SR20det fuel system

[mgbsr20det]

Hi all, I have a SR20det in a MGB roadster current setup is

Gt2871r
Nizmo 740 injectors
External FPR
walbro 255 inline pump
As well as other supporting mods
Stock engine
Currently 11psi and 210rwhp

I’m getting it retuned this Friday on e85 and more boost . The tuner said I need another fuel pump. I have a spare Bosch 044 (new) can I install this in tandem with the walbro 255 and will this be sufficient ? Also are the standard fuel lines big enough I’m guessing they are 5/16”.

Thanks steve


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[5280VertDET]

Is the the whole system ready for E85? Current fuel pump, injectors, injector o-rings, fuel lines, fuel filter(?), etc...

If so, then I would go with a E85 compatible 320LPH pump from DW, Walboro or AEM(?) EDIT: Aeromotive.

[mgbsr20det]

Yes all ready except for the fuel pump atm , tuner did suggest my injectors May be too small also so I’m looking to upgrade them too hopefully intime, my main issue is sorting the fuel system. I did a lot of research last night regarding two in-line pumps looks like it will be sufficient. Has anybody done this to confirm it is sufficient?


Fuel Tank > walbro 255 > Bosch 044 > filter > fuel rail > fpr


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[jedi03]

I see it a lot locally...a good idea I have never done myself but have coworker who has...just add second set of injectors for the extra fuel...

[TheRealSy90]

Why not just get rid of the walbro 255 and use the Bosch 044 only. The 255 is going to choke out the 044 pump.

Also you're going to want at LEAST 1000cc injectors if not larger.

[gaz_moose]

or add a swirl pot between your pumps with the fuel rail return plumbed into it.

[mgbsr20det]

Originally Posted by gaz_moose

or add a swirl pot between your pumps with the fuel rail return plumbed into it.

That would mean I would only be using the 044 as the 255 would only be working to fill the swirl pot


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[mgbsr20det]

Originally Posted by TheRealSy90

Why not just get rid of the walbro 255 and use the Bosch 044 only. The 255 is going to choke out the 044 pump.

Also you're going to want at LEAST 1000cc injectors if not larger.

I don’t think the 044 alone will be enough , with the help of the 255 it should be sufficient (I hope)

From what I have researched the 255 shouldn’t get choked but the 044 . I’ve been googling it for hours and seems quite effective

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[LoSt180]

How much flow do you need? Better option would be to just upgrade to a single pump that has the flow volume you'll need. DeatschWerks actually has a few calculators you can use to double check everything. https://www.deatschwerks.com/fuel-calculators

For example, 4x 740cc injectors with 43psi base pressure can only put out 178LPH. So your Walboro 255 is plenty.

As a comparision; 1000cc injectors will flow 240LPH. At that point, an upgraded fuel pump would be needed to give you more of a safety buffer.

740cc injectors are good for 390 crank HP on E85, but that's running at 90% duty cycle. 1000cc injectors limited to 80% will support 470hp.

A DeatschWerk DW300 would give you plenty of fuel capacity for whatever fuel type you decide to run.

[ultimateirving]

Ive ran my WB255 on e85 with 850cc injectors, boost @18psi and had no issues but Arizona changed the blend in the last few years so e85 is no longer available. Back to 91 for now until i can retune.

[S14rebuild]

Bosch 044 n 1000id injectors...crank that boost!