shoot for in my efforts to use these turbos to their peak potential while keeping in their efficiency range.

Make no mistake, I was only discussing 1.1 bar, max, for these turbos. Anything more, as you said, would limit the engine's power output and I am fully aware of that. I was just looking for a confirmation as to the power output and at what limits this output would be reached.

pole position

The x50 optioned K24's will get you to 520-540 hp max , I don't understand why you are so hell bend on those puny stock K16's for your performance needs. With high boost you will get some extra tq at the expense of a lot of hot air, a complete waste of time IMO unless you are on a major budget. Get some properly sized turbos for your individual needs and most importantly the RIGHT software for the job, hopefully not developed on a mili sec boost spike Mustang dyno and you are good to go.

I better stop now before I get bitter, abrasive, jealous, anti passion Porsche, almost forgot envy and the almighty spell check plus some other components of my personality.

Dock

And who makes the right software?

Woodster

Doc,
Good info from Ruiner, Kevin and Pole Position.
You guys know my preference for good software and it has to do with the
mapping, where the boost comes in (and how which I cannot explain because
it involves so many parameters that it makes my head hurt), and how quickly
torque is built!! I like the way RUF builds his engines and the way they make
torque down low. My car also resembles this torque curve but as expected
on the standard K-16's, it gets a little "wheezy" up top. My old 993TT with
Kevins Stage 2 K-16 HYBRIDS pulled really strong up top.
Just my $.02, I am not arguing with anybody but I did mention heat and high
boost and high RPM's above in relation to standard K-16's
cheers.
Marty K

Kaizu

In Europe 0-200km/h (about 0-125mph) is used quite much.

At least the data for eurospec cars:

official data:
997TT Tiptronic S STOCK 480hp = 0-200 km/h 12.2 secs
997TT Manual STOCK 480hp = 0-200 km/h 12.8 secs
996TT Manual STOCK 420hp = 0-200 km/h 14.2 secs

Sport Auto magazine (THE sportscar magazine in the world from Germany tests the cars at the 'Ring, for some times check out www.track-challenge.com)
tested years ago some tuned 996TT's.
Gemballa 520hp, RS Tuning 508hp, Techart 530hp, TTP 520hp and Sportec 540hp.

At the test the 0-200 km/h times were from 11.38 to 12.51 secs.
So a stage 2 car or what you call it should give the new one a quite good run!

All the cars except the RS Tuning 508hp had modified or new turbochargers. With stock K16's it's quite impossible to get much over 500 hp (at a MAHA dyno, not a Dynojet...)

If you are wondering about this "real hp" talk (or bulls*it??), I can give some insight:
Maybe because of dyno differences (engine dyno is also often used) it might be the same with Porsches as it is with BMWs. I mean that lower hp BMWs in Europe seem to be as fast or faster at 1/4 mile than more powerful BMWs in US. I'm not saying they are, but they really seem to be...
Unfortunately for this comparison people race 1/4 mile only in Scandinavia where are only few Porsches so I don't have "any" Porsche times and I won't speculate this thing any further, Porsches aren't drag cars and real track driving is the thing! (but I've been a bit disappointed to some 1/4mile times of high hp Porsches from US and yes I know about the launch problems...)
Btw. Just last year Manthey's over 600hp GT2 did 0-200 km/h in 9.3 secs...it was a test by Auto Bild magazine, faster than a CGT, that's the way

Shark

Because coming from the V8 world, I hate turbo lag. I'll sacrifice top end for instant response every day of the week.

Ruiner

It remains to be seen what they have in store for the S version of the 997TT. Do I think that the S version will have 525hp? I am leaning towards no. Will it have 530tq? Probably.