Merc Cool fuel
04-20-2010, 02:27 AM
#11
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Chaos:
Not to hijack your thread, but I'd like to use this opportunity to gain some insight on developing (optimizing) procharger fuel control by use of flow regulators only. For sake of "reversibility" I don't want to reprogram the ecu in case the procharger ever comes off.
As you'll see I have only a few post on OSO. I have been waiting to learn the basics before aggravating folks with silly redundant questions.
Smitty, thank you for the time and willingness you have shown others who have needed help. I've been searching this site for months and have bookmarked several of your posts.
I believe your design of tandem regulators offers very good resolution and repeatability. I intend to follow that design.
I bought a 5# procharged 1998 454 MAG MPI (stock) boat in January and have only seen it twice. At this time I am unsure of the status of the fuel system (lack of time under hatch) I will see the boat this weekend and will diagram the fuel system. I can say for certain it has the Aeromotive A1000 pump and a red base/ Black top aeromotive boost reference regulator.
My most immediate problem is the fuel pressure sticks at 80 psi (idle or WOT) on the Gaffrig 0-80# dash mounted electric gage. The fuel pressure transducer is mounted in the Aeromotive regulator body. The needle does drop with key off. It is certainly running rich and bogs at low end. Spark plugs are black.
Prior to buying the boat the owner had the same problem and took the boat to Dereberry at lake Texoma. Dereberry apparently took apart the cool fuel system, cleaned and reinstalled it, and (I'm happy to say) eliminated the closed fuel return loop by routing the fuel return to the (2) fuel tanks via a manual selector switch. To obtain more accurate data I intend to install additional mechanical fuel pressure gages at strategic points in the system, along with a close resolution boost gage so I can best tune the tandem regulator system. Much preliminary work to be done on my end ...
OK, so here's where I return Chaos' thread;
(Assume that by returning the bypased fuel back to the fuel tanks enough cooling capacity is generated to prevent vapor lock)
Q: Using the Aeromotive A1000 fuel pump and the tandem regulator system can I shiet can (bypass) the cool fuel system?
I don't understand how the factory fuel pump at the cool fuel system, and the small factory regulators at the cool fuel heat exchanger and fuel rail come into play in my present system, or other procharger "bolt-on" applications.
Q: If the Cool fuel system, factory fuel pump & regulators are eliminated, would't smitty's base pressure regulator serve the same purpose in place of the small factory regulators?
Q: Would the flow of this basic fuel system concept work? A1000 pump ---> water seperator /filter ----> fuel rails -----> Base pressure regulator -------> Boost reference regulator ----> Fuel tank selector switch -----> Fuel tank.
I appreciate everyone's feedback and hope Chaos will benefit from the shared knowledge.
Thanks!
Not to hijack your thread, but I'd like to use this opportunity to gain some insight on developing (optimizing) procharger fuel control by use of flow regulators only. For sake of "reversibility" I don't want to reprogram the ecu in case the procharger ever comes off.
As you'll see I have only a few post on OSO. I have been waiting to learn the basics before aggravating folks with silly redundant questions.
Smitty, thank you for the time and willingness you have shown others who have needed help. I've been searching this site for months and have bookmarked several of your posts.
I believe your design of tandem regulators offers very good resolution and repeatability. I intend to follow that design.
I bought a 5# procharged 1998 454 MAG MPI (stock) boat in January and have only seen it twice. At this time I am unsure of the status of the fuel system (lack of time under hatch) I will see the boat this weekend and will diagram the fuel system. I can say for certain it has the Aeromotive A1000 pump and a red base/ Black top aeromotive boost reference regulator.
My most immediate problem is the fuel pressure sticks at 80 psi (idle or WOT) on the Gaffrig 0-80# dash mounted electric gage. The fuel pressure transducer is mounted in the Aeromotive regulator body. The needle does drop with key off. It is certainly running rich and bogs at low end. Spark plugs are black.
Prior to buying the boat the owner had the same problem and took the boat to Dereberry at lake Texoma. Dereberry apparently took apart the cool fuel system, cleaned and reinstalled it, and (I'm happy to say) eliminated the closed fuel return loop by routing the fuel return to the (2) fuel tanks via a manual selector switch. To obtain more accurate data I intend to install additional mechanical fuel pressure gages at strategic points in the system, along with a close resolution boost gage so I can best tune the tandem regulator system. Much preliminary work to be done on my end ...
OK, so here's where I return Chaos' thread;
(Assume that by returning the bypased fuel back to the fuel tanks enough cooling capacity is generated to prevent vapor lock)
Q: Using the Aeromotive A1000 fuel pump and the tandem regulator system can I shiet can (bypass) the cool fuel system?
I don't understand how the factory fuel pump at the cool fuel system, and the small factory regulators at the cool fuel heat exchanger and fuel rail come into play in my present system, or other procharger "bolt-on" applications.
