Technical 1.2 8v swap - fuel pump Q's.

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Technical 1.2 8v swap - fuel pump Q's.

akumabito

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I could use a bit of advice: I want to transplant an 1.2 8v engine in my '87 carbed Panda. I need to get sufficient fuel to the engine.

If I swap the tank for one out of a 1.1 model, would that fuel pump be sufficient to feed the 75 engine? I believe they are 3 bar @ 70l/hr? What to do with the fuel return line? I think the Punto engine needs a return line, but the Panda doesn't have that provision, does it?

Following up on that: If I swap out the pump for one out of a Punto, do I need to change out just the little pump, or does the entire Punto unit fit the Panda tank?


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the panda 1.1 is only a 1 bar pump so would need to be replaced with a 3 bar pump to run a p75 engine. Just the little pump needs replacing and any generic in tank 3 bar pump with plenty of flow will do. The Panda has a fuel return line(y)


If your panda is a 2wd then due to the design of the panda tank sender you can run an external 3bar pump. If you use this method however, you must refill the tank when the low fuel warning light starts to come on ;)
 
hey, i did the punto 75 engine (1242cc 8v MPI) in a panda 4x4 and i had the same issue.

you can go external in line fuel pump. however with mine there was an issue. with the return line being so narrow it caused a pressure build up after the fuel rail. causing the car to run very rich, more pressure, more fuel injected.

i got around this by adding a fuel pressure regulator AFTER the fuel rail (i know crazy right?!) as the unregulated fuel was building up just over 1 bar. thats how much of a restriction the return pipe is.

i simply bled the excess pressure back into the fuel pump (the pipe that exits the fuel filter and enters the fuel pump). i set it so that it did have a little bit of pressure build up (so it would never become air locked) only about 1-5 PSI, just enough to see the needle move on the dial when the fuel pump was on.

i am using a generic (bosch clone) inline fuel pump that has.. a lot of flow rate and 5 bar of pressure.

all i can say is that it works great! almost a year now of daily use and not one problem!

ideally you dont need much flow, so long as you have the pressure. the problem that i have is that i have too much fuel trying to get through a small gap causing the pressure build up... too higher flow. if i could find a pump with half or a quarter of the flow rate the pump i am using now has, i would not need the fuel pressure regulator.

hope this will be of help to you! took me some trial and error to perfect it!
 
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Excellent info, Dragon Man!

i am using a generic (bosch clone) inline fuel pump that has.. a lot of flow rate and 5 bar of pressure.

That seems like overkill.. the Punto has a 3 bar pump. Is there any reason you picked a 5 bar pump?
 
because i am a cheapskate. it was a low cost pump so just made it work

like i say, pressure is nothing as the fuel rail has a built in regulator. excess just gets bled off to the return pipe.
it could have a 20 bar fuel pump so long as the flow rate is not high enough so it blows off the return pipe.
 
I wanted to add to this discussion that a pressure regulator is important for reliable use of the car, like Dragon Man suggests.

Even the so-called "3 bar pump" can actually produce 10 bar or more, just like the "1 bar" pump. It is RATED for 3 bar at it's stated flow rate.

Even if the car runs without a FPR, it is likely to be running poorly, inefficiently and will wear things over time.

..or you just get lucky and it's fine!
 
I fitted an after market stand alone pump and pressure regulator. With the addition of an one way valve in the flow line to prevent pressure loss on sat up bypass connected. Works. Well on 1.4 16 v. No dipping power on demand
 
I decided to go with an external pump + regulator. Where did you mount the pump? I'm a bit worried about damaging it if it's mounted under the body. Plus I'd have to drill some holes in my car to bolt the bracket in place.
 
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