More Pro Charger tuning Progress and AFR RAtios
#21
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You're talking to the right guy in Smitty.
Just a word about increasing fuel pressure. Flow will only increase in proportion to the square root of the pressure increase. Increasing fuel pressure from 45 psi to 65 psi only increases flow by 20%. That's not enough to keep up with most supercharging situations so you have to reprogram the ECU to increase pulse width anyway. I always recommend to buy bigger injectors and be done with it, especially if there are any plans for future upgrades.
Just a word about increasing fuel pressure. Flow will only increase in proportion to the square root of the pressure increase. Increasing fuel pressure from 45 psi to 65 psi only increases flow by 20%. That's not enough to keep up with most supercharging situations so you have to reprogram the ECU to increase pulse width anyway. I always recommend to buy bigger injectors and be done with it, especially if there are any plans for future upgrades.
#22
Platinum Member
Platinum Member
Boost dependent regulators are garbage. You need to reprogram the ecu to read boost. Then it will increase pulse width of the injectors for fuel not force it in with pressure, this will also retard the timing with boost. Boost dependent regulator is what they use on $1200 turbo kits for hondas. Arizona speed and marine has the program for this. If you didnt know they designed the factory program for that engine.
Last edited by articfriends; 05-26-2007 at 01:00 AM.
#23
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Thanks for the tip Smitty. I won't bother to waste money on the fuel pump booster. I'm currently running the Aeromotive 1000 pump w/ a -10 fuel line with no problems, so I agree it should supply enough fuel for Bryan. I think I'm going to upgrade to the Aeromotive Eliminator pump which flows 800lbs perhr. instead of the 600 the 1000 flows, just to be safe.
I also agree that the best thing to do is have the ECU programmed to compensate for boost. This will probably require bigger injectors though. The 42lb/hr. injectors will flow a lot more than they are rated (they are usually rated at like 45psi) when you are putting 65psi fuel pressure to them. That's the real reason blower manufacturers use the boost referenced regulator to compenstae for the extra fuel demand - it just a whole lot cheaper than requiring an ECU reprogram and new injectors. If you can find a way to make it work without the unecessary expense - like Smitty has done - kudos to you. my 2 cents...
I also agree that the best thing to do is have the ECU programmed to compensate for boost. This will probably require bigger injectors though. The 42lb/hr. injectors will flow a lot more than they are rated (they are usually rated at like 45psi) when you are putting 65psi fuel pressure to them. That's the real reason blower manufacturers use the boost referenced regulator to compenstae for the extra fuel demand - it just a whole lot cheaper than requiring an ECU reprogram and new injectors. If you can find a way to make it work without the unecessary expense - like Smitty has done - kudos to you. my 2 cents...
On a side note-I use the stock fuel pump wires from the merc mpi harness to trigger a 50 amp bosch relay thats wired with 10 gauge wire directly to alternator/battery cables,don't make the mistake of trying to run ANY of these bigger pumps off the merc power because you will have a voltage drop and pressure loss,especially at WOT (this isn't necesarily directed towards ao-2600,this is just something I want to remind ANYONE following this thread who may also be doing something similar),Smitty
#25
Platinum Member
Platinum Member
Smitty,
I am impressed with what you have accomplished with you EFI system. I have toyed with an offer of working with Keith Eickert on an EFI system on my set up, but know it won't be push button. Your system and hours of re-rigging and experimenting remind me why I am staying with a carburetor!
I am impressed with what you have accomplished with you EFI system. I have toyed with an offer of working with Keith Eickert on an EFI system on my set up, but know it won't be push button. Your system and hours of re-rigging and experimenting remind me why I am staying with a carburetor!
#26
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Thanks Smitty. I have actually completely re-wired my boat and I have a 30 amp relay with a dedicated 10 gauge supply to my pump. I have the relay triggered by the key switch so the pump comes on when the key is turned on. Trust me, I'm an old nitrous racer so I'm pretty anal about the fuel system!
You have highlighted though, the fact that with a blown EFI setup and, consequently, much higher fuel pressure than a blow-thru carb setup (say 45-65psi @WOT vs. 12-20psi @WOT), you are going to need a much bigger pump. This is so because pumps are rated at a certain flow at a certain psi- for eg. the A1000 is rated at 600lbs per hr. @45psi but the flow is without a doubt much higher than 600lb/hr at 20 psi. To illustrate my point, Aeromotive says this pump is good for 1100hp on a forced air carb motor but only 800hp on a forced air EFI motor. (This obviously is because of the difference in fuel delivery pressure, cause we all know that an EFI setup is more efficient with fuel!)
