Performance chip upgrades

[DCB]

Hello to all Porsche enthusiasts: I am a retired auto technician, and am often asked for technical advice. Recently, a friend of mine who owns a '97 Boxster, asked my opinion on so called "performance chips" that claim impressive numbers in HP and MPG increases. He cited a couple of brand names, and after reviewing these products and their claims, to me they seem to be devices that are little more than electronic components that alter the input signal from the IAT (intake air temp) sensor, simply "fooling" the computer into providing a slightly richer mixture. This is not much different than old tricks we incorporated back in the late '80s and early '90s, when we would solder in a resistor in the CTS (coolant temp sensor) circuit, to fool the computer into thinking the engine was actually running cooler than it actually was, thereby achieving the same result.

The only "true" chip I know of on the OBDII cars is to actually have someone "burn" the EEPROM with new maps, and this is usually done only after engine modifications, when the PCM needs to be retuned for optimum performance. This requires, at the minimum, experience in digital mapping, a PROM burner, and a wide-band O2 sensor; preferably, a chassis dyno is used for optimum results. Bottom line; it doesn't look as though a $69.95 "gizmo" is going to do much of anything; I don't think Porsche left much on the table for a mail order, plug in device to unlock.

Anyone out there have any real-world experience with these "plug-and-play" tuner chips??? Let me know what you've seen or experienced.

Thanks for your help.
DB, ASE Certified Master Technician (retired)

[Wayne 962]

That's correct, a $70 "gizmo" is all snake oil and scam. There's no way that it can produce the claims that it does. Even the complex software upgrades - they typically richen the mixture, advance the timing and do a few other "tricks" that remove operating margin from the engine's performance characteristics and also require you to run premium, high-octane fuel.

I have an article on the software upgrades here:

Pelican Technical Article: Installing Boxster Performance DME Map Software - 986 / 987

There is no replacement for displacement, and/or camshaft mods. Simply installing new software onto an existing engine will only get you modest gains. However, it's really the only thing that you *can* do to get nearly *any* gains, so a lot of people still do it.

-Wayne

[ronster]

If it looks, walks and quacks like a duck it is a duck. Your analysis is accurate.

[mikefocke]

It is exactly as complex as you describe. Someone I know has access to a dyno and essentially unlimited time and budget and spent at least a month fiddling with parameters within the ECU after doing all his mods trying to get something that would dyno favorably and yet would be drivable. Change, dyno, test for a few hours on the road, and repeat. Then again the next day and the next. Finally track test and prove that in the real world you do have a streetable tune giving a faster car with acceptable emissions running on pump gas available in your area. Then do it again if you change anything.

There is no such thing as a free lunch.

There is no substitute for displacement.