Y65MPH

A 996tt is capable of maybe 580 whp with bolt on mods running 93 octane. A 997tt will produce 700 whp with bolt on mods running 93 octane. I run an Switzer 800 package on my 997tt. The only reason a tuner might pick a 996tt is because they are familiar with the car not because it is the best choice.

As for your comment on running K24's at 1.3 bar is completely misguided. The K24 runs out of steam at about 1 to1.1 bar. Anything over that and you are just
sucking hot air. Plus running a journal bering turbo to that boost level is a recipe for disaster.

The idea that 1 bar of boost is the same with a k24 and a VVT turbo is once again a silly comment. A great example is a k24 built by Kevin and a stock k24 built by KKK. Both are k24's right? But Kevins probably flows 33% more air at comparable boost levels. So 1 bar does not equal 1 bar.

Craig

Kevin

Lance, give me a call and we can discuss the exhaust. Yes, a exhaust helps. But I don't want to start to "mess" this thread up with the introduction of hybrid turbochargers into the equation..

I have to make it clear that I am not trying to "dog" the 996TT. I own a couple. However, it is just not fair on a technical forum to state wrong facts. When we are talking about engine platforms the GT1 based 997TT outclasses the 996TT engine. I feel that it can be perfected with a few 959 parts. Here are a few differences.

1) The 997TT engine case has a total of 12 piston/wrist pin oil cooling nozzles. ALL previous engine air-cooled or watercooled have 6. This is huge since the engine case is NOT watercooled. The oil is lowering the piston dome temps and increasing the lube to the wrist pin bushings.

2) The vario cam runs/moves the intake camshaft at 100% duty cycle thru the RPM range if the load and torque model requires it. The movement is a little over 50degrees. This was borrowed from the GT3. The 996TT has a limited RPM range> you feel the bump at 3400 RPM's The movement is a hair over 30 degrees.

The benifit is a broader torque curve.

3) The engine bottom end has the reinforced engine case >996TT have it if manufactured in 2004 and later.

4) Cylinder head ports have been redesigned to match the one piece intake manifold.

Overall this is the perfect engine. The last turbo GT1 engine.

SimonK

Every tune I have seen on 997/996 that actually gains proper performance peaks and I did say peaks at 1.3 bar. K24 runs out of steam at 1.2 sustained and 1.3 peak? You have mistaken k24 with k16's. - I will give you the benefit of doubt here. What pipe are you smoking man? Your arguments are really dim-witted. 997=700bhp and 996=580? What am I missing, oh yes of course you have 4.2XXL engine and 996 only has tinny 3.6L with totally different internals?

Max tune on a 997 and 996 = same BHP!!! And you most certainly won't get there with variable turbines of a 997! The difference in power delivery if any will be the actual tune itself.

SimonK

I am sorry Kevin but I respectfully disagree,

The 996 and 997 use exact the same rods, pistons and block (all of which are ridiculously strong from the factory) - check PET.

- The 997 breathes better due to some headwork and different cams
- The 997 has a better fuel system

Furthermore; 996TTs, 997TTs, 996 GT2s and 997 GT2s all use the exact same rods, pistons and block.

Kevin

Simon, your information is just incorrect.

All Gen 2 and later GT2 have different pistons.. Forged pieces.

The 997TT use these same castings. Your "S" engine does not have these late forged units.

The engine case has changed. The 997TT engine case while very similar to the late 2004 model it has been machined differently in the oil galleys to provide more oil to the cooling nozzles.

Your main error is trusting your PET. What the PET fails to show you is the early part numbers. The engine cases that were used from 2001 to early 2004 were machined from the original 964 casting. ALL engine cases have the 964 part number on the case. BTW, the engine case is considered the bottom end. ALL 997TT engines have the GT3 oil pump standard, while the 996TT does not have that option. The X50 and GT2 do have one.

You are correct that the rods and crankshaft are shared between all models. Please note that the crank and rods are 993 issue!

The VE has been improved (more efficient) with the 997TT. The cylinder heads, pistons and intake allow for higher output vs the 996TT. While one can argue any point they want, the 997TT ENGINE platform is more efficient. Even to the point that Porsche needed TWO seperate MAF's to meter the air more precisely bank to bank.

SimonK

Kevin,

It honestly didn't occur to me that I would need to specify that I was referring to the 996tt and 997.1tt 3.6 engines, rather than the completely redesigned 997.2 3.8 DFI engines.

Where are you getting your info on all the improvements in 997.1tt engine? Everyone I have talked to and this includes the Porsche Tech direct from Stuttgart told me that both 996tt and 997.1tt share identical Metzger engine but for some headwork and better fuel system on the 997tt, as I have already stated. Again I have double-checked with my tuner from Munich (literally off the phone now) who told me that 996TTs, 997TTs, 996 GT2s and 997 GT2s (mark 1’s) all use the exact same rods, pistons and block.

So, could please kindly direct me to your point of info as this really is something we need to clarify?

Kevin

Simon, my post and statements ARE comparing the 996TT, 996GT2 and 997.1TT and 997GT2, not the Gen 2 997.2TT. Your TUNER is not giving you the correct information.. Pistons in the 996GT2 gen 2 and 997GT2 and GT2RS are different than ones issued in a early 996TT! There are two many parts that are different between the two engines. The design is similar. But that is where it ends.

