tim13 Posted December 14, 2015 Share Posted December 14, 2015 would be worth grabbing an infrared thermometer (about $120 on trademe) to trace where your fuel is being heated cause its hard to imagine its just heatsoak through rail mounts ? Quote Link to comment Share on other sites More sharing options...
downtrail Posted December 14, 2015 Share Posted December 14, 2015 Was that with motor off? Or running Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted December 14, 2015 Share Posted December 14, 2015 what size fuel pump .how many litres per hour davo ,my pressure is up to 75lbs 1 13mm fuel line then y joint to feed both then back to adj fuel reg then back to tank ,i was having over heating problems with the 040 bosch motor sport pump 300 litres per hr ,i went back to a 190 bosch motor sport pump 130 litres per hr 1 Quote Link to comment Share on other sites More sharing options...
Rookie Posted December 14, 2015 Share Posted December 14, 2015 Yea heat soaked fuel comes from pumping it too much, so if you have massive pump, and are returning it to a surge tank you will likely have problems if you aren't driving at wot most of the time. Quote Link to comment Share on other sites More sharing options...
Lith Posted December 15, 2015 Share Posted December 15, 2015 Yea heat soaked fuel comes from pumping it too much, so if you have massive pump, and are returning it to a surge tank you will likely have problems if you aren't driving at wot most of the time. PWM fuel pump controllers, enough pump for over 1000hp @ wheels, not more excessive fabrication than you'd normally need for a fuel system big enough to make that power and when normal driving you don't have to feel like you are in a dental surgery and your fuel doesn't end up needing it's own radiator. 2 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 15, 2015 Share Posted December 15, 2015 Any suggestions on what to use for a fuel temp sensor? I'd assume a normal water temp sensor works fine, but ideally I'd like something a little smaller. Quote Link to comment Share on other sites More sharing options...
Roman Posted December 15, 2015 Share Posted December 15, 2015 Also, what's the deal with AN- fittings? As best I can tell: Pros: -??? Cons: -Bulky and ugly, usually come in gross colours -Harder to take on/off than banjo bolts -Sometimes need two connections at a single end, so more things to potentially come undone -Need huge radius on hose bends -Risk of a hose slipping out? -Hard to know when they're tightened correctly / overtightened I guess they're the easiest option when you need a lot of custom lines, but ergh I hate the idea of using them.I've got them on my oil filter relocator currently.I'm pretty hesitant to use them for anything fuel related, especially on connections that need to be done up and undone a lot.However it looks like it might be the only option if I want an adjustable FPR. 1 Quote Link to comment Share on other sites More sharing options...
mjrstar Posted December 15, 2015 Share Posted December 15, 2015 should be able to barb fitting a FPR, the ones I have are all barbs. Pro's - no need to replace crush washers or O-rings and removal / install is pretty easy, can join a straight fitting where a banjo can't, tidy option to reduce/adapt to different size or metric threads. AN - fittings are hand tight plus 1 flat, if it leaks an additional 1/2 flat is an option. I like to use a drip of oil on the threads Risk of hose slipping out is probably only an issue if incorrect hose type or fittings not put together properly? I was also semi against them, but have used in a few places where stuff gets removed a lot and I do think they have thier place, and last well so long a no cross-thread action occurs. Just not those blingy blue/red ones with shiny ss braided hose, black fittings and fibre braid or black hose FTW. 2 Quote Link to comment Share on other sites More sharing options...
peteretep Posted December 15, 2015 Share Posted December 15, 2015 they are painful to buy but they do work really well, and you can get black for most fittings so colour isnt so bad. You need to be quite selective about which angle fittings to buy but it works out well in the end. As someone who is dedicated to getting the best out of his car, you should appreciate the good flow characteristics of the large bend radius haha I have them on my fuel system and they work well being constantly tightened and loosened 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 15, 2015 Share Posted December 15, 2015 Interesting, thanks guys. Quote Link to comment Share on other sites More sharing options...
Rookie Posted December 15, 2015 Share Posted December 15, 2015 They were designed specifically to be tightened and loosened a lot, which makes them ideal for use on hoses that get taken off a lot. 1 Quote Link to comment Share on other sites More sharing options...
Rookie Posted December 15, 2015 Share Posted December 15, 2015 Also, use pushlok fittings are the only option. The normal ones are a pig to put together, and stainless braid is dumb also. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted December 16, 2015 Share Posted December 16, 2015 Nylon braided is sweet. I reckon it looks heaps better than stainless braid too 3 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 19, 2015 Share Posted December 19, 2015 would be worth grabbing an infrared thermometer (about $120 on trademe) to trace where your fuel is being heated cause its hard to imagine its just heatsoak through rail mounts ? I guess it's easy to tell whether it's the friction/heat etc just from pumping the fuel around that causes a temp increase, turn the pump on while the motor is off. So I did this, with a thermometer sitting in a hole in the fuel rail. With the engine not running, it took a long friggen time for the temperature to go up by even 1 degree. (keeping in mind that the car has a full gas tank currently) However turn the engine on, and fuel rail temp increased by about 1.5 degrees per minute. It's possible that ambient air temp was increasing as well and biasing the results, but, it seems pretty clear that pumping the fuel around just on its own generates a negligable amount of heat increase. In my opinion I think it's radiant heat from the engine, and heat coming directly through the rail bolts causing the temp increases. So heat proofing the rail somehow and insulating the bolts looks as though it might make the best difference. 4 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 21, 2015 Share Posted December 21, 2015 In relation to above, Common Rail diesel cars generally have a fuel cooler in place, buuuuutttt its always placed on the return rail back to the tank, rather than cooling the fuel coming to the rail. I think this is more credibility towards the idea that it's generally the rail that heats up the fuel. This way you're cooling it just after it's been heated, so its not hot back at the tank and second time around. Also minimising complexity of the high pressure side.Fascinating topic! ... ... 2 Quote Link to comment Share on other sites More sharing options...
Beaver Posted December 21, 2015 Share Posted December 21, 2015 I reallyed enjoyed the use of graph to provide further evidence to your claim "it got hotter when I started the car". I was really struggling to grasp this concept until I saw the graph. 7 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted December 21, 2015 Popular Post Share Posted December 21, 2015 13 Quote Link to comment Share on other sites More sharing options...
Stu Posted December 21, 2015 Share Posted December 21, 2015 I love the fact you made a graph about how much you love graphs Thats DaveScience right there people!! Internet clocked Quote Link to comment Share on other sites More sharing options...
e30-323ti Posted December 21, 2015 Share Posted December 21, 2015 At this rate he'll need to start using logarithmic scales to contain his graphs of graphs [... of graphs] But rather interesting the fuel is getting so hot... Is this a reason the Altezza's use a return-less system? (or regulated / returned at the pump, not the engine). 1 Quote Link to comment Share on other sites More sharing options...
Testament Posted December 22, 2015 Share Posted December 22, 2015 I think returnless system is something to do with simplifying manufacturing and maybe fuel vapour stuff or something like that. re fuel cooling. its much easier to reject energy from a hotter source e.g. you can reject the smae amount of energy from the hot thing to the cold thing faster with 1x hotter thing to cold thing, than 2x not quite as hot thing hot thing with half the energy (i.e. same total engery but at lower heat) to same cold thing. funny that the rule of this was discovered by a guy called carnot. 1 Quote Link to comment Share on other sites More sharing options...
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