Q: If the Cool fuel system, factory fuel pump & regulators are eliminated, would't smitty's base pressure regulator serve the same purpose in place of the small factory regulators?
Q: Would the flow of this basic fuel system concept work? A1000 pump ---> water seperator /filter ----> fuel rails -----> Base pressure regulator -------> Boost reference regulator ----> Fuel tank selector switch -----> Fuel tank.
I appreciate everyone's feedback and hope Chaos will benefit from the shared knowledge.
Thanks!
04-20-2010, 03:53 PM
#12
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Ref: 1998 454 MAG MPI w/ 5# procharger
Thanks Smitty,
I just want to get the boat somewhat "right" (reduce meltdown potential) for this summer. The time it will see boost will be very, very little. I just bought the boat in January and will make things "right" over next winter. I haven't even taken the plenum top off yet to see how things are set-up.
More (basic) questions for the crowd ...
Q: Considering prochargers "turn key" method of using an add on bypass regulator to "pinch up" pressure during boost, wouldn't the small factory mercruiser MPI regulators actually be controlling the system pressure if the add on regulator is adjusted below their set point?
(Bare with me)
Q: So, if I did Shiet can the factory merc cool fuel system and regulators and use the tandem regulator design, in essence I would have better control over the base pressure setpoint and have a more reliable and controlable (gain adjustable) boost condition fuel pressure?
(Great!)
Q: If the above is true, can anyone recommend fuel log, rails, fittings, or other components to replace the cool fuel set-up and plug the factory regulator holes?
Thanks all!
Thanks Smitty,
I just want to get the boat somewhat "right" (reduce meltdown potential) for this summer. The time it will see boost will be very, very little. I just bought the boat in January and will make things "right" over next winter. I haven't even taken the plenum top off yet to see how things are set-up.
More (basic) questions for the crowd ...
Q: Considering prochargers "turn key" method of using an add on bypass regulator to "pinch up" pressure during boost, wouldn't the small factory mercruiser MPI regulators actually be controlling the system pressure if the add on regulator is adjusted below their set point?
(Bare with me)
Q: So, if I did Shiet can the factory merc cool fuel system and regulators and use the tandem regulator design, in essence I would have better control over the base pressure setpoint and have a more reliable and controlable (gain adjustable) boost condition fuel pressure?
(Great!)
Q: If the above is true, can anyone recommend fuel log, rails, fittings, or other components to replace the cool fuel set-up and plug the factory regulator holes?
Thanks all!
04-21-2010, 02:56 AM
#13
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Ref: 1998 454 MAG MPI w/ 5# procharger
Thanks Smitty,
I just want to get the boat somewhat "right" (reduce meltdown potential) for this summer. The time it will see boost will be very, very little. I just bought the boat in January and will make things "right" over next winter. I haven't even taken the plenum top off yet to see how things are set-up.
More (basic) questions for the crowd ...
Q: Considering prochargers "turn key" method of using an add on bypass regulator to "pinch up" pressure during boost, wouldn't the small factory mercruiser MPI regulators actually be controlling the system pressure if the add on regulator is adjusted below their set point?
(Bare with me)
Q: So, if I did Shiet can the factory merc cool fuel system and regulators and use the tandem regulator design, in essence I would have better control over the base pressure setpoint and have a more reliable and controlable (gain adjustable) boost condition fuel pressure?
(Great!)
Q: If the above is true, can anyone recommend fuel log, rails, fittings, or other components to replace the cool fuel set-up and plug the factory regulator holes?
Thanks all!
Thanks Smitty,
I just want to get the boat somewhat "right" (reduce meltdown potential) for this summer. The time it will see boost will be very, very little. I just bought the boat in January and will make things "right" over next winter. I haven't even taken the plenum top off yet to see how things are set-up.
More (basic) questions for the crowd ...
Q: Considering prochargers "turn key" method of using an add on bypass regulator to "pinch up" pressure during boost, wouldn't the small factory mercruiser MPI regulators actually be controlling the system pressure if the add on regulator is adjusted below their set point?
(Bare with me)
Q: So, if I did Shiet can the factory merc cool fuel system and regulators and use the tandem regulator design, in essence I would have better control over the base pressure setpoint and have a more reliable and controlable (gain adjustable) boost condition fuel pressure?
(Great!)
Q: If the above is true, can anyone recommend fuel log, rails, fittings, or other components to replace the cool fuel set-up and plug the factory regulator holes?
Thanks all!
04-21-2010, 01:15 PM
#14
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Now I'n starting to get some direction, thanks!
It appears in all reality for me to do this right ECU upgrade is inevitable. New chapter on learning....
I've got the ols MEFI 2 ECU. Have you heard of anyone having success with an ECU reprogram and using (for reference only)standalone O2 sensors or exhaust gas pyrometers. I'm afraid the end reality will be upgrade to a later MEFI 4 or similar ECU that has closed loop capabilities. I'd like to enjoy the boat for the few times I'll see it this summer, upgrades in the winter. Any suggestions on how to best utilize the MEFI 2 would be appreciated..