My point is apples to apples same tuner, similar exhaust.. The 997TT will PUT out more POWER, and have MORE early power off idle to engine RPM. FYI the 997TT gen 1 compressor wheel has 36% more flow STOCK vs the stock K24 compressor wheel.

SimonK

Same boost?

Kevin

Since the 997TT is more efficient it will make more power psi per psi. Do a little history check and research NEW engine case made in Spain. I don't have the time to share with you the differences with pictures> I might post them later.

The only thing between the two engines that they share is the rods, crankshaft, and intermediate shaft. It is the changes in the variocam, heads, dual intake, throttlebody, one piece intake, larger injectors and not even comparing the turbochargers that make the engine more efficient.

SimonK

Sorry Kevin but the boost question was a trick question, I am not as dim-witted you take me for...

Psi for psi 997tt cannot make more power! You are dead wrong here.

996TT has higher compression ratio 9.4:1 versus 9.0:1 of the 977tt. This means, same boost pressure yields more power in 996tt versus 997tt.

We are seriously blowing off course here so is best we stop.

Therefore, again to the OP: YES, 996tt-S (XP50) is as fast as stock 997tt in the real world.

This is mainly due to weight advantage: Here is the fact: 996tt xp50 = 294 bhp per ton. 997tt = 303 bhp per ton. There is no substitute for weight, lighter pistons or not. Bhp per ton is bhp per ton and no matter what the power delivery curve (to a point) is, once traction is go it is a bhp game. I mean I have posted standing start km between 996tt S and 997tt straight from Porsche; There is 0.3 of a second to 997.tt. I for one could not care less about “alleged reworked internals”. Marketing waffle if and techno babble you ask me...

Yes variable turbines (and any engine rework according to Kevin) perform better from a dig. They adjust blades for quicker spool up. (Think of them as k16's to begin with and k24's to end with - despite the 36% better flow Kevin claims for VTG as in the real world I just do not see any drastic pull from 996tt platform in any speed runs we have tested).

Once you get into tuning both cars for max power, both platforms can be tuned to the same levels. 997tt has the advantage of already having larger injectors and reworked head. However, considering you will pay more for 997tt, 996tt is a much better platform cost-wise and weight-wise, for achieving serious power (let's say 750bhp).

Let me tell you from my real-world experience (from racing cars not from theory and dyno numbers perspective). Between all cars there is not much in it. Simple tunes (and exhausts usually equal in similar MEASURED performance, being 996tt, 996xp50 or 997tt). If you want to measurably and notably (and I am not talking 5-10 car lengths from zero to top speed) outrun an xp50 platform you need some serious power, and 997.1tt isn’t it! You flash them both and exactly the same thing happens.

996tt is most cost-effective platform for all out power – period!

And tuned for tuned:
There we go; And I don't care for any 997tt engine reworks!

jumper5836

^ that must have been quite some mods & $ to get the center exhaust!

Y65MPH

[QUOTE=SimonK;8999213]Sorry Kevin but the boost question was a trick question, I am not as dim-witted you take me for... QUOTE]

OK!!!

Wow..You Tube, that is a great source.

A wise man once said, "Never argue with ignorance. They will bring you down to their level and beat you with experience."

Kevin

Now you are changing the bar.. You are bringing money into the picture.. That isn't what we are talking about.

Again what you are missing is.. If you take and CAP the PSI engine for engine the 997TT will put out more power ( the engine produces higher numeric values from a earlier RPM to redline >>we call that Power Under the Curve. If you cap both engines at 1.2 bars. The 997TT will be able to generate more torque earlier in the RPM range. Peak power levels will still favor the 997TT. So we can see 1.2 bars at 3300 RPM's with a tuned 997TT. On a 996TT we won't see 1.2bars till around 4400 RPM's in the BEST of the best situation and more likely at 4800 RPM's..

The torque generated from the TUNED 997.1TT platform is sooner and greater. In the end the 997.1TT when properly tuned will beat the tuned X50. We aren't bringing the money factor in. That wasn't factored into the original question. The 997GT2 and GT2RS share more components to the 997.1TT than the 996TT X50. I haven't seen a stock tuned X50 beat a stock Tuned 997GT2 or Tuned 997GT2RS..

I havne't looked at the vid..

Kevin

Now what I do agree with is the fact that the 996TT is the most cost effective turbo Porsche. It offers better performance value vs the 997TT platform. However, I think that the crown jewel for the GT1 engine is in the 997GT2 and 997GT2RS engine.

Interesting enough neither has the 996TT or 997TT received all the "go fast" performance parts that Porsche could have given us.. The perfect engine would be similar to the 993GT1... We would actually have to borrow 959 and GT3 parts to add to "our" engines such as the intermediate shaft, GT3 crankshaft and rods.. I would also borrow the early GT1 valvetrain >>more similar to the GT3..

JG 996T

Weight
997.1 turbo coupe is lighter than 996 turbo (x50) coupe.
I believe the numbers are 3,480 (996) versus 3,461 (997).

Horsepower/Torque
997.1 hp/tq = 480/457.
996 x50 hp/tq = 450/457.