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post #1 of 97 (permalink) Old 04-28-2011, 06:34 PM Thread Starter
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Best fuel pump for SPICA?

My fuel pump is on its last legs, and from what I hear these are parts that need replacing periodically. I'm making my way thru a full rebuild and starting to think about what I'll use to replace it.

IAP has a bosch pump for $200 Alfa Romeo, Fiat and Lancia Fuel Pumps

Centerline sells a Hella replacement for about the same - are there high pressure concerns with this setup? http://centerlinealfa.com/cgi-local/...87d+1319063189

But Spruell has dire warnings about this setup, claiming the lack of internal regulation can lead to high pressure in the hoses. I thought the fuel pressure sensor/return valve handled this? FUEL PUMP KIT For all Spica Injected cars 1969 to 1981 - Spruell Motorsport, Inc - Performance and Your Store for Sports Car Performance and Racing Parts

Then there is some talk about using generic pumps - can anyone share their experience with any of these 3 options?

Last edited by r-mm; 04-28-2011 at 06:42 PM.
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post #2 of 97 (permalink) Old 04-29-2011, 10:55 AM
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The primary method that the Spica system uses to regulate fuel pressure is the outlet restrictor on the front fuel fitting on the injection pump. This small hole allows excess fuel to be routed back to the tank. The hole is sized to have about 15 psi on the higher pressure side of the system, even with a pump like the L-Jet Bosch pump. In the case of the Spica system pressure higher than 17 psi is completely unnecessary and in fact detrimental. The system is designed for between 10 and 17 psi.

That said, the secondary safety relief is different depending on the model year. Up through the 74 model year the front fuel filter had a Pressure Relief valve (set at 17psi) intergral in it. The 75s and later used a 3-port Bosch supply pump that had it's own PRV in it. Hence on the 75s and later, the front fuel filter did NOT have a PRV.

Hence, if you have a car that was fitted with a 3 port pump and substitute a 2 port pump, you have no safety PRV. Is that a problem? Well, it might be if you deadhead the pump somehow by pinching off a fuel line, causing the pressure to go up to the supply pump's capacity. Under normal operation with the outlet restrictor, the pressure should stay at 15 psi or so. Anytime you sub a different pump from the original (which is about ALL the time now since the originals are NLA), you should check the exact fuel pressure to be sure you're in spec. It may require you (as in the case with the L-Jet supply pump subs) to solder up the restrictor hole in the outlet fitting, and redrill it to 1/16th inch. This is because the capacity of the L-Jet pump is slightly less than the original OEM pumps, although still adequate the Spica system.

That said, I certainly recommend that there be a safety PRV in the system, even though most fuel hoses can take the pressure. That's as simple as getting a used front fuel filter (with an integral PRV), and fitting it to the car. It's a drop in replacement for the current one, with the exception that you'll need to cut the rubber return line and connect it up to the PRV ports on the fuel filter.

See the Fuel System guide you can download free from Ingram Enterprises, Inc. || Spica Pump Rebuilds

As far as suitable substitute pumps, some people have used the Master E2000 generic pump available in US auto parts stores. Otherwise, the L-Jet supply pump is a good subsitute as well. It's important however, that the pump have about a .6 gallon per minute unrestricted fuel capacity flow to provide adequate cooling to the injection pump (cooled by recirculated fuel).

John Stewart
74 Spider
91 164S

Last edited by Roadtrip; 04-29-2011 at 11:02 AM.
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post #3 of 97 (permalink) Old 04-29-2011, 11:42 AM Thread Starter
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Quote:
Originally Posted by Roadtrip View Post
The primary method that the Spica system uses to regulate fuel pressure is the outlet restrictor on the front fuel fitting on the injection pump. This small hole allows excess fuel to be routed back to the tank. The hole is sized to have about 15 psi on the higher pressure side of the system, even with a pump like the L-Jet Bosch pump. In the case of the Spica system pressure higher than 17 psi is completely unnecessary and in fact detrimental. The system is designed for between 10 and 17 psi.

That said, the secondary safety relief is different depending on the model year. Up through the 74 model year the front fuel filter had a Pressure Relief valve (set at 17psi) intergral in it. The 75s and later used a 3-port Bosch supply pump that had it's own PRV in it. Hence on the 75s and later, the front fuel filter did NOT have a PRV.
.
Thanks for the comprehensive reply.

So for a 73 car with a front mounted PRV, are there any outlet restrictor mods necessary to either the L-Jet or generic .6 GPM pump?
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post #4 of 97 (permalink) Old 04-29-2011, 12:22 PM
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Maybe. For instance, my 74 when I bought it had an original Bosch 2 port pump (not the same as the L-Jet substitute pump you get now). When I installed a Bosch L-Jet supply pump, the fuel pressure was a little low, so I narrowed the restrictor (per guidance from Wes Ingram). I determined that the fuel pressure was low because, after installing the new pump, I'd get an occasional low pressure warning light under high engine demand.

Some people have installed an L-Jet pump and had to do nothing to the outlet restrictor. YMMV.

As long as the low pressure warning light is working correctly, and it does not come on with the engine running, fuel pressure is sufficient (>7 psi). If you use some other kind of pump, I'd highly recommend that you check the actual fuel pressure in the system to be sure it falls in the 10-17 psi range. You really don't want it much past 15 psi because you really don't want the pressure relief valve to be constantly open. If you find that the fuel pressure is right at 17 psi (relief valve open), I'd widen the restrictor ever-so-slightly to bring it down below the relief threshold.

BTW, with the 1/16" restrictor and the alternator charging the battery (higher than normal 12v battery voltage), my fuel pressure is running about 13-15 psi. That's perfect. Keep in mind to that the electric supply pumps are VERY sensitive to under voltage. Even slight under voltage will seriously affect output volume/pressure. Old dirty wiring and terminals can decrease voltage to the pump even if the battery and alternator are good. Check wiring for good condition and terminals clean and tight.

