997 GT2'S exhaust is made by Akrapovic (famous for motorcycle exhausts)

 

I don't have a side by side. We are modifiying the internals of the stock VTG units from the non-GT2 cars.

 

u mean u guys are using the TT turbo's but modifiying them from inside the internal so it wont look any different from the out side , Q iz no planz to modify the GT2 turbos from inside ?
so we can buy a modified GT2 turbos ?
which i believe there will be several companies goin to do them in soon future !

 

Mike,

Can you please compare your VTG turbos to stock 997tt and stock 997 GT2?

Like;

Are your compressor and turbine housings bigger than these OEM's?
Are your compressor and turbine wheels bigger than these OEM's?

THank you!

 

wow no answer again, us usual.

all tuners are doing same things with the turbines.
on the exhaust side they modify the exhaust wheel, I don't know what is the proper name for this in English but the result is that more gases are going out because of the sharper wheel wings.

on the air side they change the wheel for bigger which is not always better.( I mean too big)

of course tuners are lying saying that turbines they offer are better than the gt2 ones.
of course they can install bigger air wheel (46,48 or 50mm) but basically the whole housing of gt2 is better of all.
all the inside dimensions are bigger on the intake side and exhaust housing is even bigger outside.
I have all the pictures.

At present I'm using modified gt2 turbines in my car.

 

The typical mod done to "wheel wings" is referred to as clipping them which can reduce backpressure by allowing more gas flow but increases spool up time due to the reduced surface area.


We're not modifying the turbine side of the 997TT turbos simply because we did not want to sacrifice low end response and were able to significantly improve high end power via compressor and intake side mods, while also improving spool up via proper exhaust header geometry.

We're having the compressor housing machined to accept a larger compressor wheel that mates to the stock shaft and is properly sized to the compressor housing geometry.

There is a lot more math and testing involved in our modification than just slapping in a larger wheel. A larger wheel than what we are using can be shoehorned into the compressor housing, but it results in the wheel "outflowing" the housing, which results in a soft top end where the map hits the surge line.

We have worked with BorgWarner's engineering department directly on this project, and have had our turbo assembler create some specialized fixtures in order to properly balance the new rotating assembly. The software we worked on with GIAC keeps the turbos within a safe maximum rotation speed while producing significantly more boost at a higher efficiency rate (lower IATs).

Anything else I can help you with?

 

Todd let's not pollute this thread with science

 

yes that is true.
All turbines I drive where modified by kkk directly.
The exhaust wheel at gt2 turbines is already modified.
Which size of air wheel you are using?

 

I hope you can understand, but we do not want to share that information as it is one of our secrets to such a broad powerband.

However, please note that wheel size is not the only factor to consider on the compressor side. Inducer size, blade count, and blade pitch are just as important.

 

Dear Todd: how does your chip compare to the evoms EVT S1 550?

 

That's kind of a loaded question.

Evo used GIAC software up until very recently, but they did not change the names of their "packages".

We have always used GIAC software.

So, if you are comparing our stock turbo GIAC chip to an Evo stock turbo chip from earlier this year or before, they are identical.

They are very much different now according to user reports we are getting from GIAC users unknowingly getting flashed with Evo chips.

Very touchy subject.

 

Who would flash someone secretly w/ another software? This makes NO SENSE whatsoever.

And if they are VERY MUCH different now, how can one determine by what degree they are so different? Very strange indeed....

 

It is save for the engine,tranny etc to install this mod turbos since they produce bug amounts of extra power?

 

Here's how the "switch" happens.

Someone takes their GIAC chipped Porsche into the dealer for service and the dealer does a factory software update and overwrites the GIAC performance program.

This person then goes back to the place they originally purchased the GIAC program from to get reflashed. Free reflash is every GIAC dealer's policy in case of a dealer overwrite, since that commonly happens.

However, the place that originally was a GIAC dealer is no longer a GIAC dealer, but now has another software line that they use. The problem occurs when this place neglects to make that point clear to the Porsche owner and instead flashes in their own software.

The owner questions why he no longer has the ability to use his handheld GIAC switcher unit to switch between the programs he used to have before the dealer update, and is told that he no longer needs to have that option because the new software version is able to do it on its own. The owner then drives away and over the next several days notices that boost is lower than before and drivability at part throttle is not smooth.

The owner then takes it upon himself to contact GIAC directly to find out what the heck is going on, and GIAC instructs him to take the ECU to another authorized GIAC dealer, who then downloads the current program from the ECU and sends it to GIAC. GIAC then confirms that the program in that ECU is not theirs.

This is not some hypothetical story I just made up. It actually has happened. Multiple times.

Bizarre, I know.

 

Todd: that's terrible --safe to say these former GIAC dealer's are unscrupulous. So can we then infer, since this is a reply to my specific question comparing to EVOMS, that some of these former GIAC dealers are flashing to EVOMS?

May we infer then that EVOMS "boost is lower than before and drivability at part throttle is not smooth"?

EVOMS also supplies new diverter valves w/ flash -- is this necessary for a 997tt flashed w/ GIAC?