Cannga, you appear to have a pretty big drop in hp ~90 and torque ~110 ft/lb drop from 6000-6800 RPM? It drop some, but not nearly as much on the stock run...maybe 30 hp and 60 ft/lb. Did GIAC say anything about this? It looks like your ECU is giving you a really good midrange push, but at the expense of top end power. Even with 91 octane fuel, your drop off on the top end looks funny.

 

Bob,

Sharp eyes. It's either 1. too little power from heat causing timing to be pulled, or 2. "too much power" causing clutch slipping (one possibility pointed out by a local forum friend today). So it's either power or the clutch.

Scenario one would make me happy and unhappy. Scenario two would make me unhappy but happy (clutch gone, more power). So you said you like the LWFW?

I have not noticed slipping possibly because I drive mostly in Normal Mode and dyno was done in Sport Mode.

 

Do you have access to 93 octane or race gas? That would probably answer the question.

I LOVE my LWFW...but I would warn you...your ears may be a little sensitive .

 

Well done Can and flashing a TT is something special... you're a great asset to the community! You're in-depth reviews are great

 

^^^Thanks Alex. My only "complaint" is this modding process is like the Energy Bunny. It keeps going... and going... and going...

Bob, thanks. I am sure I'll have more questions in the next few weeks.

 

Latest shot of my Turbo baby. In case you don't already know, rating of PDK is rumored to be 790 NM/582 lbs-ft, meaning the new-engine 997.2 Turbo with PDK may not be mod friendly at all.

 

You could always just go with the manual but there's also the fact that the new engine isn't as "robust" as the older GT1 block either.

What is "metzgler turbo?"

 

Hi there Jason. Metzger is the name of the Porsche Motorsport engineer who was involved in the early development of this engine. It's therefore also referred to as the "Metzger engine."
"Metzger Turbo" was made up by me for fun. Thanks for the Porsche font, again. Am having great fun with it.

BTW, I know you are on the fence about this.
Because of the ability to load any tune program to another ECU, therefore keeping your original ECU completely intact, and
Because of the ability of GIAC tune program to go back to stock and therefore allows you to compare and contrast as much as you'd like, and
Because there is a free trial period,
I would recommend the GIAC tune without hesitation. It will make you not want to drive car in stock form again and you'll wonder why you haven't done it sooner. Even with a Stage 2 tune, cars next to you will simply vanish when you step on the gas; very neat, like the Warp effect of Star Trek.
With GIAC the plus is that anytime you want an easy, relaxed drive, one push and you'll be right back to stock. I am very careful with what I recommend and don't own GIAC stock - LOL, just wanting to share the fun here.

The only thing, as you probably already read, is that, some Stage 2 cars do slip the clutch. I am still on my stock clutch since it only happens when I try to reproduce the dyno run.

 

I have my Flashloader permanently connected. So one push and I could be back to stock; during traffic jam, during long cruise, when conversation with wife is important , etc..

 

I found a very nice discussion of Air Fuel Ratio below. BTW that web site has lots of great basic and not so basic info on turbo and tuning; you might want to explore on your own. (Garrett/Honeywell makes OEM turbo's for various car companies.) As always, anyone please correct me as needed and feel free to add more info.

For anyone new to this, the 3 parameters that tuners play around with to increase power:
1. Timing
2. Boost
3. Air fuel ratio (AFR)

A glimpse into ECU tuning: During my time at GIAC, among the myriad of other things that the guys were looking at that went right above my head, the one thing that I did notice was the AFR curve. The AFR curve, or that’s what I think it was (I was trying not to be in the way and not impede their work too much.), was in fact superimposed on the dyno curve and was manipulated by the engineers during the various dyno runs.
In retrospect, it’s too bad I don’t know enough to ask them more meaningful questions (I would have loved to; this stuff somehow fascinates me.), but the gist of it is I think, meaning I am speculating , they were trying to make the curve smooth and to meet a certain goal for the AFR that is:
a. safe with respect to knock and EGT
b. bring more power.

I haven’t got permission to post what’s going on with my car's AFR after the tune, but FWIW and for comparison with the numbers below, before the tune I believe the average stock AFR is around 13 and the range within +/- 10% of this.

>>>>>>>>>>>>>>>>>>>>>>>>>>
http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech102.html
Air/Fuel Ratio tuning: Rich v. Lean, why lean makes more power but is more dangerous
When discussing engine tuning the 'Air/Fuel Ratio'(AFR) is one of the main topics. Proper AFR calibration is critical to performance and durability of the engine and it's components. The AFR defines the ratio of the amount of air consumed by the engine compared to the amount of fuel.
A 'stoichiometric'AFR has the correct amount of air and fuel to produce a chemically complete combustion event. For gasoline engines, the stoichiometric A/F ratio is 14.7:1, which means 14.7 parts of air to one part of fuel. The stoichiometric AFR depends on fuel type-- for alcohol it is 6.4:1 and 14.5:1 for diesel.
So what is meant by a rich or lean AFR? A lower AFR number contains less air than the 14.7:1 stoichiometric AFR, therefore it is a richer mixture. Conversely, a higher AFR number contains more air and therefore it is a leaner mixture.
For Example:
15.0:1 = Lean
14.7:1 = Stoichiometric
13.0:1 = Rich
Leaner AFR results in higher temperatures as the mixture is combusted. Generally, normally-aspirated spark-ignition (SI) gasoline engines produce maximum power just slightly rich of stoichiometric. However, in practice it is kept between 12:1 and 13:1 in order to keep exhaust gas temperatures in check and to account for variances in fuel quality. This is a realistic full-load AFR on a normally-aspirated engine but can be dangerously lean with a highly-boosted engine.
Let's take a closer look. As the air-fuel mixture is ignited by the spark plug, a flame front propagates from the spark plug. The now-burning mixture raises the cylinder pressure and temperature, peaking at some point in the combustion process.
The turbocharger increases the density of the air resulting in a denser mixture. The denser mixture raises the peak cylinder pressure, therefore increasing the probability of knock. As the AFR is leaned out, the temperature of the burning gases increases, which also increases the probability of knock. This is why it is imperative to run richer AFR on a boosted engine at full load. Doing so will reduce the likelihood of knock, and will also keep temperatures under control.
There are actually three ways to reduce the probability of knock at full load on a turbocharged engine: reduce boost, adjust the AFR to richer mixture, and retard ignition timing. These three parameters need to be optimized together to yield the highest reliable power.