It appears in all reality for me to do this right ECU upgrade is inevitable. New chapter on learning....
I've got the ols MEFI 2 ECU. Have you heard of anyone having success with an ECU reprogram and using (for reference only)standalone O2 sensors or exhaust gas pyrometers. I'm afraid the end reality will be upgrade to a later MEFI 4 or similar ECU that has closed loop capabilities. I'd like to enjoy the boat for the few times I'll see it this summer, upgrades in the winter. Any suggestions on how to best utilize the MEFI 2 would be appreciated..
04-23-2010, 03:53 AM
#15
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Closed loop is seldom used on boats,your mefi2 will work. Closed loop is seldom used because 02 sensors will not live long in a marine exhaust system that has water added to it. With such low boost a generic reprogram of your mefi2 from a like combination should do everything you need to do,Smitty
04-23-2010, 08:31 AM
#16
There is no reason to upgrade from the 2 to a 4 unless you are getting a 4b at a good price.
The 2 will do everything you need to do so long as you can all the factory fuel injection stuff & build a good fuel system.
The 2 will do everything you need to do so long as you can all the factory fuel injection stuff & build a good fuel system.
04-23-2010, 01:26 PM
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Great input, thanks for bearing with me as I learn what I need to know. There are a lot of smart folks on this site
I believe I have read MEFI-2 does not have the capability to process any sensor inputs above atmospheric pressure (can't recognize boost conditions), no reason to go with wide band sensors?
Therefore, with MEFI-2 the only way to control A/F mixture during boost is by using manifold vacuum / pressure as a signal to drive the add-on boost reference regulator to increase fuel pressure and force more fuel across the injectors orifice. (We'll consider the fuel injector a fixed orifice because no control pulse bandwidth modification can be made exclusive to boost conditions)
Using prochargers method of increasing base fuel pressure and always having the ECU sense cold start will make the A/F mixture rich during manifold Vac. up to atmospheric pressure.
Since:
* MEFI-2 can't control boost condition A/F.
* A/F mixture is rich from vacuum to atm pressure condition.
Q: Does a tuner change the ECU program to shorten injector pulse width and reduce the overly rich condition that occurs outside of boost, and allow the rich condition carry over and combine with the manifold signal driven fuel pressure increase at the onset of boost, where it is needed?
Has anyone had success with an ECU reprogram of a MEFI-2 w/ 5# BOOST?
Seems to me like you could design a vacuum / pressure switch to monitor mainfold vac/pressure and transition the cold start (engine coolant) signal to the ECU from an input that reads "hot" during manifold vacuum conditions (non boost) and "cold" while in boost. This could help to balance the A/F mixture at all manifold conditions.
Either I'm catching on, or I've proven myself to be a total moran. Thanks!
I believe I have read MEFI-2 does not have the capability to process any sensor inputs above atmospheric pressure (can't recognize boost conditions), no reason to go with wide band sensors?
Therefore, with MEFI-2 the only way to control A/F mixture during boost is by using manifold vacuum / pressure as a signal to drive the add-on boost reference regulator to increase fuel pressure and force more fuel across the injectors orifice. (We'll consider the fuel injector a fixed orifice because no control pulse bandwidth modification can be made exclusive to boost conditions)
Using prochargers method of increasing base fuel pressure and always having the ECU sense cold start will make the A/F mixture rich during manifold Vac. up to atmospheric pressure.
Since:
* MEFI-2 can't control boost condition A/F.
* A/F mixture is rich from vacuum to atm pressure condition.
Q: Does a tuner change the ECU program to shorten injector pulse width and reduce the overly rich condition that occurs outside of boost, and allow the rich condition carry over and combine with the manifold signal driven fuel pressure increase at the onset of boost, where it is needed?
Has anyone had success with an ECU reprogram of a MEFI-2 w/ 5# BOOST?
Seems to me like you could design a vacuum / pressure switch to monitor mainfold vac/pressure and transition the cold start (engine coolant) signal to the ECU from an input that reads "hot" during manifold vacuum conditions (non boost) and "cold" while in boost. This could help to balance the A/F mixture at all manifold conditions.
Either I'm catching on, or I've proven myself to be a total moran. Thanks!
04-23-2010, 01:44 PM
#18
You can use a 2 bar MAP sensor to read boost/vac conditions with a MEFI2. That ECM will support boost signals.
A good tuner will reprogram your ecm to do exactly what it needs to do to control the engine without having to add stuff on to fool it into thinking it is doing something else.
Learn away!
MEFItuning.com
A good tuner will reprogram your ecm to do exactly what it needs to do to control the engine without having to add stuff on to fool it into thinking it is doing something else.
Learn away!
MEFItuning.com
