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CIS Fuel pump for EFI?
I can't seem to locate the specs for the OEM fuel pump in my '81. Is it adequate for an EFI system, or should I be budgeting for a replacement?
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04-14-2023, 07:15 AM
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Location: mt. vernon Wa. USA
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pump
I set the fuel pressure to 40 psi and have found the CIS pumps to work fine.
 
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[B]Current projects: 69-911.5, Previous:73 911X (off to SanFrancisco/racing in Germany).77 911S (NY), 71E (France/Corsica), 66-912 ( France), 1970 914X (Wisconsin) 76 911S roller..off to Florida/Germany RGruppe #669 http://www.x-faktory.com/ |
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04-14-2023, 07:31 AM
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CIS lives from fuel pressure. So the system pressure has to be close at 5bar or a little more. They deliver up to 200l/min as shown with the 044. Don't know which EFI you have but afaik EFI need only 2.5-3 bars pressure in general with way lower delivery rates. So any of the CIS pumps might be too strong and delivers too much fuel. I would choose a smaller one, first refer to the specs of your EFI system.
Thomas
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1981 911 SC Coupé, platinum met. (former tin (zinc) metallic), Bilstein shocks, 915/61,930/16,WebCam20/21, Dansk 92.502SD,123ignition distributor with Permatune box as amplifier,Seine Systems Gate Shift Kit,Momo Prototipo. Want to get in touch with former owners of the car. Last registration in US was in 2013 in Lincolnshire/lL. |
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04-14-2023, 07:51 AM
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 Current pump ^ I figured an FPR would take care of any excess pressure.
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04-14-2023, 08:00 AM
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I wrote last night in this thread some more info about the SC / CIS fuel pumps:
https://forums.pelicanparts.com/porsche-911-technical-forum/1104838-bosch-69466-length-vs-oem-fuel-pump.html#post11972568 The shown Bosch 0 580 254 967 / Porsche no. 911 608 102 02 (starting from 1980) & the 911 608 102 00 (used on earlier SCs up to 1979) are (as the Porsche parts catalogue for the 911SC says) both replaced by the Bosch 0580 464 126, link to its datsheet here. Yes - the pressure regulator will take care of any excess pressure. But - I don't know how long it lasts while operating at double the pressure and fuel amount... As always: See what the tech. specs of your EFI says... Thomas
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1981 911 SC Coupé, platinum met. (former tin (zinc) metallic), Bilstein shocks, 915/61,930/16,WebCam20/21, Dansk 92.502SD,123ignition distributor with Permatune box as amplifier,Seine Systems Gate Shift Kit,Momo Prototipo. Want to get in touch with former owners of the car. Last registration in US was in 2013 in Lincolnshire/lL. Last edited by Schulisco; 04-14-2023 at 08:30 AM.. |
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04-14-2023, 08:12 AM
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Quote:
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04-14-2023, 08:28 AM
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Fuel pressure regulators, with a fuel return, regulate the system pressure/flow (out to the injectors) and route the rest back to the tank.
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[B]Current projects: 69-911.5, Previous:73 911X (off to SanFrancisco/racing in Germany).77 911S (NY), 71E (France/Corsica), 66-912 ( France), 1970 914X (Wisconsin) 76 911S roller..off to Florida/Germany RGruppe #669 http://www.x-faktory.com/ |
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04-14-2023, 09:26 AM
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Have the stock CIS fuel pump on my 79 EFI conversion going on several years now with no issues whatsoever. As others have said, the fuel pressure regulator sets the pressure. I also have it set at 40 psi.
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1979 SC, Slant nose wide-body cab conversion. AEM Infinity EFI, COP, supercharged! |
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04-14-2023, 12:13 PM
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My car runs on a Megasquirt with a stock fuel pump and a regulator set to around 35psi. It’s all good, you’ll be fine.
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'80 SC Targa Avondale, Chicago, IL |
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04-14-2023, 07:16 PM
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Quote:
Quote:
In other words, you could use a pump originally specified for used with CIS with carbs instead, given a regulator with a suitable setting.  Bosch started a "universal fuel pump program" around the turn of the century - rationalizing/obsoleting many obscure pump types - like the ones originally fitted by Porsche. Might need to futz with fittings and/or electrical terminals. The 044 was generally much cheaper (economies of scale - due to being widely used in Motorsport) and a better performing replacement with higher specifications than almost all of the original Porsche pumps. The 930 rear pump, for example, was nearly $700 decades ago - but the 044 out-performed it massively and was readily available much cheaper. I paid $120 for mine in 2006... Even the 044 has been obsoleted since https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/1110321-bosch-fuel-pumps-0580-464-200-versus-0580-254-044-a.html
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'77 S with '78 930 power and a few other things. Last edited by spuggy; 04-15-2023 at 10:13 AM.. Reason: Bah, wrong link for 044 replacement - corrected |
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04-15-2023, 10:09 AM
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Porsche 911 SC
