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Samba Member
Joined: November 19, 2017
Posts: 673
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 Posted: Fri May 26, 2023 6:08 pm Post subject: Best fuel pump for a 2.5 suby conversion |
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Any opinions?
Currently using an 03 mustang fp and am having issues
Thanks
T
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82 westy
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2.5 JDM Subie
Rear discs |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16508
Location: Brookeville, MD
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17155
Location: Retired South Florida
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| Posted: Fri May 26, 2023 6:16 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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Try running the pump and engine with the inlet hose in a gas jug. The 82 tank had a small outlet compared to later years. When comparing pumps, you compare flow values. From memory the Vanagon pump flows a quart in 15 second. That would be a gallon a minute times 60 for gallons per hour. The Bentley manual has the actual spec. Your ford pump should also be rated.
A Subaru 2.5 will run fine on a stock Vanagon pump with no restriction on the inlet. Later tanks have 12 mm tank outlets. Much better flow. Filler neck would need to be modified or upgraded to run the later tank.
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dobryan
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Joined: March 24, 2006
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Location: Brookeville, MD
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syncrodoka
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Joined: December 27, 2005
Posts: 12008
Location: Santa Cruz, CA
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| Posted: Fri May 26, 2023 7:18 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| Are you still running the little square box prefilter? |
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Samba Member
Joined: November 19, 2017
Posts: 673
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| Posted: Fri May 26, 2023 7:56 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| MarkWard wrote: |
Try running the pump and engine with the inlet hose in a gas jug. The 82 tank had a small outlet compared to later years. When comparing pumps, you compare flow values. From memory the Vanagon pump flows a quart in 15 second. That would be a gallon a minute times 60 for gallons per hour. The Bentley manual has the actual spec. Your ford pump should also be rated.
A Subaru 2.5 will run fine on a stock Vanagon pump with no restriction on the inlet. Later tanks have 12 mm tank outlets. Much better flow. Filler neck would need to be modified or upgraded to run the later tank. |
The specs I could find for the Ford fp was "minimum 21gph"
Not sure that helps
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82 westy
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2.5 JDM Subie
Rear discs |
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Samba Member
Joined: November 19, 2017
Posts: 673
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| Posted: Fri May 26, 2023 7:57 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| syncrodoka wrote: |
| Are you still running the little square box prefilter? |
No it's been replaced
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Rear discs |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50353
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| Posted: Fri May 26, 2023 10:44 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| dobryan wrote: |
| Mark how can the outlet size of the tank really make a difference in this situation? Say the engine is getting 15 mpg and going 60 mph. In one hour it needs 4 gallons. No way the tank outlet size is an issue delivering 4 gallons per hour. Am I missing something? |
The pump puts out much more flow than 4 gallons an hour, with the excess going back to the tank through the fuel pressure regulator. The pressure loss through the 7mm hose is enough to cause the pump to cavitate, especially when combined with the undersized white cube filter. When VW upgrades something as they design later models, its a good idea to follow suit on your earlier model as they needed a fairly major reason to make a change. |
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crazyvwvanman
Samba Member
Joined: January 28, 2008
Posts: 9940
Location: Orbiting San Diego
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| Posted: Sat May 27, 2023 1:44 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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Since his 2.5 conversion is a few years old it does it make sense that the size of the tank outlet is the cause of a recent problem?
Has the same tank been in there a while without this issue?
Mark |
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wesitarz
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Joined: August 20, 2012
Posts: 1491
Location: Victoria,B.C.Canada
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| Posted: Sat May 27, 2023 4:41 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| Are the Ford F250 or Mustang pumps made in China? I had a Bosch pump from Rockauto that worked fine. If the question is best pump then Pierburg? but I have no experience with it. |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50353
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| Posted: Sat May 27, 2023 5:25 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| There are several threads on problems with the earlier fuel systems. With my 83 1/2 I used to buy a six pack of the stupid little cube filters to take with me on long trips because the system was designed so poorly and then 8-10 years ago upgraded it to more closely resemble the later system and haven't had to change a filter since. |
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MarkWard
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Joined: February 09, 2005
Posts: 17155
Location: Retired South Florida
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| Posted: Sat May 27, 2023 6:53 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| dobryan wrote: |
| Mark how can the outlet size of the tank really make a difference in this situation? Say the engine is getting 15 mpg and going 60 mph. In one hour it needs 4 gallons. No way the tank outlet size is an issue delivering 4 gallons per hour. Am I missing something? |
Dave can’t say that it is a problem. The timing of VW going with the larger tank outlet seemed to coincide with the larger engine. VW also deleted the pre filter which is actually a good idea for an after filter that let any debris move through the pump. Not ideal.
