ajazyasin Posted December 27, 2006 Share Posted December 27, 2006 I see where you are going with that. The fuel press. need to be set at the pressure the injectors are tested at or designed to operate at. Im pretty confident 2 walbros will do the business in terms of the flow to the rail. On a side note, wouldnt the pressure required to move 'x' amount of fuel, drop when we increase the ID of a pipe? Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 Exactly. Really though, I'm wondering if the mass flow rate of fuel that is delivered by a single 255l/hr pump operating at say 73.5psi (3 bar static plus 2 bar boost) will still be more than the 800cc/min that the injectors are flowing? Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 Actually scrub what I said about the pump supplying enough fuel if the pressures are equal. I fogot that 6 800cc injectors are flowing 288000cc/hour. However, that said if the pressure that the pump is rated to is different.... Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 Found this info on the Walbro 341 and 342 pumps. Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 Bosch 044 : 8bar outlet pressure (approx 117psi) it flows 165lph. Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 Just found this Info on the Bosch :- Bosch 660hp fuel pump 044 model This Bosch 660hp pump is commonly called the "044" Bosch Motorsport fuel pump. This is a K-Jetronic style pump and doesnt mind pumping at much higher than normal fuel pressures. Approx 270L per hour flow rate at 3 bar fuel pressure. More methanol tolerant than most other EFI pumps. In tank 600hp fuel pump 040 model This pump is a Bosch K-Jetronic pump which is capable of pumping efficiently at high fuel pressures and suits high boost , high flow applications. It has a built in strainer on the base of the pump and can usually be adapted to suit most in-tank applications. It is commonly called an Audi Motorsport pump by people in the trade. Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 That's cool Wez, So at 73psi, a single Walbro can supply 189.3 l/hr of fuel (assuming 12 volt source) which is woefully short of the required 288l/hr required to fully supply 800cc injectors at 2bar of boost. So basically losing a single pump on a dual set-up really could be disastrous. Quote Link to comment Share on other sites More sharing options...
michael Posted December 27, 2006 Share Posted December 27, 2006 Have you seen flow charts for that bosch pump? I don't think they flow much (if any) more than the stock Supra pump? They are a good pump quality-wise, but the flow is lacking. Some good info here That data isn't for the 044 though is it? I was under the impression the Bosch 044 flowed up to 270lph and didn't drop off as much as the Walbro once the pressure goes up. I was also having a look at the SX Performance pumps last night, the 18207 in particular, they sound promising but I was tired and the gallons per hour ratings weren't meaning much to me http://www.sx-performance.com/Fuel_Pumps.htm Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 Just found this Info on the Bosch :- Bosch 660hp fuel pump 044 model This Bosch 660hp pump is commonly called the "044" Bosch Motorsport fuel pump. This is a K-Jetronic style pump and doesnt mind pumping at much higher than normal fuel pressures. Approx 270L per hour flow rate at 3 bar fuel pressure. More methanol tolerant than most other EFI pumps. In tank 600hp fuel pump 040 model This pump is a Bosch K-Jetronic pump which is capable of pumping efficiently at high fuel pressures and suits high boost , high flow applications. It has a built in strainer on the base of the pump and can usually be adapted to suit most in-tank applications. It is commonly called an Audi Motorsport pump by people in the trade. Ideally we would want to know what the 044 model (or any model for that matter) will flow at say 6 bar fuel pressure... 4 bar static, (not many injectors will be flow tested at more than 4 bar) plus 2 bar boost (Not many people will run more than 2 bar boost) If we can find an in-tank pump that can supply 288l/hr (not many people will run larger than 800cc injectors) then we've found the holy grail. You'd then just bung two in for redundancy and hey presto! Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 I was also having a look at the SX Performance pumps last night, the 18207 in particular, they sound promising but I was tired and the gallons per hour ratings weren't meaning much to me http://www.sx-performance.com/Fuel_Pumps.htm It looks pretty good as it will flow around 300l/hr at 75psi. It's a pity that it's not an intank pump though, would mean having to have swirl pots and lifter pumps and losing some of the already limited boot space... Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 Aeromotive do some big pumps, not intank though :- http://www.aeromotiveinc.com/listing.php?cat=1 Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 Just been thinking about this... As I mentioned earlier, ideally you would have 2 pumps, each of which was capable of delivering enough fuel on it's own in case either one stops working. So failing that, you want to know when a pump is going to fail, before it fails. So that got me thinking about the failure mode of a pump. I guess one of two things is going to happen the current draw will either increase massively or drop massively. So I've just been and spoken to one of the electronics engineers here at work, who recons he could build a circuit that detects the current draw and would send an output (which could be connected to an alarm or LED or whatever) whenever the current draw went outside of a range (say between 15 - 25 amps). He reconned it could be made for as little as £70 (without really looking into it and just guessing at prices) What do you think? Viable option? Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 I still think one decent pump is better, if it fails then you get no fuel. The only multi pump setup I would personally use is an in tank lifter pump to swirl pot and then single highflow pump to filter etc. Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted December 27, 2006 Author Share Posted December 27, 2006 I still think one decent pump is better, if it fails then you get no fuel. The only multi pump setup I would personally use is an in tank lifter pump to swirl pot and then single highflow pump to filter etc. However the defi system i use will let you know if fuel pressure drops while on boost (rather too late perhaps) P.S. must remember not to ask technical questions Quote Link to comment Share on other sites More sharing options...
