Tombola Posted February 20, 2017 Share Posted February 20, 2017 Do these come preset out the box? When I tried the fuel pump today it was about 12psi to the carbs from standing I'm sure my return is free flowing enough. Can anyone also recommend a smaller fuel pump, I have a Bosch replica but don't know if this is my issue. Quote Link to comment
Leblowski Posted February 20, 2017 Share Posted February 20, 2017 Never used one but i have red others shortened the spring to get base pressure down to 2 3 psi 1 Quote Link to comment
Tombola Posted February 20, 2017 Author Share Posted February 20, 2017 Interesting! doesn't make sense I thought these referenced inlet pressure, so I expected to see no pressure at standing then I had to adjust the pressure for couple psi and it would rise with boost! Quote Link to comment
El Gringo Posted February 20, 2017 Share Posted February 20, 2017 They're supposed to be 5psi out of the box. Mine adjusted down to just under 3psi with the adjuster wound right off, needs the spring clipped a bit to get down to 1-2psi 2 Quote Link to comment
Tombola Posted February 20, 2017 Author Share Posted February 20, 2017 Thanks gringo, 1 Quote Link to comment
Diebythereaper Posted February 22, 2017 Share Posted February 22, 2017 No more than 3 psi, 2.5 is the optimum, best person to buy these from is FBM if he's still on here - best in the business on carb'd turbos! Quote Link to comment
Tombola Posted February 23, 2017 Author Share Posted February 23, 2017 El gringo how much did you clip off your spring?? Quote Link to comment
El Gringo Posted February 24, 2017 Share Posted February 24, 2017 12 hours ago, Tombola said: El gringo how much did you clip off your spring?? I haven't done mine yet, but i'm sure it's probably worth going half a coil at a time 2 Quote Link to comment
Tombola Posted February 25, 2017 Author Share Posted February 25, 2017 I could wait till you do yours gringo 1 Quote Link to comment
El Gringo Posted February 25, 2017 Share Posted February 25, 2017 32 minutes ago, Tombola said: I could wait till you do yours gringo You might be waiting a while. I can't even get my bike running normally aspirated, let alone with the turbo! I'll see about clipping the spring soon though, i'm aiming for 1-2 psi base pressure because the carbs on the 400 are so delicate Quote Link to comment
Tombola Posted February 25, 2017 Author Share Posted February 25, 2017 Ergh I might have to the plunge then, I want to dyno mine soon to set the carbs up. strange it won't start I take you your checked spark, fuel, compression? Did you move your timing at all? Some people have others haven't not sure which side of the fence to be on I shall mention the fact I put 15psi to them first time I turned on the fuel pump makes a mess... Quote Link to comment
MrS819 Posted February 25, 2017 Share Posted February 25, 2017 Any chance of pictures of your installation? Quote Link to comment
Tombola Posted February 25, 2017 Author Share Posted February 25, 2017 Yeah sure I'll take a few pictures later Quote Link to comment
Tombola Posted February 25, 2017 Author Share Posted February 25, 2017 As promised, there probably a lot I've done that is quite backwards and a lot I want to change. Relay coil is operated from the coil live so on off with the kill switch, 5.8psi spring in Chinese wastegate. Quote Link to comment
Tombola Posted February 25, 2017 Author Share Posted February 25, 2017 Oh @El Gringo I took this much off my spring and had just under 2 Psi on the gauge at standing, not sure if it changes with the engine running. 1 Quote Link to comment
Gixer1460 Posted February 25, 2017 Share Posted February 25, 2017 On 2/20/2017 at 6:57 PM, Tombola said: Interesting! doesn't make sense I thought these referenced inlet pressure, so I expected to see no pressure at standing then I had to adjust the pressure for couple psi and it would rise with boost! They do but you have to set a baseline static pressure first then they add boost pressure on to it. If you had no pressure static you wouldn't get any fuel! 1 Quote Link to comment
MrS819 Posted February 26, 2017 Share Posted February 26, 2017 Thanks for the pictures. Like the setup. 1 Quote Link to comment
Tombola Posted February 26, 2017 Author Share Posted February 26, 2017 Thank you, like I said there is plenty I want to change like everything is in stainless so heat will be a issue, fuel tap is a pain in the arse, shouldn't of put the oil return so high, don't like how the pipes route round, I could go on But it works I can 'hopefully' use it on the road, keep interest and change bits as I go! Quote Link to comment
El Gringo Posted February 27, 2017 Share Posted February 27, 2017 On 2/25/2017 at 4:47 PM, Tombola said: Oh @El Gringo I took this much off my spring and had just under 2 Psi on the gauge at standing, not sure if it changes with the engine running. Thanks @Tombola, gives me a good idea where to start, Cheers I'm having a nightmare with mine at the moment, hopefully be at a point to clip the spring soon Quote Link to comment
Scara Posted May 22, 2017 Share Posted May 22, 2017 A Malpassi FPR is supposed to operate 1:1 ratio. What does that mean ? referenced boost pressure taken from carbs or plenum is always 1 psi thereabouts above boost to maintain fuel going into the bowls and the engine doesnt lean out. I fitted a fuel pressure gauge before the FPR but after the fuel pump, and another after the FPR but before the carbs and took measurements to set the static pressure key on only fuel pump active. Preset to between 2-3 psi is what I found to work best for my set up, anything less and the boost pressure overcomes the fuel delivery. Once I achieved that, I started the bike and watched as the Fuel pressure dropped to 1-1.5 psi running. This should therefore always give you fuel pressure over boost pressure at any throttle position. Boost reference for mine had to be taken from the carbs between 2 and 3, where as most take the boost reference from the plenum. This is ok on the 36 and over carbs, but the 34's were not happy with that. I run two fuel pumps. Why ? because I had a fuel pump failure on a run 300 k's from nowhere and had to organise a pick up only to find out it was a melted earth lead. SO now, I am prepared for this eventuality - bad luck for the most part, but in Australia, an Ice cream truck will melt on the country roads. 2 Quote Link to comment
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