Technical Options for a new LPFP? Stock one is getting weak....

NoGuru

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From what I've gathered......you only starve the bucketless setups if you are doing hard cornering.....not straight line acceleration. Must be the placement of the pump or something??
I can't comment on that because I don't have facts or Data. What I can say is if you take out the fuel pump and look, you will see the pump at the front of the tank so if this way true, drag racing it would starve it for fuel.
I can drive until my fuel light comes on (only done it a few times) with no issues.

That said, I do the the bucket is better but only marginally.
 

martymil

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I don't see the desire to run bucketless. The cons seem to outweigh the pros...

Just add another 450 pump and FPR and you will have more fuel that you will ever likely need(875whp on 100% E85). Look at the cost of hydramats $200 each.

Edit: There is a reason basically every vehicle manufacturer for the last 30+ years has used a bucketed design.

From PR:

Stage 3 (4.3 gallons per minute)
Our Stage 3 bucketed fuel pump includes all necessary wiring and pump activation switch (hobbs switch). This pump boasts dual Walbro 450 (F90000274) fuel pumps and can support up to 1000whp* (Rated for 875whp on 100% E85) and is ready to grow with you as your needs demand. With a modular plug and play design this kit can be upgraded with our Stage 3.5 or Stage 4 module and have everything you need to match your future horsepower goals.

While all bucketless fuel pumps flow .2gpm more than a bucket design that retains the venturi it comes at a cost. Bucketless pumps should not be driven on tanks lower than ¼ full and should not be used for road course racing. This is not a disadvantage of only bucketless designs but also a disadvantage for any bucket design which deletes the venturi. If you do not plan on road course racing (not street racing) and are responsible at maintaining ¼ tank of fuel during spirited driving bucketless pumps can be a cheaper alternative for you.

A single bucketless pump flows around 20% more than a bucketed one.

From my calculations the 535 bucketless pump should flow around 75% capacity of twin 450s

Two pumps only flow 0.2 less than bucketed because the rest of the fuel system is the restriction.

Two pumps at full blast will draw around 30 to 40 amps and 1 a max of 18 to 19 amps.

1 pump puts far lest heat into the fuel too.

A single pump is more than ample for most people, can be built for under 500 to 600 usd with hydramat and is a simple drop in solution.

Its also totally and extremely easy to rebuild and upgrade unlike a bucketed setup.

At the end its your car and choice, but there are lots of advantages to bucketless.
 
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martymil

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The reason for fuel starvation on a standard buckeless setup is because the size of the pickup mat, increase the size like i did and problem solved.

Also placing the venturi balance tank line to feed directly onto the hydramat will ensure a good source of fuel and reduce or to go as far to say eliminate any starvation issues

The reason I designed this system for myself is because it was far cheaper than fixing my stage 3 pump and is more than ample for 95% of users.

If you a serious devoted track junkie you should look into a proper racing setup from radium and not rely on a modified and hacked bmw bucket.
 

houtan

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Yep...that looks like a pretty easy way to still use the venturi. Are those plastic dorman fittings ethanol compatible? I get nervous when you start using plastic fittings if you don't know what they are rated for.

I'm still trying to get a feel for how bad an open bucket system really is........
Had a chat with them. Yes it is e85 compatible 👍🏽
 

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IQraceworks

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Had a chat with them. Yes it is e85 compatible 👍🏽

Good to know!!

At this point.....I have all the parts to either do a bucketless setup with no Venturi....or keep the bucket intact and plumb in the Venturi. Both will be very clean installs (thanks to the fittings you found on Amazon).......just need to figure out which way to go.

I will be doing the install next week.....just need to decide on bucketless with the Venturi.....or cut the bottoms out and use no Venturi.....
 
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IQraceworks

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Had a chat with them. Yes it is e85 compatible 👍🏽

Any ideas on how to restrict the flow to the venturi? I don't think that venturi needs all of the extra fuel flow and pressure that the Walbro 450 puts out. I wonder if some some of restricter could be put inline? That would also help to not take as much fuel from the main output line?

Just thinking out loud......
 

IQraceworks

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What about all the companies out there "tuning" the Venturi in order to reduce the flow with the bigger 450 pumps? I'm assuming they do that for a reason.
 

martymil

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Put a bigger single pump in like the 535 or two 450 without complicating everything, problem solved.

The venturi is not a problem but the actual hat.
 
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Torgus

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Put a bigger single pump in like the 535 or two 450 without complicating everything, problem solved.

The venturi is not a problem but the actual hat.

I agree. I still think two 450s in a bucket is the way to go vs a single 535 bucketless with a large hydramap but agree to disagree ;)

Both get the job done.
 
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martymil

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Dude what ever works, if I can get away using 1 pump and the fuel pressure doesn't drop in all situations why would I run 2 pumps.

Like I always say ypur car your choice I'm just providing an alternative and not.pushing my choices and opinions onto others.
 

Torgus

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it's me again ...
there is a tutorial for the assembly of two 450 ?

PFS can help you:


Shoot an email over to [email protected]
 

N54TT

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I recently went with the BMP Stage 2 bucket less LPFP. Installation was straight forward and simple. The only thing you have to do is trim the bottom of the hat, but that was easy with a dremel. My car does run a lot smoother it was obvious my low pressure pump was weak.
 

houtan

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PFS can help you:


Shoot an email over to [email protected]
Thanks for this. Didn’t know it existed. Seems like a very clean and affordable way to upgrade. If you go the dual walboro setup, some sort of activation switch is required right? Like a hobbs switch?
 
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Torgus

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Thanks for this. Didn’t know it existed. Seems like a very clean and affordable way to upgrade. If you go the dual walboro setup, some sort of activation switch is required right? Like a hobbs switch?

Yes their dual pump has it optional: Optional Wiring Kit w/Hobbs Switch
 
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IQraceworks

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I recently went with the BMP Stage 2 bucket less LPFP. Installation was straight forward and simple. The only thing you have to do is trim the bottom of the hat, but that was easy with a dremel. My car does run a lot smoother it was obvious my low pressure pump was weak.

Any issues with fuel starvation while cornering hard? I'm still going back and forth between keeping the bucket and Venturi....or just ditching the Venturi and cutting the bottom out of the bucket. I should have time to get to it here in a few days.
 

N54TT

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Any issues with fuel starvation while cornering hard? I'm still going back and forth between keeping the bucket and Venturi....or just ditching the Venturi and cutting the bottom out of the bucket. I should have time to get to it here in a few days.

My freeway on-ramp I use is a hairpin and at times i take the entrance at a faster rate and i did it the other day with a little less then a 1/4 tank and did not feel any sort of fuel loss or hesitation on the throttle.
 

fmorelli

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Hopefully I'll have some decent data by the end of the month
Hoping to hear more on progress. We have an E90 track car in flight and I believe the setup you are working to validate would be an effective solution.

Filippo