Irrelevant Posted July 18, 2007 Share Posted July 18, 2007 Right . .. making a twin tank for my car so I can carry normal super unleaded in one tank - the main tank, and also have some 118 octane rocket fuel in the smaller tank. I want to find an electrical valve that I can use to switch the fuel supply and return circuits so that the fuel isn't mixed. Short term, fuel will be switched by a manual switch, longer term, I've got some plans involving a boost sensor, an active boost controller, and using the ECU to switch fuels so this is why I need electrically operated valves. Just use 2 fuel pumps I hear you cry . . . . well I'd rather not as my fuel pump is not cheap. Plus it's a bit of unnecessary weight. And there's still the problem of switching the returns. I've seen the fuel/LPG valves and they don't look to be of much use - well at least the ones I've seen don't. Not having a good day on Google so was wondering if anyone knew of anything that might do the job - maybe from the aviation world? TIA Link to comment Share on other sites More sharing options...
nickh7 Posted July 18, 2007 Share Posted July 18, 2007 How are you mounting the tanks? Its Yellow And Black and Makes me 😬here Link to comment Share on other sites More sharing options...
Irrelevant Posted July 18, 2007 Author Share Posted July 18, 2007 How are you mounting the tanks? I'm cutting and shutting a carb'd Caterham long range tank (which is what I currently use) so it has a wall about 70% of the way along. This should give me a couple of gallons of race fuel. The necessary fuel collectors/baffles/etc. will all be added and a proper job will be done. I have an ally rear tonneau and there will be filler on each side. Fuel level senders will be switched at the same time as the fuel valves. Edited by - AdamHay on 18 Jul 2007 14:29:39 Link to comment Share on other sites More sharing options...
dannylt Posted July 18, 2007 Share Posted July 18, 2007 Surely there will be too much lag in the fuel arriving if activated by a boost sensor? I mean from the rear of the car to the rail. Also, how can you possible avoid mixing the return fuel? Surely a far simpler idea is to have two fuel rails and just have two pumps? Another pump has to be a far simpler solution than a valve. That way the outboard injectors can trigger above a certain load/rpm and you get all the benefit? In fact, that sounds like a great idea, but I'm thinking E85 instead... Link to comment Share on other sites More sharing options...
Irrelevant Posted July 18, 2007 Author Share Posted July 18, 2007 dannylt: Admittedly, the long term solution with all the electronics hasn't completely chrystalised yet dedicated rocket fuel injectors is one way of doing it . . . Immediate term, I still want to be able to switch between fuels whilst on the go. I don't want to be stopping, unbelting, and going round the back to twiddle with some fuel taps. I can't see any other way of doing it than 2 complete systems that share a pump. Yes, there will be a bit of mixing as some fuel will be left downstream of the pump, but this shouldn't cause a problem. Even if I do use 2 pumps I still need to switch the returns. Link to comment Share on other sites More sharing options...
dannylt Posted July 19, 2007 Share Posted July 19, 2007 Why do you need to switch the returns with two pumps? You have two returns from two totally independent systems. I disagree about the mixing though. If you have mapped for 110 octane and knowing it will be the smaller tank, any mixing of normal fuel could cause your engine to blow up. Two injector rails is the safest and simplest option IMHO! Link to comment Share on other sites More sharing options...
Irrelevant Posted July 19, 2007 Author Share Posted July 19, 2007 dannylt: It's not 2 independent fuelling systems throughout. The same injectors and fuel rails will be used. Also, the same fuel supply and return pipes will be used - it's just that I will be pumping different fuels down them depending on what I set the (cockpit adjustable) boost at - my car's turbocharged you see. The reason for this is that I do not want to run the car at full boost all the time. It goes pretty well with the minimum 0.8bar and 100% super. Now and again though I will want full boost, and this; at a lot more that 0.8 bar, requires 50/50 super and VP C16. This transition won't be an instant thing, when the car/tyres are warm I'll switch over fuels, turn the wick up, give it a lap or so, then hoon for a bit. For sprints and hillclimbs, I'll run solely on the 50/50 C16 mix. Anyway, I think I've found something now . . . 4 of these linked up to a 5 pin (87/87a) relay should switch the fuel supply/returns like I want . . . . waiting for more details. Link to comment Share on other sites More sharing options...
jackb_ms Posted July 19, 2007 Share Posted July 19, 2007 Hi Adam Have a look at duel tank Diesel system, disel, vegetable oil. There is a lot of info on the web on that, and it is basicaly the same thing you are doing Jack Emily, The Very Yellow 21 Link to comment Share on other sites More sharing options...
Irrelevant Posted July 19, 2007 Author Share Posted July 19, 2007 jackb_ms: Ta . .. the dual fuel keywords got me on the right track and I found some interesting stuff on nerdy 4x4 and LPG fora. Apparently what I want to do is very common but 'hammer head' fuel solenoid valves (2 switched inlets, 1 outlet) are not commonly available for anything much below £100 each as they are designed for aircraft. I will need to make do with 4 fuel shut-off solenoids as used in LPG conversions. These can be had for c.£15 each. The OMVL ones seem the most popular. Just need to get the internal bore sizes now before I buy some. Link to comment Share on other sites More sharing options...
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