Stillen SC fuel pump mod
 

So, I'm stuck because Stillen's instructions are made for someone who's done this once before as a reminder lol

http://uploads.tapatalk-cdn.com/2016...c65a08769b.jpg

In step 14 and 15 they ask to drill through the pressure regulator. They ask not to drill too deep yet in the bottom picture the drill bit is all the way through the pressure regulator. It is very contradictory.

Anyone who has done this before please chime in. If you need more pics let me know.


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Yea this was difficult for me and my buddy as well...my friend and I did the install in his driveway and pretty much flew through everything until we got to this point. I had never done this before so i let him do it and it worked but he was definitely sweating while doing it. Maybe call dean over at stillen he was the one who helped us with all of our questions. Im sure those guys have more experience than anyone else. Just go to the source

Follow the CAPITALIZED instructions. If you drill through the regulator, it will definitely be ruined. YOU ARE JUST DRILLING THE TIP lol :D

Its basically just a single layer of sheet metal at its outlet orifice that you are drilling through. If you continue to drill up into the internals of the regulator, you will be in trouble!

Like what Phunk said, you only drill through a thin layer of metal. Use a slow speed and light pressure so that when the bit breaks through you don't go to far. You will be able to feel it happen. Just take your time drilling.

and dont worry if you do accidentally drill through your regulator I can set you up with a full return system and external regulator :D

Just the tip. Just this once. Just to see how it feels.

Stillen SC fuel pump mod
 

Haha I like the humor, I think I drilled a bit too much before I read these replies. But I reinstalled the pump and let the car warm up and rev the engine for a while to see if I feel anything wrong. Seems to be working just fine.

How would I know if I damaged the regulator and it's not working correctly?


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You would need to hook up a fuel pressure gauge to find out.

In case it is bad, what kind of problems are possible?


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It would be a bit difficult to predict. But if you damaged a regulator enough to effect its function, you would of course see the fuel pressure not being properly regulated, which would lead to causing richer or leaner burns depending on its new behavior. If your A/F is safe, I wouldnt worry about it.

Okay, so on a tuned car I would be able to see a fluctuating AFR ratio? Or should it be constant?


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That question is a can of worms. Target A/Fs vary all over the place pending engine load, temperatures, etc. A/F is almost never constant, and the target range in which it stumbles is always changing.

phunk - is this thread topic the same as the 'venturi drilling' topics you have discussed and provided guides for?

I think the only way you are really going to know is if
A) your tuner is like WTF is going with this thing?

or

B) You get a fuel pressure gauge and watch it.
You could get the CJM mini+fueltap (its cheap!) and then watch it on the dyno. If you aren't going to dyno, you could stick a go pro under the hood and drive around....

Its a different thing. The venturi has to be drilled for larger fuel pumps, with or without a return system. The regulator only has to be drilled for larger fuel pumps if you dont have a return system, since a return system gets rid of the regulator anyway you wouldnt need to drill it.

I see... I am running a Walbro 255 (returnless) and I didn't drill anything. My fuel pressure is a little high at idle but I don't have any issues... You've previously told me i don't need to worry about the venturi since I'm not having idle problems.... What are the potential consequences of not drilling the regulator?

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