I haven't seen any issues with my A1000 as yet but admittedly I haven't even been able to hold the throttle down for too long because it runs right to the limiter at 6600 RPM so quick I have to back it off. I'm trying to get the right prop on the boat and I hope theEliminator will be big enough for me, since Aeromotive claims this is big eneough for 1500HP forced air carb motors (and 1100HP EFI blown motors).
All in all, I am very impressed with your setup but I couldn't agree more with what Benperfected is saying - after all the help and guidance that I've gotten over the years from you guys (Smitty and Tomcat in particular) I've finally got a carb setup that seems to produce a linear AFR throughout the RPM range, so I think I'll stick to it now rather than pull more hair out with an EFI setup!!
You have highlighted though, the fact that with a blown EFI setup and, consequently, much higher fuel pressure than a blow-thru carb setup (say 45-65psi @WOT vs. 12-20psi @WOT), you are going to need a much bigger pump. This is so because pumps are rated at a certain flow at a certain psi- for eg. the A1000 is rated at 600lbs per hr. @45psi but the flow is without a doubt much higher than 600lb/hr at 20 psi. To illustrate my point, Aeromotive says this pump is good for 1100hp on a forced air carb motor but only 800hp on a forced air EFI motor. (This obviously is because of the difference in fuel delivery pressure, cause we all know that an EFI setup is more efficient with fuel!)
I haven't seen any issues with my A1000 as yet but admittedly I haven't even been able to hold the throttle down for too long because it runs right to the limiter at 6600 RPM so quick I have to back it off. I'm trying to get the right prop on the boat and I hope theEliminator will be big enough for me, since Aeromotive claims this is big eneough for 1500HP forced air carb motors (and 1100HP EFI blown motors).
All in all, I am very impressed with your setup but I couldn't agree more with what Benperfected is saying - after all the help and guidance that I've gotten over the years from you guys (Smitty and Tomcat in particular) I've finally got a carb setup that seems to produce a linear AFR throughout the RPM range, so I think I'll stick to it now rather than pull more hair out with an EFI setup!!
#27
Platinum Member
Platinum Member
Thanks Smitty. I have actually completely re-wired my boat and I have a 30 amp relay with a dedicated 10 gauge supply to my pump. I have the relay triggered by the key switch so the pump comes on when the key is turned on. Trust me, I'm an old nitrous racer so I'm pretty anal about the fuel system!
You have highlighted though, the fact that with a blown EFI setup and, consequently, much higher fuel pressure than a blow-thru carb setup (say 45-65psi @WOT vs. 12-20psi @WOT), you are going to need a much bigger pump. This is so because pumps are rated at a certain flow at a certain psi- for eg. the A1000 is rated at 600lbs per hr. @45psi but the flow is without a doubt much higher than 600lb/hr at 20 psi. To illustrate my point, Aeromotive says this pump is good for 1100hp on a forced air carb motor but only 800hp on a forced air EFI motor. (This obviously is because of the difference in fuel delivery pressure, cause we all know that an EFI setup is more efficient with fuel!)
I haven't seen any issues with my A1000 as yet but admittedly I haven't even been able to hold the throttle down for too long because it runs right to the limiter at 6600 RPM so quick I have to back it off. I'm trying to get the right prop on the boat and I hope theEliminator will be big enough for me, since Aeromotive claims this is big eneough for 1500HP forced air carb motors (and 1100HP EFI blown motors).
All in all, I am very impressed with your setup but I couldn't agree more with what Benperfected is saying - after all the help and guidance that I've gotten over the years from you guys (Smitty and Tomcat in particular) I've finally got a carb setup that seems to produce a linear AFR throughout the RPM range, so I think I'll stick to it now rather than pull more hair out with an EFI setup!!
