Difference Between 997.2 and 991.1 Engine/Cup Electric Pump - Page 1 - Porsche General - PistonHeads UK

Does anyone know what the difference between the 997.2 and 991.1 Carrera S engine is, or know where I can find out? I see that the codes for the two engines are MA1.01 (997.2) and MA1.03 (991.1), according to Wikipedia. I'm interested in where the extra 15 PS come from that the 991.1 engine has. I know there was a switch to electric steering, so they got rid of the steering pump from the back of the engine. Were there any other major differences or was the rest it just from tuning? I'm interested because I'm wondering about putting an Cup car electric pump in my 997.2 and wondering what effect it would have. I did read someone guestimate that the steering pump might cost about 8-10 PS, but there was no supporting evidence. The people I've spoken to have said it wouldn't feel much different, but then why did Porsche get rid of them? I guess there was a bit of weight saving to be had, but I've heard it said also that the modern electric system it has is more efficient. My thinking is if the saving is 8-10 PS that's about half the gain you'd get from the power pack but it would hopefully be cheaper. Interested to know what anyone else thinks of my no-doubt crack pot scheme! Probably not interested in whether the current electric or hydraulic system is the best. That seems to have been covered at length elsewhere.

The later engine was completely new, and based around a number of significant changes, not least the switch to DFI. There's some useful info further down the first page here: https://www.pistonheads.com/gassing/topic.asp?h=0&... I've not had a 911 with either engine but I've had a few 987.2 with DFI engines. I found them very effective, with a broad range of torque and good economy, if perhaps a little more linear in power delivery than older models. Perhaps a touch less aural character too.

If you do decide to put a Cup car electro-hydraulic steering pump in your 997, remember it's from a Vauxhall Astra/Zafira and nothing Porsche specific.

Wasn’t the switch to DFI between the M97 in the 997.1 and the 997.2? The 997.2 has the MA1.01 (I’ve also seen it written as 91A engine)

Tripe Bypass said: If you do decide to put a Cup car electro-hydraulic steering pump in your 997, remember it's from a Vauxhall Astra/Zafira and nothing Porsche specific. Ha. Interesting!

oldmanskateclub said: Wasn’t the switch to DFI between the M97 in the 997.1 and the 997.2? The 997.2 has the MA1.01 (I’ve also seen it written as 91A engine) Sorry, you're right. I misread your post completely!

Tripe Bypass said: If you do decide to put a Cup car electro-hydraulic steering pump in your 997, remember it's from a Vauxhall Astra/Zafira and nothing Porsche specific. Do have experience using the electro-hydraulic system? Have you installed it? Just wondering if you had experience of a car before and after installation.

Hhmm, that does make sense. Would the electro-hydraulic system need to be powered up all the time though? It sounds like the reason McLaren use an electro-hydraulic system is that they can deliver more assistance at low speeds (i.e., when parking) and less at higher speeds https://www.motorauthority.com/news/1132438_hydrau... Wouldn't that mean the electric motor could be turned off/down at speed to reduce the energy cost? I suppose it would depend on the system used. Also, what benefit are the Cup cars getting from the pump? Was that because those engines didn't have belt-driven pumps to begin with?

The benefits for the Cup cars is a reduction in weight and mechanical complexity. If you’re wanting a performance increase on a 997.2, the DFi engine is very easily “de-restricted”, though doing so would invalidate any official warranty. The fitment of some high quality exhaust manifolds along with higher flowing, less restrictive 200 cell cats (still emissions compliant) a better flowing inlet plenum and a live remap would see 997.2 3.8 S motor produce power figures equal to, or better than the factory powerkit.

oldmanskateclub said: Tripe Bypass said: If you do decide to put a Cup car electro-hydraulic steering pump in your 997, remember it's from a Vauxhall Astra/Zafira and nothing Porsche specific. Do have experience using the electro-hydraulic system? Have you installed it? Just wondering if you had experience of a car before and after installation. Back in the Olden Day Times I was an engineer at TRW Steering Systems when they supplied the steering for the 986/996/987/997 platform and a lot of GM platforms. I just remember that they used the EPHS from a Zafira/Astra T3000 platform for the steering pump for the Cup cars. It moves the pump from the engine bay to the front boot/frunk so doing away with most of the pipework and the EPHS is slightly more efficient. As a mod to purely increase performance it's not worth doing although Malcolm Wilson Motorsport wanted to know if we could do a feasibility study for their rally Fiestas. I'm pretty sure Slippydiff himself owned and built Zanzicup, a 996 GT3 that was heavily modified, including the EPHS mod.

Yes, it's really great info. Thanks!

Slippydiff said: The benefits for the Cup cars is a reduction in weight and mechanical complexity. If you’re wanting a performance increase on a 997.2, the DFi engine is very easily “de-restricted”, though doing so would invalidate any official warranty. The fitment of some high quality exhaust manifolds along with higher flowing, less restrictive 200 cell cats (still emissions compliant) a better flowing inlet plenum and a live remap would see 997.2 3.8 S motor produce power figures equal to, or better than the factory powerkit. Any ideas on who does 200 cell cats for the 997.2 seems to be a loads for the gen 1 but haven't seen any gen 2 ones (I assume that's because they are fitted to the manifolds).

Halfway down the thread, you may find it useful http://911uk.com/viewtopic.php?t=134930&postda...

oldmanskateclub said: Do have experience using the electro-hydraulic system? Have you installed it? Just wondering if you had experience of a car before and after installation. This was a popular mod on modded 964s a few years ago https://rennlist.com/forums/964-forum/1235844-diy-...