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Walbro 255l/h Vs Bosch 044 200l/h

boosted_32

By boosted_32,
in Engines & Forced Induction

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boosted_32 Proficient

boosted_32

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Ok as im sure every one knows theres a big debate on wot pumps are better! one thing that my brain still can get around is how some people say that there walbro 255l/h pumps start to max out at 250-280kw but on the other hand ive seen many dyno charts of 300-400kw with the bosh 044 but wot I dont understand is how the bosh 044 which pumps out 200l/h can handle a shit load more then a pump that pushes out 255l/h shouldnt it be the other way round?

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Jmaac Proficient

Jmaac

Posted
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Depends which series walbro pump but generally bosch units are better. If you put them side by side the bosch units are physically bigger. I've seen current/voltage vs flowrate comparisons and walbro's generally drop off and top end, unlike the bosch units

boosted_32 Proficient

boosted_32

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so the walbro and bosch where running the same current and the walbros where dropping off top end is that right? you may be able to help me out do you think a bosch 023 intake could handle 300-300kw? I think they flow 168l/h there the biggest intake style pump bosch make?

Sydneykid Grand Master

Sydneykid

Posted
Posted
Ok as im sure every one knows theres a big debate on wot pumps are better! one thing that my brain still can get around is how some people say that there walbro 255l/h pumps start to max out at 250-280kw but on the other hand ive seen many dyno charts of 300-400kw with the bosh 044 but wot I dont understand is how the bosh 044 which pumps out 200l/h can handle a shit load more then a pump that pushes out 255l/h shouldnt it be the other way round?

Bosch 044 is rated for 200 l/h @ 72.5 psi

Walbro is rated at 255 l/h @ 36 psi

Say you are running 20 psi boost and standard fuel pressure (38 psi), meaning 58 psi in total.

The 044 will deliver MORE than 200l/h because it is running at LESS than its rated pressure

The Walbro will deliver LESS than 255l/h because it is running at MORE than its rated pressure

It's the same problem as the stupid "500 hp fuel pump" rating, 500 hp in an N/A engine is NOT the same as 500 hp in a turbo engine running 20 psi boost.

Cheers

Gary

rob82 Mentor

rob82

Posted
Posted
Depends which series walbro pump but generally bosch units are better. If you put them side by side the bosch units are physically bigger. I've seen current/voltage vs flowrate comparisons and walbro's generally drop off and top end, unlike the bosch units

Its more to do with the pressure. Bosch pumps typically have higher flow rates at higher pressures than the walbro's that the difference.

THis is the problem with the industry - there isn't enough info. You really need to plot flow rate vs pressure to compare pumps.

The other is injector flow rates - as some injectors are rated at 3bar some are 4bar and so. For proper injector selection you also need to know dynamic flow rates at different frequencies.

boosted_32 Proficient

boosted_32

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Bosch 044 is rated for 200 l/h @ 72.5 psi

Walbro is rated at 255 l/h @ 36 psi

Say you are running 20 psi boost and standard fuel pressure (38 psi), meaning 58 psi in total.

The 044 will deliver MORE than 200l/h because it is running at LESS than its rated pressure

The Walbro will deliver LESS than 255l/h because it is running at MORE than its rated pressure

It's the same problem as the stupid "500 hp fuel pump" rating, 500 hp in an N/A engine is NOT the same as 500 hp in a turbo engine running 20 psi boost.

Cheers

Gary

cheers mate, makes more sence when you lay it out they way you did

DECIM8 Grand Master

DECIM8

Posted
Posted

I understand all the above but how do we know how much fuel we will neeed p/h??

For example a 2.5L Neo running 15psi with a walbro pump? Can we work out how much fuel that engine would need prior to buying a pump?

I assume it will always be better than stock?

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Mate you asked the question, and has the appropriate responses not even a week ago.

Please READ what people post.

http://www.skylinesaustralia.com/forums/Wa...55-t204507.html

The posts in this thread are not going to be any different or less confusing as they are saying the same thing...

The Graph from The Mafia clearly explains whats going on without even having to type it.

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