Scott Posted May 14, 2011 Share Posted May 14, 2011 Definitely sounds like a hot tank. Understandable considering your setup though, when cruising along you are going to be getting a lot of fuel going back in through the return. Surprised it heats up THAT much but it does make sense. Have you felt the tank when it's happened Jamie? Obviously it would point to the return fuel being hot and heating up the fuel in the tank. Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted May 14, 2011 Share Posted May 14, 2011 Sounds more like fuel aeration to me. How full was the tank and do you run the pumps vertically or horizontally (are they in tank?) Quote Link to comment Share on other sites More sharing options...
Scott Posted May 14, 2011 Share Posted May 14, 2011 Sounds more like fuel aeration to me. How full was the tank and do you run the pumps vertically or horizontally (are they in tank?) Surely it would still happen after cooling the car if that was the case though? JP said it has rectified itself after a fill up as well as just letting it all cool. I took that as 2 seperate occasions. In the first instance the cold fuel chilled the tank and brought it back to normal, in the second it naturally cooled without any further fuel being added. Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted May 14, 2011 Share Posted May 14, 2011 Surely it would still happen after cooling the car if that was the case though? JP said it has rectified itself after a fill up as well as just letting it all cool. I took that as 2 separate occasions. In the first instance the cold fuel chilled the tank and brought it back to normal, in the second it naturally cooled without any further fuel being added. I haven't the faintest idea at the moment, not enough questions have been asked. Is hot fuel the cause or a consequence? Quote Link to comment Share on other sites More sharing options...
dandan Posted May 14, 2011 Share Posted May 14, 2011 Without wanting to appear too sad ...I ran some very rough numbers based on 12A drawn per pump at 12volts equating to 144watts or 288w for the pair. Then working on a conservative pressure at the pump of 5bar flowing 560litres/hr between them I reckon that needs about 80watts total. The difference there is pretty much 200watts so that's a significant heat source for the fuel in the tank purely from efficiency losses in the pumps. Quote Link to comment Share on other sites More sharing options...
dandan Posted May 14, 2011 Share Posted May 14, 2011 I've done a little googling and apparently a 15amp draw is not uncommon at 5bar pump pressure (this is not the pressure at the rail). If they're running at 13volts and 15amps then the power would increase to 390watts which (by the same workings above) works out to a 310watt heater in the tank. With a quarter tank of fuel I think that only works out to a 14degreeC temp rise in an hour. Quote Link to comment Share on other sites More sharing options...
hodge Posted May 15, 2011 Share Posted May 15, 2011 Is there any issues documented on SF of such issues. With it being a hotter climate over there and the twin 044 being a quite popular mod I'd have thought it would have been flagged up by now. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 15, 2011 Share Posted May 15, 2011 You could use the Syvecs water injection strategy to activate the 2nd pump if it's not already being used. Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 15, 2011 Author Share Posted May 15, 2011 Sounds more like fuel aeration to me. How full was the tank and do you run the pumps vertically or horizontally (are they in tank?) In tank, vertical mounted, pickups right on the bottom as per stock, first time it did it the tank was 75% full, second time 30% full. Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 15, 2011 Author Share Posted May 15, 2011 Just been out for a 40min drive and its perfect again, it just dont seem to like traffic, i did a couple of videos of the afr's, will see how they have come out. Quote Link to comment Share on other sites More sharing options...
SilentAgro Posted May 15, 2011 Share Posted May 15, 2011 As you said before. Sticking a fan on the Fuel Cooler that comes on when the radiator ones come on could do the trick. Should be quite simple to do.. Maybe?! Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 15, 2011 Author Share Posted May 15, 2011 (edited) Crappy video i just did on my phone but you get the idea, will get a proper video soon as Ryan sorts out my speedo, afr's are fine again now, 10.5 on full boost (safe map on it till we get to TDI) 15ish on cruise. What the video dont show is the 1/2mile long black lines the car leaves every time i put my foot down (still got dyno tyres on) in the car it feels like im getting full grip but the picture says otherwise:D http://www.youtube.com/watch?v=n55LkS2ESE0 Edited May 15, 2011 by JamieP (see edit history) Quote Link to comment Share on other sites More sharing options...