You have highlighted though, the fact that with a blown EFI setup and, consequently, much higher fuel pressure than a blow-thru carb setup (say 45-65psi @WOT vs. 12-20psi @WOT), you are going to need a much bigger pump. This is so because pumps are rated at a certain flow at a certain psi- for eg. the A1000 is rated at 600lbs per hr. @45psi but the flow is without a doubt much higher than 600lb/hr at 20 psi. To illustrate my point, Aeromotive says this pump is good for 1100hp on a forced air carb motor but only 800hp on a forced air EFI motor. (This obviously is because of the difference in fuel delivery pressure, cause we all know that an EFI setup is more efficient with fuel!)
I haven't seen any issues with my A1000 as yet but admittedly I haven't even been able to hold the throttle down for too long because it runs right to the limiter at 6600 RPM so quick I have to back it off. I'm trying to get the right prop on the boat and I hope theEliminator will be big enough for me, since Aeromotive claims this is big eneough for 1500HP forced air carb motors (and 1100HP EFI blown motors).
All in all, I am very impressed with your setup but I couldn't agree more with what Benperfected is saying - after all the help and guidance that I've gotten over the years from you guys (Smitty and Tomcat in particular) I've finally got a carb setup that seems to produce a linear AFR throughout the RPM range, so I think I'll stick to it now rather than pull more hair out with an EFI setup!!
#29
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Thanks Smitty. Weather looks good today so I might give it a run later and let you all know how it goes. When I get all the data I need I'm going to start a new thread on blow thru carb mods.
BTW:On the point I was making on fuel pressure vs. volume:
According to the info on Jegs website, the Eliminator Pump flows 800lbs/hr @ 45 psi and over 1,000lbs/hr @ 8 psi, so its easy to see how these pumps are more than sufficient for just about any carb motor.
HP: Good to hear you got the LM-1. These things are a godsend. I just bought the Innovate XD-16 Gauge, but I've just now discovered that I still need at least the LC-1 cable to connect it to the 18' extension cable I've got. I'll probably just buy the LM-1 RPM kit as well so that I can do just about anything I need. The good thing about the XD-16 is that it is an LED gauge which gives you better "real-time" visiblity of your AFR, cause we found it was hard to read of the LM-1 in the boat because the glare made it hard to read off the LCD display. Just another option to consider! Let us know how it goes.
BTW:On the point I was making on fuel pressure vs. volume:
According to the info on Jegs website, the Eliminator Pump flows 800lbs/hr @ 45 psi and over 1,000lbs/hr @ 8 psi, so its easy to see how these pumps are more than sufficient for just about any carb motor.
HP: Good to hear you got the LM-1. These things are a godsend. I just bought the Innovate XD-16 Gauge, but I've just now discovered that I still need at least the LC-1 cable to connect it to the 18' extension cable I've got. I'll probably just buy the LM-1 RPM kit as well so that I can do just about anything I need. The good thing about the XD-16 is that it is an LED gauge which gives you better "real-time" visiblity of your AFR, cause we found it was hard to read of the LM-1 in the boat because the glare made it hard to read off the LCD display. Just another option to consider! Let us know how it goes.
#30
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Took delivery of my newzed boat today.........couple of questions.
502MPI, M-1 Procharger with FMU, SX pump (not sure which model)
1. On the FMU - how should this thing be plumbed? On my motor, the top port went to the stock fuel pressure regulator and the bottom port was simply stuck into the inlet side of the procharger. This can't be right. Can someone tell me how they have theirs plumbed?
2. The motor is leaning out. Pump is currently wired to the factory harness and I plan on putting it on a dedicated ckt tomrrow. 30psi and as soon as you bring it off idle, fuel pressure drops to 27psi. Never goes up. Also noticed the battery voltage was 10.5 and doesn't appear the alternator is charging. I'm sure the pump isn't getting enough voltage. This could contribute to the low fuel pressure, couldn't it?
502MPI, M-1 Procharger with FMU, SX pump (not sure which model)
1. On the FMU - how should this thing be plumbed? On my motor, the top port went to the stock fuel pressure regulator and the bottom port was simply stuck into the inlet side of the procharger. This can't be right. Can someone tell me how they have theirs plumbed?
2. The motor is leaning out. Pump is currently wired to the factory harness and I plan on putting it on a dedicated ckt tomrrow. 30psi and as soon as you bring it off idle, fuel pressure drops to 27psi. Never goes up. Also noticed the battery voltage was 10.5 and doesn't appear the alternator is charging. I'm sure the pump isn't getting enough voltage. This could contribute to the low fuel pressure, couldn't it?