 

Was let out of work early and finally had a chance to take my Turbo out to the "country" to let it flex its muscles.
Since the GIAC flash, I've felt the car could not adequately unwind in Los Angeles traffic, as if constantly there is a monster inside trying to get out.
This day is a "landmark" because although I've had the car for nearly 2 years, this is first time that I've really driven it with all mods completed (see my signature). Now, its performance has finally met my expectation of what a Porsche Turbo should be.

On the open road, the car shows enormous power reserve, and that power arrives instantly. The GIAC flash has virtually eliminated all Turbo lag above 3000 rpm. With Bilstein set to firm, GIAC on Sport, it is rather fast & ferocious. Moderately stiff, very noisy, very aggressive, and demands attention every moment of driving. It's a good thing my wife was not in the car because I don't think it would have been possible to carry civilized conversations. LOL
The car's clutch had slipped when I was being abusive a while ago (slam the throttle at 2000 rpm in fourth gear). In this test drive, with the car driven as aggressive as I could ever be - while still obeying the law , the stock clutch functions perfectly, so I am safe with stock clutch still.

The Bilstein suspension is perfect for someone looking for a street/track combination. Unlike the stock PASM, Bilstein PASM works, and works to perfection. Car is firmer yet does not feel nervous or jittery and intolerably harsh like stock PASM.
The stiffer coilover has significantly reduced the excessive side to side and front to back movement of the stock car. I actually prefer carving canyon roads to going all out on the straight, so Bilstein remains a most critical addition to the stock Turbo.

I have a lot of appreciation for the Turbo's 4WD system because of its outstanding corner grip. Without 4WD and with this much power, I actually think the car would not be as safe to drive. You really have to be careful in corners with this much power. I followed slow-in fast-out dictum as if my life depends on it.

The beauty of all this is that with 2 button push: GIAC to normal, PASM to normal, my Turbo transforms into a docile daily driver.

I really should do this more often and too bad I was only out there by myself.

 

Very interesting can.
Got a question to throw out there; When you have mods like mine, Larger VTG's colder spark plugs that demand different setting on your ECU such as timing, fuel map and etc... How would switching your ECU back to stock would affect the actual drivability of the vehicle? in my humble knowledge of things i gathered around dealing with my tune, this may not be a good solution for a set up like mine or is there something to compensate such modifications?
I would love to have such feature, I will always pass state inspections and it could keep the MPG under control.

 

Whether stock timing/boost/afr would work in your particular car, with what sounds like advanced level modification, I would give Todd or Alex a call and seek their advice.
What you could also do, after checking with your tuner of course , is to buy a second ECU (The spare ECU is avail. for $650 from Sunset Porsche, plus 200 or so from the dealer to load the original Porsche DME program.) and install and see for yourself.

What I think (speculate!) is that the ECU has choices of maps, tables, etc. to pick from, and has safety parameters written in, such that it should be ok. It obviously won't make the same power, but it should be ok.
It appears that GIAC/AWE advanced kit still retains the switch-back-to-stock ability.

BTW, again I would encourage anyone who is modding their ECU to load the mod ECU program on a second ECU and keep the original one intact. It's so cheap to do and provides some peace of mind. Not burning your bridge so to speak.

 

KA 997TT,

G.I.A.C., as I am sure you already know, is our software tuning partner. They do all the software we sell for cars with stock turbos and all the way up to our 750R package.

Regardless of what package you have or get, G.I.A.C. has the unique ability to offer as many as 5 unique programs at the same time on the DME.

Even our 750R kit has a stock mode where the computer will back you down to proper timing, fuel, and boost just like your car was delivered to you.

Other options available:

Valet mode: This is a VERY low power setting for when a valet is handling the car.

Kill mode: Just another layer of protection on top of the factory alarm system.

Race gas mode: This is on our opinion is the most unique. With the addition of race gas, you can advance the ignition timing for more power. How they do this is by writing the program like they would for pump fuel, just with more timing.

Our competitors say this feature is useless and their programming will detect the race gas and take advantage of that. To date I have yet to see how this is safely possible and nobody has yet to be able to explain it otherwise.

How we see it is they have the timing set overly aggressively with their base program. Once the knock sensors pick up activity due to too low and octane, they will retard timing so it can run on pump.

While I am not an engineer, I do know that knock is bad, and there should be none at all.

G.I.A.C.'s pump programs are for pump. Their race programs are for race. That is the bottom line and the knock sensors are NEVER to be used as a tuning aid.

I hope this post was informative and answered your questions.

 

Thank you for the explanation. You learn something everyday here that's why i follow good threads.