Alex Posted January 4, 2007 Share Posted January 4, 2007 To answer Jon's initial question, If 1 pump on a twin setup stops, you'll not really notice. Unless you are pushing the engine to a load point where you NEED the second pump, and the moment you do that, you'll see a fuel pressure drop, run mega lean, and toast the engine. On a single pump setup you'll just stop. Link to comment Share on other sites More sharing options...
michael Posted January 4, 2007 Share Posted January 4, 2007 What is your HP target? Eventually "Lots" but for the initial build whatever it produces at whatever is safe... I'm just planning ahead, stage 1 will probably involve one UK pump. Link to comment Share on other sites More sharing options...
Mike B Posted January 4, 2007 Share Posted January 4, 2007 To answer Jon's initial question, If 1 pump on a twin setup stops, you'll not really notice. Unless you are pushing the engine to a load point where you NEED the second pump, and the moment you do that, you'll see a fuel pressure drop, run mega lean, and toast the engine. This has to be reason enough for fitting 2 pumps no? If your system can't detect the det and throttle back to save the engine it's an almost mandatory upgrade when running big singles...? I have heard of more than a few engines toasting because of the fuel system failing after the car has been proclaimed safely mapped. Link to comment Share on other sites More sharing options...
Wez Posted January 4, 2007 Share Posted January 4, 2007 Thats the reason for not fitting dual pumps Link to comment Share on other sites More sharing options...
Terminator Posted January 4, 2007 Share Posted January 4, 2007 I think several of the big power guys inj the USA use three Walbro pumps. PHR springs to mind for a triple hanger. PHR Triple Fuel Pump Bracket. The text below is taken form the PHR web site. http://www.powerhouseracing.com/media/catalog/Toyota/Supra%20TT/thumbs/DCP_3845.JPG This CNC machined fuel pump bracket is a direct replacement for the factory single fuel pump hangar. It makes installation of twin or triple Walbro GSS341 fuel pumps a breeze! All mounting hardware included, and includes a tri-merge collector to merge two or three fuel pump connections into a single 1/2" NPT fitting. You can then plumb a single 8AN or 10AN braided fuel feed line, eliminating the need for the stock fuel line altogether. This setup has been proven to support 1100 horsepower and beyond. Also available as an option in any PHR Fuel System Upgrade package. Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 This has to be reason enough for fitting 2 pumps no? If your system can't detect the det and throttle back to save the engine it's an almost mandatory upgrade when running big singles...? I have heard of more than a few engines toasting because of the fuel system failing after the car has been proclaimed safely mapped. What I was saying is actually the reason why 2 pumps can be more dangerous. You might not know one has stopped till you go for a high speed run. And then you suddenly get a massive leaning out of the fuel supply because the 2nd pump isn't boosting the fuel pressure. This won't be anything that a simple tweak of the ecu on the fly can over come....it will be shut down or blow up. The only way to really help the situation is to have some sort of system, checking fuel pressure, afr's, egts and boost pressure....and having alarms set for different scenario's....because the fuel pressure goes up with boost. Link to comment Share on other sites More sharing options...
Wez Posted January 4, 2007 Share Posted January 4, 2007 I would say alarms are no good due to human reaction times, you would need something automatic to cut the ignition when a prob arises. Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 I think several of the big power guys inj the USA use three Walbro pumps. PHR springs to mind for a triple hanger. PHR Triple Fuel Pump Bracket. The text below is taken form the PHR web site. http://www.powerhouseracing.com/media/catalog/Toyota/Supra%20TT/thumbs/DCP_3845.JPG This CNC machined fuel pump bracket is a direct replacement for the factory single fuel pump hangar. It makes installation of twin or triple Walbro GSS341 fuel pumps a breeze! All mounting hardware included, and includes a tri-merge collector to merge two or three fuel pump connections into a single 1/2" NPT fitting. You can then plumb a single 8AN or 10AN braided fuel feed line, eliminating the need for the stock fuel line altogether. This setup has been proven to support 1100 horsepower and beyond. Also available as an option in any PHR Fuel System Upgrade package. Yeah a lot of the drag cars are running them, and I expect it's also a kind of safety thing for street use - because 3 pumps means street supra's have redundancy...but you still have a problem knowning that your redundant pump has gone... But I'd still recommend 1 pump if you can find one meaty enough for your requirements. A GSS341 will run 40psi fuel pressures which will support a T67 at (at least) 1.4bar and produce about 630 at the crank. Can anyone tell me of a bigger single fuel pump not including the UK stock pump? The Bosch 044 for instance, anyone got any flow rates for it? Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 I would say alarms are no good due to human reaction times, you would need something automatic to cut the ignition when a prob arises. Well I think the system to action an ignition cut or alarm etc will be easy enough so that's not where the thought needs to go in....it's getting the other things monitored and x-ref'd that's the issue. Link to comment Share on other sites More sharing options...
