Well for good or bad I decided to Mod one of my spare fuel pumps. Not sure how Im going to test it as I dont have HPT. Using a low speed drill press and homemade fixture I opened the inlet and outlet to 3/16. The stock size being 11/64 and a brass restrictor in the other side which was very small. It was so small I couldnt measure it. Weather it was there for a purpose we will fine out. If the fuel pressure goes up to 4000 then I will know if I f--ked up a good pump

Before and after

 

Wouldn't a larger opening give you lower pressure, but more volume, ultimately canceling itself out? Just thinking out loud here. Its always fun to try stuff with spare parts, lol.

 

Normally on a pump when you enlarge the inlet and outlet the resulting pressure (resistance to flow) and fluid velocity (how quickly the fuel is delivered to the rail and injectors) will go down if flow rate (GPM) is kept the same. If the pump is being restricted by the size of the inlet and outlet this is a good mod if not a low rail pressure code will likely result as well as slower fuel delivery. Must test to find out.

 

Subbed

 

You might be right and now we need to test it. I need to get a measurement of the ID of the High pressure fuel rail

 

You will only have reduced the internal loss of charge of the pump. These pumps are fixed displacement (piston type) pumps, and the only way to get more flow is to fit in a bigger piston. Like they do with audi / mazda etc pumps.

AWE A3 2.0T FSI Fuel Pump Upgrade

 

Lets look at it this way then. Given maximum drive to the pump, which pump would produce more pressure at the rail?

 

OK Vince and I are going to test it. As soon as I get the needed File and some good weather Ill try It out on E85. Will Keep you posted.

 

My thought exactly.

 

My guess is this will make no difference. As I said in my previous post, this pump is a fixed displacement pump, so when it pushes the fuel out, it goes out no mater what. With a bigger hole, it will be easier for the pump to push the fuel out, but the flow remains the same.

 

It might or it might blow the fuel rail apart.

 

lol There's a "HPFP Pressure Too High" code. It'll probably go limp before that happened.

 

And if it was that easy to modify the pump, don't you think that some vendor would have done the same and charged big buck for it?

 

If it's a piston-type pump, then let's bore it!

 

Who knows ? If they only made 3400 of our cars who would really care. Its fun to try different stuff out though

It looks like they made it tamper proof

 

Bore it, stroke it port and polish it.

 

technologic.... technologic....
(daft punk ftw)

 

That is the solution. Problem is, you need to keep tolerances in the range of +/-0.00005" for each part. This is why the audi pump upgrade kit is 380$, for some parts that would be worth 5$ with normal machining tolerances.

 

I might of been strokin it when I thought of this.

 

I like it, let's hope it works out for you!!

You can ask Vince for a copy of Palmer and log it yourself

 

[SIZE="2"]I it dosnt work I might take one of the other pumps I have and open the restricted hole up .0001 at a time.]

 

Lunch and couch time

 

LOL, it's the internals you have to make bigger. Have you looked at the parts for the audi pump I linked in my first post?