Stillen SC fuel pump mod

Kamillio

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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370z

phunk

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.

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Jayhovah

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....

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2013 Gun Metallic Sport - Gamma V3 Twin Turbogized
DIY Gamma V3 TT Install * Jayhovah's Gamma V3 TT Install Pic'Z and Vid'Z * DIY: Washer Reservoir for the Boosted

phunk

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.

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Jayhovah

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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2013 Gun Metallic Sport - Gamma V3 Twin Turbogized
DIY Gamma V3 TT Install * Jayhovah's Gamma V3 TT Install Pic'Z and Vid'Z * DIY: Washer Reservoir for the Boosted

phunk

The higher fuel pressure at idle is the consequence. A 255 isnt much larger than the stock pump, so it wont be too bad. A few psi spike at idle isnt going to hurt anything, the o2 feedback will compensate and keep the A/F in range. With a 350z a 255 can cause a really big spike. A 370z its not as big of a deal, and there is a pressure blow-off on the return side to help.

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Jayhovah

Understood. Thanks! Very informative, as always! =)

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2013 Gun Metallic Sport - Gamma V3 Twin Turbogized
DIY Gamma V3 TT Install * Jayhovah's Gamma V3 TT Install Pic'Z and Vid'Z * DIY: Washer Reservoir for the Boosted