michael Posted January 4, 2007 Share Posted January 4, 2007 Can anyone tell me of a bigger single fuel pump not including the UK stock pump? The Bosch 044 for instance, anyone got any flow rates for it? There is a bit of fuel pump banter in this one towards the end: http://www.mkivsupra.net/vbb/showthread.php?t=93767& SX Performance 18207 flows well but it's external. Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 There is a bit of fuel pump banter in this one towards the end: http://www.mkivsupra.net/vbb/showthread.php?t=93767& SX Performance 18207 flows well but it's external. Thanks for the link - looks like Ian's running about 60psi on the Walbro and that's just over 220L/h - I'd say that he's on the limit. The Bosch would add some nice headroom. Link to comment Share on other sites More sharing options...
Ian C Posted January 4, 2007 Share Posted January 4, 2007 I would say alarms are no good due to human reaction times, you would need something automatic to cut the ignition when a prob arises. If I can ever get this Knock Link Amp Thingy to work I'm thinking about prising open the case and wiring a relay onto the alarm signal (or seeing if one of it's outputs to an F-Con can be shanghai'd) to trigger a fuel cut of some sort. Just cut the power to the injectors for a few seconds. -Ian Link to comment Share on other sites More sharing options...
Ian C Posted January 4, 2007 Share Posted January 4, 2007 Heh, just done some maths: 6* 720cc injectors = 4320cc/min = 259,200cc/hour = 259.2lph I've peaked at about 80% duty running 1.4bar, at 6600rpm or thereabouts, so that's 259.2 * .8 = 207.36lph, call it 210lph usage. So that's 20.3psi (call it 21) on top of my static pressure of 38psi, which gives me 59psi of fuel pressure. Using that funky graph the max delivery of the pump is about 235lph, so I'm using just under 90% of it's maximum flow capacity. The AFRs at this point are 11.3:1, pretty safe. So that pump on it's own is perfectly capable of running my setup, but probably not much beyond. Edit: As a theoretical exercise I did some investigation into running 1.6bar. This would run me up to about 90% duty cycle, which gives a peak flow of 233lph, but also we shift the point on the graph up by 3psi which drops it to about 225lph maximum flow. So it'd start falling apart right about there. I started on this path but upping the fuel pressure to give me better headroom on the duty cycles shagged up my lovely map (it wasn't a simple case of removing x% duty cycle across the board, much to my suprise and disgust ) and I REALLY couldn't be arsed to remap the whole car so I gave up. Looks like the fuel pump wouldn't have coped then, so good decision me -Ian Link to comment Share on other sites More sharing options...
Wez Posted January 4, 2007 Share Posted January 4, 2007 Good info Link to comment Share on other sites More sharing options...
Thorin Posted January 4, 2007 Share Posted January 4, 2007 Very good info Link to comment Share on other sites More sharing options...
Wez Posted January 4, 2007 Share Posted January 4, 2007 Would be good to add the useful bits to FAQ or make a sticky. Link to comment Share on other sites More sharing options...
Pig Posted January 4, 2007 Author Share Posted January 4, 2007 Brilliant, thanks for the replies to this guys. It seems to me that if you need more than one. Then the best option is 3 and check them every 3000 miles with your oil change?!?? Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 Brilliant, thanks for the replies to this guys. It seems to me that if you need more than one. Then the best option is 3 and check them every 3000 miles with your oil change?!?? And that if you're looking to push 1 beyond 550Hp then you'd be best off looking at the Bosch 044. Link to comment Share on other sites More sharing options...
