[Brule]

Been testing and logging for a few years. Some of my results didnt line up with vendors and know it alls.

Heres the reality of lpfp upgrades. If you dont have port injection just get 1 pump.

A $100 lpfp will pump enough fuel for you hpfp to crash. You can make a bit more power if you mix e60 or e40 ect but really it is bugger all.

Dont bother buying a dual pump "Stage 3" if you dont have port injection or a hpfp upgrade.

Its really a waste of time and wont give you anymore power.
I had a walbro 255 inline pump for 5 years sitting for periods of time with ethanol in the tank. Mostly e40 mixes for 4 years. It kept pressures up on the lpfp side and outdid the hpfp on e40 mixes. Running rb evos 22 psi on e40 the hpfp would dip into 1300ps at peak torque.

I dont suggest installing a walbro 255 although it served me well but simply putting a walbro 450 or ti274 in thats e85 rated is all 90% need.


All these setups without pi have made very similar power of around 550hp au or 750 hp on a usa dyno. lol joking, not really.
Around 550hp.


E40 rb evos 22psi inline 255 - lpfp holds pressure, hpfp 1300psi dips at peak torque

E60 6266 17psi walbro 1/450/ti 274 lpfp dips 5 psi, hpfp 1200psi dip peak torque
E60 7675 17psi walbro 1/450/ti 274 lpfp dips 5 psi, hpfp dip 1100psi peak torque
(estimated e60 as my fuel it pos bluetooth ethanol sensor doesnt mc fn work)

Adding the 2nd walbro 450 didnt improve the hpfp or any power.

Just testing the past few weeks on sigle turbo was easy to see this proven.
1 lpfp TI 274 will hold 70 psi and drop 5 psi at peak torque.
At the same time the hpfp will drop to 1100psi peak torque.

Today i literally did the above log, pulled over seen the lpfp dip so I plugged the 2nd lpfp Ti 274 in and did another log.
Lpfp stays at 70psi the whole pull. Hpfp still dips 1100psi.

My suggestion if upgrading your fuel system is to keep it simple. If you do not have port injection or intend to just install 1 walbro 450 or ti274. This will out flow your hpfp on e85 and pump fuel.


Enjoy your isolation time!

[Aus335iguy]

Thanks Brûlé I reckon some just like adding a second pump for peace of mind

[Socket]

Great info
Thanks for sharing Brule

Wish this was available before dropping all that cash on my stage 3

[Brule]

You have a spool hpfp.
Wring its kneck make some power.