Since I can't reply yet I thought I'd reply this way for now.

Thanks dndodd and MCLC26 for your responses. One question - my car has the sport chrono pkg and wondering what are the positive/negatives of adding the ECU software? Or is it basically the same thing?

 

The sport chrono can be worked into the ECU upgrade format . The technician will know as soon as he sees it.

 

The sport button still works like before. I just don't use it. I think I have tried it once since the upgrades. I like the non-sport mode profile better especially with the upgrades I have made.

 

I think you're asking if ECU flash and Sport mode are the same - the answer is no - Sport mode just changes the throttle response and adds nothing to performance while an ECU flash changes lots of the programming parameters (sorry I can't be more technical - I don't really know what it does to the computer) and greatly enhances performance.

 

my hunch is the ecu flash does the same thing as the sport mode..increases throtte response - tricks people to think they are getting more hp

 

The Sport button does more than that. It stiffens the clutch engagement. That with the PASM make the car just more aggressive. Big difference in my opinion

 

Here's what Sport Mode does - has no effect on the clutch.

 

You can search and find lots of discussion on what Sport Mode does to changing throttle inputs - check the pdf file I just posted for a very simple explanation of what happens. An ECU flash changes air/fuel mixtures, ignition advance plus other things that the engine gurus have programmed in. Based on dyno reports, ECU flashes don't trick you into thinking you have more hp, you actually get more hp - not so with the Sport Mode.

 

keep telling yourself that..i added evo intake, giac aoftware and suncoast headers = zer hp gain..yes thats right = zero!!!

same dyno

 

Dyno's can be imprecise but even if the runs were completely accurate, have you gone back to the performance shop and asked what's wrong. I've always doubted if intakes and headers add much but your's is the first report I've heard that ECU programming hasn't worked. Maybe some of the experts can respond too.

 

You missed the magic part the Plenum!!!

In all seriousness the plenum made a difference in my car. But I wouldn't give up any of the mods I have made.

 

you are right - i did not have the plenum...could the plenum really add 25hp? surely porsche would have figured this out? i mean in todays world of more hp = better car im sure porsche would have saved money by simply putting in the plenum in their S cars rather than using a 3.8 liter engine instead of the 3.6 L...im no engineer..i can only give you my first hand experience...giac + evo intake and headers = zero additonal power...i dynoed my care before and after on the same dyno...i also dynoed again on a different dyno..still no power...the after dynos on the 2 different machines were almost identical.....

 

The guys who did these mods for you must be embarrased if they can't explain why no increases. I'm sure GIAC would like to know too...unless they really are in the "snake oil" business - I doubt that though since AWE and Imagine Auto and I'm sure others all use ECU mods from GIAC.

 

Don't forget that Porsche still needs to consider things like gas mileage for marketing purposes... I'm sure they were aware of the possibility of increased performance but they may have decided that a more efficient exhaust system and plenum providing an additional 30-40 hp wasn't worth the loss of fuel economy... also consider the additional revenue coming from performance upgrades... all p-car buyers are not hp junkies like us...

 

The Carrera engine is limited by business more than engineering .. why offer 400hp off the bat? when you can sell 25hp for an extra 8000$ (X51).

The engineers at Porsche could higher numbers from the engines if they wanted to .. but then it would cross into their other model-markets.