All that said, there is one retrofit that you should make to your fuel system. Install an inertial cutoff switch. In the case of an collision, you want the fuel system to stop pumping fuel and remove electrics from the pump. Inertial switches were fitted to later models. Just about any generic inertial switch will work. I think the one I have was sourced from an later model MGB. In any case, Larry at Alfa Parts Exchange probably has a boxes 'em sitting around.

John Stewart
74 Spider
91 164S

Last edited by Roadtrip; 04-29-2011 at 12:39 PM.
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post #5 of 97 (permalink) Old 07-26-2011, 05:28 AM Thread Starter
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Master E2000

Hey Roadtrip

Just getting around to the fuel pump while I have the rear suspension fully dissembled. I looked up the Master E2000 and found this: Airtex Master/Fuel Pump (E2000) | AutoZone.com

the Max flow rate is .66 GPM (good), but the Max and min PSI are listed as 95 and 70?
Am I misreading these numbers?

I've read elsewhere on the BB that this pump works for SPICA alfas, but I'm not sure how to read those stats.
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post #6 of 97 (permalink) Old 07-26-2011, 10:00 AM
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If I were replacing a fuel pump, then I would certainly get one from an Alfa specific supplier. That is one part you want to work 100% correctly.

Don Sanders - 1977 Spider
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post #7 of 97 (permalink) Old 07-26-2012, 07:07 AM Thread Starter
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The Bosch universal pump is on sale at IAP for $140. Bought one and will report back when I have it hooked up (won't be soon...)
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post #8 of 97 (permalink) Old 12-22-2012, 08:17 AM
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r-mm,

Did you ever get the fuel pump hooked up? Does anyone else have any info on replacement fuel pumps for my 1981 Spica Spider?

Thanks

1989 Alfa Milano (Daily Driver)/1981 Alfa Spider (Current Project)/1987 Alfa Spider (RIP)
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post #9 of 97 (permalink) Old 12-22-2012, 08:40 AM Thread Starter
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If only...

Its sitting in my garage. I'm making a serious push to have the car on the road for June so I'll report back
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post #10 of 97 (permalink) Old 12-22-2012, 08:59 AM
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Wow, that is an excellent price at $81! I used a $106 variant, the MSD Ignition 2225 - MSD High Pressure Electric Fuel Pump. Available at both Summit and Jegs. But next time, I'll buy that one.

Stefano
Concord, CA
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post #11 of 97 (permalink) Old 04-11-2013, 11:11 AM
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alternative

I spoke to Airtex and tech suggested the E8094. $92 off ebay and I'll let you know how it works out.Max 15psi and 50 gallons per hour. I still plan to measure the return pressure after a trip to Harborfreight for a pressure gauge.
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post #12 of 97 (permalink) Old 04-11-2013, 01:54 PM
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Max 15 psi and 50 gph might be a little light. Remember, the pressure is regulated not by the pump, but the restrictor in the outlet fitting of the injection pump. The OEM supply pumps were capable of producing much higher pressure (50+ psi) but were regulated down by the restrictor.

What you don't want to do is deadhead the supply pump into the injection pump. The excess pressure/fuel is used to cool the injection pump.

John Stewart
74 Spider
91 164S
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post #13 of 97 (permalink) Old 04-11-2013, 02:44 PM
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Roadtrip,
Don't you want the pressure to be 17 psi so the PRV opens and then lets the excess fuel cool the injection pump? If it stays below 17 psi, (for whatever reason, the pump specs, or you have widened the restrictor) then fuel won't flow back to the tank.

What do I know? not much, just asking, 'cause I always have 17-18 psi as measured downstream of the Bosch pump, (and before the front fuel filter) I got from IAP about a year ago.
Although, I haven't measured psi downstream of the injection pump, and before the filter again.
Bill

Series 1 Euro GTV - a long time ago when I lived in Italy, US Navy 1985-86.
Series 2 USA 2000 Spider Veloce - current. - - - AROCSC - - -
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post #14 of 97 (permalink) Old 04-11-2013, 03:14 PM
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Bill - No. The PRV on the '74 and earlier cars is a safety valve only. Ideally it should never be needed or used. And remember, it's in the front fuel filter before the fuel gets to the injection pump, so if the PRV opens, the fuel is sent right back to the tank before it even gets to the injection pump. The fuel pressure is regulated by the size of the hole in the outlet fitting (restrictor) of the injection pump. Ideally, with the alternator providing voltage, you'd like to see 10-15 psi or so. You want the vast majority fuel flowing THRU the injection pump (excess to the engine demand) and back to the tank . . . recirculating system.

On later cars, the PRV was integral to the three-port Bosch pumps. When retrofitted, there is no PRV anymore, except for a high pressure one inside the supply pumps (much much higher than the Spica 17 psi spec).

After the injection pump in the return line, pressure will be very very low if any measurable at all. Where you want to measure input pressure is between the front filter and the injection pump inlet.

John Stewart
74 Spider
91 164S

Last edited by Roadtrip; 04-11-2013 at 03:18 PM.
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post #15 of 97 (permalink) Old 04-11-2013, 03:38 PM
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Thanks. I am re-studying the Wes Ingram fuel guide, pages 10 and 11.
I will relocate my "T" fitting per your note and Wes' guide.
I have a feeling I will have to widen the restrictor.

I wonder John, could excess fuel pressure at the PRV, before the injection pump, cause a little fuel starvation to the pump itself?

Series 1 Euro GTV - a long time ago when I lived in Italy, US Navy 1985-86.
Series 2 USA 2000 Spider Veloce - current. - - - AROCSC - - -
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