Mike B Posted January 4, 2007 Share Posted January 4, 2007 If I can ever get this Knock Link Amp Thingy to work I'm thinking about prising open the case and wiring a relay onto the alarm signal (or seeing if one of it's outputs to an F-Con can be shanghai'd) to trigger a fuel cut of some sort. Just cut the power to the injectors for a few seconds. This is what mine uses - knock link to the fcon + rotary dial to advance or retard the ignition should it start to pull throttle on wot with bad fuel. It can virtually shut the engine down in an instant - I know because I ran out of fuel on highish boost... fuel guage stopped working. Was scratching my head but the ECU did it's job perfectly! It took quite a while to relearn the map. Also to answer alex - I had the same question to terry who built my car - joining two pumps together - if one fails and causes a leak, through flow back out of the busted pump... the hanger has a one way valve in each side to stop backflow. I have the second pump switchable on the dash.. turn it off and the fuel pressure at idle drops very slightly, switch it on and the pressure rises a little, so they do work independantly. Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 This is what mine uses - knock link to the fcon + rotary dial to advance or retard the ignition should it start to pull throttle on wot with bad fuel. It can virtually shut the engine down in an instant - I know because I ran out of fuel on highish boost... fuel guage stopped working. Was scratching my head but the ECU did it's job perfectly! It took quite a while to relearn the map. Also to answer alex - I had the same question to terry who built my car - joining two pumps together - if one fails and causes a leak, through flow back out of the busted pump... the hanger has a one way valve in each side to stop backflow. I have the second pump switchable on the dash.. turn it off and the fuel pressure at idle drops very slightly, switch it on and the pressure rises a little, so they do work independantly. Most dual/triple pump setups arn't on independent switches...it's a good idea but non generally do it. I'm surprised there is much in the way of fuel pressure change at idle though as the FPR controls that. But of it does it's a useful thing to have so yes YOU can can check the pump works. But like I say, so far that car is pretty unique in having that switchable setup. I never said the fuel could flow backwards through the failed pump. Link to comment Share on other sites More sharing options...
Pig Posted January 4, 2007 Author Share Posted January 4, 2007 And that if you're looking to push 1 beyond 550Hp then you'd be best off looking at the Bosch 044. Doh, i own 3 walbro's Link to comment Share on other sites More sharing options...
Ian C Posted January 4, 2007 Share Posted January 4, 2007 This is what mine uses - knock link to the fcon + rotary dial to advance or retard the ignition should it start to pull throttle on wot with bad fuel. If that's a HKS knock Amp can I tap you up for your config and possibly wiring? -Ian Link to comment Share on other sites More sharing options...
Alex Posted January 4, 2007 Share Posted January 4, 2007 Doh, i own 3 walbro's Well if you have them already... Link to comment Share on other sites More sharing options...
Ian C Posted January 4, 2007 Share Posted January 4, 2007 I'm surprised there is much in the way of fuel pressure change at idle though as the FPR controls that. Actually thinking about this an FPR is just an adjustable restriction, so you set this restriction vs a given input and that results in a pressure. I guess if you push a bit harder with a second pump it'll need the restriction opening up a bit to compensate, otherwise fuel pressure would go up. Having said that, how then the vacuum/boost reference gives a consistent 1:1psi rate is open to question -Ian Link to comment Share on other sites More sharing options...
bondango Posted January 4, 2007 Share Posted January 4, 2007 Actually thinking about this an FPR is just an adjustable restriction, so you set this restriction vs a given input and that results in a pressure. I guess if you push a bit harder with a second pump it'll need the restriction opening up a bit to compensate, otherwise fuel pressure would go up. Having said that, how then the vacuum/boost reference gives a consistent 1:1psi rate is open to question -Ian Ian It is just an adjustable restriction, but given the way its designed, i.e Spring loaded valve referenced to boost, it will still keep the same restriction in place i.e. fuel pressure, no matter if 1 or 2 pumps suddenly come online. Guess you could look at it like an external waste gate, no matter how much boost you can make, it will still release at your referenced setting. well that my theory on it anyway lol Link to comment Share on other sites More sharing options...
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