Fuel Pressure dropping while under boost
Drifting
Joined: Aug 2008
Posts: 1,399
Likes: 30
Probably just a mistake putting the regulator that high but at least it caused him to dump the crap pump and get something that works.
Thread Starter
Advanced
Joined: Oct 2016
Posts: 72
Likes: 2
From: Calgary Alberta
That picture was the first tune. We have set the fuel pressure at 55psi and still having the issue with the pump running lean after it been running a long time. Either way the Walbro 450 still hasn't gone lean after a long time running.
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Melting Slicks
Joined: Jul 2004
Posts: 2,844
Likes: 144
From: Northern Ireland
Drifting
Joined: Nov 2014
Posts: 1,979
Likes: 110
From: Switzerland
well, i thought i would mention it. post #1 showed a pressure of 72 psi base and 85 psi max. i dont think that is anything extraordinary.
on the topic of "stupid high fp": when the fuel systems used to run 3 bars (or 2.5 bars) i would set up my cars to run at 4- 4.5 bars. the atomisation is better at these levels, keeping in mind that around 6 bars the injectors stopp working. so if you then run say 1.5 bars of boost you end up with 90 psi fp max. its not much different on a referenced ls1. and a pump upgrade yields around 65 psi at idle returnless anyway.
of course you need a pump supporting that and if you dont find one in the walbro catalog, dont despair, there are plenty of unexpensive pumps that will support 6-8 bars. i preferred to use bosch pumps for the ke-jetronic in audis. those systems ran 6 - 6.5 bars stock.
on the topic of "stupid high fp": when the fuel systems used to run 3 bars (or 2.5 bars) i would set up my cars to run at 4- 4.5 bars. the atomisation is better at these levels, keeping in mind that around 6 bars the injectors stopp working. so if you then run say 1.5 bars of boost you end up with 90 psi fp max. its not much different on a referenced ls1. and a pump upgrade yields around 65 psi at idle returnless anyway.
of course you need a pump supporting that and if you dont find one in the walbro catalog, dont despair, there are plenty of unexpensive pumps that will support 6-8 bars. i preferred to use bosch pumps for the ke-jetronic in audis. those systems ran 6 - 6.5 bars stock.
Last edited by romandian; Jun 15, 2017 at 03:31 AM.
Drifting
Joined: Nov 2014
Posts: 1,979
Likes: 110
From: Switzerland
well, i thought i would mention it. post #1 showed a pressure of 72 psi base and 85 psi max. i dont think that is anything extraordinary.
on the topic of "stupid high fp": when the fuel systems used to run 3 bars (or 2.5 bars) i would set up my cars to run at 4- 4.5 bars. the atomisation is better at these levels, keeping in mind that around 6 bars the injectors stopp working. so if you then run say 1.5 bars of boost you end up with 90 psi fp max. its not much different on a referenced ls1. and a pump upgrade yields around 65 psi at idle returnless anyway.
of course you need a pump supporting that and if you dont find one in the walbro catalog, dont despair, there are plenty of unexpensive pumps that will support 6-8 bars. i preferred to use bosch pumps for the ke-jetronic in audis. those systems ran 6-6.5 bars stock.
on the topic of "stupid high fp": when the fuel systems used to run 3 bars (or 2.5 bars) i would set up my cars to run at 4- 4.5 bars. the atomisation is better at these levels, keeping in mind that around 6 bars the injectors stopp working. so if you then run say 1.5 bars of boost you end up with 90 psi fp max. its not much different on a referenced ls1. and a pump upgrade yields around 65 psi at idle returnless anyway.
of course you need a pump supporting that and if you dont find one in the walbro catalog, dont despair, there are plenty of unexpensive pumps that will support 6-8 bars. i preferred to use bosch pumps for the ke-jetronic in audis. those systems ran 6-6.5 bars stock.
Last edited by romandian; Jun 15, 2017 at 08:08 AM.
Melting Slicks
Joined: Jul 2004
Posts: 2,844
Likes: 144
From: Northern Ireland
well, i thought i would mention it. post #1 showed a pressure of 72 psi base and 85 psi max. i dont think that is anything extraordinary.
on the topic of "stupid high fp": when the fuel systems used to run 3 bars (or 2.5 bars) i would set up my cars to run at 4- 4.5 bars. the atomisation is better at these levels, keeping in mind that around 6 bars the injectors stopp working. so if you then run say 1.5 bars of boost you end up with 90 psi fp max. its not much different on a referenced ls1. and a pump upgrade yields around 65 psi at idle returnless anyway.
of course you need a pump supporting that and if you dont find one in the walbro catalog, dont despair, there are plenty of unexpensive pumps that will support 6-8 bars. i preferred to use bosch pumps for the ke-jetronic in audis. those systems ran 6 - 6.5 bars stock.
on the topic of "stupid high fp": when the fuel systems used to run 3 bars (or 2.5 bars) i would set up my cars to run at 4- 4.5 bars. the atomisation is better at these levels, keeping in mind that around 6 bars the injectors stopp working. so if you then run say 1.5 bars of boost you end up with 90 psi fp max. its not much different on a referenced ls1. and a pump upgrade yields around 65 psi at idle returnless anyway.
of course you need a pump supporting that and if you dont find one in the walbro catalog, dont despair, there are plenty of unexpensive pumps that will support 6-8 bars. i preferred to use bosch pumps for the ke-jetronic in audis. those systems ran 6 - 6.5 bars stock.
If you were using the Bosch pumps, then that is a different matter, but you were not using those ? And you cannot compare an ancient jetronic system to modern fuel injectors. They're just vastly different.