JamieP Posted December 27, 2006 Share Posted December 27, 2006 If a single pump on a twin system was to fail then surely you notice your afr's change imediatly? Quote Link to comment Share on other sites More sharing options...
ajazyasin Posted December 27, 2006 Share Posted December 27, 2006 If a single pump on a twin system was to fail then surely you notice your afr's change imediatly? I think with a warning system setup it should be fine. Hope so cause Im running twin walbros! I dont actually want a swirl pot kicking about in the boot. Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 If a single pump on a twin system was to fail then surely you notice your afr's change imediatly? When hurtling down a straight at 7500rpm how often do you look at the AFR gauge and how quickly can you safely respond. How long would it take to turn an engine into useless metal when the fuel pressure has halved. Quote Link to comment Share on other sites More sharing options...
JamieP Posted December 27, 2006 Share Posted December 27, 2006 When hurtling down a straight at 7500rpm how often do you look at the AFR gauge and how quickly can you safely respond. How long would it take to turn an engine into useless metal when the fuel pressure has halved. I have my gauge directly infront of me for this very reason... i cant mis it. Has anyone ever had a pump go like this? Quote Link to comment Share on other sites More sharing options...
Wez Posted December 27, 2006 Share Posted December 27, 2006 Not doubting your abilities Jamie, these are my concerns and reasons why have not gone for dual pumps setup in this way. Another reason i guess is that my car does not need it Quote Link to comment Share on other sites More sharing options...
JamieP Posted December 27, 2006 Share Posted December 27, 2006 Valid point im just curious bud... i wonder if there is a way to wire them so if one was to fail then both would cut out. Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 If a single pump on a twin system was to fail then surely you notice your afr's change imediatly? Absolutely, but it could potentially be too late then... Quote Link to comment Share on other sites More sharing options...
ajazyasin Posted December 27, 2006 Share Posted December 27, 2006 Correct me if Im wrong but the injectors need the full potential of the twin pump setup under heavy load/boost. Under normal-slightly excited driving the pressure of fuel from one would be enough. Therefore, the only dangerous area is under WOT and one pump fails. All you would need is an audible siren to warn of a fuel pressure drop and straight away you're off WOT and one pump is supplying enough pressure. then drive normally until problem is diagnosed. It also gives the added benifit of actually being able to still drive your car to the garage. Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 Valid point im just curious bud... i wonder if there is a way to wire them so if one was to fail then both would cut out. I think that would be possible using the circuit that this guy at work has suggested through some kind of logic gate. Quote Link to comment Share on other sites More sharing options...
TLicense Posted December 27, 2006 Share Posted December 27, 2006 Correct me if Im wrong but the injectors need the full potential of the twin pump setup under heavy load/boost. Under normal-slightly excited driving the pressure of fuel from one would be enough. Therefore, the only dangerous area is under WOT and one pump fails. All you would need is an audible siren to warn of a fuel pressure drop and straight away you're off WOT and one pump is supplying enough pressure. then drive normally until problem is diagnosed. It also gives the added benifit of actually being able to still drive your car to the garage. Again, it's whether by the time you hear the alarm and let off the throttle it's too late or not... Quote Link to comment Share on other sites More sharing options...
bondango Posted December 27, 2006 Share Posted December 27, 2006 If you have a circuit with the potential of producing a warning, why not go a step furthur and get it to control say the power to the Ignitier, which would initiate a type of Spark cut (just ike normal fuel cut function) Quote Link to comment Share on other sites More sharing options...
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