johnny g Posted May 15, 2011 Share Posted May 15, 2011 Jamie, would a small 2 pass PAS cooler work, with 6AN fittings? They're about £50 and pretty small. Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 15, 2011 Author Share Posted May 15, 2011 Jamie, would a small 2 pass PAS cooler work, with 6AN fittings? They're about £50 and pretty small. I think -6 will be to small mate, you can get proper fuel coolers so id rather have the right thing for the job tbh, will check with Lee but im sure i need -10 http://www.esesautoengineering.com/products.html http://www.barrygrant.com/news/articles/products/product_005.aspx Quote Link to comment Share on other sites More sharing options...
jagman Posted May 15, 2011 Share Posted May 15, 2011 Jaguar V12 s had vapour lock/start issues due hot fuel/engine so they fitted an in line cooler in the engine bay using the air con as an exchanger I have used before a seat diesel fuel cooler on the return line they fit under car and are compact rising fuel temp will alter the mass flow of fuel downwards as specific gravity alters , most heat would come from the pressure rise of fuel and be returned to tank . If you know the tank temp you could calc the mass flow drop , but it would not be that great I suspect Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 15, 2011 Share Posted May 15, 2011 Even one 044 on a car driven on the road that returns most of the fuel back to the tank, rather than using it for combustion will heat the fuel. Are you running a swirl pot, or are they both in tank? A big swirl pot helps keep fuel cooler. If both are in tank ensure they both have the OE Bosch none return valves and set an output of the ecu to only energize the second one over "X" PSI of boost. Run a fuel temp sensor to enrich the mixture if fuel temps go over "Y" degrees. Fuel coolers need very careful thinking about in case they get ruptured, but are an option. Something else to consider is running one pump on a lower voltage off boost, and bringing both in on full voltage under boost. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 15, 2011 Share Posted May 15, 2011 Another option would be to move both pumps out of the tank, Paul did this on one his race cars, from memory he had twin 044s mounted outside with feeds from the bottom of the tank with pre-filters, the airflow over the pumps should help keep them cool Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 16, 2011 Author Share Posted May 16, 2011 Is there any issues documented on SF of such issues. With it being a hotter climate over there and the twin 044 being a quite popular mod I'd have thought it would have been flagged up by now. Larry at Sound Performance said they always stage the pumps, one runs 99% of the time, the other when on boost. Quote Link to comment Share on other sites More sharing options...
Jamesy Posted May 16, 2011 Share Posted May 16, 2011 Interesting read as im going with twin 044's at the end of the month Lee is goign to do as detailed on here and have only one 044 running below 4k rpm and then the other comes in after 4k ..... should help a lot while in traffic or at low speeds. Quote Link to comment Share on other sites More sharing options...
Guest jaredb-123 Posted May 16, 2011 Share Posted May 16, 2011 I had the same problem , i run 2 o44 with 1 walbro lift pump . Found my AFRs would shoot up around 5oohp 6-7k mark . Left it for 20 min did one dyno run ,fine , 2nd one shit . Soulution Fuel filter , if u have one of those micron filters like me it will be clogged , if not replace the one u have . Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 16, 2011 Share Posted May 16, 2011 I would not base the switch over on RPM, but on load, based on MAP sensor output. You will have to see if the fuel map itself needs tweaking on change over, as there may be a rail pressure rise if the FPR and return line can't keep up with added fuel flow, and change occurs. Running 044 pumps externally or internally to the fuel tank makes little difference to fuel heating, in my experience. Quote Link to comment Share on other sites More sharing options...
jagman Posted May 16, 2011 Share Posted May 16, 2011 One solution would be fuel temp controlled output , ie as fuel temp rises the pump output also rises ,controlled by voltage . voltage step up unit circa 100 pounds , temp sensor a few quid and control loop circuit a few quid This would need calibration to compenate for density loss , so start and max fuel temps needed and pump flows at various voltages over 12 v to say 18volts or simply have 2 stages less accurate but would work a la stock car but higher output Or just cool the fuel return under car and if pipe rupture is a worry fit an in line fuse Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 16, 2011 Share Posted May 16, 2011 How difficult would a control circuit be to shut the pumps down if line pressure dropped due to a rupture anywhere except the return line, yet still allow starting if line pressure was zero due to maintenance work? Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted May 16, 2011 Share Posted May 16, 2011 Syvecs has engine trips for oil, fuel and crank case pressure as well as many more for temps. I.e if fuel pressure drops below a set threshold the Ecu stops the engine until it has had a power cycle. I don't know any other Ecu that does this tho so other Ecu owners would have to source an external unit to do it. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted May 16, 2011 Share Posted May 16, 2011 Also you would want the second pump to kick in based on injector duty cycle. Most Ecus can be set to do this Ryan Quote Link to comment Share on other sites More sharing options...
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