The noisy pump, loss of power after a long drive, sitting on my phone, seemed like a fuel delivery problem. I’d bet the majority of the fuel through the pump or at least half returns to the tank.
Samba help is often. “This was my fix” “try this”. That is really not an efficient way to diagnose a problem. It’s best to use testing, deduction and elimination. My first suggestion was to verify fuel pressure and volume. Not to buy a tank or a pump. Carry on.
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Wildthings
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| Posted: Sat May 27, 2023 9:56 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| Fuel pumps have a larger inlet than outlet for a reason, why the German engineers chose to go with a smaller hose and an odd filter that acts as an adapter for two different size hoses is a mystery. Yes they got away with it on the FI'd Bays, but there the fuel tank sits noticeably higher than the engine apparently creating enough pressure to make the odd little cube filter work. While a prefilter is nice, it shouldn't be as fine as a filter on the pressure side of the pump can be as it makes the filter susceptible to high pressure drop and clogging. Bus Dept lists the same fuel pump for everything from a 1972 Super Beetle through the end of the Vanagon run, so all would be pumping pretty much the exact same amount of fuel. I imagine VW got a ton of negative feed back because of their engineering blunder on the early Vanagons and chose to correct it when they did the reengineering for the later Vanagons. |
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Crankey
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Joined: July 11, 2004
Posts: 2659
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| Posted: Sat May 27, 2023 10:36 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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It was recommended to me I get the larger outlet tank when I swapped in a 2.5 so I did. It's working fine.
Also recommend to go with the Bosch pump which I believe is original to my 85 and that also seems to be doing fine.
Pump does make a little noise but I was advised that, if it's working, keep it. I can't remember the location of the filter cause I haven't looked in a year but I do remember conversation about it.
I'm using an aeromotive fpr in the engine bay which I just happened to have as part of the previous engine swap. Everything fuel related, besides the pump and fuel regulator is new.
I took all these recommendations because the people doing the work have daily familiarity with this and I'm confident they didn't want me calling with a problem so I allowed them to do what they wanted, also if I forced them off their script they wouldn't be able to guarantee it.
These folks are vanaru installers, I chose that route because of I went diy the whole thing would still be scattered parts in the garage due to my tendency towards distraction, and the collection of parts in the package that I liked. |
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space
Samba Member
Joined: November 19, 2017
Posts: 673
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| Posted: Sat May 27, 2023 11:29 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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Thanks for all the ideas
Going with Bosch when I get back home
T
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82 westy
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2.5 JDM Subie
Rear discs |
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PJ Snow
Samba Member
Joined: June 24, 2018
Posts: 27
Location: Colorado
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| Posted: Sun May 28, 2023 4:05 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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My 2cents.
My 1980 with the stock tank and 2.5 Subaru motor made the fuel pump loud.
A new tank with bigger outlet made the fuel pump quiet.
I’m also running a pre and post pump filters.
I don’t have part #’s for the filters handy.
I would swap to a later model tank with the bigger outlet.
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syncrodoka
Samba Member
Joined: December 27, 2005
Posts: 12008
Location: Santa Cruz, CA
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| Posted: Sun May 28, 2023 6:04 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| Running a hayg walbro fuel pump in a ej22 van and it is silent. Ford ranger? fuel pump in my truck is silent. They are both syncro though so the fuel tank has the larger outlet. |
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R0ckyMtnCamper
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Joined: May 30, 2022
Posts: 97
Location: CO
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| Posted: Sun May 28, 2023 6:05 pm Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| I've been using a WIX 33299 just before the pump. |
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Nitramrebrab72
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Joined: November 10, 2018
Posts: 485
Location: France
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| Posted: Mon May 29, 2023 2:40 am Post subject: Re: Best fuel pump for a 2.5 suby conversion |
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| space wrote: |
Thanks for all the ideas
Going with Bosch when I get back home
T |
I have run the Magneti Marrelli VW Oem over 100k with early 8mm tank and a 8mm to 12mm wire mesh pre-filter.
The problems came when the square 8mm to 12mm pre-filters where incorrectly replaced with the fine paper filled filled as apposed to the original wire mesh pre-filter. Both look the same from the outside. |
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