Removing Secondary Air Injection 996.1

Has anybody removed SAI from a 3.4l 996 with electronic throttle? I understand it was introduced in MY2000. Does anybody know if it can be coded out? I would like to remove the equipment and just fit blanking plates. I know on earlier cars a ROW tune car be used, but is this try for these? If so how is it done? MC

How do you mean by coded out? Do you mean a different fuel map to compensate for what it does?

Whilst obviously i don't know everything .. I don't ever remember seeing a coding option for this , as its save the planet stuff then i very much doubt it could be coded off . It's there for fast warm up of the cat as i'm sure you know and from memory the car operates it once in a drive cycle at operating temps and looks at the lambda sensors to see a lean mixture to prove this system is working ok . I can't see a way of mimicking this to fool the system . I've seen these systems being defective with no eml on but there is always a fault code listed . A remap does not alter the actual coding of a dme so as this is a software instruction then i think you are a bit stuck .. but if no eml then does a fault code really matter :?: Software is different for each year .. the dme i believe is coded to Row for our market so it will be year dependant . A bit out of my comfort zone so all i can offer . My thoughts anyways .

I thought the only time the SAI pump operates is at cold start and pumps extra air into the cats to fool them the engine is running lean and therefore adds more fuel - so it acts as a choke system? :dont know: The only time it runs on mine is at cold start.

They do only operate when cold but the car can't see if they are working at that point as no lambda sensors .. open loop . Extra air when cold causes the cats to run lean and generate more heat .. a fast warm up of them due to the extra oxygen . The car will turn them on .. from memory when it's at operating temps as a test to see if they are working or not .. at this point it will flag a fault code if it doesn't see a response from the lambda sensors . That's how i understand it anyways

More info here: https://books.google.co.uk/books?id...&q=what does the sai pump do on a 996&f=false

Alex .. i'm far too old to be learning new stuff .. the amount i forget every day is getting scary That does explain it nicely though :thumb:

:grin: :thumb:

The previous owner has had the SAI pump removed from my car, which is a 1999 C4 so electronic throttle / PSM. No codes, but I don't know if the car's been mapped and the shop who did my engine rebuild 2 years ago couldn't tell for sure either as they don't do remaps. The car runs fine and the revs stay up a while when cold, so I haven't paid more attention to it.

AFAIK the C4 was always e-throttle, is your a 1999 MY car then? I.E. registered before August 1999? MC

From Porsche: MY1999 The cabriolet and four-wheel-drive Carrera 4 versions of the 996 were unveiled at the Paris MotorShow in October 1998 for the 1999 model year. The Porsche Side Impact Protection System (POSIP)was introduced, as were clear indicator lenses front and rear to distinguish the car from the Boxster,and to counter criticism of the 'fried egg' look of the front lights. The cabriolet mechanism was fast,and could lower or raise in just 20 seconds. Cabriolets came with a removable hardtop, colour-coded to the bodywork. The cabriolet was around £6000 more to purchase than the Coupe equivalent.The 4 wheel drive system was available for both Coupe and Cabriolet, and was nearly £4000 morethan the 2 wheel drive model. Various modifications to the front end were required to make room for the front axle final drive, which resulted in a smaller front luggage compartment, and the use of a deflated space-saver wheel under the floor of the compartment. The C4 was also available in tiptronic transmission for the first time. Engine management was by Bosch Motronic 7.2, which introduceddrive-by-wire throttle control, often referred to as eGas. The four wheel drive system added 55kg to the overall weight, but performance figures were quotedidentical to the C2 equivalent due to improved traction. The extra weight at the front end gave aweight balance of 40-60, compared with 38-62 for the C2. The 4-piston calipers manufactured forPorsche by Brembo were painted in a 'titanium' (silver) colour for the C4, as opposed to black for theC2. Perhaps the most significant introduction on the C4 was Porsche Stability Management (PSM). Toquote the Porsche Service Information Document of the time: 'PSM is an active control system forstabilising a vehicle at the limit of its driving dynamics capability. PSM includes functions such as ABS,ABD, ASR (traction-slip control), EBV (Electronic Brake-force Distribution), as well as a longitudinaldynamics control system MSR (engine drag torque control). In addition to this, the vehicle is stabilisedat the limit of its driving dynamics capability within the transverse dynamics control system by FDR(driving dynamics control system)."From the outside there is virtually no difference in appearance, other than the Carrera 4 enginecompartment badge, silver calipers, and a new design of 17" alloy wheels.

Great, thanks, so I just need to find somebody who can reflash with a MY 1999 version of the firmware and maps. MC

My C4 was registered 1998 with e-gas and no air-pump. The only reason I knew when I dropped the engine using Pelican parts blog. I could not find the 'elusive' air pump and assumed this was US emissions. Only later did I find this fitted to RoW in later cars. Whether there is a blank plug in the engine bay I do not know.

well above what i know about this but just a query .. maps = the running parameters of the individual sensors... these can be adjusted . Firmware or software is whats fitted . Would there be any other differences between the software from a 99 to a 2000 model that might be altered with a software change :?: ie something other than the SAI is what i'm wondering and this will stop working ... early cars have x1 cam sensor .. later and x2 .. will one stop working ?

Yes, I have done it to my MY2001. Wayne Schofield flashed the ECU when the car was being mapped. In removing the Secondary Air Pump, and using a different code, you can also lose two of the O2 sensors, I cant remember if they were pre or post, I can check if you like.